EXSC 292 - Section 1 (Winfrey-Kovell)
EXSC 292 - Section 1 (Winfrey-Kovell) EXSC 292
Popular in Anatomy
Popular in Exercise Biology
verified elite notetaker
This 10 page Class Notes was uploaded by Natalie Shively on Thursday January 28, 2016. The Class Notes belongs to EXSC 292 at a university taught by Marry Winfry-Kovel in Winter 2016. Since its upload, it has received 21 views.
Reviews for EXSC 292 - Section 1 (Winfrey-Kovell)
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 01/28/16
EXSC292-SECTION1 SPRINGSEMESTER2016 INSTRUCTOR:WINFREY-KOVELL 29 January 2016 Chapter 6 Part 1: Bones and Skeletal Tissues ● Cartilage - found throughout body - i.e. nose, ear, larynx, trachea - articular and costal cartilage - intervertebral discs, pubic symphysis, and articular discs ● All cartilages share some similarities ○ Cell type is the chondrocyte ○ Chondrocytes are located within lacunae ○ Matrix contains - Fibers - Jelly like ground substance ● Cartilage Characteristics - primarily water (80%) - perichondrium: around cartilage ~ Collagen ﬁber ring ~Girdle/Growth/Repair - Resilient tissue - springs back - No nerves/blood supply ● Types of Cartilage - Hyaline: glassy; most abundant; support through ﬂexibility - Elastic: elastic ﬁbers; tolerates repeated bending - Fibrocartilage: resists strong compression and strong tension; intermediate between hyaline and elastic ● Growth of Cartilage - Appositional - perichondrium: chondroblasts = new cartilage - Interstitial: chondrocytes within; stops growing end of skeletal growth; regenerates poorly in adults calciﬁed cartilage ~ sign of aging 1 ● Bone Characteristics: “Bone is living tissue” - increases in size; ability to heal self; rich blood supply; nerve supply; nutritional needs ~ minerals, vitamins, K-B12 ~ Can lose up to 500mg of calcium a day if not enough nutritional calcium provided ● Function of Bones - Support: provide hard framework - Movement: skeletal muscles use bones as levers - Protection: underlying organs - Mineral storage: reservoir for important minerals - Blood cell formation: bone contains red marrow - Energy metabolism: osteoblasts secrete osteocalcin ● Bone Tissue: Extracellular Matrix - 35% organic components ~ collagen, cells - osteocytes ~ﬂexibility/tensile strength - 65% inorganic components ~large = calcium phosphate crystal ~small = magnesium, manganese, ﬂoride ~exceptional hardness/resists compression - Bone stronger reinforced concrete compression ~ almost equal in tensile strength ~collagen = steel rods; mineral salts = sand/rock in concrete ● Cell types produces / maintain bone ● Bone Cells - Osteoblasts— produce / secrete bone matrix- osteoid - Osteocytes— living bone cell, maintain osteoid ● Osteoclasts: remove bone; resorption of bone; hydrochloric acid/lysosomal enzymes; digest organic materials ● Classiﬁcation of Bones - long bones: longer than wide; shaft plus ends - short bones: roughly cube-shaped - ﬂat bones: thin and ﬂattened; curved - irregular bones: various shapes ~ ﬂat, short and irregular bones contain: bone marrow but no marrow cavity; diploe; internal spongy bone of ﬂat bones ● Gross Anatomy of Bones - reﬂects stresses - compression and tension ~ external surfaces 2 - lines of stress: trabeculae, osteons, tendons, ligaments, gravity ● Bone Markings - projections for muscle attachment - surfaces that form joints - depressions and openings ** Table 6.1 for extra detail Chapter 6 Part 2: Microscopic Structures and Development of Bone ● Microscopic Structure of Compact Bones - Structures in the central canal: artery with capillaries, vein, nerve ﬁber - collagen ﬁbers run in diﬀerent directions lamellae ● Microscopic Structure of Spongy Bone - less complex than compact bone - layers of lamellae and osteocytes - covered by endosteum - red bone marrow ● Bone Development - Ossiﬁcation centers appear in the ﬁbrous connective tissue membrane: mesenchymal cells cluster and diﬀerentiate > osteoblasts = ossiﬁcation center - Bone matrix (osteoid) is secreted within ﬁbrous membrane and calciﬁes: osteoblasts secrete > calciﬁed within days; trapped osteoblasts become osteocytes ● Endochondral Ossiﬁcation - Week 9 > month 3: bone collar forms around diaphysis of hyaline cartilage model > cartilage in the center of the diaphysis calciﬁes ~ develops cavities > periosteal bud invades internal cavities ~ spongy bone forms - month 3 > birth > childhood adolescence: diaphysis elongates > medullary cavity forms (ossiﬁcation continues) > secondary ossiﬁcation centers appear in epiphyses > epiphyses ossify > hyaline cartilage remains only in epiphyseal plates and articular cartilages ● Postnatal Growth ~ Hormonal Regulation of Bone Growth ● Growth hormone: pituitary gland; stimulates epiphyseal plates ● Thyroid hormone: skeleton retain proper proportions - calcitonin: bone absorb calcium from blood = levels high ● Parathyroid hormone: releases calcium from bone = tissue levels low ● Sex hormones: estrogen and testosterone; promote bone growth; induce closure epiphyseal plates ● Childhood/adolescence: bones lengthen = epiphyseal plates - interstitial growth: inside bone 3 ● Adolescence ends: ossiﬁcation of epip. plates; growth stops = diaphysis/epip. fuse ● Appositional growth: osteoblasts: add external surface ● Bone Remodeling - dynamic living tissue - 500 mg of calcium may enter or leave skeleton ea. day - bone matrix and osteocytes are continually removed and replaced - cancellous bone of the skeleton is replaced every 3-4 years - compact bone is replaced every 10 years ● Bone deposit and removal: occurs at periosteal and endosteal surfaces ● Bone remodeling - deposition: accomplished by osteoblasts - reabsorption: accomplished by osteoclasts ● Osteoclast ~ A Bone-Degrading Cell - giant; many nuclei - crawls along bone surfaces - breaks down bone tissue - secretes concentrated HCI - lysosomal enzymes are released - derived from hematopoietic stem cells ● Periosteal/endosteal surfaces: remodeling not uniform ● Bone deposition: osteoblasts; mechanical stress; fracture ● Bone resorption: osteoclasts; inactivity; lack of calcium; prolonged bed rest (0 gravity) ● Repair of Bone Fractures - simple and compound fractures - treatment by reduction: closed and open - hematoma forms > ﬁbrocartilaginous callus forms > bony callus forms > bone remodeling occurs ● Common fractures: - comminuted: fragments in 3 pieces or more; common in aged - compression: bone is crushed; common in porous bones (osteoporotic bones) - spiral: ragged break; excessive twisting; common sport - epiphyseal: separates from diaphysis along epiphyseal plate; occurs where cartilage cells are dying - depressed: broken bone portion is pressed inward; skull - greenstick: incomplete break; common in children ● Disorders of Bones ● Osteoporosis: low bone mass; bone resorption outpaces bone deposition; occurs in women after menopause ● Osteomalacia: soft bones - adults: bones are inadequately mineralized; no calciﬁcation; pain weight bearing ● Rickets: weakened/bowed legs - children = osteomalacia; severely aﬀects bone development; inadequate vitamin D 4 ● Paget’s disease: excessive rate of bone deposition; bones thicken irregular pattern ● Osteosarcoma: form of bone cancer; origination in long bones ● The Skeleton Throughout Life ● Cartilage: youth grows quickly; elderly fewer chondrocytes ● Skeleton: grows until 18-21 yrs.; children/adol. bone formation exceeds resorption; young adults bone formation/resorption in balance; old age resorption predominates; bone mass declines with age 5
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'