Exam 2 Study Guide
Exam 2 Study Guide 80887 - BIOL 3150 - 001
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This 52 page Study Guide was uploaded by Abigail Towe on Thursday October 1, 2015. The Study Guide belongs to 80887 - BIOL 3150 - 001 at Clemson University taught by Tamara L. McNutt-Scott in Fall 2015. Since its upload, it has received 476 views. For similar materials see Functional Human Anatomy in Biological Sciences at Clemson University.
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Date Created: 10/01/15
Chapter 6 Cartilage and Bone Connective Tissue o Cartilage bone Skeleton which serves to 0 internal framework that muscles attach to o supportprotection for organs 0 dynamic structure meaning that it is constantly rebuilding and remodeling itself interacts with other organ systems made up of bone cartilage ligaments other connective tissues all work together to stabilize and connect bones Cartilage Connective Tissue o cartilage is a semirigid connective tissue 0 cartilage is weaker than bone but more flexible and resilient return to normal shape after compressed 0 functions I supports soft tissue o example trachea supports the soft tissues of the throat I provides gliding surfaces for articulations I provides a model for bone formation 0 3 types I hyaline cartilage 0 found in articular cartilage of joints costal cartilage and cartilages in nose most abundant offers support flexibility and resilient surrounded by perichondrium translucent appearance of extracellular matrix 0 there are fine cartilage fibers throughout the entire matrix 0 the translucent appearance doesn39t mean there aren t any fibers it just means that you need a dye to see them I fibrocartilage 0 found in cartilage of intervertebral disc and meniscus o numerous thick collagen fibers for tensile and compressional forces o lacks perichondrium I elastic cartilage found in ear and epiglottis highly branched elastic fibers highly flexible form of support has perichondrium 0 cells of cartilage I chondroblasts cells that producesecrete the matrix of cartilage o once the cell has become surrounded by matrix through secreting enough it becomes chondrocytes I chondrocytes the mature cartilage cell that makes sure that the matrix remains healthy and viable o located within the small spaces lacunae I cells are scattered across the matrix of protein fibers and are embedded in a gellike ground substance o Growth Patterns of Cartilage 0 two types of growths interstitial growth and appositional growth I both occur simultaneously during embryonic development I interstitial growth growth from within the cartilage itself I appositional growth growth along the cartilage outside edge or periphery 0 however interstitial growth declines rapidly as cartilage matures therefore later growth is mainly appositional growth once fully mature new cartilage growth stops only resumes when damage occurs Bone 0 basic functions 0 support and protection 0 movement I skeletal muscles soft tissues and organs attach to bones o skeletal muscles use bones as series of levels by pulling on skeleton I big motions gross I small meticulous motions precise o hematopoiesis I blood formation occurs in red bone marrow I location varies with age o also as you get older you have fewer sites of bone marrow production o the red bone marrow degenerates and turns into a fatty tissue called yellow bone marrow 0 storage of mineral and energy reserves within extracellular matrix this make bone matrix sturdy and rigid the deposit of minerals in matrix a process called calcification mineralization minerals include calcium and phosphorous 0 calcium is important for muscle contraction blood clotting and nerve impulse transmission o phosphate is needed for ATP utilization located within yellow bone marrow c which is also a storage site for adipose tissue o composed of osseous tissue bone connective tissue 0 also composed of periosteum connective tissue proper articular cartilage cartilage connective tissue forming the walls of blood vessels that supply bone smooth muscle tissue blood fluid connective tissue lining the inside opening of blood vessels epithelial tissue o Classification of Bones 0 long I I I I 0 short 0 flat 0 length gt width elongated shaft diaphysis distinct ends epiphyses example femur length and width similar o example sesamoid bone patella 0 functions to protectshield knees o example tarsal bone thin flattened usually curved because it s flattened there is an increase in available surface area for attachment sites for muscles and it also means more protection for the soft tissues located under the flat bone example frontal bone irregular I elaborate complex shape I examplevertebra 0 Bone Markings o distinctive surface features that characterize each bone 0 types I proiections from the bone surface mark the point where tendons and ligaments attach o anatomic terms condyle facet head trochlea I sites of articulation between adjacent bones are smooth flat areas o anatomic terms alveolus fossa sulcus I depressions groovestunnels through bones indicate sites where blood vessels and nerves either lie alongside or penetrate the bone o anatomic terms crest epicondyle line process ramus spine trochanter tubercle tuberosity I openings and spaces shows passageways through a bone 0 anatomic terms canal fissure foramen sinus Connective Tissue wraps around bones o periosteum o dense irregular connective tissue I outer layer of fibrous layer I inner layer cellular layer 0 serves to cover the outer surface of bone except where there is articular cartilage o anchored to bone by many strong collagen fibers perforating fibers I these fibers run perpendicular to the diaphysis 0 functions I isolates and protects bone from surrounding structures I anchors blood vessels and nerves to surface I provides stem cells osteoprogenitor cells and osteoblasts for bone growth appositional growth around outer edge I fracture repair 0 endosteum o incomplete layer 0 contains osteoprogenitor cells osteoblasts and osteoclasts I all of these cells are important for bone growth repair and remodeling Bone Cells 0 osteoprogenitor stem cells derived from mesenchyme 0 when they divide the produce another stem cell and a committed cell that develops into osteoblasts 0 located in both the periosteum and endosteum o osteoblasts build bone up by forming bone matrix 0 sometimes they differentiate into osteocytes o osteoclasts break bones down 0 they are large multinuclear phagocytic cells 0 process of bone breakdown I osteoclasts secrete hydrochloric acid to dissolve mineral parts of bone matrix I osteolysis the release of stored calcium and phosphate from bone matrix 0 osteocytes maintains bone matrix 0 also serve as sensor for stress I they detect mechanical stress on a bone I when there is stress the information is communicated to osteoblasts so that they can deposit new bone matrix at surface Composition of bone matrix 0 organic components make up 1A of the total composition of bone 0 organic components give bone the ability to resist stretching and twisting and contribute to overall flexibility 0 includes I cells osteocytes osteoblasts osteoclasts I osteoid ground substance and collagen fibers which are both synthesized by osteoblasts o inorganic components 0 inorganic components provide bone its compressional strength 0 includes I hydroxyapatites mineral salts 65 of bone mass o hydroxyapatite calcium phosphate calcium hydroxide o deposits around collagen fibers in extracellular matrix o gives bone its hardness Compact vs Spongy Bone o compact bone 0 dense bone 0 cortical bone 0 solid relatively dense 0 example of where it is found outside of bone along the borders microscopic anatomy of compact bone I the basic functional and basic structural unit of mature compact bone is osteons o osteons cylindrical units that run parallel to the diaphysis of the long bone 0 components of osteon I central canal the channel located in the center of the osteon that allows blood vessels and nerves to pass through so that it can supply the bone 0 concentric lamellae rings of bone connective tissue that surrounds the central canal 0 each of the concentric lamellae around the osteon has collagen fibers oriented in opposite directions as the layers increase out from the central canal o the change in directions gives bone part of its strength and resilience I lacunae the dark spots that look like spiders located within the rings of each concentric lamellae I canaliculi tiny interconnecting channels that extend from lacuna the legs of the spider o the canaliculus help to connect lacunae to each other and the central canal where there is blood vessels and nerves I osteocytes cells that are located within the lacunae o spongy bone OOOO cancellous bone trabecular bone more porous and spongelike forms an open lattice of narrow plates of bone trabeculae example of where it is found in the head of the femur and down into the head region microscopic anatomy of spongy bone I does NOT have osteons I has trabeculae the loose material that is only a few layers thick 0 assists bone when multidirectional stress is applied o trabeculae contains irregular lamellae is present parallel lamellae 0 between the lamellae there are osteocytes resting in lacunae o trabeculae meshwork of crisscrossing bars and plates of bone pieces 0 the structure of compact bone functions to I reduce stress because of the cross bracing I because it s porous gt reduces weight I supports and protects marrow red bone marrow Ossification o osteogenesis physical process of bone formation o calcification deposition of calcium salts o ossification is the formation and development of bone connective tissue growth bone replaces other tissues during development and childhoodadolescence even into adulthood o bony skeleton begins around 8 weeks of development 0 ossification for childrenyoung bone grows in thickness 0 ossification in adults used to remodel and repair bones o intramembranous ossification dermal ossification 0 bone growth within membrane I the membrane thin layer of mesenchyme o mesenchyme embryonic connective tissue that is characterized by loosely associated cells that lack polarity and surrounded by a large extracellular matrix these cells have the ability to develop into other tissues 0 process I mesenchyme cells divided into committed cells that form osteoprogenitor cells some of the osteoprogenitor cells become osteoblasts the osteoblasts secrete osteoid semisolid organic component of bone matrix I ossification centers a group of osteoblasts form in the thick regions of mesenchyme I osteoid semisolid matter undergoes calcification calcium salts are deposited and then crystallized as calcification occurs some osteoblasts are trapped within the lacunaes of the matrix that is solidified these trapped osteoblasts gt osteocytes I woven bone and surrounding periosteum forms 0 woven bone immature bone connective tissue primary bone I eventually lamellar bone secondary bone replaces woven bone lamellar bone replaces the trabeculae of woven bone 0 compact bone spaces between trabeculae are filled o spongy bone trabeculae slightly modified 0 intramembranous ossification forms flat bones o endochondral ossification o endochondral ossification forms long short and irregular bones 0 bone formation with help of cartilage template 0 process I fetal hyaline cartilage model develops when chondroblasts secrete cartilage matrix hyaline cartilage model forms chondroblasts gt chondrocytes perichondrium surrounds cartilage I cartilage calcifies and a periosteal bone collar forms chondrocytes start to enlarge hypertrophy and resorb eat surrounding cartilage matrix gt this creates holes in matrix while the chondrocytes enlarge the matrix calcifies the calcified matrix ends up killing chondrocytes because they cannot get nutrients blood vessels grow toward cartilage through the holes perichondrium stem cells divide to form osteoblasts that start secreting osteoid semisolid matrix through vascularization and osteoblast development the perichondrium because periosteum all the osteoid matrix hardens and forms periosteal bone collar around the diaphysis o as this bone collar forms the cartilage in the center degenerates I primary ossification center forms in the diaphysis o periosteal bud brings in blood vessels into the diaphysis to aid the primary ossification process I secondarily ossification centers form in epiphyses I bone replaces cartilage except articular cartilage and the epiphyseal plates I epiphyseal plates ossify and from epiphyseal lines 0 long bones have both primary and secondary ossification centers 0 short bones only have primary ossification centers 0 irregular bones irregular bone ossification all over Growth of Bone o interstitial a long bone s growth in length 0 occurs epiphyseal plate region of hyaline cartilage 0 there are 5 distinct regionszones found in the epiphyseal plate I zone 1 zone of resting cartilage o located farthest out from medullary cavity o healthy cartilage matrix that helps secure epiphysis to the epiphyseal plate I zone 2 zone of proliferating cartilage o chondrocytes undergo rapid mitotic cell division start enlarging and become arranged in longitudinal columns of flattened lacunae like a stack of coins I zone 3 zone of hypertrophic cartilage o chondrocytes do not divide anymore they just enlarge greatly o during this enlargement process the walls of lacunae become thin and absorb matrix I zone 4 zone of calcified cartilage o narrow zone of cartilage that is only a few cells thick 0 since the lacunae are absorbing matrix the gaps where it goes missing is filled willed minerals o the calcification kills chondrocytes I zone 5 zone of ossification o walls break down between lacunae in columns 0 this forms longitudinal channels 0 the channels are filled with capillaries and osteoprogenitor cells from medullary cavity o new matrix is of bone is deposited o osteoblasts new bone and epiphyseal cartilage grow at same rate I so as long as epiphyseal cartilage can grow then bone can grow but when you hit puberty the hormones cause bone growth osteoblasts to produce at faster rate than epiphyseal cartilage so the epiphyseal cartilage gradually disappears I closure when the bone growth overtakes cartilage growth so that cartilage o appositional growth long bone s growth in diameterthickness 0 increase of width occurs within periosteum and along medullary cavity 0 what happens I osteoblasts in the inner cellular layer of periosteum lays down bone matrix in layer parallel to the surface the circumferential lamellae increases in layers I the medullary cavity expands to retain proportion it expands by resorbing bone matrix I there is a balance of bone resorption and bone deposition to keep proportions as bone grows 0 however during puberty absorption formation is greater 0 but as you age bone deposition is greater Bone Remodeling the process of continuously depositing new bone and resorption of old bone bone continues to grow and renew itself bone is a mechanosensitive organ so it alters structure to suite its mechanical environment to support the weight put on it o remodeling is guided by stress 0 stress mechanical stress and gravity 0 Wolff s Law bone grows and remodels itself according to stressforces I McNuttScott said this is why you need weight bearing exercises occurs at periosteal and endosteal surfaces over the course of one year about 20 of the adult skeleton is replaced 0 age influences rate 0 compact bone replaced slower than spongy bone Blood supply and innervation o bones are highly vascularized with blood vessels but also as nerves and nutrient blood vessels o blood vessels and nutrient vessels enter from the periosteum o nutrient vessels I supplies nutrients to diaphysis and central canals of osteons within compact bone and marrow cavity o metaphyseal vessels I supplies blood to the diaphyseal side of the epiphyseal plate 0 epiphyseal vessels I supplies blood to the epiphyses of bone 0 periosteal vessels I provide blood to external circumferential lamellae and the superficial osteons in compact bone at external ends of shaft 0 nerves enter through nutrient foramen o nerves go through nutrient foramen with blood vessels to innervate the bone periosteum endosteum and marrow cavity 0 mainly sensory nerves that signal injuries to the skeleton Homeostasis and Bone Growth through hormones and vitamins 0 Effects of hormones control growth patterns they do so by altering activity of osteoblasts amp osteoclasts o increase in osteoclasts activity ends up increases bone GH growth stimulate liver somatomedins that directly stimulate cartilage rowth at E H Ethyroid influences the BMR of bone cells CT calcitonin is your friend encourage Ca deposition into bone depresses osteoclast activity so we are slowing downretarding bone resorption PTH parathyroid stimulates osteoclast activity to resorb bone PTH alway39s wins even if it s negative effects to skeletonbone Sex ormones dramatically accelerate bone growth stimulate osteoblasts at epiphysis HOWEVER at puberty signal EP closure Glucocorticoids stress hormones normal levels no effect but if chronically high increase bone resorptionloss of bone mass I Effects of vitamins impt for normal growth Vitamin A I accelerates osteoblasts Vitamin C I required for normal cartilage synthesis Vitamin D I stimulates absorption amp transport of Ca and P ions into blood 0 exercise is required for normal bone remodeling because when bones encounter mechanical stress it gains strength 0 there is an increase in amount of mineral salt deposition and collagen fibers synthesized Fracture Repair 1 fracture hematoma forms a because there are blood vessels within the bone when a fracture occurs it disrupts vessels and causes a bleeding When the blood clots there is a hematoma that formed 2 fibro cartilaginous soft callus forms a first a procallus forms of actively growing connective tissue the fibroblasts within this procallus aid in connecting broken ends of bones b leads to formation of dense irregular connective tissue to form a fibrocartilaginous callus soft callus c lasts 3 weeks 3 a hard bony callus forms a the osteoprogenitor cells around the fibrocartilaginous callus become osteoblasts and produce trabeculae of primary bone to form a hard callus bony callus b this occurs within a week 4 bone is remodeled a hard calllus lasts 34 months b osteoclasts remove excess bony material c compact bone replaces primary bone Aging of Skeletal System 1 tensile strength decreases because less protein synthesis a this leads to reduced production of organic portion of bone matrix and an increase in the inorganic portion causing bone to become brittle 2 demineralization losing calcium and other minerals a when ossification is insufficient osteopenia then the bones become thinner and weaker i osteopenia weakening bones 1 lower than noral bone mineral density BMD but not low enough to be osteoporosis ii osteoporosis less bone 1 such a reduction in bone mass that it compromises normal func on o Paget s Disease 0 old bone is broken down faster than new bone is made 0 to counteract the bone being broken down so fast body tries to make bones faster but the new bones are weaker and softer this diseases leads to bone pain deformities and fractures more common in Europe and Australia and more common in men than women Review Cartilage Cartilage in external ear Epiglottls 9 Respiratory tract cartilages in the lungs trachea and larynx Meniscus padlike cartilage in knee joint Articular cartilage of a joint 8 Articular cartilage of a joint Costal cartilage Cartilage of intervertebral disc Pubic symphysis Hyaline cartilage Fibrocartilage Elastic cartilage w 39 39 39 j Extraoellular matrix 39 39 I 39 39LTr Lacuna 39 with chondrocyte Lacunae 39 with chondrocytes Extracellular matrix Collagen bers Elastic bers Lacunae with chondrocytes Extracellular matrix d Elastic cartilage fibrocartilage Matrix Chondrocyte in lacuna b Appoeltlonel Growth Two cells now called chondroblasts are produced by mitosis from one chondrocyte and occupy one lacuna Each cell produces new matrix and begins to separate from its neighbor Each cell ls now called a chondrocyte D Mitotic activity occurs in stem cells within the perichondrium quot Mesenchymal Perichondrium cells Dividing Newcamlage v undifferentiated matrix stem cell Older cartilage matrix New undifferentiated stem cells and committed cells that differentiate lnto chondroblasts are tormed Chondroblasts produce new matrix at the periphery Undiflerentiated stem cells Committed cells differentiating Into chondroblasts mixigartilage Chondroblast secreting new matrix Older cartilage matrix As a result of matrix formation the chondroblasts push apart and become chondrocytes Chondrocytes continue to produce more matrix at the periphery ed Perichondrium Undifferentiated stem cells Chondrocyte New cartilage 59 th quot9W matrix mamquot Older cartilage A 33 e matrix Flat bone frontal bone Irregular bone vertebra Long bone femur Short bon e tarsal bone a Head A Trochanter Tubercle Sulcus t Head Sinus Tuberosity Fissure Process Ramus Foramen Epicondyle Fossa Alveolus LH Epicondyle Conder Trochlea Femur Skull anterior view Skull sagittal view Humerus Facet General Anatomic Description Crest 39 Structure Term Fossa Articulating Condyle Large smooth rounded articulating oval structure surfaces Facet Small flat shallow articulating surface Spine Head Prominent rounded epiphysis Line Trochlea Smooth grooved pulleylike articular process Depressions Alveolus Deep pit or socket in the maxillae or mandible pl alveoli Foramen Fossa Flattened or shallow depression Ramus 39 pl fossae Pelvis Sulcus Narrow groove Projections for Crest Narrow prominent ridgelike projection taerddlci 3amem Epicondyle Projection adjacent to a conder attachment Line Low ridge Process Any marked bony prominence Ramus pl rami Angular extension of a bone relative to the rest of the structure Spine Pointed slender process Trochanter Massive rough projection found only on the femur Tubercle Small round projection Tuberosity Large rough projection Openings Canal Passageway through a bone and Spaces lquotIssure Narrow slitlike opening through a bone Foramen Rounded passageway through a bone pl foramina Sinus Cavity or hollow space in a bone Proximal epiphysis i i Metaphysis Al Diaphysis shaft V Metaphysis Distal epiphysis i a Anterior view A 5 l b Sectional view I quotr Epiphyseal Articular cartilage Spongy bone contains red Proximal bone marrow 7 39 epiphysis I Metaphysis Compact bone l I Meduliary C Vlty artery and vein contains Ye39IQW through nutrient bone marrow In foramen PeriosteumJ Perforating fibers 4 i J 39 Diaphysis in l i Epiphyseal line Metaphys s Distal Articular cartilage epiphysis C Nerve f vl r Collageni ber r v orientation Central canal External t If circumferential Iamellae 1 Perforating Periosteum Cellular Osteocyte Fibrous layer I layer Interstitial Canaliculi Iamellae Trabeculae oi Canaliculi spongy bone opening at surface Interstitial Iamellae Space for bone marrow Trabeculae Perforating Central I canals canal I I I I l Compact Bone Spongy Bone Iamellae Osteocyte in lacuna Osteoblasts 39 aligned along trabecula of new bone compare intramembranous and endochondral ossification intramembranous endochondral starting tissue mesenchyme hyaline cartilage initial development 8 weeks 812 weeks ossification centers multiple diaphysis first then epiphyses examples of bones flat bones of skull some upper and lower limb facial bones mandible bones pelvic vertebrae and central clavicle ends of clavicle ribs Capyn39 gm 39O The McGraw39 Hill Cdnipmies Inc gm reamed for emanate display 3 quot 5 33 1 a quot 4quot amp Zone 1 Zone of 1 39 2 quot3 T 2 resling cartilage 3quot 0 1 9 u 1 39 fr f 52h Zone 2 Zone of 39 prolileraling cartilage i quot Zone 3 Zone ol 5 w 1 hypertrophic cartilage i 4 6 t c 39 7 f I 39x 391 7G f 39 tv a w a l l 1 I Zone 4 Zone of 391 f 39 1 g f 39 calcified cartilage 4 LM 70x Zone 5 Zone of ossification a Epiphyseal plate Epiphyseal plate zones zone 1 secures epiphysis to epiphyseal plate zone 2 rapidly growing enlarge and arrangement of chondrocytes in longitudinal columns zone 3 chondrocytes stop dividing enlarge greatly zone 4 narrow layer where minerals are deposited in matrix between columns of lacunae chondrocytes die zone 5 longitudinal channels form the spaces between are filled with capillaries and osteoprogenitor cells new bone matrix is depos ed Chapter 9 Articulations Articulations joints the place of contact between two bones bone and cartilage or bones and teeth joints allow range of motion inverse relationship between joint mobility and stability 0 more mobile less stable joints are considered weakest part of skeleton arthrology study of joints examples 0 most mobile shoulder joint glenohumeral joint 0 hip joint 0 elbow joint 0 intervertebral joints 0 least mobile sutures of skull o joints are classified based on function and structure 0 function amount of movement range of motion I Synarthrotic immovable joints I amphiarthrotic slightly movable joints I diarthrotic freely movable joints o examples limbs 0 structure what material binds bones together and if there is a joint cavity or not I fibrous joints fibrous tissue length effects amount of movement o no joint cavity o mostly synarthrotic immovable but some amphiarthrotic slightly movable o 3 types 0 sutures articulating bones overlap or interlock I has very short connective tissue fibers that are continuous with periosteum and penetrate bone 0 svndesmoses bones connected by ligaments cords or bands of fibrous tissue dense regular connective ssue I fibers vary in length I amphiarthrotic slightly movable I interosseous membraneligament articulating bones held side by side by a ligamentous sheet c this provides pivot point for bones to rotate against each other o example interosseous membrane between radius and ulna OR between tibia and fibula o gomphoses peg in socket joint I example articulation of tooth in bony alveolar E I I A i K c W 7 r l m Suture quot39 j Ulna r 5 Lliirr391 I I K L 39H 24 quotw r J F Radius r 1 arrR quot c jaw r g A 1 Iv Syndesmosis quotf R interosseous f A j membrane 4 I V 3 39 v rso EX 2 it membranes Gomphosrs 39a t J 2 39 Alveoar 71 7 39 739 process of quot mandible g a Gomphosis b Suture c Syndesmosis cartilaginous joints cartilage is used to connect bones no joint cava o 2 types 0 svnchondroses bar or plate of hyaline cartilage o symphyses the articular cartilage fused to a pad or plate of fibrocartilage I designed for strength with flexibility I amphiarthrotic slightly movable I resits compression and tension stressors I acs as a resilient shock absorber the pads or plates of fibrocartilage helps with this I synovial joints articulating bones meet at synovial joint cavity Synchondroses contain hyaline cartilage Costochondral joints immobile joints between the rib and its costal cartilage Epiphyseal plate Joint between first rib and sternum 35 a Symphyses contain fibrocartilage lntervertebral lntervertebral disc joint Pubic symphysis Body of vertebra b the cavity contains fluid synovial joints are most abundant provides widest range of motion diarthrotic synovial membrane only has epithelial cells features 0 articular capsule fibrous is continuous with periosteum synovial membrane made of loose connective tissue I site of synovial fluid origination joint cavity synovial cavity synovial fluid weeping lubrication I this fluid is viscous and thins with joint activity I contains phagocytic cells I provides nutrients I fluid helps to absorb shock articular cartilage I cushion I lacks perichondrium o perichondrium dense irregular connective tissue that surrounds cartilage of developing bone I synovial fluid comes in and releases weeping lubnca on o reinforcing ligaments strengthens and reinforces joint I two types intrinsic and extrinsic o examples of synovial joints limbs and long bones has widest range of motion 0 movements allowed 0 uniaxial movement in 1 plane 0 biaxial movement in 2 planes 0 multiaxial movement in 3 plates Periosteum Yellow bone marrow Fibrous layer 8 I Articular ynov39a capsule membrane Joint cavity containing synovial fluid Articular cartilage Ligament Typical synovial joint Types of Svnovial Joints KNOW THESE 6 1 Ball and Socket a spherical head fits into cuplike socket b freely movable c most multiaxial a round end of bone goes into a sleeve or ring of bone OR ligaments on bone b uniaxial rotation of 1 bone i along longitudinal axis Hinge a cylindrical projection into troughlike groove b mechanical hinge c uniaxial planar gliding a simplest b least movable c surface flat translational movement d uniaxial saddle a convex and concave surfaces articulate b greater degree of movement c biaxial Condylar ellipsoid a oval convex fits into depression i both surfaces oval so they complement each other to fit together b allows all angular movement c biaxial Plane joint uniaxial 39 V 2 g Ballandsockel joint mulllaxlal a n g g a J Saddle joint blaxlal Condylar joint blaxial Dans of axis Head oi femur 1 Uniaxlaljolnl 3 Blaxlal iolnt III Multlaxlal 101m 0 joint disorder 0 EDS EhlersDanlos syndrome disorder with collagen and hypermobility Accessorv Joint Structures 0 not part of joint but closely associated o bursae 0 reduces friction o flattened fibrous sacs with synovial membrane 0 thin layer of synovial fluid 0 tendon sheath 0 elongated bursa that wraps around tendon to create friction free environment 0 example in hand o fat pads o protection 0 distributed along peripheryedge of synovial joint 0 tendons o dense regular connective tissue 0 attaches muscle to bone Attachment of bones o skeletal muscle is attached to muscle by at least two points 0 origin muscle attached to immovable bone 0 insertion muscle attached to movable bone I insertion moves toward origin 39 I Tendon sheath opened 1 Tendon of ilexor 0 v 39 vquot r k digitOrum profundus o z I quot 5 I u 3 i 39i n t aquot l t 4 J v Suprapatellar bursa n I Bursa deep to 1 pic A Synovial membrane gas rocnemius 5 muscle 39 MN u V quot Tendon of flexor digitorum superiicialis Femur 39 quot Digital tendon quot sheaths 3931 Patella Articularcapsule 39v quot p t n t g r t f 39 5 1quot Prepatellar Articular cartilage l n AL bursa Meniscus t t u g Fat pad Joint cavity filled fr I I fu quot fth with synovial fluid r LT1 quot3 t u i l39 Intrapatellar 5 A 5 3 I bursae pollims longus Common exor waxy 39 quotf f tendon tendon sheath Tibia 139i39a t Patellar ligament 39wf a I 3 5 31 jl 1 I Tendon oi tlexor 3571quot 39 carpi radialis Tendons of flexor VQ I It digitorum superiicialis 39f 12 g K Tendon of flexor and flexor digitorum 3 r pollicis longus profundus a Bursae ot the knee joint sagittal section bTendon sheaths of wrist and hand anterior view TVDes of Movement 1 Gliding movements a linear motion b simplest c similar surfaces of bone glide or slide over each other d translation 2 Angular movements a chances angle between bones b types i flexion decrease angle ii extension increase angel iii hyperextension extend joint beyond 180 degrees iv lateral flexion trunk moves away from body 1 mainly cervical and lumbar regions v abduction movement of limb away from body midline vi adduction movement of limb toward body midline 1 midline of foot 2nd toe 2 midline of fingers 3rd finger vii circumduction 1 movement of limbs around joint forms in cone in space 2 example rotating arm about shoulder 3 rotational movements a rotation turing bone around longitudinal axis i can occur toward or away from midline 1 toward midline medial rotation 2 away from midline lateral midline ii examples 1 rotation turning head 2 mediallateral rotation bringing arm toward and away from body about elbow b supination palm up i radius and ulna are parallel c pronation palm down i radius and ulna cross Gliding an Extension Flexion a i u i b I 1 sit Flexion Extension Hyperextension Extension b Lateral exion 3 Hyperextension Kj Extension 4r Flexion f c Abduction Adduction Abduction t Abduction Adduction dduc 390 a b c Abduction Adduction d a b 0 The McGrawHili Companies IncPhoto by JW Ramsey d The McGrawHill Companies IncPhoto by Eric Wise a Circumduction b Circumduction Medial rotation Lateral rotation Rotation a b Lateral rotation is 91 K b Medial rotation M A Pronation Supination c d Lanes of Special Movements Elevation movement of body part superiorly depression movement of body inferiorly inversion turning foot inward arches up eversion turning food outward tilting side of foot up dorsiflexion movement of foot at ankle up plantar flexion movement of foot at ankle down protraction non angular anterior movement move forward retraction non angular posterior movement move backward opposition touching thumb and little finger QWNQWPWNT Depression Elevation Dorsiflexion Plantar flexion 393 Opposition of thumb and little finger Inversion Eversion gt Retraction c d Axial Skeleton Articulations o temporomandibular joint small complex joint 0 hinge movable o gliding and some pivot joint movements Appendicular Skeleton Articulation 0 largest 0 most complex diarthrosis freely movable 0 there is a fibrocartilage wedgediscpad 0 this divides the synovial cavity into 2 separate cavities o improves fit of bones together Homoeostatic lmbalances of Joints common ioint iniuries o sprains stretched or torn ligament o cartilage torn menisci in knee growth plate fissures overuse of articular cartilage that has been damaged 0 the repair for cartilage injuries are slow or not at all depending on age 0 can require surgery if it doesn t repair itself o luxation bones forced out of alignment 0 subluxation partial dislocation bursitis inflamed bursa because of excessive stress blow or friction tendonitis inflamed tendon sheath Osteoarthritis o articular surface gt rough because continuous friction o osteophytes form at joint edges 0 when parts of bonecartilage breaks off and floats inside joint it causes pain and more damage o degenerative joint disease 0 deterioration of cartilage at ends of bones ends become rough o muscles ligaments and tendons that hold the joint together become weaker gt joint becomes deformed stiff and painful occurs in ends of fingers thumbs neck knees and hips wear and tear arthritis Rheumatoid Arthritis 0 autoimmune disease 0 chronic inflammatory disease 0 typically arises in ages 4050 0 women affected 3x more than men 0 early stages 0 joint tenderness and stiffness because the synovial membrane is inflamed cause is unknown pannus formation 0 thicldinflamed synovial membrane gt erodes cartilage gt scar tissue formation at bone ends course of rheumatoid arthritis has flareups and remissions other symptoms o anemia osteoporosis muscle atrophy and cardiovascular problems Are 0A and RA the same disease No they are different diseases o Rheumatoid arthritis is caused by inflammation in the lining of the joint 0 Osteoarthritis is more like a wear process in which the cartilage in the joint fails to withstand the loads placed on it o Some inflammation does occur in osteoarthritis but it is not the same as that in rheumatoid arthritis Some wear may take place in damaged joints in rheumatoid arthritis but this is a late complication of the disease The two diseases are quite different in their treatment and it is important not to confuse the two Normal Joint Osteoarthritis Rheumatoid Arthritis Muscle Bone erosion Synovial Bursa membrane Synovial uid Joint capsule Thinned Tendon cartilage Cartilage Bone ends Swollen in amed rub together Synovial membrane Normal and Arthritic Joints Chapter 10 Muscle Tissue and Organization 0 There are 3 types of muscle tissue 0 smooth 0 cardiac o skeletal I over 700 skeletal muscles in body 0 These 3 muscles work to allow movement of body movement within body and movement throughout body 0 There are fibers within muscles that exhibit specific characteristics 0 excitability responsiveness I reaction to stimuli I uses chances in electrical charges across the permeable membrane to signal internal events to cause muscle contractions o contractility cell shortens I stimulation causes tension within cells to initiate contractile elements and the cells shortens o elasticity cell recoils to original shape I when the tension is removed the contracted muscle returns to its original length 0 extensibility I contraction of opposing muscle leads to muscle to extend in length 0 Anatomic microscopic characteristics of skeletal muscle 0 striated I due to the size and density differences between thin and thick filaments o elongated with peripherally located nuclei 0 long cells that are usually in length of the muscle 0 skeletal muscles 0 composed of the 4 primary tissue types 0 attaches to one or more bones o shape various Functions of Skeletal Muscle Tissue 0 body movement 0 bones move when skeletal muscles contract 0 also pulls on tendons that are attached to bone 0 the movement is highly coordinated because muscles functions are coordinated with bones and joints 0 maintenance of posture 0 because skeletal muscles are attached to bones it helps stabilize joints and maintain postureposition the postural muscles work continuously while awakeconscious when a person is unconscious their skeletal muscles relax because skeletal muscles are voluntary 0 temperature regulation 0 muscle activity creates heat byproducts as a waste as energy is used 0 storage and movement of materials 0 sphincters throughout digestive tract to allow movement when necessary of materials 0 support 0 muscles arranged in sheetslayers gt protects organs and supports their weight within the abdomen Structural Organization of Skeletal Muscle o skeletal muscles are formed by layers of muscle fibers blood vessels nerves connective tissue sheets 0 the CT sheets surround fibers and aid in connecting muscles to bone myofilaments gt myofibrils gt muscle fiber muscle cell gt fascicles gt muscle endomysium wraps around muscle fibers perimysium wraps around fascicles epimysium wraps around the muscle myofilaments actin myosin o actin thin filaments I subunit G actin polymerizes to form F actin I two regulatory proteins troponin and tropomyosin o these proteins regulate the attachment of myosin head to Gactins o while tropomyosin coiled protein covers Gactins myosin cannot bind to Gactin therefore muscle contraction is inhibited o troponin controls the position of tropomyosin troponin is regulated by calcium concentrations in sarcoplasm 0 when the concentration of calcium increases troponin chances conformation shape gt tropomyosin cannot block gt Gactins are uncovered so that myosin can bind gt contraction occurs 0 myosin thick filaments I structure a tail with two heads o tail points toward center o heads point toward edges Muscle Attachments 0 muscles can attach through tendons in two different ways 1 tendons in the form of thick cordlike structures a located at the end of a muscle the connective tissue merges to form a fibrous tendon cord b example in elbow 2 aponeurosis sheet of tendon a the tendon is a sheet that s thin and flattened b example bottom of foot Blood vessels and nerves o epimysium blood vessels and nerves pass through this layer 0 perimysium in this layer blood vessels and nerves are directed to go to specific compartments 0 the blood vessels lymphatics and nerves travel in a neurovascular bundle together through these layers 0 controlled by nerves of somatic nervous system 0 the somatic NS is part of the peripheral NS associated with skeletal muscle voluntary control 0 as efferent and afferent nerves 0 voluntary I motor neurons stimulate muscle contractions through axons of nerves I neuromuscular junctionjunction between axon and muscle fiber 0 when muscles move it uses anaerobic produces lactic acids and aerobic mechanisms 0 lactic acids make you sorefatigue so the more fit you are the less pain you will have Microscopic Anatomy of Skeletal Muscle 0 some myoblasts fuse together during embryonic development gt multinucleated skeletal muscle the myoblasts that don t fuse gt satellite cells 0 they differentiate when repairs or regeneration of injured skeletal muscle has to take place 0 review sarcomeres gt myofilaments gt myofibrils gt muscle fiber muscle cell gt fascicles gt muscle 0 myofibrils long cylindrical and extends the entire length of muscle fiber 0 myofibrils shorten as myofilaments change position during contraction o the plasma membrane of skeletal muscle fibers sarcolemma the plasma sarcoplasm o connective tissue runs in vessels sarcoplasmic reticulum stores calcium 0 calcium is the ghost signal for contraction o transverse T tubule runs perpendicular to the fibers and the sarcoplasmic reticulum connects to these tubules 0 serves as the communication link on the inside and within the muscular junc on o triadcommunication link between sarcoplasmic reticulum and T tubules Histoloy Lab Part Slide 45 w g V m a wquot 39 T 5 ll llll I l jlts li u ll mm l l all 3 l l l 56 l E Sarcoplasm V Mitochondria 7 Openings into transverse tubules Triad Transverse T tubule Terminal cisternae Sarcoplasmic reticulum Sarcomere Organization 0 multiple sarcomeres gt myofibril o sarcomeres are the functional contractile unit of skeletal muscle fibers o sarcomere distance between 2 Z linesdiscs o made up of o A band dark band 0 I entire thick filament I some of thin filament lbandthtband I contains thin filament only 0 thick filaments I H zone central region of A band 0 only thick filaments I M line center of H zone o thin protein that runs down center of H zone 0 attachment site for thick filament o stayed aligned during contraction 0 thin filaments I Z line thin protein structure attachment site for thin filaments Contraction of Skeletal muscles 0 Sliding Filament Theory interactions between filaments cause them to slide over each other to cause contraction of muscles 0 O sarcomere shortens because it s the distance between Z discs and the Z discs in the thin filaments change position as the thin filament moves past thick filaments thick filaments DO NOT move thin filaments move toward M line centrally to bring Z lines closer together Summary thin and thick filaments remain the same length I thin filaments move past thick filaments o contraction occurs when the nerve impulse traveling along a motor neuron reaches the neuromuscular junction to stimulate a muscle fiber 0 motor neurons control many muscle fibers motor unit I fine motor units wiggling fibers usually 4 muscle fibers associated I gross motor units kicking leg muscle fibers are spread out All or None Principle all of the fibers under the motor neuron s control contract or none do there is resting tension in skeletal muscles because some motor units remain activated even when a muscle is at rest This serves to keep muscle firm healthy and ready to respond to stimulation I motor units are stimulated randomly I they assist to stabilize position of bones stabilize joints and maintain posture o muscle tension the force exerted by a contracting muscle on some object 0 load weight reciprocal force exerted by an object on a muscle 0 muscle contraction types 1 isotonic changes length of muscle a can be concentric contractions or eccentric contractions i concentric muscles shorten to generate force ii eccentric muscles elongate in response to greater opposing force 2 isometric contraction generates force without changing length of muscle 0 the physiology of muscle contraction Synaptic knob Sarcolemma Neuromuscular junction Myofibril A nerve impulse triggers release of ACh from the synaptic knob into the synaptic cleft ACh binds to ACh receptors in the motor end plate of the neuromuscular junction initiating a muscle impulse in the sarcolemma of the muscle ber 2 As the muscle impulse spreads quickly from the sarcolemma along Ttubules calcium ions are released from terminal cisternae into the sarcoplasm Active sites blocked 5 When the impulse stops calcium ions are actively transported into the sarcoplasmic reticulum tropomyosin recovers active sites and filaments passively slide back to their relaxed state Active site Thin filament 4 Thick filament Myosin heads pivot moving thin filaments toward the sarcomere center ATP binds myosin heads and is broken down into ADP and PI Myosin heads detach from thin laments and return to their prepivot position The repeating cycle of attach pivot detachreturn slides thick and thin filaments past one another The sarcomere shortens and the muscle contracts The cycle continues as long as calcium ions remain bound to troponin to keep active sites exposed Calcium ions bind to troponin Troponin changes shape moving tropomyosin on the actin to expose active sites on actin molecules of thin filaments Myosin heads of thick filaments attach to exposed active sites to form crossbridges Axonal tamina39 Neurotransmitter released diffuses across the synaptic cleft and attaches quot synapuc to ACh receptors on the sarcolemma cleft 39 Q I Sarcoiemma Tmbule N N 6 Action potential B along the sarcolemma and down the T tubules f 75 from terminal cisternae of SR o I 0 39 2 63quotquot 39 C39azquot ca Tropomyosin blockage restored blocking actin Calcium ions bind to troponin active sitecontraction troponin changes shape removing ends and Caz the blocking action of tropomyosin muscle 39 actin active sites exposed tiber mam Removal of Ca2 by active transport 39 39 into the SR after the action potential ends c820 39 39 39 Contraction myosin cross bridges alternately attach to actin and detach pulling the actin laments toward the center at the sarcomere release of energy by ATP hydrolysis powers the cycling process Copynghi 03 2004 Pearson Education Inc puhlishn as Benjamin Cummings Summary excitationcontraction coupling 1 Neurotransmitter released a diffuses across synaptic cleft b attaches to acetylcholine receptors on the sarcolemma plasma membrane 2 action potential generated is propagated along the sarcolemma and down the T tubules 3 calcium ions bind to troponin a the troponin chances shape conformation b removing the blocking action of tropomyosin c actin active sites exposed 4 myosin bridges alternately attach to actin and detach contraction a pulls actin filaments toward the sarcomere b releases energy by ATP through hydrolysis 5 removal of calcium by active transport into the sarcoplasmic reticulum after the action potential ends 6 tropomyosin blockage restored to block actin active site a now that the actin active site is blocked contraction ends fibers relaxes Tvnes of Skeletal Muscle Fibers 1 slow oxidative SO fibers prolonged contractions a if dominate in muscle red muscle 2 fast glycolytic F0 or FG rapid intense movments a if dominate in muscle white muscle Skeletal Muscle Fiber Organization 0 muscle fibers gt fascicles o the bundle pattern can vary there are 4 different patterns 1 circular a fibers arranged concentrically b examples sphincters orbits mouth anus 2 parallel a fibers are parallal b example rectus abdominis high endurance not very strong 3 convergent a fibers arranged in triangular pattern to meet at common attachment site b example pectoralis major 4 pennate a muscle body has one or more tendons b unipennate all muscle fibers on same side of tendon c bipennate fibers on both sides of tendon d multipennate tendon branches within the muscle Lever Svstems of Muscles o lever rigid bar that moves on a fixed point fulcrum when a force is applied fulcrum joints lever bone load bone or anything you try to move effort provided by muscle contraction mechanical advantage power lever mechanical disadvantage speed lever the site of muscle insertion can affect the force a muscle must generate to move a given load 0 the position of effort fulcrum and load influences amount of force needed Actions of Skeletal Muscle o muscles PULL they cannot push o 3 primary actions 1 prime moversagnoists msucle provides major force 2 antagonists opposereverse particular movement 3 synergists aids agonists a muscle can act as any of these types depends on movement Characteristics of Cardiac Muscle Endomysium 8 Cardiac muscle cell Z discs M arranged in thick bundles within heart wall fibers are straited but shorter and thicker 1 or 2 nuclei per cell numerous mitochondria aid in aerobic respiration forms Yshaped branch to join adjacent msucle fibers via intercalated discs Intercalated disc cardiocyte lntercalated discs Centrally located nucleus Endomysrum M Gap junctions Desmosomes a l 3 r 39 39quot ijj j g 1 1 K it I 39 I t I i I V Mitochondrion Sarcolemma Nucleus Cardiac muscle cell b Characteristics of Smooth Muscle short fusiform shape single central nucleus nonstraited even though smooth muscle has thin and thick filaments they just aren t aligned in a pattern 0 the thin filaments are attached to dense bodies sarcoplasmic reticulum is in small quantity T tubules and Z discs are absent contraction is slow but sustained for an extended period of time involuntary controlled by autonomic nervous system Chapter 14 Nervous Tissue 0 Structural organization CNS amp PNS o CNS brain spinal cord 0 PNS cranial nerves spinal nerves ganglia 0 NS together sensory motor forms 3 general functions 1 PNS receptors collect information and send to CNS sensory receptors sensory input 2 CNS processes information to determine if there should be a response 3 If response then CNS initiates by sending signal to PNS to command effectors motor output 0 Functional Organization sensory amp motor 0 sensory information in somatic sensory visceral sensory 0 motor information out somatic motor autonomic motor I somatic voluntary I autonomic involuntary Cytology of Nervous Tissue o neurons basic functional unit 0 excitable cells that start and transmit nerve impulses o glial cells neuroglia non excitable cells support and protect neurons found in CNS amp PNS smaller than neurons capable of mitosis unlike neurons assist neurons in their function protects and nourish neurons provides framework for nervous tissue little connective tissue present mostly glial cells far outnumber neurons glial cells are different within CNS and PNS because size intracellular organization and specific cytoplasmic processes change between the two systems OOOOOOOOOOO c Mlcmgllal cell CNS Glial Cells Central canal of spinal cord PNS Gllal Coll mam at 39i A Lin t 1 Astrocytes CNS a b c most abundant perivascular feet CLING to neurons amp capillaries regulates tissue fluid in brain regulates what flows out of blood vessels i blood brain barrier has cytoskeletal elements robust structure When neurons are damaged astrocytes fill in the space but don t perform the functions that the neuron did less need for connective tissue when neurons are young astrocytes help to guide the neurons in building synapses 2 Ependymal cells CNS a b C epithelial cells that are ciliated lines cavities of brain and spinal cord i cilia helps move cerebrospinal fluid through these areas forms fibrous network because the processes of the ependymal cells branch extensively to make contact with other glial cells d choroid plexus production of cerebrospinal fluid microglia CNS a ramification many branches b when activated microglia become macrophages to remove what doesn t belong i important because neural tissue doesn t have immune response c small cells with thorny processes that monitor nearby neurons health Oligodendrocytes PNS a large cells with bulbous body cytoplasmic processes ensheath portions of multiple axons myelin sheath b need fluorescents to view these cells Satellite cells PNS a satellite cells basically astrocytes in the PNS b flat cells that physically separate ganglion cells from interstitial fluid c regulate nutrients and wastes and removal of those wastes i between neurons and the environment Schwann Cells PNS a neurolemmocytes b Neurolemmocytes are used to wrap around to form myelin sheath around PNS axons c They are also able to act as phagocytic cells to remove dead cells d helps in regeneration e Oligodendrocytes do not offer regeneration only function to form myelin sheath Neurons Neurons are highly specialized communication cells 0 generate ATP 0 love glucose as fuel source 0 amitotic do not have centrioles so they cannot divide Structure Nissl bodies chromatic philic substances they are in a condense area where we see rough ER and ribosomes pigment inclusions as neurons get older they get darker in color retrograde toward the cell body anterograde away from cell body Anaxonic neurons neurons that do not have an axon ONLY HAVE DENDRITES not common only found in CNS no idea of functionality Neuron Classification 0 when in doubt choose multipolar most common 0 bipolar axon dendrites o sensory neurons information in 0 motor neurons information out o interneuron serve to connect sensory and motor I aids in forming reflexes o sensory and motor are almost always multipolar Mvelination of Axons Why only myelination of axons 0 has significant impact on nerves serves as insulation 0 it wraps around until it looks stacked myelin sheath 0 the organelles are located in the outer layers no change in voltage can occur where myelination is present 0 There is a change in voltage across the plasma membrane because there is high sodium on the outside of the cell but low on the inside The charge difference gt voltage occurs Mvelination in CNS and PNS o in the CNS oligodendrocytes they wrap the axon but in small portions 1 mm sized portions individually wraps one neurolemmocyte on one axon o in PNS schwann cells neurolemmocytes myelinates a 1 mm area on axon o saltatory conduction wherever there is myelination no chance in voltage so the signal pops through each node super fast Unmvelinated axons 0 much slower conduction because the signal must travel through the entire length and change voltage a lot Svnaptic Communication 1 electrical infrequent a gap junctions are utilized b message passes directly from one cell to the next c so there is a local flow of current gt which is the movement of charge ion d no synaptic delay 2 chemical more frequent most numerous uses nervous tissue there is a synaptic delay very precise sequence of events so that the rate of nerve impulse conduction are only influenced by 2 factors 1 axon s diameter 2 myelin sheath present or not a present faster b absent slow e there is a synaptic delay 9065 o synaptic delay 0 occurs in a chemical synpase because it takes time for us to relase the neurotransmission diffuse and bind to the channel on the post synaptic membrane Events of Chemical Svnapse 1 nerve impulse that flows down axon gt terminal region of axon gt synaptic knob 2 arrival of nerve impulse gt causes increase in calcium ion movement into synaptic knob a this is because it s a voltageregulated calcium ion channel 3 when calcium ions enter the synaptic knob synaptic vesicles move also to bind to the side of membrane a then neurotransmitters that are inside the vesicles are released into synaptic cleft by exocytosis 4 the neurotransmitters diffuse across synaptic cleft to the plasma membrane of the postsynaptic cell 5 neurotransmitters then bind to protein receptors of postsynaptic cell gt causing ion gates to open 6 influx of sodium ions moves into postsynaptic cells while gates are open gt changes charge across membrane Summary 1 nerve impulse gt synaptic knob gt increase in calcium ions into synaptic knob 2 synaptic vesicles move in and attach to plasma membrane gt they release neurotransmitters 3 neurotransmitters diffuse across syanptic cleft toward the plasma membrane of postsynaptic cell 4 neurotransmitters bind to specific protein receptors gt ions gates open gt sodium ions move in gt charge chances across membrane Neural Integration and Neuronal Pools 0 neuronal pools complex patterns that neurons are arranged in o 4 types 0 converging circuit I many inputs into single output concentrates signal 0 this creates strong stimulation or inhibition 0 diverging circuit I one input into multiple outputs amplifying circuit 0 amplifies the information o Reverberating circuit I continuously runs until inhibitory signal that will stop the signal or synaptic fatigue when you run out of neurotransmittors or gets to levels so low that it can t communicate with the subsequent cell I it oscillates into itself o parallelafterdischarge circuit I single output but the pathway to getting there is a burst of impulses 0 one input in but 5 out through the single output because there are many input neurons in the pathway to get to output I responsible for higher level thinking Axon Regeneration 0 when you have trauma in the peripheral nervous system skeletal muscle fiber neurolemma schwann cells 0 the end of the axon seals itself out and swells up and anything distal to this breaks down 0 the hope is that the endomysium stays in tact and that there is some aspect of schwann cells left that survived I with the endomysium and schwann cells it forms a regeneration tube to help the axon regenerationreconnect o limits I more damage the harder it is to repair I distance 0 if close it s likely to occur 0 but far away as in 34 mm will decrease probability I and have some schwann cells to release nerve growth cells to help reach 0 In CNS 0 regeneration is limited 0 because no release of nerve growth factors 0 cellular density is greater and tends to complicate regrowth o higher cellular density increases chance of connecting to wrong axon so it tries to use a different pathway or retrain another area of perform 0 when there is damage there are astrocytes and connective tissue coverings that may form scar tissue 0 this scar tissue obstructs pathway for axon regrowth NerveTracts ln PNS a bundle of parallel axons nerve ln CNS a bundle of parallel axons tract Nervetract is surrounded by 3 consecutive connective tissue 0 endoneurium wraps around axon O perineurium wraps around fascicle o epineurium wraps around the entire collect c There is vasculature in each wrapping Sensory neuron O afferent motor neurons 0 efferent mixed 0 some neurons carry motor but some other ones carry sensory neurons
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