Histology and Physiology

Question 1

What are the physiological functions of skeletal muscle?

Answer 1

Maintenance of posture
Purposeful movement in relation to external environment
Respiratory movements
Heat production
Contribution to whole body metabolism

Question 2

Describe skeletal muscle and its innervation

Answer 2

Striated and innervated by somatic nervous system

Question 3

Describe cardiac muscle and its innervation

Answer 3

Striated and innervated by autonomic nervous system

Question 4

Describe smooth muscle and its innervation

Answer 4

Unstriated and innervated by autonomic nervous system.

Question 5

What is the neurotransmitter at the neuromuscular junction?

Answer 5

Acetylcholine

Question 6

What is the motor unit of the skeletal muscles?

Answer 6

A single alpha motor neuron and all the skeletal muscle it innervates

Question 7

What determines the number of muscle fibres per motor unit?

Answer 7

Depends on the functions served by the muscle. Muscles with fine movements have fewer fibres per motor unit.

Question 8

What does skeletal muscle consist of?

Answer 8

Parallel muscle fibres bundled by connective tissue. Fibres usually extend the length of the muscle.

Question 9

Describe skeletal muscle histologically?

Answer 9

It is striated, unbranched and multinucleated.

Question 10

Where are the nuclei in skeletal muscle?

Answer 10

At the periphery of the fibre just under the cell membrane (in muscle cells this is the sarcolemma)

Question 11

What are bundles of fibres called?

Answer 11

Fascicles

Question 12

What is the name of the tissue that surrounds the muscle?

Answer 12

Epimysium

Question 13

What is the name of the tissue around a single fascicle?

Answer 13

Perimysium

Question 14

What is the name of tissue around a single muscle fibre?

Answer 14

Endomysium

Question 15

What are the units of contraction of a muscle cell?

Answer 15

Sarcomeres

Question 16

Where does the sarcomere extend from and to?

Answer 16

Extends from one Z line to another

Question 17

Describe Type I Skeletal muscle

Answer 17

Relatively slow contracting fibres that depend on oxidative metabolism. They have abundant mitochondria and myoglobin, are resistant to fatigue and produce relatively less force.

Question 18

Describe Type IIa Skeletal muscle

Answer 18

intermediate between the other two types. They are relatively fast contracting but are also reasonably resistant to fatigue. They are relatively uncommon.

Question 19

Describe Type IIb skeletal muscle.

Answer 19

fast contracting fibres that depend on anaerobic metabolism. They have few mitochondria and less myoglobin than Type I fibres. They fatigue relatively easily and produce relatively greater force.

Question 20

Describe bone.

Answer 20

Rigid, non-permeable.
Cells within the bone must eb nourished by blood vessels that pervade the tissue

Question 21

Explain the composition of bone.

Answer 21

65% bioapatite
23% collagen
10% water
2% non-collagen proteins

Question 22

What is the diaphysis and what is it made of?

Answer 22

The shaft of the bone. Made up of dense cortical bone as an outer shell.

Question 23

What is the epiphyses and what is it made of?

Answer 23

The ends of the bone are made up of cancellous or trabecular bone