Flashcards in Physiology Deck (11):
Types of muscle
Skeletal, smooth and cardiac
Cardiac and skeletal
One motor unit consists of:
A single motor neuron and all its connecting muscle fibres (muscle fibres are muscle cells).
The more muscle fibres to a motor unit the..
Less refined the action will be.
The fewer muscle fibres to a motor unit the..
More precise an action will be e.g. muscles in the eye, hand movements etc
What are muscle cells made up of? What is the functional unit within them?
Myofibrils- the functional units with muscle cells are sacromeres.
What do sacromeres contain?
Actin (thin) and myocin (thick) filaments.
How is muscle contraction brought about?
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.
In sacromeres, describe the H zone
Thin filaments don't reach
In sacromeres describe the M line
Extends vertically down the middle of the A band in the centre of the H zone.