Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Biology by me > Muscle, Bone, SKin > Flashcards

Muscle, Bone, SKin Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

H Zone

A

Only has myosin. The middle zone

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

M line

A

line going down the middle of the H zone

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

A Band

A

The thick band. Has both actin and myosin. A band includes the H zone. Covers most of the sarcomere in the middle

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

I band

A

only has actin. Thin band. Covers regions of two separate sarcomeres

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

What makes up a muscle? From the smallest unit to a muscle. What’s a muscle cell, also known as muscle fiber?

A

Myofibril –> sarcomeres wrapped around in sheet, sarcolemma covering it up. Several myofibrils wrapped by sarcolemma have multiple nuclei and mitochondria embedded between above, and around the bundle of myofibrils. This bundle make up a muscle cell (muscle fiber). Several muscle cells make up a muscle fascicle, which is a bundle of muscle cells. Muscle fascicles then make up a muscle.

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

Muscle fascicle

A

A bundle of muscle fibers which are bundles of muscle cells

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

relationship between T-tubule and sarcoplasmic reticulum

A

the action potential is transferred from T-tubule to the sarcoplasmic reticulum to contract the muscle

the ion channels get activated in the sarcolemma creating an action potential that travels down into the T-tubules then into the sarcoplasmic reticulum which releases the calcium ions

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

Physiology of skeletal muscle contraction. Describe the states of myosin when the ATP, and ADP+PI are on. What happens when ADP+PI is dislodged. What happens when the ATP is added on again?

A

myosin head is straight up with ADP+PI, its default mode. once tropomyosin exposes the binding site (calcium attached to troponin), the myosin head attaches to the actin binding site forming a cross bridge)`. The removal of ADP+PI causes the head to tilt, causing the contraction of the muscle.

Attachment of ATP to myosin dislodges the myosin from the actin. The head is still tilted. But catalysis of ATP to ADP+PI causes the head to tilt.

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

Muscle fatigue

A

running out of ATP, unable to generate a muscle contraction

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

Type I

Contraction time, force production, resistance to fatigue, activity

Aerobic or anaerobic

Where is it found?

A

Slow twitch

Red - lots of myoglobin

Contracts slowly, weak force production but resistant to fatigue; Force distributed over a long period of time

more efficient at using oxygen to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibers and can go for a long time before they fatigue - marathon and bicycle for a long time

Aerobic

postural muscles

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

Type II - A

Contraction time, force production, resistance to fatigue, activity, myoglobin content, where it’s found

Long or short term; Aerobic or anaerobic oxidation

A

AKA: Fast/Oxidative twitch

Appears Red (lots of myoglobin)

Upper Legs

fast contraction time, strong force, easy to fatigue

short term anaerobic activity, can be aerobic

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

Type II - B

Contraction time, force production, resistance to fatigue, activity, myoglobin content

A

AKA: glycolytic twitch - lots of glycogen

B - white (low myoglobin, lots of glycogen, appear white)

upper arms

Fast contraction time, really strong force, easy to fatigue,

long term anaerobic activity

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

Cardiac muscle -

Is it striated?

multi or single nucleus

what is intercalated discs in cardiac muscle

A

Striated (has sarcomeres)

single nucleated

intercalated dics - has gap junctions that allow an easy electrical flow between the cells through the synapse, easy synchronization of the contraction of the cardiac muscle cells - make the cell function like a net that contracts upon it self like squeezing a fist

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

Why is the repolarization time much longer in the heart? What is the importance of calcium in the heart contraction?

A

Calcium lingers much longer inside the cell - slow voltage gated calcium channels

It lengthens the time of the contraction - preventing a new action potential from starting in the middle of the previous contraction. This prevent tetanus that happens in the skeletal muscles which can be deadly in the heart

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

Smooth muscle - striation, nucleation, structure

How does the smooth muscle contract?

A

No striation (no sarcomeres)

single nucleus

organized into dense bodies. contain intermediate filaments (like actin) which are attached to dense bodies distributed throughout the cell (network of highways). Upon contraction, this dense network system causes the smooth muscle cell to contract and shrink

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

How are the single units of smooth muscle cells connected?

A

connected by gap junctions

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

Osteoblast and osteocyte

Can they both multiply?

A

osteocyte is an osteoblast trapped in lacunae that communicate via canaliculi - differentiated version of osteoblast.

both can’t multiply

osteoblast secrete collagen (matrix - network it surrounds itself in).

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

Differentiation of osteoblast

A

osteocyte

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

Function of osteocyte

A

exchanges nutrients and waste with the blood. Osteoblast and osteocyte both can’t multiply. Specialized in mediating input and output

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

Osteoclast are thought to have developed from what?

A

WBC - monocytes

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

Epiphyseal plate

A

sheet of hyaline cartilage between metaphysis and epiphysis in the long bone

grows in response to growth hormone in childhood and adolescence

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

long shaft of bone

A

diaphysis

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

Spongy bone vs. compact bone

A

Spongy bone (trabecular bone) - contain red bone marrow; RBC formation and storage

Compact bone (cortical bone) - surrounds the hollow cavity called the medullary cavity, contain yellow bone marrow; adipose cells for fat storage

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

Remodeling in the bone

A

formation of osteon by osteoclast and osteoblast

osteoclast tunnels and makes way, osteoblast then adds on the matrix on the tunnel wall, making concentric rings called the lamellae. Osteoblasts leave open space in the center of lamellae to for Haversian canals which include blood and lymph nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Calcium solubility in blood

A

only slightly soluble in blood - not found in free forms in the blood

usually bound to phosphates, and other anions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Joint

A

where bones connect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Fibrous joint

A

two bones held closely and tightly together by fibrous connective tissues.

Extremely minimal movement; teeth connected to the mandible, skull bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Cartilaginous joints

A

two bones tightly connected by the cartilage such as the ribs and sternum.

allow little movement

29
Q

Synovial joints

What is it?
Range of movement
What is significant about synovial fluid? Function?

A

not directly bound b the intervening cartilage

wide range of movement is possible; shoulder and knee

two bones are separated by a capsule filled with synovial fluid that provide nourishment and lubrication to the cartilage. The synovial fluid contains phagocytic cells that remove microbes and particles.

30
Q

90% of epidermis is composed of _______

A

keratinocytes

31
Q

Keratinocytes

where is it

A

cells that produce keratin

epidermis

32
Q

Melanocytes

where is it

A

transfer melanin to keratinocytes

epidermis

33
Q

Langerhans cells

where is it

A

interact with the helper T cells of the immune system

epidermis

34
Q

Merkel cells

where is it

A

attach to the sensory neurons and function in the sensation of touch

epidermis

35
Q

The deepest layer of the epidermis contain _____ and _____ cells

A

Merkel cells, and stem cells

36
Q

tendon

A

muscle to bone

37
Q

ligament

A

bone to bone

38
Q

the origin of the muscle

which part of the muscle, where it attaches to, and the breadth of movement, and how close it is to the midpoint of the body

A

point on the muscle that attaches to a larger bone and remains relatively stationary

closest to the midpoint of the body

39
Q

the insertion of the muscle

where it is on the muscle, where it attaches to, how close it is to the midpoint

A

farthest from the origin

attached to small bones and farthest from the midpoint of the body

40
Q

how do synergistic muscles help the agonist muscles

A

help the agonist muscle by stabilizing the origin or by positioning the insertion bone during the movement

41
Q

The shivering reflex:

what muscle does it contract?
what is the purpose?
and how does it affect the body?

A

the shivering reflex affects the skeletal muscles. it is controlled by the hypothalamus upon stimulation from the skin and spinal cord

it happens because there is glycogen storage in the skeletal muscles so the body tries to release the energy so that it can provide heat for the body

42
Q

is there mitochondria and nucleus within the muscle fibril/muscle cell?

A

nope but around it between the muscle fibrils

43
Q

levels of organization of the muscle

A

from smallest to biggest

bundles within bundles within bundles

muscle cell/muscle fibril –> fiber –> fascicle

44
Q

distinction of heart’s mitochondria

A

large and ample for production of ATP

45
Q

functionality of the slow repolarization of the heart muscle

A

it gives the heart enough time to refill with blood and prevents tetanus, the sustained contraction that can occur in skeletal muscle that could be deadly if it occurred in the heart

46
Q

where do intercalated discs occur

A

in the Z line - desmosomes and gap junctions forming a fused mass of cells

47
Q

What’s responsible for the plateau after depolarization? and what is the charge inside the membrane?

what is the purpose of slower rate of repolarization of the cardiac muscle?

A

slow voltage-gated calcium channels which allow calcium to enter and maintain the inside of the membrane at a positive potential difference

as a result, the repolarization of the cardiac muscle is slower and more frequent than that of skeletal muscle

The action potentials of cardiac muscle are unusually sustained. This prevents premature relaxation, maintaining initial contraction until the entire myocardium has had time to depolarize and contract

48
Q

are smooth muscles organized into sarcomeres?

A

nope

49
Q

what are dense bodies in the smooth muscle cells

A

dense bodies function as Z lines in the skeletal muscle containing actinin and Z-line proteins

the intermediate filaments are attached to the dense bodies, being organized into a network

50
Q

single unit vs. multi-unit of smooth muscle

A

depends on the attachment of autonomic neuron to the smooth muscle cells.

in a single unit, autonomic neuron attaches to a single mass of smooth muscle cells connected by gap junctions so that electrical activity travels down fast

in multi unit, each muscle cell is attached to one or more than one neuron. each fiber is attached directly to a neuron so each group of multi-unit smooth muscle fibers can contract independently of other

51
Q

where are single unit smooth muscles found?

where are the multi unit smooth muscles found?

A

single unit - small arteries, veins, stomach, intestines, uterus, urinary bladder

multi unit - large arteries, bronchioles, pili muscle attached to hair follicles and the iris

52
Q

what is the dermis of the skin

what does it contain

A

connective tissue derived from mesodermal cells

blood vessels, nerves, glands, and hair follicles, collagen and elastin fibers

sensation of touch: pressure, pain, temperature

53
Q

what is in the subcutaneous layer?

A

fat functioning as a heat insulator for the body

some nerve endings reaching deep down into the fat layer

54
Q

in the epidermis:

what is in the corneum, granulosum, spinosum, and basale

A

corneum: keratinized cells
granulosum: granular cells
spinosum: spinous cells

55
Q

what is cartilage mainly consisted of

what happens if cartilage is worn out and bones grind against each other

A

collagen

osteoarthritis

56
Q

what is a hyaline cartilage?

A

it’s the most common type of cartilage that reduces friction and absorbs shock in joints

57
Q

fibrous joints

A

two bones held closely and tightly together by a fibrous connective tissue permitting minimal movement

teeth with the mandible

after early childhood, skull bones form fibrous joints with each other, strengthening and hardening the skull

58
Q

cartilaginous joints

A

little movement

bones connected by cartilage

ribs and sternum

59
Q

synovial joints

A

not bound directly by intervening cartilage so a wide range of movement is possible

separated by a capsule called synovial fluids - lubrication and nourishment to the cartilage, contain phagocytotic cells that remove microbes and particles

shoulder and knee

between femur and tibia

60
Q

types of joints

A

differ by the range of movement

what’s holding the two bones together

61
Q

what do osteoblasts secrete

are they capable of mitosis

when they trap themselves with the matrix material they release, what do they differentiate to

A

secrete collagen and organic compounds upon which the bone is formed

incapable of mitosis

trap themselves and become osteocytes

62
Q

what do osteocytes do

do they mutilply by mitosis?

A

exchange nutrients and waste materials with the blood. ex. release Ca2+ in response to PTH

cannot under mitosis - can’t multiply to replace more cells

63
Q

how do osteoclasts develop

A

develop from monocytes

64
Q

What is the myofibrils wrapped in

A

Sarcoplasmic reticulum

65
Q

Myofibril is wrapped in what layers?

A

Sarcoplasmic reticulum and sarcolemma

66
Q

Type 1 muscle

A

Red muscle, less powerful; slower of contract

In the calf

Slower to control and slower to fatigue; marathon

67
Q

Type 2 muscle

A

White, biceps

Faster to contract and faster to fatigue

68
Q

Are cardiac muscles striated?

Describe cardiac muscles

A

Yes

Involuntary, intercalated discs, only one nucleus, not attached to a bone.

They are connected via intercalated discs which has gap junctions between them.

69
Q

Smooth muscle

A

Dense bodies

Actin filaments radiate from dense bodies

One nucleus; NOT striated

MCAT Biology by me (16 decks)

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