Muscle Tissue Function

Question 1

What are the 3 different forms of muscle?

Answer 1

• Skeletal
• Cardiac
• Smooth

Question 2

Name a striated and a non-striated muscle

Answer 2

Striated - Skeletal, Cardiac

Non-Striated - Smooth

Question 3

What is Myoglobin? Which molecule does it interact with?

Answer 3

• Molecule with high O2 affinity
• Receives oxygen from haemoglobin
• Released when striated muscle dies

Question 4

What are the four layers of skeletal muscle from inner to outer?

Answer 4

• Muscle fibre
• Fasicle of Endomysium
• Perimysium
• Epimysium

Question 5

What prefix relates to skeletal muscle?

Answer 5

Sarco

Question 6

In which direction does skeletal muscle move?

Answer 6

Along the direction of a fibre

Question 7

What are myofibrils?

Answer 7

Building blocks of muscle fibres

Question 8

What two bands are present in myofibrils and what colour are they?

Answer 8

I-Band is light

A-Band is dark

Question 9

Which 2 types of filament form a myofibril and what is their function?

Answer 9

• Actin and Myosin

- Make the basic contraction machinery

Question 10

What is the name of the skeletal muscle unit that falls between 2 Z-Lines?

Answer 10

Sarcomere

Question 11

Name 3 differences between slow twitch and fast twitch fibres

Answer 11

Slow Twitch - rich capillary supply, aerobic, many mitochondria and cytochromes, red, fatigue resistant, used for endurance

Fast Twitch - poor capillary supply, anaerobic, few mitochondria and cytochromes, white, rapidly fatigue, used for strength

Question 12

Name 3 characteristics of cardiac muscle

Answer 12

• Central nuclei
• Have intercalated discs
• Branched
• Made of cardiomyocytes
• Endocrine
• Communication through gap junctions

Question 13

What are Purkinje fibres and where are they located?

Answer 13

• Large cells which conduct action potentials to allow contraction
• Between Endocardium and Myocardium

Question 14

What is the pathway of conduction through the heart?

Answer 14

SA node > AV node > Atria Contract > AV bundle > Intraventricular septum > Right/Left bundle branches > Purkinje fibres > Ventricular walls

Question 15

Name 3 characteristics of smooth muscle

Answer 15

• Spindle-shaped cells
• Single, large central nucleus
• Stretchable
• Respond to stimuli - nerves/hormones
• Form sheets, bundles or layers

Question 16

Name 3 characteristics of smooth muscle contraction

Answer 16

• Relies on actin-myosin interactions
• Slow contraction
• Requires minimal ATP
• Can remain contracted for hours/days

Question 17

What constitutes smooth muscle ultrastructure?

Answer 17

• Myofilaments
• Dense plaques and bodies
• Caveolae

Question 18

Where is the majority of smooth muscle found?

Answer 18

In contractile walls of passageways and cavities

Question 19

Name 3 clinical conditions related to involuntary smooth muscle disorders

Answer 19

• High blood pressure
• Asthma
• Abnormal gut motility
• Incontinence

Question 20

How is skeletal muscle repaired?

Answer 20

Regenerated by mitotic activity of Satellite cells

Question 21

Which muscle type cannot be repaired?

Answer 21

• Cardiac muscle

- Fibroblasts invade, divide and lay down scar tissue

Question 22

How is smooth muscle repaired? Give an example

Answer 22

• New cells formed by Mitosis

- E.g. Pregnant uterus