9. Muscle Tissue Structure And Function

Question 1

What are the 2 types of striated muscle?

Answer 1

Skeletal

Cardiac

Question 2

Is myoglobin present in any of the 3 muscle types?

Answer 2

In skeletal and cardiac, not smooth

Question 3

Are the muscles voluntary or involuntary?

Answer 3

Skeletal is voluntary

Cardiac and smooth is involuntary

Question 4

What is myoglobin?

Answer 4

Red protein, similar to subunit of haemoglobin
Stores oxygen
No cavity for CO2

Question 5

What happens when striated muscle dies?

Answer 5

Myoglobin is released into the blood

Question 6

What is the sarcolemma?

Answer 6

Outer membrane of muscle cells (like the plasmalemma)

Question 7

What is the sarcoplasm?

Answer 7

Cytoplasm of muscle cell

Question 8

What is the sarcosome?

Answer 8

Mitochondrion

Question 9

What is a sarcomere?

Answer 9

Contraction unit in striated muscle

Question 10

What is the sarcoplasmic reticulum?

Answer 10

Smooth endoplasmic reticulum of muscle cell

Contains Ca2+ for contraction

Question 11

What is each fascicle surrounded by in skeletal muscle?

Answer 11

Perimysium

Question 12

Is skeletal muscle uni or multinucleated?

Answer 12

Multinucleated

Question 13

What is a striated muscle cell called?

Answer 13

Muscle fibre

Question 14

What are myosin, actin and titin?

Answer 14

Actin in think filament
Myosin is thick filament
Titin acts as spring, pulls actin back to position

Question 15

What are slow twitch muscle fibres?

Answer 15

Type 1
Red
Rich capillary supply
Aerobic
Lots of myoglobin, mitochondria and cytochromes
Endurance type activities

Question 16

What are intermediate twitch fibres?

Answer 16

Type 2A
Red to pink
Rich capillary supply
Aerobic
Lots of myoglobin
Many mitochondria and cytochromes
Assist type 1 and 2B activities

Question 17

What are fast twitch fibres?

Answer 17

Type 2B
White
Poor capillary supply
Anaerobic
Low myoglobin, mitochondria and cytochromes
Strength activities

Question 18

What are intercalated discs?

Answer 18

In cardiac muscle for electrical and mechanical coupling with adjacent cells

Question 19

What are the 2 peptides that are released by the heart during heart failure and what do they do?

Answer 19

ANP (atrial natriuretic peptide) - released by atria
BNP (brain-type natriuretic peptide) - released by ventricles
Reduce arterial pressure by decreasing blood volume and resistance

Question 20

What is hypertrophy?

Answer 20

Enlargement of individual cells

Question 21

What is atrophy?

Answer 21

Shrinking of individual cells

Question 22

What is hyperplasia?

Answer 22

Multiplication of cells

Question 23

Where is the nuclei located in cardiac muscle cells?

Answer 23

In centre

Question 24

Where is the nuclei located in skeletal muscle cells?

Answer 24

Peripheral

Question 25

Where is the nucleus located in smooth muscle cells?

Answer 25

Centre, large nucleus

Question 26

What stimuli do smooth muscle cells respond to?

Answer 26

Nerve signals
Hormones
Drugs
Local concentrations of blood gases

Question 27

How can skeletal muscle be repaired?

Answer 27

Can regenerate by mitosis of satellite cells (stem cells)

Satellite cells also fuse with existing muscle cells to increase mass

Question 28

How are cardiac muscle cells repaired?

Answer 28

Adult is incapable of regeneration

Scar tissue forms instead

Question 29

How are smooth muscle cells repaired?

Answer 29

Retains mitotic activity, can form new cells

E.g. in pregnant uterus