7. Autonomic Nervous System Flashcards
The autonomic nervous system is part of which nervous system?
The peripheral nervous system
Which way to afferent nerves go?
Carry TO CNS
Which way to efferent nerves go?
Carry FROM CNS
What are ganglions?
Group of nerve cell bodies in PNS
(where nerve = more than one neuron)
Where is ANS information integrated?
ANS information is integrated in the hypothalamus at the base of the thalamus
What makes up the hindbrain?
Pons, medulla, cerebellum
Label the hindbrain
Why is the hindbrain important in CNS control of ANS?
Hindbrain is an important gateway of nerves between the spinal cord and cortex
What are the two branches of the ANS?
Sympathetic and Parasympathetic
What is the sympathetic nervous system for?
Fight or flight (catabolic)
Activities that use energy
Most active during exercise and stress
What is the parasympathetic nervous system for?
Rest and digest (anabolic)
Controls activities that conserve energy
What are the parasympathetic nervous system response?
Decreased HR (bradycardia)
Increased GI motility
Bronchial constriction
Pupil constriction
Gastric acid secretion
Where are the parasympathetic neurons and what type are they?
Cranial/Medullary and sacral regions of the spine
Acetylcholine neurons (for both pre and post ganglionic neurons)
Label the neural outputs
Note: gap between 2 neurons is synapse
What type of neurons make up the Sympathetics ANS?
Preganglionic neurons are acetylcholine
Post ganglionic neurons are either acetylcholine or noradrenaline (aka norepinephrine)
What are the two types of acetylcholine receptors?
Nicotinic
Muscarinic
What do nicotinic receptors do?
Control ion channels (where ACh is the ligand)
Where are nicotinic receptors found?
At the ganglionic synapses of the sympathetic and parasympathic divisions
Where are muscarinic receptors found?
In target tissue of parasympathetic postganglionic neurons
What blocks muscarinic receptors?
Atropine (from atropa belladona aka deadly nightshade) is the antagonist
What blocks nicotinic receptors?
Curare is the antagonist
Explain the path of the sympathetic adrenergic neurons?
What are the sympathetic nervous system responses?
Increase HR (tachycardia
Increase BP
Increase blood flow to muscle
Increase blood sugar level (energy for muscle)
Inhibits GI peristalsis ( no point in digestion if you’re running away)
Relaxes airways (bronchial dilation) (get more oxygen)
Pupil dilation (more light to retina to see better)
Orgasm
Explain the path of sympathetic splanchnic neurons?
Note: Stress also causes hormones to be released in the brain and adrenal gland, cortisol is released by the adrenal cortex, cortisol leads to changes in brain of long term stressed
How does cocaine act as a stimulant via sympathetic nervous system?
Stimulant, appetite suppressant etc
Enhances sympathetic effects by prolonging action of neurotransmitter Noradrenaline (and serotonin and dopamine)
Peripheral NS and central NS
How does amphetamine act as a stimulant via sympathetic nervous system?
Psychostimulant, increased wakefulness, focus; decreased fatigue, appetite
Prolongs action of neurotransmitters Noradrenaline serotonin and dopamine
Mainly central NS
Explain the path of the parasympathetic cholinergic neurons?
The enteric nervous system is made up of two complex networks, what are these called?
Myenteric plexus
Submucous plexus
What does the enteric nervous system do?
Controls a lot of the processes in food transport and digestion from mouth to anus
List some ANS problems?
Orthostatic hypotension (low blood pressure on standing)
Inability to sweat/excess sweating
Severe constipation
Impotence
What can cause ANS problems?
Diabetes
Old age
Drugs/medications
Autoimmune degradtion of nerves (MS)
Spinal injury
Brain tumours
