Autonomic Nervous System Pt 1 Flashcards
What are the two divisions of the nervous system?
Somatic and Autonomic
What does the Somatic NS control?
Voluntary control of skeletal muscle
What does Autonomic NS control?
Reflex control of smooth & Cardiac muscle (non voluntary)
Autonomic NS is responsible for…
Regulation of our bodies unconscious internal environment.
Auto = Self
Nomic = Governing
How does the ANS operate?
Via Reflex Arcs
Input - relay - Output
What are some ANS Inputs?
Temperature Receptors
Pain Receptors
Chemo Receptors
Blood Pressure Receptors (baroreceptors)
Where are these ANS Input receptors found?
Heart, Blood Vessels, Lungs, Kidneys, gut, bladder
There are two divisions of the ANS Output , what are they?
Sympathetic Nervous System
Parasympathetic Nervous System
What is Dual innervation?
Most organs have dual innervation in that they receive impulses from both sympathetic and parasympathetic divisions.
What is another name for the Sympathetic ANS Division?
Thoracolumbar Division, due to the fact sympathetic division nerve fibres leave the CNS in the thoracic and lumbar levels.
What is another name for the Parasympathetic ANS Division?
Cranialsacral Division, due to the fact parasympathetic nerve fibres leave the CNS via cranial nerves and Sacral regions.
Both divisions of ANS have a two-neurone pathway from spinal cord to target organ. What are the names of each neuron?
Pre-ganglionic nerve fibre and post-ganglionic nerve fibre.
What is the site of synapse between the two nerve fibres?
Autonomic ganglion.
In the sympathetic Division it is specifically the sympathetic trunk ganglia.
Describe the sympathetic pathway in terms of neurone size?
The pre-ganglionic nerve fibre is short and the post-ganglionic nerve fibres are long.
Describe the parasympathetic pathway in terms of neurone size?
The pre-ganglionic nerve fibres are long and the post-ganglionic nerve fibres are short (sometimes post are within the target organ)
What neurotransmitters are used by each division?
At the synapse in the autonomic ganglion both divisions Acetylcholine (ACh) while at the target organ parasympathetic division uses ACh while sympathetic division uses Noradenaline (NA).
The sympathetic and parasympathetic divisions operate antagonistically meaning?
When activate they perform the opposite action to their counterpart?
Give an example of antagonist ANS in action?
The sympathetic division when stimulated will increase heart rate while the parasympathetic division decreases it.
Describe the function of the adrenal medulla?
The middle portion of the adrenal gland. Its cells are similar to post-ganglionic nerve fibres but rather than extending to an organ they release hormones (adrenaline and noradrenaline) into circulation. These hormones intensify the responses elicited from other sympathetic neurons.
