exam4
1
What structures make up the skeletal system?
Bones, cartilage, ligaments, and connective tissues.
2
How many bones are in the adult human body?
206.
3
What are the 5 primary functions of the skeletal system?
Support, storage, blood cell production, protection, leverage.
4
What minerals are stored in bone?
Calcium and phosphorus.
5
Where does hematopoiesis occur?
Red bone marrow.
6
What are long bones?
Bones longer than they are wide.
7
What are short bones?
Box-shaped bones.
8
What are flat bones?
Thin flattened bones.
9
What are irregular bones?
Bones with complex shapes.
10
What are sesamoid bones?
Bones formed within tendons.
11
What is compact bone?
Dense solid bone.
12
What is spongy bone?
Bone made of trabeculae with open spaces.
13
What is an osteon?
Functional unit of compact bone.
14
What are trabeculae?
Branching columns of spongy bone.
15
What do osteoblasts do?
Build bone.
16
What do osteoclasts do?
Break down bone.
17
What do osteocytes do?
Maintain bone matrix.
18
What are osteogenic cells?
Stem cells that produce osteoblasts.
19
What is ossification?
Bone formation.
20
What is endochondral ossification?
Cartilage replaced by bone.
21
What is intramembranous ossification?
Mesenchyme replaced by bone.
22
What is interstitial growth?
Growth in length.
23
What is appositional growth?
Growth in width.
24
What is the epiphyseal plate?
Growth plate.
25
What hormone raises blood calcium?
Parathyroid hormone (PTH).
26
What hormone lowers blood calcium?
Calcitonin.
27
What is bone remodeling?
Continuous replacement of bone matrix.
28
What is a greenstick fracture?
Partial break common in children.
29
What is a spiral fracture?
Fracture caused by twisting.
30
What is a comminuted fracture?
Bone shattered into fragments.
31
What is a compression fracture?
Crushed bone, common in vertebrae.
32
What are the 3 types of muscle tissue?
Skeletal, cardiac, and smooth muscle.
33
Which muscle tissue is voluntary?
Skeletal muscle.
34
What are the 4 properties of muscle tissue?
Excitability, contractility, extensibility, elasticity.
35
What is excitability?
Ability to respond to stimuli.
36
What is contractility?
Ability to shorten.
37
What is extensibility?
Ability to stretch.
38
What is elasticity?
Ability to recoil after stretching.
39
What does the epimysium surround?
Entire muscle.
40
What does the perimysium surround?
Fascicles.
41
What does the endomysium surround?
Individual muscle fibers.
42
What is a fascicle?
Bundle of muscle fibers.
43
What is a tendon?
Bundle of connective tissue attaching muscle to bone.
44
What is an aponeurosis?
Sheet of connective tissue attaching muscle to bone.
45
What is the neuromuscular junction?
Connection between motor neuron and muscle fiber.
46
What is the sarcolemma?
Plasma membrane of muscle fiber.
47
What is the sarcoplasm?
Cytoplasm of muscle fiber.
48
What is the sarcoplasmic reticulum?
Stores calcium.
49
What is a T-tubule?
Carries depolarization deep into muscle fiber.
50
What is a triad?
2 terminal cisternae and 1 T-tubule.
51
What is a sarcomere?
Contractile unit from Z disc to Z disc.
52
What is the thin filament?
Actin.
53
What is the thick filament?
Myosin.
54
What is the Z disc?
End of sarcomere.
55
What is the M line?
Middle of sarcomere.
56
What is the A band?
Contains actin and myosin.
57
What is the I band?
Contains only actin.
58
What is the H zone?
Center region with little or no overlap.
59
What happens to the I band during contraction?
It shortens.
60
What happens to the H zone during contraction?
It shortens.
61
What happens to the A band during contraction?
It stays the same size.
62
What is the sliding filament theory?
Actin slides toward the M line causing shortening.
63
What does troponin bind to?
Calcium.
64
What does tropomyosin do?
Blocks active sites on actin.
65
What happens when calcium binds troponin?
Tropomyosin moves and exposes active sites.
66
What is the first step of the cross bridge cycle?
Cross bridge formation.
67
What happens during the power stroke?
Myosin head pivots toward M line.
68
What causes detachment in the cross bridge cycle?
ATP binding.
69
What happens during reactivation?
ATP is hydrolyzed and myosin recocks.
70
What neurotransmitter is released at the NMJ?
Acetylcholine (ACh).
71
What ion enters the axon terminal first?
Calcium.
72
What ion enters the muscle fiber after ACh binds receptors?
Sodium.
73
What does the sarcoplasmic reticulum release during contraction?
Calcium.
74
What enzyme breaks down acetylcholine?
Acetylcholinesterase.
75
Why does rigor mortis occur?
No ATP available for detachment.
76
What is treppe?
Stair-step increase in tension.
77
What is wave summation?
Stronger contraction before full relaxation.
78
What is incomplete tetanus?
Repeated contractions with slight relaxation.
79
What is complete tetanus?
Sustained maximum contraction.
80
What happens to the sarcomere during contraction?
It shortens.
81
What happens to actin during contraction?
It slides toward the M line.
82
What happens if ATP is unavailable during contraction?
Myosin cannot detach from actin.
83
What happens when acetylcholine binds receptors on the motor end plate?
Sodium enters the muscle fiber causing depolarization.
84
What happens during depolarization of the sarcolemma?
The sarcoplasmic reticulum releases calcium.
85
Why is the A band unchanged during contraction?
The thick filament length does not change.
86
What is the difference between compact and spongy bone?
Compact bone contains osteons; spongy bone contains trabeculae.
87
What is the difference between osteoblasts and osteoclasts?
Osteoblasts build bone; osteoclasts break down bone.
88
What is the difference between endochondral and intramembranous ossification?
Endochondral replaces cartilage; intramembranous replaces mesenchyme.