Skeletal System Flashcards
1
Q
list the 5 functions of the skeletal system
A
- protection
- support
- locomotion
- mineral storage (Ca and P)
- blood cell formation (in bone marrow)
2
Q
what are the two subsections of the skeleton?
A
- axial skeleton
2. appendicular skeleton
3
Q
what does the axial skeleton contain?
A
all bones along or attached to the median plane, including the skull, vertebrae, ribs, and sternum
4
Q
what does the appendicular skeleton contain?
A
bones of the limbs
5
Q
how many cervical vertebrae do all mammals have?
A
7
6
Q
how many cervical vertebrae do birds have? are they all separate?
A
14, but they’re all fused together
7
Q
why do birds have a larger sternum?
A
to support breast muscles
8
Q
list and describe the 5 bone shapes
A
- long bones: longer than they are wide, found in limbs
- short bones: more cube-shaped, found in carpus and tarsus
- flat bones: flatter than other bones, found in skull, sternum, ribs, scapula
- irregular bones: don’t fit with other classifications, usually unpaired, ex. vertebrae
- sesamoid bones: resemble sesame seeds, found in the patella and digits
9
Q
describe pneumatic bones
A
contain air spaces called sinuses, lighter than others, avian skeleton has more than mammalian because flight
10
Q
list and describe the 5 types of vertebrae
A
- cervical: most cranial, all mammals have 7
- thoracic: attached to/joined with ribs
- lumbar: lower back
- sacral: joined with pelvis, fused together
- caudal: most caudal, make up the tail
11
Q
list the 8 basic vertebrae structures
A
- vertebral body
- spinous process
- pair of transverse processes
- pair of lamina
- pedicle
- pair of articular processes
- vertebral foramen
- transverse foramen
12
Q
describe the location of the vertebral body
A
on the ventral side of the vertebrae, contains intervertebral disk
13
Q
describe the spinous process
A
projects dorsally off vertebrae
14
Q
where do the transverse processes project?
A
laterally off the vertebrae
15
Q
what do the paired lamina do?
A
connect spinous process to transverse processes
16
Q
what does the pedicle connect?
A
transverse processes to the vertebral body
17
Q
describe the location of the paired articular processes
A
sit on the pedicle, where one vertebrae joins with the next
18
Q
describe what the vertebral foremen contains
A
site of the spinal cord
19
Q
describe the transverse foramen
A
holes in pedicle of cervical vertebrae, where blood vessels and nerves run through neck
20
Q
where are transverse foramen found?
A
ONLY in cervical vertebrae!!
21
Q
list the 3 types if bone cells
A
- osteoblasts
- osteoclasts
- osteocytes
22
Q
give the function of osteoblasts
A
ossification, secrete hydroxyapatite, the mineral component of bone that makes bone hard
23
Q
what is ossification?
A
formation of bone by osteoblasts
24
Q
where are osteoblasts found?
A
found on the outside/lining bone surfaces so they can secrete bone on top of existing bone
25
describe osteocytes
mature bone cells, form when osteoblasts are surrounded by bone and become osteocyctes
26
describe the function of osteoclasts
resorption (breakdown of bone)
27
give the 6 structures specific to long bones
1, epiphysis
2. diaphysis
3. metaphysis
4. epiphyseal plate
5. epiphyseal line
6. medullary cavity
28
describe the epiphysis
either end of a long bone (proximal epiphysis on top, distal epiphysis on bottom)
29
describe the diaphysis
the long shaft of a long bone
30
describe the metaphysis
connects epiphysis to diaphysis (proximal and distal end)
31
describe the epiphyseal plate and give the location
found in the meatphysis, is a layer of hyaline cartilage where growth of long bone occurs
32
describe the epiphyseal line
replaces epiphyseal plate when growth ceases, made up of compact bone
33
describe the medullary cavity
in center of diaphysis, does not contain bone, but bone marrow, and is hollow
34
describe red bone marrow
found in young animals, blood cell formation site
35
describe yellow bone marrow
found in adults, made of adipose (fat) tissue
36
list 3 structures found in all bones
1. articular cartilage
2. periosteum
3. endosteum
37
describe articular cartilage
thin layer of hyaline cartilage that covers surfaces of a bone within a joint
38
describe the periosteum
covers the rest of the bone, 2 layers
39
list and describe the 2 layers of the periosteum
1. superficial/outermost layer: dense irregular connective tissue, provides protection
2. deep/inner layer: single layer of osteoblasts
40
describe the endosteum
lines internal surfaces of bone, thin layer of osteoblasts AND osteoclasts
41
list the 2 classifications when bone is classified by amount of extracellular matrix to amount of space
1. spongy (cancellous) bone
| 2. compact bone
42
describe spongy bone
more space is found around matrix, made up of trabeculae, spaces between trabeculae contain red bone marrow and blood vessels, even as animal ages
43
what are trabeculae?
interconnecting rods of bone
44
describe compact bone
less space is found around matrix, more dense, found on the outside and is tougher, arranged in osteons
45
what are osteons?
the basic unit of compact bone, also called Haversian systems
46
list the 5 structures in osteons
1. central canals
2. lamellae
3. lacunae
4. canaliculi
5. perforating canals
47
describe the central canals of osteons
contains blood vessels and nerves
48
describe the lamellae of osteons
circular plates of bone that surround the central canal
49
describe the lacunae of osteons
structures within the lamellae that house osteocytes
50
describe the canaliculi of osteons
tiny canals that connect lacunae
51
describe the perforating canals of osteons
connect central canals
52
what is calcification?
the deposition of calcium salts in any tissue other than bone
53
what is a functional result of calcification?
the os penis
54
what are centers of ossification?
location where ossification begins after calcification
55
what is intramembranous ossification?
occurs in a primitive connective tissue membrane (embryonic growth), how most flat bones are formed
56
what is endochondral ossification?
occurs in a hyaline cartilage model, which is already in the shape of the bone and gets replaced through the process; formation of limbs, as the connective tissue is now specialized and happens during fetal development
57
list the 5 zones in growth in length of a long bone in order
1. resting zone
2. zone of proliferation
3. zone of hypertrophy
4. zone of calcification
5. zone of ossification
58
where is the resting zone located and what happens there?
at the epiphyseal plate, closest to the epiphysis; chondrocytes are at rest here
59
what happens in the zone of proliferation (2nd zone in long bone length growth)?
chondrocytes begin to divide rapidly, dividing chondrocytes form columns
60
what happens in the zone of hypertrophy (3rd zone in long bone length growth)?
chondrocytes enlarge
61
what happens in the zone of calacification (4th zone in long bone length growth)?
chondrocytes absorb bone matrix and die; blood vessels from diaphysis enter lacunae leftover from dead chondrocytes; osteoblasts differentiate from blood vessels
62
what happens in the zone of ossification (5th zone in long bone length growth)?
osteoblasts secrete bone; epiphysis has been pushed away from diaphysis to add length; happens on both ends of long bones
63
what 3 things affect the rate of bone growth?
1. nutrition
2. growth hormone
3. sex hormones
64
how does nutrition affect bone growth?
malnutrition inhibits growth as cells don't get enough nutrients to divide and grow
65
how does a calcium, phosphorus, or vitamin D deficiency affect bone growth?
osteoblasts can't form hydroxyapatite, meaning they can't form bone
66
what does a vitamin C deficiency impair?
Collagen synthesis
67
how does growth hormone affect rate of growth?
acts on liver to cause secretion of insulin-like growth factor (IGF)
68
what does IGF (insulin-like growth factor) do for rate of growth?
acts on chondrocytes to cause proliferation
69
how do sex hormone affect rate of growth? (2 ways)
testosterone and estrogen stimulate the secretion of growth hormone, resulting in a growth spurt during puberty, and they also stimulate the closure of the epiphyseal plate to cease growth
70
list the 7 steps of intramembranous ossification
1. cells within a connective tissue membrane differentiate into osteoblasts
2. osteoblasts begin to secrete bone and calcify surrounding tissue
3. a center of ossification forms
4. osteoblasts secrete bone around collagen fibers in connective tissue membrane, forming tiny trabeculae
5. osteoblasts line the tiny trabeculae and secrete bone to thicken the trabeculae, forming true trabeculae
6. spaces between trabeculae develop into red bone marrow
7. periosteum forms and osteoblasts in the periosteum secrete compact bone around trabeculae
71
where does endochondral ossification take place?
in a hyaline cartilage model
72
list the 10 steps of endochondral ossification
1. hyaline cartilage model forms
2. cells on outside of model differentiate into osteoblasts and secrete bone along outside of cartilage model
3. cells inside the model absorb bone matrix, become calcified, and die
4. blood vessels enter cartilage model through lacunae left behind by dead cells
5. osteoblasts will differentiate inside cartilage, start to secrete bone, and form a primary center of ossification
6. osteoblasts continue to replace cartilage with bone
7. osteoclasts form and break down bone to form medullary cavity
8. red bone marrow develops in medullary cavity
9. cartilage in epiphysis of model begins to absorb bone and secondary centers of ossification form
10. osteoblasts continue to secrete bone until all cartilage has been replaced with bone
73
what 2 hormones regulate blood calcium homeostasis?
calcitonin and parathyroid hormone (PTH)
74
what causes the thyroid to secrete calcitonin?
high blood calcium levels
75
what does calcitonin do and how?
lowers blood calcium levels by targeting osteoclasts to reduce activity/resorption
76
what causes the parathyroid to release PTH?
low blood calcium levels
77
what does PTH do and how?
raises blood calcium levels by targeting osteoclasts to increase activity/resorption
78
what is hyperparathyroidism?
oversecretion of PTH, causes increased bone resorption leading to weakened bones
79
what is hypoparathyroidism?
undersecretion of PTH, leads to muscle cramping and twitching (tetany), major muscle contraction issues
80
list the 3 aspects of bone mechanics
1. bone is not elastic
2. bone is subjected to stresses
3. bone is dynamic
81
what is the major reason for breaks and permanent bone stretching (of bone dynamics)?
bone is not elastic
82
list and describe the 4 types of stresses that bones are subjected to?
1. compression: press together
2. shearing: rub together
3. bending: pressure
4. torsion: pivoting
83
what is the implication of the fact that bone is dynamic?
it can repair and rebuild, the reason for normal bone healing
84
describe a simple fracture
skin over fracture is intact
85
describe an open fracture
skin over fracture is damaged and exposing fractured bone
86
describe a displaced fracture
broken ends of bone are out of alignment
87
describe a nondisplaced fracture
broken ends of bone remain in alignment
88
describe a complete fracture
bone is broken across entire length/width
89
describe an incomplete fracture
bone is not broken across entire length/width
90
describe a transverse fracture
bone broken perpendicular to axis
91
describe an oblique fracture
bone not broke perpendicular to axis
92
describe a spiral fracture
bone has twisted apart due to torsion stresses
93
describe a comminuted fracture
bone has splintered or been crushed into small fragments
| communes have many parts
94
describe a segmental fracture
fracture in more than one part of the bone (segments)
95
describe an avulsed fracture
fragment is separated from rest of bone, common at ends of long bones
96
describe an impacted fracture
bone fragments are driven together due to compression stresses
97
describe a torus/buckle fracture
break in spongy bone causes bulging from inflammation
98
describe a greenstick fracture
bone is broke on one side and other side is only bent
99
what do torus and greenstick fractures have in common?
they are incomplete fractures, commonly found in young animals
100
list the 4 phases of normal bone healing
1. hematoma formation
2. callus formation
3. callus ossification
4. bone remodeling
101
describe the hematoma formation step of normal bone healing
hematoma forms due to broken blood vessels, and blood accumulates around broke ends of bone, blood clots around bone
102
describe the callus formation step of normal bone healing
chondroblasts secrete cartilage (inner callus) and osteoblasts secrete bone (outer callus) around outside of break and between broken ends of bone, the cartilage/bone mixture forms a callus to hold broken ends of bone in place
103
does the callus form if a bone isn't in alignment? what does this mean?
yes, it forms whether the bone is in alignment or not, which is why we have to reset bones sometimes
104
describe the callus ossification step of normal bone healing
callus gets replaced with bone, similar to endochondral ossification
105
describe the bone remodeling step of normal bone healing
osteoblasts and osteoclasts secrete and breakdown bone to return it to its normal shape
106
how long does bone remodeling take and what factors affect it?
can take up to a year, and bone will still be slightly larger at break site, depends on blood supply, age, and damage to surrounding tissue
107
what is osteodistrophy?
any abnormality in bone development
108
give an example of osteodistrophy?
rickets (young animals)/osteomalacia (adults)
109
describe rickets/osteomalacia
inadequate mineralization of bone leads to softer bones, causing bow leggedness
110
what two things causes rickets/osteomalacia and which one is preventable?
hyperparathyroidism (nonpreventable) or a deficiency in vitamin D, P, or Ca (preventable)
111
what is osteoporosis?
porous bone, or loss of bone mass itself, causes brittle bones
112
what causes achondroplasia?
fusion of epiphyseal plates early in development means bone doesn't continue to grow in height, only in width, leading to short stubby legs
113
what animals are bred for achondroplasia?
dachsunds, mini cattle, mini cats
