Autonomic nervous system Flashcards
How is the ANS defined anatomically and physiologically?
Anatomically: it is defined as all those neural pathways that leave the brain that do not innervate the volntary muscles
Physiologically: Homeostasis
What are the levels to the organisation of the nervous system?
Homeostasis can trigger two types of responses, what are they and the length of their effect?
What are the divisions of the ANS and what does each system help with?
- Sympathetic: Fight or flight
- Parasympathetic: Rest and digest
- Enteric: sometimes considered part of the ANS and sometimes considered an independent system
What are the physiological roles of the ANS?
- pupillary dilation
- accommodation for near vision
- dilation and constriction of blood vessels
- force and rate of heartbeat
- movements of the gastrointestinal tract
- secretions from most glands
- energy metabolism, particularly in liver and skeletal muscle
The point of contact between the first and second efferent neuron in the pathway pccurs in a neural structure called what?
A ganglion
What is a ganglion?
A group of nerve cell bodies that lie outside the central nervous system
With the sympathetic and parasympathetic nervous systems, tell me about the length of ganglion before and after the target tissue
How do drugs influence the ANS?
They mimic or block the effects of the two primary neurotransmitters, Ach and Noradrenaline/ adrenaline
Drugs that mimic neurotransmitters are referred to as what?
How do they effect receptors?
receptor agonists
These drugs activate receptors
Drugs that block neurotransmitters are referred to as what?
How do these effect receptors?
They are known as receptor antagonists
These drugs block the endogenous neurotransmitters from activating receptors
What does the sympathetic nervous system innervate?
Where is the preganglionic neuron located?
It innervates many different tissues
The preganglionic neuron is located in the midbrain, medulla or lateral horn of the spinal cord
What does the ganglia form in the sympathetic nervous system?
A sympathetic chain
What does the sympathetic nervous system provide?
Provides diffuse innervation of target tissues
What does the parasympathetic nervous system innervate ?
Where is the preganglionic neuron located?
Located in meduall or sacral segment of the spinal cord
Where are the ganglia located in the parasympathetic nervous system?
In the target tissue