Chapter 7 Skeletal System Flashcards
1
Q
What are the 4 classes of bone?
A
- Long
- Short
- Flat
- Irregular
2
Q
What is the one class under irregular?
A
Sesamoid
3
Q
Parts of a Long Bone
A
- epiphysis
- articular cartilage
- diaphysis
- periosteum
- processes
- medullary cavity
- endostuem
- marrow
4
Q
Epiphysis
A
- expanded portion of long bone that articulates with another bone
- made of spongy bone which has bony plates (trabeculae)
5
Q
Articular Cartilage
A
-hyaline cartilage that coats articulating part of epiphysis
6
Q
Diaphysis
A
- shaft of bone between epiphysis
- wall of diaphysis is compact bone which has a continuous extracellular matrix with no gaps
7
Q
Periosteum
A
-tough, vascular, fibrous membrane that covers diaphysis of the bone
8
Q
Function of Periosteum
A
to form and repair bone tissue
9
Q
Processes
A
-provide site for attachment for tendon or ligament
10
Q
Bones usually have ____ bone overlying ____ bone.
A
compact, spongy
11
Q
Medullary Cavity
A
- runs through diaphysis
- is a semi-rigid tube w hollow chamber
12
Q
Endosteum
A
- lines medullary cavity and spaces of spongy bone
- contains bone-forming cells
13
Q
Marrow
A
-tissue that fills spaces of bone
14
Q
2 types of Marrow
A
- red
- yellow
15
Q
Osteocytes have to be seen how?
A
Microscopically
16
Q
Osteocytes
A
- bone cells located in tiny, bony chambers (lacunae)
- Lacunae form circles around central canals
17
Q
Function of Osteocytes
A
-transport nutrients and wastes to &from nearby cells
18
Q
Cell processes of Osteocytes through ________.
A
Canaliculi
19
Q
Another name for central canals is _____.
A
Haversian Canals
20
Q
What is extracellular matrix made of?
A
-collagen and inorganic salts
21
Q
The inorganic salts and collagen in extracellular matrix give bones their what?
A
-strength and resilience
22
Q
Composition of Compact Bone
A
- osteons are cemented together forming substance of compact bone
- each central canal contains bv&nerves
- perforating canals (Volkmann’s Canals) connect central canals & contain larger bv & nerves
23
Q
Osteon
A
-cylinder shaped unit of compact bone
24
Q
Spongy Bone
A
- composed of osteocytes & extra cellular matrix
- bone cells live within trabeculae & get nutrients from substances diffusing into canaliculi that lead to thin, bony plates
25
When do the parts of the skeleton start to form?
during first few weeks of prenatal development
26
Bones form by replacing existing ___.
CT
27
Bones continue to grow & develop into ____.
adulthood
28
_________________ bones originate within sheetlike layers of CT.
Intramembranous
29
____________ bones begin as masses of cartilage that are later replaced by bone tissue.
Endochondral
30
How do intramembranous bones form? (6 steps)
- during osteogenesis, membranelike layers of unspecialized CT appear at sites of future bones
- dense bv supple CT layers with nutrients
- cells enlarge & become further differentiated into osteoblasts (bone forming cells)
- osteoblasts then deposit bony matrix around themselves
- Result: spongy bone forms in all directions along bv within CT
- later spongy bone becomes compact bone as spaces fill with bony matrix
31
Examples of Intramembranous bones
-broad, flat bones of skull
32
As development continues, osteoblasts become surrounded by ______ & become secluded within _______.
matrix, lacunae
33
This matrix then encloses processes of ______ and give rise to ______.
osteoblasts, canaliculi
34
Once those are isolated, osteoblasts become ___________.
osteocytes
35
Most _______ bones are enchochondral bones.
Skeletal
36
Steps of how an endochondral bone forms
1. develops from masses of hyaline cartilage
2. cartilaginous cells enlarge & lacunae grow
3. surrounding matrix breaks down & cartilaginous cells die & degenerate as it decomposes, periosteum forms from CT & encircles the structure
4. osteoblasts form spongy bone in space occupied by cartilage
5. osteoblasts become osteocytes when bony matrix completely surrounds them; then become osteocytes
6. osteoblasts beneath periosteum deposit compact bone around spongy bone
37
Primary ossification center
when bony tissue replaces hyaline cartilage in center of diaphysis
-epiphysis of developing bone remains cartilaginous & continue to grow
38
Secondary ossification center
appears later in epiphysis & spony bone forms in all difections
- as it is deposited in diaphysis & epiphysis, band of cartilage forms called epiphyseal plate & remains between ossification centers
39
Growth of cartilaginous cells of epiphyseal plate forms 4 layers
- 1st layer: deepest
- 2nd layer: second deepest
- 3rd layer: thickest layer because it contains older&new cells
- 4th layer: outside layer
40
1st layer of epiphyseal plate
-anchors epiphyseal plate to bony tissue of epiphysis (closest to end of epiphysis & cells do not participate in growth)
41
2nd layer of epiphyseal plate
-rows of many young cells undergoing mitosis. Cartilaginous plate thickens as new cells appear.
42
3rd layer of epiphyseal place
-formed by older cells left behind as new cells appear & those enlarged thicken the epiphyseal plate, lengthening the bone
43
4th layer of epiphyseal plate
- composed of dead cells & calcified extra cellular matrix (thin)
44
What do osteoclasts do?
- act as scavengers
- break down calcified matrix
- phagocytic parts of bony matrix
- after osteoclasts remove matrix, osteoblasts deposit bone tissue in place of calcified cartilage
45
Long bones continue lengthening while _____________ cells are active.
cartilaginous
46
Once ossification centers of diaphysis & epiphysis meet, plates ____ & _____ is not possible.
close, growth
47
Over the course of life, _____ resorb bone tissue & _________ replace bone.
osteoclasts, osteoblasts
48
Factors that affect bone development, growth& repair are...
- Nutrition
- Hormonal secretions
- Physical stress
49
What are the 3 vitamins that support bone growth & what do they do for the bones?
- Vitamin D: to absorb calcium (received through UV light)
- Vitamin A: for osteoblast & osteoclast activity
- Vitamin C: for collagen synthesis
50
What are the 3 hormonal secretions influencing bone growth, development, and repair?
- growth hormone: stimulates division of cartilaginous cells in epiphyseal plates
- parathyroid hormone: stimulates increase in the number & activity of osteoclasts
- sex hormones: promote formation of bone tissue; females reach maximum height earlier due to estrogen effects on epiphyseal plates are stronger than testosterone
51
How does physical stress affect bones?
-stimulates bone growth: Wolff's Law
52
Bone Functions are...
- gives shape to structures
- support body weight; lower limbs, pelvis, vertebral column
- protects organs like eyes, ears, brain, heart, abdominal, internal reproductive organs
- blood cell formation- hematopoiesis which begins in the yolk sac in embryonic development; later made in the liver, spleen, bone marrow
53
What is marrow?
-soft, netlike mass of CT within the medullary cavity, irregular spaces of spongy bone, and central canals of compact bone
54
What is the function of red marrow?
forms RBC, WBC & platelets
occupies most cavities of bones in infants
as adults, found in spongy bone in skull, ribs, sternum, clavicles, vertebrae & pelvis
55
As adults, ____________ marrow replaces ______ marrow. _____ marrow stores fat.
yellow, red, yellow
