NURS 163 Chapter Notes - Chapter 4: Proteoglycan, Hypothyroidism, Ultimate Tensile Strength
Skeletal System: Study Guide 4 Answers
1. Functions of skeletal system:
A. Support
B. Protection
C. Movement
D. Storage: minerals, growth factors
E. Hemopoiesis: RBC production in red bone marrow
2. Four basic components of skeletal system:
1) Bones
2) Cartilage
3) Ligaments
4) Joints
3. Cartilage characteristics:
A. Perichondrium surrounds cartilage
a. Dense irregular CT
b. Resists outward expansion during compression
c. Contains BV, providing nutrients through ECM to chondrocytes
B. Avascular, no nerves
C. Molded to fit its location, function
D. Lots of water= withstands compression
E. ECM: ground substance & fibers
F. Chondrocytes w/in lacunae
4. Three types of cartilage: location, structure, function
1) Hyaline:
a. Most common
b. Location: costal cartilage, larynx, external nose, epiphyseal growth
plates, ends of long bones (articular cart)
i. No perichondrium on articular cart
c. Function: support, flexible, resilience
d. Fine collagen fibers
2) Elastic:
a. Location: epiglottis, external ear
b. Function: withstands bending, stretchy
c. Many elastic fibers
3) Fibrocartilage:
a. Strongest
b. Function: withstand heavy pressure, high mechanical stress
c. Location: intervertebral discs, pubic symphasis, knee menisci
d. Thick collagen fibers
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5. Two types of cartilage growth:
1) Interstitial: growth from within
a. Lacunae divide and secrete new matrix, pushing themselves farther
apart
2) Appositional: growth from outside
a. Cells beneath perichondrium secrete new cartilage, adding to external
surface
6. Bones of axial skeleton:
A. 80 bones
B. Skull, vertebrae, sternum, ribs
7. Bones of appendicular skeleton:
A. 126 bones
B. Upper/lower extremities, shoulder girdle, pelvic girdle
8&27. Four bone shape categories:
1) Long bone:
a. Shaft w/ two expanded ends
b. EX: femur, humerus
2) Short bone:
a. Cube shaped
b. EX: carpals, tarsals
3) Flat bone:
a. Thin, flat, slight curve
b. EX: sternum, scapula
4) Irregular bone:
a. Complicated shapes
b. EX: vertebra, os coxae
10. Organic portion of bone matrix: Osteoid
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9. Four types of cells that form/maintain bone tissue:
1) Osteogenic: unspecialized
a. Derived from mesenchyme
b. Highly mitotic
c. Location: inner periosteum & endosteum
2) Osteoblasts: secretion
a. Secrete: collagen fibers, osteoids
b. Initiate matrix calcification
c. =Osteoblasts trapped in lacunae → osteocytes
3) Osteocytes: monitor, maintain ECM
a. Spidery shaped
4) Osteoclasts: breakdown of bone *This is explained in depth later on too
a. Huge cells w/ many nuclei
b. Derive from cells that make macrophages (not mesenchyme)
c. Formed in bone marrow by fusion >50 monocytes
d. Structure:
i. Ruffled border against bone surface engulfs bone minerals,
etc.: bone resorption
ii. Releases minerals → blood
iii. Maintains blood ion homeostasis
iv. Helps with bone remodeling
11-12. Organic and inorganic bone matrix materials:
A. Organic: Osteoid
a. 25-30% matrix
b. Ground substance (proteoglycans, glycoproteins) & collagen fiber
c. Gives bone tensile strength
d. *No osteoids = brittle bones
B. Inorganic: mineral salts
a. Hydroxyapatite: crystalline mineral salts parallel to collagen fibers
b. Makes bone tissue hard
c. Helps bone resist compression forces
d. Mostly calcium phosphate
13. Minerals stored by bone: calcium phosphate
14. Function of spongy & compact bone:
A. Spongy: makes bones lightweight
B. Compact: gives bones strong structure
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Document Summary
: (cid:498)bone resorption(cid:499: releases minerals blood, maintains blood ion homeostasis, helps with bone remodeling. Periosteum: double membrane, outer layer: dense irregular ct, (cid:498)fibrous layer(cid:499, inner layer: osteoblasts & osteoclasts, (cid:498)osteogenic layer(cid:499, covers surface of long bone (except articular cartilage, vascular: bv/nerves pass through periosteum nutrient foramen bone (cid:883)8. Growth in length of long bones: appositional: beneath periosteum, interstitial: epiphyseal growth plate. Bone remodeling: osteoblasts: external bone deposit, osteoclasts: internal bone resorption, function: bone renewal, healing; calcium homeostasis, bone diameter increases as medullary cavity increases, creates balance between size/weight of bone. Vitamin c"s influence on bone structure: vit c helps osteoblasts secrete collagen, deficiency, slow bone growth, repair, bones slender, fragile. Most important blood calcium & calcium storage regulation hormone: Aging"s affect on skeleton: decreased rate of protein synthesis, low production of organic bone (collagen, decreased hgh, =pitted, weak bone, demineralization, loss of ca2+ & other minerals from matrix, best bone density, women: 18, men: 20.
