The peripheral nerves system Flashcards
Week 4
What is the main role of the PNS
It co-ordinates the transmission and receiving of impulses, to and from the central nervous system
How many pairs of spinal nerves are there?
31
How many pairs of cranial nerves are there?
12
What do neurones do?
Initiate, relay and re-direct electrical impulses by converting chemical energy into electrical energy; they control muscle activity, regulate glands, and support and protect the nervous system
DRAW A NEURON AND LABEL
What is acetylcholine?…
Adrenaline & Noradrenaline…
What is serotonin?
It is a key hormone that stabilizes our mood, feelings of wellbeing, and happiness, also helps with sleeping, eating, and digestion
What is dopamine?
Dopamine plays a role in how we feel pleasure, it’s a big part of our unique human ability to think and plan
What is histamine?
produces many varied effects within the body, including the contraction of smooth muscle tissues of the lungs, uterus, and stomach; the dilation of blood vessels, which increases permeability and lowers blood pressure; the stimulation of gastric acid secretion in the stomach
How do impulses travel and at what speed?
They travel via the sodium / potassium pump at a speed of 130m per second
How would alkalosis alter synaptic conduction?
A pH of 7.8+ can cause cerebral convulsions…
How would acidosis alter synaptic conduction?
A pH of 6.5- will depress neural activity causing coma
Sensory nerve fibres are…
Afferent…
Motor nerve fibres are…
Efferent…
Efferent nerves are divided into…
Somatic (voluntary) and autonomic (involuntary)
Where do efferent nerves originate?
CNS - brain, spinal cord and autonomic ganglia
What do afferent neurons do?
They are nerve cells which convey information from in the periphery e.g. skin / sense organs to the CNS or connector neurons of the REFLEX ARC…
Out of the 31 pairs of spinal nerves, how many are:
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
- Cervical - 8
- Thoracic - 12
- Lumbar - 5
- Sacral - 5
- Coccygeal - 1
What constitutes to a reflex?
Motor response to sensory impulse without intervention from conscious thought
What five things are required for reflex action?
- A receptor
- A sensory neurone
- An associated neurone?
- A motor neurone
- An effector
Define a spinal reflex
Sensory impulse for quick action
Define a cortical reflex
Overrides spinal reflex under conscious control
Define a co-ordinating reflex
Modifies movement and co-ordinates
