Physiology

Question 1

Types of muscle

Answer 1

Skeletal, smooth and cardiac

Question 2

Striated muscles

Answer 2

Cardiac and skeletal

Question 3

One motor unit consists of:

Answer 3

A single motor neuron and all its connecting muscle fibres (muscle fibres are muscle cells).

Question 4

The more muscle fibres to a motor unit the..

Answer 4

Less refined the action will be.

Question 5

The fewer muscle fibres to a motor unit the..

Answer 5

More precise an action will be e.g. muscles in the eye, hand movements etc

Question 6

What are muscle cells made up of? What is the functional unit within them?

Answer 6

Myofibrils- the functional units with muscle cells are sacromeres.

Question 7

What do sacromeres contain?

Answer 7

Actin (thin) and myocin (thick) filaments.

Question 8

How is muscle contraction brought about?

Answer 8

Calcium is released from lateral sacs of the sacroplasmic reticulum when an action potential passes. The AP passes down T tubules. The calcium then binds to troponin creating tropomyosin which causes cross bridge formation of actin and myocin.

Question 9

In sacromeres, describe the H zone

Answer 9

Thin filaments don’t reach

Question 10

In sacromeres describe the M line

Answer 10

Extends vertically down the middle of the A band in the centre of the H zone.

Question 11

In sacromeres describe the A band?

Answer 11

Thick and thin filaments overlap at both ends of the filament.