Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCAT > Biology: Chapter 11 > Flashcards

Biology: Chapter 11 Flashcards

1
Q

Types of muscle

A

skeletal, cardiac, smooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Skeletal muscle

A

-Responsible for voluntary movement, is innervated by the somatic nervous system, and is multinucleated
-Appears striped or striated due to arrangement of actin and myosin into repeating units called sarcomeres
-slow-twitch fibers and fast-twitch fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Red fibers/slow-twitch fibers

A

-high myoglobin and primarily derive their energy aerobically
-Carry many mitochondria to carry out oxidative phosphorylation
-Muscles that contract slowly but sustain activity contain a predominance of these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

White fibers/fast-twitch fibers

A

-contain less myoglobin and are lighter in color because there is less iron
-Muscles that contract rapidly, but fatigue quickly contain mostly these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Myoglobin

A

oxygen carrier that uses iron in a heme group to bind oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Smooth muscle

A

-Responsible for involuntary action, controlled by the autonomic nervous system, and have a single nucleus
-Contain actin and myosin, but fibers aren’t as well organized and striations cannot be seen
-Capable of more sustained contractions contained to skeletal muscle
-Can contract without nervous system input in what is known as myogenic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tonus (smooth muscle)

A

a constant state of low-level contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cardiac muscle

A

-Primarily uninucleated (can have two nuclei), contract involuntarily, and innervated by the autonomic nervous system
-Appears striated
-Cardiac muscle cells are connected by intercalated discs, which contain gap junctions. Gap junctions allow for the flow of ions directly between cells which allows for rapid and coordinated depolarization of muscle cells and efficient contraction of cardiac muscle
-Able to define and maintain their own rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Sarcomere

A

-Basic contractile unit of skeletal muscle
-Made of thick and thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thick filaments (sarcomere)

A

organized bundles of myosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Thin filaments (sarcomere)

A

made of actin along with troponin and tropomyosin. Troponin and tropomyosin help to regulate the interaction between actin and myosin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Titin (sarcomere)

A

acts as a spring and anchors actin and myosin filaments together, preventing excessive stretching of the muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Z-line (sarcomere)

A

define the boundaries of each sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

M-line (sarcomere)

A

runs down the center of the sarcomere, through the middle of the myosin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

I-band (sarcomere)

A

region containing exclusively thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

H-zone (sarcomere)

A

contains only thick filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A-band (sarcomere)

A

contains thick filaments in their entirety, including any overlap with thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

A sarcomere during contraction

A

the H-zone, I-band, the distance between Z-lines and the distance between M-lines all become smaller while the A-band’s size remains the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Myofibrils

A

sarcomeres that are attached end to end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Sarcoplasmic reticulum

A

-surround myofibrils
-specialized endoplasmic reticulum that contains a high concentration of Ca2+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Sarcolemma

A

-the cell membrane of a myocyte
-The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle through using transverse tubules (T-tubules)
-T-tubules are oriented perpendicularly to the myofibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Myocyte

A

-muscle cell
-each myocyte contains many myofibrils arranged in parallel and can also be called a muscle fiber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Muscle

A

many myocytes in parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Simple twitch

A

-response of a single muscle fiber to a brief stimulus at or above threshold
-consists of a latent period, contraction period, and relaxation period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Latent period (simple twitch)
-time between reaching threshold and the onset of contraction -it is during this time that the action potential spreads along the muscle and allows for calcium to be released from SR
26
Frequency summation
-if a muscle fiber is exposed to a frequent and prolonged stimulation and has insufficient time to relax -This causes the contractions to combine, become stronger and more prolonged
27
Tetanus
-if the contractions become so frequent that the muscle is unable to relax at all -Prolonged tetanus will result in muscle fatigue
28
2 Supplemental energy reserves in muscle
-Creatine phosphate: created by transferring a phosphate group from ATP to creatine during times of rest. This reaction can then be reversed during muscle use to quickly generate ATP from ADP -Muscle contains myoglobin which binds to oxygen with high affinity. As exercising muscles run out of oxygen, they use myoglobin reserves to keep aerobic metabolism going
29
Slow-twitch fibers (ATP
-have high levels of mitochondria and use oxidative phosphorylation to make ATP -High concentrations of oxygen are required to generate the large amounts of ATP muscle cells need
30
Fast-twitch fibers (ATP)
have fewer mitochondria and must rely on glycolysis and fermentation to make ATP under most circumstances
31
Oxygen debt
the difference between the amount of oxygen needed by the muscles and the actual amount present
32
Axial skeleton
consists of skull, vertebral column, rib cage, and hyoid bone; provides basic central framework for the body
33
Appendicular skeleton
consists of bones of the limbs, the pectoral girdle, and pelvis
34
Compact bone
hard outer portion of bone that gives it strength
35
Spongy/Cancellous bone
-internal core of bone -trabeculae -bone marrow
36
Trabeculae
bony spicules (points) that make up lattice structure of spongy bone
37
Bone marrow
-fill the cavities of trabeculae -Red marrow: filled with hematopoietic stem cells which are responsible for the generation of all cells in our blood -Yellow marrow: composed primarily of fat and is relatively inactive
38
Diaphysis (long bone)
cylindrical shafts of long bones
39
Metaphysis (long bone)
swell at the end of each diaphyses and terminate in epiphyses
40
Epiphysis (long bone)
-the end part of a long bone -initially growing separately from the shaft
41
Epiphyseal plate
-cartilaginous structure and the site of longitudinal growth -Prior to adulthood, this is filled with mitotic cells that contribute to growth -During puberty, these close and vertical growth is halted
42
Periosteum
A fibrous sheath that surrounds the long bone to protect it as well as serve as a site for muscle attachment
43
Tendons
attach muscle to bone
44
Ligaments
hold bones together at joints
45
Bone matrix
-where the strength of bone comes from -Has both organic and inorganic components
46
Organic components of bone matrix
collagen, glycoproteins, and other peptides
47
Inorganic components of bone matrix
calcium, phosphate, hydroxide ions
48
Osteons/Haversian systems
structural units of the bony matrix
49
Lamellae (osteons)
concentric circles of bony matrix that each osteon contains
50
Haversian canals (osteons)
-longitudinal channels -contain blood vessels, nerve fibers, and lymph vessels
51
Volkmann's canals (osteons)
-transverse channels -contain blood vessels, nerve fibers, and lymph vessels
52
Lacunae
small spaces between lamellar rings that house mature bone cells known as osteocytes
53
Canaliculi
tiny channels that interconnect lacunae and allow for the exchange of nutrients and wastes between osteocytes and the Haversian and Volkmann’s canals
54
Osteoblasts
build bone
55
Osteoclasts
resorb or break bone down
56
Parathyroid hormone (bone formation)
promotes resorption of bone, increasing the concentration of calcium and phosphate in the blood
57
Calcitonin
released in response to high blood calcium and promotes bone formation, lowering blood calcium levels
58
Cartilage
-Softer and more flexible than bone -Consists of a firm but elastic matrix called chondrin which is secreted by chondrocytes -Differs from bone by being avascular (without blood and lymphatic vessels) and is not innervated
59
Endochondral ossification
-creation of bone through the hardening of cartilage -how a majority of long bones in the body are created
60
Intermembranous ossification
undifferentiated embryonic connective tissue is transformed into, and replaced by, bone; occurs in bones of the skull
61
Immovable joints
consist of bones that are fused together to form sutures; found primarily in the head
62
Movable joints
-permit bones to shift relative to one another -Strengthened by ligaments which are pieces of fibrous tissue that connect bone to one another -Synovial capsule: encloses the actual joint cavity -Synovium: layer of soft tissue that secretes synovial fluid -Synovial fluid: lubricates the movement of structures in the joint space -Articular cartilage: contributes to the joint by coating the articular surfaces of the bones so that impact is restricted to the lubricated joint cartilage, rather than the bones

MCAT (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions