Tri A - Muscle

Question 1

What are the 2 basic types of muscle?

Answer 1

Striated,
Smooth

Question 2

Describe muscle structure

Answer 2

Filaments
–>Myofibrils
–>Striations
–>Muscle Fibres
–>Fascicles
–>Skeletal Muscle

Question 3

What are thick and thin filaments composed of?

Answer 3

Thick –> Myosin
Thin –> Actin

Question 4

Describe Filaments

Answer 4

Muscle Proteins
They overlap each other
Arranged in a 3 dimensional way

Question 5

Describe the changes to a muscle when contracted

Answer 5

1. Sarcomere is shortened
2. Length of filaments remains the same
3. Shortening has occurred as actin and myosin have slid past each other
4. Actin/myosin overlap has increased

Question 6

Describe the interaction between myosin and actin

Answer 6

1. Relaxed: myosin heads seen
2. Activated: myosin heads attach to actin, forming crossbridges
3. Contracting: Myosin heads rotate, pulling the actin filaments

Question 7

What causes rigor mortis?

Answer 7

No ATP is available so there is no detachment of the myosin heads

Question 8

What prevents muscle contraction from happening all the time?

Answer 8

There are 2 regulatory proteins:
Troponin,
Tropomyosin
They regulate the sliding filament process but require Ca2+

Question 9

Where are calcium ions released from?

Answer 9

The Sarcoplasmic Reticulum

Question 10

What is a single muscle contraction known as?

Answer 10

A muscle twitch

Question 11

What produces higher levels of muscle tension?

Answer 11

Increased frequency of stimulation

Question 12

Describe the length-tension relationship

Answer 12

The length of muscle fibres is important in determining the force of contraction

Question 13

Describe how length of filaments affects force of contraction

Answer 13

Too much overlap causes the filaments to interfere with each other
Not enough overlap means there are less crossbridges formed