Chapter 11: The Musculoskeletal System Flashcards
(121 cards)
1
Q
Muscle can be divided into the three different subtypes: ___________ muscle, __________ muscle, and ____________ muscle.
A
- Skeletal muuscle
- Smooth muscle
- Cardiac muscle
2
Q
All muscle is capable of contraction, which relies on _____________ ions.
A
Calcium ions
3
Q
_____________ muscle is responsible for voluntary movement and is therefore innervated by the somatic nervous system.
A
Skeletal muscle
4
Q
Due to the arrangement of actin and myosin into repeating units called _____________, it appears striped or striated when viewed microscopically.
A
Sarcomeres
5
Q
Does skeletal muscle have one, two or multi nuclei?
A
Skeletal muscle is multinucleated.
6
Q
______________, also known as ______________, have high myoglobin content and primarily derive their energy aerobically.
A
- Red fibers
- Slow-twitch fibers
7
Q
______________ is an oxygen carrier that uses iron in a heme group to bind oxygen, imparting a red colour.
A
Myoglobin
8
Q
______________, also known as _______________, contain much less myoglobin. Because there is less myoglobin, and therefore less iron, the colour is lighter.
A
- White fibers
- Fast-twitching fibers
9
Q
Muscles that contract slowly, but that can sustain activity (such as the muscles that support posture), contain a predominance of ___________ fibers.
A
Red fibers
10
Q
Muscles that contract rapidly, but fatigue quickly, contain mostly ___________ fibers.
A
White fibers
11
Q
________________ is responsible for involuntary action. It is controlled by the autonomic nervous system. Their cells have a single nucleus located in the centre of the cell.
A
Smooth muscle
12
Q
______________ cells contain actin and myosin, but the fibers are not as well-organized, so striations cannot be seen.
A
Smooth muscle
13
Q
Compared to skeletal muscle, smooth muscle is capable of more sustained contractions; a constant state of low-level contraction, as may be seen in the blood vessels, is called ____________.
A
Tonus
14
Q
Smooth muscle can actually contract without nervous system input in what is known as __________________. The muscle cells contract directly in response to stretch or other stimuli.
A
Myogenic activity
15
Q
______________ is primarily uninucleate, but cells may contain two nuclei. Its contraction is involuntary and innervated by the autonomic nervous system. It appears striated like skeletal.
A
Cardiac muscle
16
Q
Cardiac muscle cells are connected by _________________, which contains many gap junction.
A
Intercalated discs
17
Q
Cardiac muscles are able to define and maintain their own rhythm, termed ________________.
A
Myogenic activity
18
Q
The _____________ provides parasympathetic outflow to the heart and slows the heart rate.
A
Vagus nerve
19
Q
________________ from sympathetic neurons or ________________ from the adrenal medulla binds to adrenergic receptors in the heart, causing an increased heart rate and greater contractility.
A
- Norepinephrine
- Epinephrine
20
Q
The _____________ is the basic contractile unit of skeletal muscle.
A
Sarcomere
21
Q
____________ acts as a spring and anchors the actin and myosin together, preventing excessive stretching of the muscle.
A
Titin
22
Q
____________ define the boundaries of each sarcomere.
A
Z-lines
23
Q
The ___________ runs down the centre of the sarcomere, through the middle of the myosin filaments.
A
M-line
24
Q
The ___________ is the region containing exclusively thin filaments.
A
I-band
25
The ___________ contains only thick filaments.
H-zone
26
The ___________ contains the thick filaments in their entirety, including any overlap with thin filaments.
A-band
27
Sarcomeres are attached end to end to form ________________.
Myofibrils
28
Myofibrils are surrounded by a covering known as the ___________________ (_____), a modified endoplasmic reticulum that contains a high concentration of Ca2+ ions.
Sarcoplasmic reticulum (SR)
29
The ______________ is a modified cytoplasm located just outside of the sarcoplasmic reticulum.
Sarcoplasm
30
The cell membrane of a myocyte is known as the _____________.
Sarcolemma
31
The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle using a system of _________________ (__________) that are oriented perpendicularly to the myofibrils.
Transverse tubules (T-tubules)
32
Each myocyte, or muscle cell, contains many myofibrils arranged in parallel and can also be called a ______________.
Muscle fiber
33
Many myocytes in parallel form a __________.
Muscle
34
Muscle contraction starts at the _________________, where the nervous system communicates with muscles via motor (efferent) neurons.
Neuromuscular junction
35
The signal from neuromuscular junction travels down the neuron until it reaches the ________________ (______________), where acetylcholine is released into the synapse.
Nerve terminal (synaptic bouton)
36
In the case of the neuromuscular junction, the nerve terminal can also be called the _______________.
Motor end plate
37
Acetylcholine binds to receptors on the sarcolemma, causing ______________.
Depolarization
38
Each nerve terminal controls a group of myocytes; together, the nerve terminal and its myocytes constitute a ______________.
Motor unit
39
Calcium ion binds to ____________, leading to a conformational change in ____________, which exposes the myosin-binding sites of actin.
- Troponin
- Tropomyosin
40
Actin-Myosin Cross-Bridge Cycle (1)
Myosin carrying hydrolyzed ATP (ADP and an inorganic phosphate, Pi) is able to bind with the __________________.
Myosin-binding site
41
Actin-Myosin Cross-Bridge Cycle (2)
The release of the inorganic phosphate and ADP in rapid succession provides the energy for the ______________ and results in sliding of the actin filament over the myosin filament.
Powerstroke
42
Actin-Myosin Cross-Bridge Cycle (3)
ATP binds to the myosin head, releasing it from actin. This ATP is hydrolyzed to ADP and Pi, which ___________ the myosin head so that it is in position to initiate another cross-bridge cycle.
Recocks
43
The repetitive binding and releasing of myosin heads on actin filaments allows the thin filament to slide along the thick filament, causing sequential shortening of the sarcomere. This is known as the _____________________.
Sliding filament mode
44
When a sarcomere contracts, both the H-zone and I-band shorten, while the ______________ is unchanged.
A-band
45
It is the dissociation of ADP and Pi from myosin that is responsible for the ______________, not the hydrolysis of ATP. The binding of ATP is required for releasing the myosin head from the actin filament.
Powerstroke
46
Acetylcholine is degraded in the synapse by the enzyme known as __________________.
Acetylcholinesterase
47
The _______________ takes up calcium from sarcoplasm. It tightly controls intracellular calcium concentrations so that muscles are contracted only when necessary.
Sarcoplasmic reticulum
48
A _______________ is the response of a single muscle fiber to a brief stimulus at or above threshold.
Simple twitch
49
A simple twitch consists of a ____________ period, _____________ period, and ______________ period.
- Latent
- Contraction
- Relaxation
50
The ________________ is the time between reaching threshold and the onset of contraction.
Latent period
51
During _________________, the action potential spreads along the muscle and allows for calcium to be released from the sarcoplasmic reticulum.
Latent period
52
The _____________ happens when calcium is cleared from the sarcoplasm, the muscle is therefore relaxed.
Relaxation period
53
If a muscle fiber is exposed to frequent and prolonged stimulation, it will have insufficient time to relax. The contractions will combine, become stronger and more prolonged. This is known as ___________________.
Frequency summation
54
If the muscle contractions become so frequent (frequency summation) that the muscle is unable to relax at all, this is known as ____________.
Tetanus
55
______________ is created by transferring a phosphate group from ATP to creatine during times of rest.
Creatine phosphate
56
The difference between the amount of oxygen needed by the muscles and the actual amount present is called the ______________.
Oxygen debt
57
There are two types of skeletons: _____________ and ______________.
- Exoskeleton
- Endoskeleton
58
______________ encase whole organisms and are usually found in arthropods, such as crustaceans and insects.
Exoskeleton
59
Vertebrates, including humans, have _____________. These are internal, but are not able to protect the soft tissue structures as well as exoskeleton.
Endoskeleton
60
_______________ are much better able to accommodate the growth of a larger organism.
Endoskeleton
61
_______________ must be shed and regrown to accommodate growth.
Exoskeletons
62
The components of our skeletal system are divided into ___________ and ___________ skeletons.
- Axial skeleton
- Appendicular skeleton
63
The ______________ consists of the skull, vertebral column, rib cage, and hyoid bone (a small bone in the anterior neck used for swallowing); it provides the basic central framework for the body.
Axial skeleton
64
The _________________ consists of the bones of the limbs (humerus, radius, ulna, carpals, metacarpals, and phalanges in the upper limb; and femur, tibia and fibula, tarsals, metatarsals, and phalanges in the lower limb); the pectoral girdle (scapula and clavicle); and pelvis.
Appendicular skeleton
65
The skeleton is created from two major components: ____________ and ____________.
- Bone
- Cartilage
66
_____________ is a connective tissue derived from embryonic mesoderm.
Bone
67
Bone's characteristic strength comes specifically from _____________.
Compact bone
68
The other type of bone structure is ____________ or _______________ bone.
- Spongy
- Cancellous
69
The lattice structure of spongy bone is visible under microscopy and consists of bony spicules (points) known as _____________.
Trabeculae
70
The cavities between trabeculae are filled with _______________, which may be either red or yellow.
Bone marrow
71
_______________ is filled with hematopoietic stem cells, which are responsible for the generation of all the cells in our blood.
Red marrow
72
_____________ is composed primarily of fat and is relatively inactive.
Yellow marrow
73
Bones in the appendicular skeleton are typically _______________.
Long bones
74
Long bones in the appendicular skeleton are characterized by cylindrical shafts called _____________ that swell at each end to form _____________, and that terminate at _____________.
- Diaphyses
- Metaphyses
- Epiphyses
75
The outermost portions of bone are composed of ____________ bone, whereas the internal core is made of ____________ bone.
- Compact bone
- Spongy bone
76
Long bone diaphyses and metaphases are full of ______________.
Bone marrow
77
At the internal edge of epiphysis is an _____________ (__________) __________, which is a cartilaginous structure and the site of longitudinal growth.
Epiphyseal (growth) plate
78
A fibrous sheath called the ______________ surrounds the long bone to protect it as well as serve as a site for muscle attachment.
Periosteum
79
Some _____________ cells are capable of differentiating into bone-forming cells; a healthy ______________ is necessary for bone growth and repair.
- Periosteal cells
- Periosteum
80
_____________ attach muscle to bone.
Tendons
81
______________ hold bones together at joints.
Ligaments
82
The strength of compact bone comes from the ______________, which has both organic and inorganic components.
Bone matrix
83
The inorganic components in bone matrix include calcium, phosphate, and hydroxide ions, which harden together to form _________________ crystals.
Hydroxyapatite crystals
84
The bony matrix is ordered into structural units known as ___________ or ________________.
- Osteons
- Haversian systems
85
Each of the osteon contains concentric circles of bony matrix called ____________ surrounding a central microscopic channel.
Lamellae
86
Longitudinal channels (those with an axis parallel to the bone) are known as _________________.
Haversian canals
87
Transverse channels (those with an axis perpendicular to the bone) are known as ________________.
Volkmann's canals
88
Between the lamellar rings are small spaces called ______________.
Lacunae
89
The lacunae house mature bone cells known as _____________.
Osteocytes
90
The lacunae are interconnected by tiny channels called ______________ that allow for the exchange of nutrients and wastes between osteocytes and the Haversian and Volkmann's canals.
Canaliculi
91
Two cell types are largely responsible for building and maintaining strong bones: ______________ and ______________.
- Osteoblasts
- Osteoclasts
92
______________ are the polynucleated resident macrophages of bone, resorb bone.
Osteoclasts
93
____________ build bone.
Osteoblasts
94
____________, a peptide hormone released by the parathyroid glands in response to low blood calcium, promotes resorption of bone, increasing the concentration of calcium and phosphate in the blood.
Parathyroid hormone
95
____________, which is activated by parathyroid hormone, promotes the resorption of bone.
Vitamin D
96
_____________, a peptide hormone released by the parafollicular cells of the thyroid in response to high blood calcium, promotes bone formation, lowering blood calcium levels.
Calcitonin
97
____________ is softer and more flexible than bone.
Cartilage
98
Cartilage consists of a firm but elastic matrix called _______________.
Chondrin
99
Chondrin is secreted by cells called __________________.
Chondrocytes
100
Cartilage differs from bone in that it is ______________ (without blood and lymphatic vessels) and is not innervated.
Avascular
101
Most of the bones of the body are created by the hardening of cartilage into bone. This process is known as ____________________ and is responsible for the formation of most of the long bones of the body.
Endochondral ossification
102
Bones may be formed through ____________________, in which undifferentiated embryonic connective tissue is transformed into, and replaced by, bone. This occurs in bones of the skull.
Intramembranous ossification
103
Undifferentiated embryonic connective tissue is also called _______________.
Mesenchymal tissue
104
Like bone and cartilage, joints are made of connective tissue and come in two major varieties: _______________ and ______________.
- Immovable
- Moveable
105
______________ consist of bones that are fused together to form sutures or similar fibrous joints. These joints are found primarily in the head, where they anchor bones of the skull together.
Immovable joints
106
_______________, include hinge joints (like the elbow or knee), ball-and-socket joints (like the shoulder or hip), and others. They permit bones to shift relative to one another.
Movable joints
107
Movable joints are strengthened by _____________, which are pieces oof fibrous tissue that connect bones to one another.
Ligaments
108
Movable joints consist of a ________________, which encloses the actual joint cavity.
Synovial capsule
109
Joint cavity is also called _________________.
Articular cavity
110
A layer of soft tissue called the ______________ secretes synovial fluid, which lubricates the movement of structures in the joint space.
Synovium
111
The _______________ contributes to the joint by coating the articular surfaces of the bones so that impact is restricted to the lubricated joint cartilage, rather than to the bones.
Articular cartilage
112
The end of the muscle with a larger attachment to bone (usually the proximal connection) is called the ____________.
Origin
113
The end with the smaller attachment to bone (usually the distal connection) is called the _____________.
Insertion
114
Often, our muscles work in ________________; one relaxes while the other contracts. Such is the case in the arm, where the biceps brachia and triceps brachia work antagonistically.
Antagonistic pairs
115
Muscle can be _______________ - working together to accomplish the same function.
Synergistic
116
A _____________ muscle decreases the angle across a joint (like the biceps brachii).
Flexor
117
An ____________ increases or straightens the angle across a joint (like the triceps brachii).
Extensor
118
An ______________ moves a part of the body away from the midline (like the deltoid).
Abductor
119
An _____________ moves a part of the body toward the midline (like the pectoralis major).
Adductor
120
A _________________ rotates the axis of the limb toward the midline (like the subscapularis).
Medial rotator
121
A _______________ rotates the axis of the limb away from the midline (like the infraspinatus).
Lateral rotator
