Muscular System Flashcards

1
Q

What are the important functions of the muscular system?

A

Mobility, posture, and movement

The muscular system is essential for voluntary and involuntary movements.

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

What types of muscles are involved in voluntary movements?

A

Skeletal muscles

Skeletal muscles are attached to bones and facilitate body movements.

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

What type of muscle is under autonomic control and is involuntary?

A

Cardiac muscle and smooth muscle

These muscles function without conscious control.

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

What response occurs when thermoreceptors detect a drop in temperature?

A

The shivering reflex

This reflex involves smooth muscle contractions to generate heat.

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

What is the role of valves in the peripheral veins?

A

Prevent backflow of blood

They ensure unidirectional blood flow toward the heart.

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

What effect does muscle contraction have on blood flow?

A

Increases blood flow toward the heart

Muscle contraction compresses veins, enhancing blood return.

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

What is the shape and nucleus count of a skeletal muscle myocyte?

A

Cylinder-shaped and has many nuclei

This structure contributes to the muscle’s striated appearance.

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

Where is smooth muscle tissue found?

A

Walls of hollow organs and vessels

Smooth muscle aids in the movement of substances such as food and blood.

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

What is the shape and nucleus count of smooth muscle cells?

A

Spindle-shaped and uninucleate

Smooth muscle fibers are non-striated.

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

What is the structure of cardiac muscle cells?

A

Branched, striated, usually uninucleate

Cardiac muscle cells may have two nuclei and are interconnected by intercalated discs.

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

What role do T-tubules play in muscle contraction?

A

Help depolarize the cell and carry impulses to the sarcoplasmic reticulum

T-tubules are invaginations of the sarcolemma with high concentrations of ion channels.

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

What is the function of the sarcoplasmic reticulum (SR)?

A

Stores and releases calcium ions

The SR is specialized smooth endoplasmic reticulum surrounding myofibrils.

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

What is a sarcomere?

A

Basic within muscle tissue specialized for contraction

Sarcomeres consist of actin and myosin filaments.

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

What happens to the filaments during muscle contraction?

A

They slide over each other without changing length

Myosin heads pull on thin filaments causing sarcomeres to shorten.

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

What are the three main types of skeletal muscle fibers?

A
  • Slow-twitch oxidative (SO type I)
  • Fast-twitch oxidative-glycolytic (FOG type IIa)
  • Fast-twitch glycolytic (FG type IIb)

The proportions of these fibers vary depending on muscle function.

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

Which type of muscle fibers are associated with maintaining posture?

A

Slow-twitch fibers

These fibers are more prevalent in muscles that require endurance.

17
Q

Fill in the blank: The contractile apparatus describes a unit within muscle tissue that is specialized for _______.

A

[contraction]

18
Q

What are the characteristics of Slow Twitch, Type I fibers?

A

Smaller diameter, high capillary density, high myoglobin, high aerobic capacity, low anaerobic capacity, high concentration of mitochondria, high resistance to fatigue, slow contractile velocity, low force production, used for prolonged, low-intensity aerobic activities.

Slow Twitch fibers are ideal for endurance activities.

19
Q

What are the characteristics of Fast Twitch, Type IIa fibers?

A

Intermediate diameter, moderate capillary density, moderate myoglobin, both aerobic and anaerobic capabilities, moderate concentration of mitochondria, moderate resistance to fatigue, rapid contractile velocity, moderate force production, used for moderate intensity activities such as running.

Type IIa fibers are versatile and can adapt to different types of training.

20
Q

What are the characteristics of Fast Twitch, Type IIb fibers?

A

Larger diameter, low capillary density, low myoglobin, low aerobic capacity, high anaerobic capacity, low concentration of mitochondria, low resistance to fatigue, rapid contractile velocity, high force production, used for short bursts of activity such as sprinting or heavy lifting.

Type IIb fibers are primarily used in explosive movements.

21
Q

What initiates cardiac muscle contraction?

A

Myogenic activity generated by pacemaker cells of the sinoatrial (SA) node.

This action potential travels through the heart’s conduction system, including the AV node and Purkinje fibers.

22
Q

What is oxygen debt?

A

The amount of oxygen required to restore metabolic conditions to resting levels after physical activity.

It is associated with the buildup of lactic acid and depletion of ATP and oxygen during intense exercise.

23
Q

What causes muscle fatigue?

A

Buildup of lactic acid, depletion of ATP, and depletion of oxygen.

Lactic acid is a byproduct of anaerobic respiration.

24
Q

What is the neuromuscular junction?

A

The synapse between a motor neuron and a skeletal muscle cell.

It is critical for initiating muscle contraction.

25
Q

What happens when an action potential reaches a motor neuron axon terminal?

A

Voltage-gated calcium ions open, allowing Ca²⁺ to enter, triggering the release of acetylcholine (ACh).

ACh binds to receptors on the muscle cell, causing depolarization.

26
Q

What is the role of the medulla oblongata in involuntary muscle control?

A

It sends signals to involuntary muscles that regulate functions like digestion and heart rate.

This part of the brainstem plays a crucial role in autonomic functions.

27
Q

What causes the muscle to contract?

A

Release of calcium into the sarcoplasm

Calcium is released when a nerve impulse travels down the axon of a motor neuron.

28
Q

What structure opens to allow calcium to enter the sarcoplasm?

A

Sarcoplasmic reticulum

Calcium channels in the sarcoplasmic reticulum open in response to a nerve impulse.

29
Q

What is the role of T-tubules in muscle contraction?

A

They transmit the nerve impulse to the muscle cell

T-tubules facilitate the rapid spread of the action potential.

30
Q

What is released by synaptic vesicles at the neuromuscular junction?

A

ACh (acetylcholine)

ACh is crucial for transmitting signals from nerves to muscles.

31
Q

What is the synaptic cleft?

A

The space between the nerve terminal and the motor end-plate

It is where neurotransmitters like ACh are released.

32
Q

What happens when ACh binds to its receptor?

A

The channel opens

This allows ions to flow, leading to muscle contraction.

33
Q

Fill in the blank: The _______ surrounds the axon of a motor neuron.

A

Myelin sheath

The myelin sheath insulates the axon and facilitates faster signal transmission.

34
Q

What are the components of a motor neuron at the neuromuscular junction?

A

Axon terminal, synaptic end bulb, synaptic vesicle

These components work together to release ACh into the synaptic cleft.