Autonomic System Flashcards
What is the autonomic nervous system
CNS and PNS
Somatic
Voluntary action, conscious control
Enteric
Functions independently to regulate GI activity
Voluntary activities
Movement of skeletal muscles
Sensory inputs
Automatic activities
Regulations of activity of smooth muscles in blood vessels and visceral
Activity of many glands
Regulation of heartbeat
Regulation of activity of the digestive tract
Autonomic ganglia
Neuronal fibres leaving the cns make a synapse in small bundles of nerve cells
Parasympathetic
Rest and digest
Restful mode
Increases digestion, slows heartbeat, constructs bronchioles in the lungs
Both pre and post ganglionic neurons are cholinergic (release ach)
Sympathetic
Fight or flight
Life cycle of norepinephrine
What makes people with asthma hard to breathe
Muscles of the bronchial tubes tighten and thicken
Air passage becomes inflamed and mucus filled
How does salbutamol help asthma
B2 adrenergic agonist
Relaxes bronchial tubes by blocking adrenaline from blood stream
Enteric nervous system
In the lining of the gut
Regulates activity of intestines, local blood flow, glands
How does ens work
Moves food (bolus) from oesophagus to rectum
Sensory neurone : detects stretch
Interneuons=reports to neighbours
Neuron behind bolus: contract smooth muscle
Neuron ahead of bolus : relax smooth muscle, opening
Serotonin
Released by gut in response to food (stretching)
Causes increased ach release (contraction behind)
Increased transmitter release ahead of bolus (relaxation)
More movement
Dopamine
Indirectly released in response to sympathetic activity
Reduce ach release (less contraction behind)
Reduces transmitter release ahead (less relaxation)
Less digestion, reduces secretion
