Muscles

Question 1

Where is smooth muscles found?

Answer 1

1. walls of blood vessels
2. gut

Question 2

Which type(s) of muscles are controlled voluntarily?

Answer 2

skeletal
- smooth + cardiac- unconsious + involuntary

Question 3

What are individual muscles made up of?

Answer 3

myofibrils

Question 4

What is a sarcoplasm?

Answer 4

separate muscle cells fuse tgt into muscle fibres –> share nuclei + cytoplasm
- around circumference of fibre

Question 5

What is found within the sarcoplasm?

Answer 5

large conc of:
1. mitochondria
2. ER (endoplasmic reticulum)

Question 6

What is actin?

Answer 6

• thinner
• 2 strands of actin molecules twisted around each other

Question 7

What is myosin?

Answer 7

• thicker
• long myosin tails
• bulbous heads

Question 8

What are the light bands called?

Answer 8

I (isotropic) bands
lighter ∵ thick + thin filaments x overlap

Question 9

What are dark bands called?

Answer 9

A (anisotropic) band
darker ∵ filaments overlap

Question 10

What is the H zone?

Answer 10

lighter coloured region- centre of A band

Question 11

What is the Z-line?

Answer 11

centre of each I band

Question 12

What is a sacromere?

Answer 12

distance betw. 2 Z-lines

Question 13

What happens to sacromere when muscle contracts?

Answer 13

shortens

Question 14

What is the advantage of sacromere being parallel to each other?

Answer 14

force is generated in 1 direction

Question 15

What is a tropomyosin?

Answer 15

• protein
• forms fibrous strand around actin

Question 16

What is a neuromuscular junction?

Answer 16

where motor neurone meets skeletal muscle fibre

Question 17

What is a motor unit?

Answer 17

all muscle fibres supplied by a single motor neurone act tgt as a single function unit

Question 18

How is the intensity of force exerted controlled?

Answer 18

intensity ∝ no. of units stimulated