Brainscape's Knowledge GenomeTM

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


See full index

Body Logistics > Muscle > Flashcards

Muscle Flashcards

1
Q

What are the three types of muscle?

A

Non striated - smooth muscle
Striated - skeletal muscle
- cardiac muscle

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

What type(s) of muscle is myoglobin present in?

A

Skeletal and cardiac muscle

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

More muscle destruction than muscle replacement = ____________

A

Atrophy

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

More muscle replacement than muscle destruction = _____________

A

Hypertrophy

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

What are the two types of atrophy in skeletal muscle?

A

Disuse atrophy - weakness due to not using muscle e.g. In elderly, loss of protein, reduced muscle diameter, loss of power and loss of temperature regulation

Denervation atrophy - lower motor neurone lesions - weakness, flaccidity. Re-nervation within 3 months for recovery

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

What is skeletal muscle hypertrophy?

A

More contractile proteins, increased fibre diameter. Increased enzyme activity for glycolysis, increased mitochondria, stored glycogen and blood flow (gym gains)

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

What is the power stroke?

A

Activated myosin heads bind to actin filaments, myosin pull actin towards M line (sarcomere gets shorter)

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

What proteins regulate actin in skeletal muscle?

A

Troponin - globular

Tropomyosin - fibrous

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

How does calcium control muscle contraction?

A

When Ca ions released from sarcoplasmic reticulum in response to depolarisation travelling down T tubules, binds to TnC of troponin which displaces tropomyosin - exposing binding sites

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

What happens in irreversible overstretching?

A

A and I lines no longer overlap (thought to feature in some cardiac pathologies such as enlarged ventricles)

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

How is skeletal muscle contraction initiated?

A

Nerve impulse along motor neurone arrives at NMJ, causes realease on acetyl Choline. Binds sarcolemma and causes local depolarisation, voltage gated sodium channels open, sodium floods in - depolarisation spreads over sarcolemma into T tubules. Voltage sensor proteins change conformation, activating voltage gated calcium channels on adjacent cisternae - calcium released into sarcoplasmic

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

What is cell hyperplasia?

A

Increase in cell number

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

What are natriuretic peptides? And when are they released?

A

Peptide hormones synthesised in the heart and brain. Release by the heart is stimulated by atrial and ventricular distension (stretching) usually in response to heart failure

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

What is the function of natriuretic peptides?

A

To lower arterial pressure by decreasing blood volume and systemic vascular resistance (promote Na release in kidneys)

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

How is smooth muscle contraction different from skeletal muscle?

A

Still relies on actin-myosin interactions (no sarcomeres) - sower, more sustained and requires less ATP

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

How much circulating blood volume is there in the average 70kg person?

A

5L circulating blood - 2L red cells and 3L plasma

17
Q

What major arteries arise from the aorta?

A

Carotid arteries - to brain
Subclavian arteries - down arms
Descending aorta down abdomen splits into two iliac arteries

18
Q

What is systole?

A

Contraction of the heart- left ventricle contraction causes increases in blood pressure in the aorta - walls of aorta stretch

19
Q

What is diastole?

A

Aortic valve closes (and pulmonary). Aorta walls recoils - maintains pressure on blood - move if towards heart and smaller vessels. Aortic pressure drops

20
Q

What shape are skeletal muscle cells?

A

Long parallel cylinders

Multiple peripheral nuclei

21
Q

What shape are cardiac muscle cells?

A

Short branched cylinders

Single central nucleus

22
Q

What shape are smooth muscle cells?

A

Spindle shaped

Single central nucleus

23
Q

Creatine kinase in the blood may be high due to…

A 
Intramuscular injection
Vigorous exercise 
A fall
Severe muscle breakdown 
Acute kidney injury
24
Q

How are actin and myosin arranged in cardiac muscle cells?

A

Distinct myofibrils are absent, actin and myosin firm continuous masses in the cytoplasm

Intercalated discs in a step-type arrangement substitute for the Z band (where cells meet end to end) and allow electrical and mechanical coupling to adjacent cells

25
Q

Natriuretic peptides serve as a counter regulatory system for what?

A

The renin- angiotensin- aldosterone system

26
Q

What are purkinje fibres?

A

Specialised myocardial cells that carry electrical impulses from the AV node to the ventricles rapidly - enables the ventricle to contact in synchronicity

27
Q

What are the structural features of purkinje fibres?

A

Large Demi’s with abundant glycogen, sparse myofilaments and extensive gap junctions

28
Q

What stimuli does smooth muscle respond to?

A

Nerve signals
Hormones
Drugs
Local blood gas concentrations

Body Logistics (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions