Week 11 - Structure and function of muscle, muscle contraction

Question 1

Functions of muscle tissue?

Answer 1

• produce bodily movement
• stabilise body positions
• store and move substances within the body
• generate heat

Question 2

Properties of muscle tissue?

Answer 2

• electrical excitability
• contractility
• extensibility
• elasticity

Question 3

What is electrical excitibility?

Answer 3

Muscle can respond to certain stimuli by producing electrical signals called action potentials.
Most commonly in response to chemical stimuli e.g. neurotransmitters, hormones or changes in pH.
Can be created by muscle itself.

Question 4

3 Types of muscle?

Answer 4

Smooth muscle
Cardiac muscle
Skeletal muscle

Question 5

Properties of smooth muscle?

Answer 5

→ Located within walls of hollow internal organs e.g. blood vessels, airways and organs within abdominal cavity and in the skin.
→ Non striated – no specific pattern found within the structure of the tissue, proteins are located in a haphazard way so no particular distribution pattern.
→ Non voluntary – autonomic nervous system
→ Slow speed of contraction
→ Intermediate fibre length (30-200um)

Question 6

Properties of cardiac muscle?

Answer 6

→ Only in heart
→ Forms the heart walls
→ Striated
→ Involuntary – pacemaker
→ Intercalated discs – where heart cardiac muscle fibres connect
→ Hormones and neurotransmitters can alter heart rate by effecting the pacemaker
→ Moderate speed of contraction
→ Large fibre length (50-100um)

Question 7

Properties of skeletal muscle?

Answer 7

→ Striated (alternating white and dark bands) – uniform orientation of the proteins within the muscle.
→ Voluntary controlled by neurons as part of the somatic nervous system
→ Although most contraction occurs subconsciously. E.g. contractions in the trunk which maintain your posture.
→ Fast speed of contraction
→ Very large fibre length (100um- 30cm - 12 in.)