Weekly Notes October 19th-23rd
Weekly Notes October 19th-23rd BSC 215
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This 8 page Class Notes was uploaded by Paige Carson on Friday October 23, 2015. The Class Notes belongs to BSC 215 at University of Alabama - Tuscaloosa taught by Dr. Jason Pienaar in Summer 2015. Since its upload, it has received 53 views. For similar materials see Human Anatomy and Physiology in Biological Sciences at University of Alabama - Tuscaloosa.
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Date Created: 10/23/15
Weekly Notes BSC 215 Pienaar Week of Oct 19 Oct23rOI Also Oct 15th Bone Formation Embryonic Connective Tissue Hyaline Cartilage Model Intramembranous Ossi cation Endochondral Ossi cation Primary Woven Bone Primary Woven Bone Mature Secondary Bone Mature Secondary Bone Intramembranous Ossi cation Starting material Mesoderm Ectoderm and Exoderm Mesenchymal produces osteogenic cells then osteoblasts then osteocytes Mesenchymal also forms the periosteum Periosteum covers the bone Endosteum extracellular matrix in muscle is endomysium Trabeculae forms around blood vessels Endochondral Ossi cation 1 Hyaline cartilage model formed by chondroblasts in perichondrium membrane 2 Chondroblasts in perichondrium differentiate into osteoblasts and deposit a bone collar around the shaft that grows toward epiphyseal plates perichondrium becomes periosteum 25 Simultaneously internal chondrocytes in ate and die in primary ossi cation center thin walls between them calcify leaving cavities surrounded by calci ed cartilage calci cation 3 Osteoclasts arrive in blood digest external foramina and internal calci ed tissue creating the primary marrow cavity Osteoblasts also arrive deposits layers of bone Both cell types follow wave of chondrocyte death replacing cartilage with bone 4 Secondary ossi cation center develops in epiphysis creating secondary bone marrow cavity repeat 13 After birth epiphysis cavity lls with spongy bone 5 Hyaline cartilage becomes limited to epiphyseal plats where elongation occurs until late teens then replaced by bone to form epiphyseal lines 6 Osteoclasts continue to hollow out diaphysis bone marrow cavity articular cartilage remains on parts that form joints Bone Growth Longitudinal Growth Increase in length All about epiphyseal plate Chondrocyte division in epiphyseal plate Appositional Growth Increase in width Osteoblasts underneath periosteum deposit new compact bone Longitudinal Growth Middle of epiphyseal plate Listed from the bottom to the top Zone of Reserve hyaline cartilage Reserve chondroblasts Zone of Cell Proliferatin Actively dividing chondrocytes Zone of Cell Hypertrophy Mature expanded chondrocytes Zone of Cell Calci cation Dead calci ed chondrocytes Zone of Ossi cation Osteoblasts deposit bone tissue becoming entrapped in osteocytes Appositional Growth Basically same as intramembranous ossi cation and bone remodeling involves osteoblasts in periosteum With addition of osteoclasts and secondary bone formation osteons around blood vessels to form Haversion canals Bone Remodeling Remodeling continuous cycle of deposition and bone resorption Calcium ion homeostasis Bone repair Replacement of primary bone with secondary bone Bone adaption to sustain stress and tension Muscle Tissue Skeletal muscle always has a neuromuscularjunction Consists of cells and ECM Skeletal Muscle Cells Long multi nucleated and connected to nerves Cardiac Muscle Cells Shorter Uni or multi nucleated Branched Involuntary Connected to each other by gap junctions Smooth Muscle Cells Short Spindle shaped Uninucleated Connected by gap junctions Endomysium holds muscle cells together Muscle Cell Characteristics Contractility ability of protein bers within myocytes to draw together Excitability responds to stimuli electrical or chemical Conductivity conduct stimulus electricity Extensibility can be stretched up to 3x resting length Elasticity ability to regain original state after stretching Muscle Cells All have nucleus except mature red blood cells erythrocytes Mitochondria Cytoplasm in muscle cells is called the sarcoplasm Plasma membrane in muscle cells is called the sarcolemma Smooth endoplasmic reticulum in the muscle cells is called the sarcoplasmic reticulum Myo bril bundle of protein bers Skeletal Muscle Organization Epimysium surrounds muscle and continues to the tendon Perimysium surrounds the fascile Fascile contains many muscle bers Endomysium surrounds bundles of muscle bers The Muscle Fiber Plasma membrane of a muscle cell sarcolemma Cytoplasm of a muscle cell Sarcoplasm Nucleus Mitochondria Myo brils Sarcoplasmic Reticulum Terminal cisternae Ttubule Triad Myo lament Thick lament myosin A banddArk Thin lament actin l bandlght Sarcoplasmic Reticulum Neuromuscularlunction Release Ach by synaptic vesicles Electrical signal sent to plasma membrane Na oods in Lowering voltage closer to O lons involved Na Ca K Myo brils A band thick lament thin laments l band thin laments and elastin Filament proteins are actin thin lament myosin thick lament elastin titin tropomyosin and troponin 7 39 1 r 7115quot 39 ED HJE inf rDAgs39arlazp LEN E 3931 E HaFj F i Li e Sat camera l band H zone decreases during contraction Zone of overlap increases A band does not Membrane Potential Electrical Gradient Separation of charged particles electrolyte pairs across plasma membrane sarcolemma Electrical Potential Potential energy due to barrier sarcolemma maintaining gradient Vb age Difference in electrical potential between two points Example 110 voltage potential difference between wall outlet and toaster Membrane Potential Electrical potential difference either side of the cell membrane polarized membrane charged Resting membrane potential 0 For Myocytes 85 mV when ion channels are closed NaK pump generate resting membrane potential 3 Na outside 2 K inside ECM high Na Low K Sarcoplasm high K Low Na Action Potential Quick local temporary change in membrane potential 3 types of cells that use action potential extensively Motor neuron 70 mV Skeletal muscle 85 mV Cardiac ventrice 85mV During depolarization there is a vast amount of Na owing inside During repolarization there is a vast amount of K owing out 1 Resting phase gated channels are closed Na and K gradients maintained by NaK pumps 2 Depolarization phase Na channels open in response to a depolarizing stimulus Na enters the cell down its concentration gradient and further depolarize the membrane 3 Repolarization phase Na channels close K channels open K exits the cell down its gradient and repolarizes the membrane 4 NaK pump restores resting potential Action potential propagation through neurolemma Neuromuscular Junction possible essay Axon branches off motor neurons synapse with muscle bers at neuromuscularjunction Synaptic vescices at the end of axons contain acetylcholine a neurotransmitter Ach is secreted into synaptic cleft by exocytosis and interacts with Ach receptors ligand gated Na channels on motor end plate on sarcolemma Putting it all together 1 Action potential from neuron results in Ach secretion in synaptic cleft 2 Ligand gated Na channels in sarcolemma open when bound to Ach 3 Generates action potential wave that travels down Ttubules of sarcolemma 4 Ttubule depolarization results in Ca channels in terminal cisternae of sarcoplasmic reticulum to open 5 Ca interacts with troponin triggers thin laments to slide over thick laments resulting in sarcomere contraction 6 Muscle relaxes when Ach is no longer present and Ca in sarcoplasm returns to normal Excitation phase generating action potential muscle cell 1 Action potential from neuron triggers exocytosis of synaptic vescicles 2 Synaptic vescicles release Ach into synaptic cleft 3 Ach binds to ligand gated ion channels in motor end plate 4 Na diffuses through ion channels depolarizing sarcolemma locally producing end plate potential 5 Continuous multiple end plate potentials generate a sarcolemma action potential Excitation contraction coupling 1 Action potential travels to Ttubules via Voltage gated Na channeb 2 Ttubule depolarizes leads to the opening of voltage gated Ca channels in terminal cisternae of sarcoplasmic reticulum Preparation for Contraction 1 At rest tropomyosin twists around actin blocking its active sites 2 Ca binds to troponin causing tropomyosin to fall off the actin exposing the active sites Contraction Phase 1 ATP hydrolysis cocks the myosin head 2 Myosin heads bind to actin active sites 3 Myosin releases ADP and Pi power stroke pulls actin towards M line 4 Binding of a new ATP breaks cross bridge 5 Cycle starts again Muscle Contraction 1 Acetylcholinesterase degrades acetylcholine in synaptic cleft 2 Sarcolemma returns to resting membrane potential 3 Ca ion pump return Ca to sarcoplasmic reticulum active transport 4 Troponin and Tropomyosin block active sites on actin Nervous Tissue Don t know much about ECM Nervous System Organ system collection of organs working for a common function Organs of the nervous system Brain Spinal Cord Nerves Anatomical Subdivision CNS central nervous system consists of brain and spinal cord PNS peripheral nervous system consists of cranial nerves 12 pairs spinal nerves and branches 31 pairs Functional Subdivision CNS lters and integrates sensory input coordinates appropriate responses SENSON Division Division Somatic carries sensory signals from skin muscles bones joints and special organs eyes ears nose etc Visceral carries sensory signals form internal organs Somatic motor carries CNS generated signals to skeletal ANS carries CNS signals generated signals to smooth and cardiac muscles and glands Neuron Structure Nervous Tissue ECM 20 tissue basal amin and gycoproteins thousands Ces 80 tissue cells 10 of cells neurons 90 of cells neuroglia Neuron Structure Ce body Contains nucleus and maintains cytoplasm Some nerves can be gt1 meter long Only have 1 nucleus Produces all proteins required for nerve signaling Numerous mitochondria Nissil bodies dark staining associations of ribosomes and rough ER Golgi apparatus Neuro brils Axon 1 Dendrites many