Autonomic Nervous System (ANS) Flashcards
What does the ANS control?
Involuntary activities in
Smooth muscle
Cardiac muscle
Organs
Various glands
What are the 2 divisions of the ANS?
Sympathetic NS
Parasympathetic NS
What nerves does the parasympathetic NS affect?
cranial nerves
oculomotor (3), facial (7), glossopharyngeal (9), vagus (10)
spinal nerves
sacral 2-4
What nerves does the sympathetic NS affect?
spinal nerves
thorax 1 - lumbar 2
Where is the ganglion in a parasympathetic neuron of the ANS?
close to effector organ
Where is the ganglion in a sympathetic neuron of the ANS?
midway between preganglionic neuron and (post)ganglionic neuron
What is the ganglion?
collection of neuron cell bodies that lie outside the CNS
What is the endocrine component of the sympathetic NS?
Adrenal medulla - produces and releases adrenaline into the bloodstream
Where does the para NS generally have actions?
eyes, mouth and nose, lungs, heart, digestive tract, waste removal, reproductive system
What are the conservative, anabolic effects of the parasympathetic NS?
Storing energy - digestion etc- Slowing heart
Where does the sympathetic NS generally have actions?
more widespread action - often affecting the whole body
associated with homeostasis - blood pressure, thermoregulation
fight, flight or fright
meeting demands of active muscles
What gland releases adrenaline?
adrenal medulla
What parts of the body does the ANS affect?
smooth muscle (blood vessels in various parts of the body, bronchi and bronchioles),
heart (gastro-intestinal tract, rate and force of contraction),
glands (salivary glands, gastro-intestinal glands and sweat glands),
metabolism
What does the autonomic nervous system NOT control?
BREATHING
skeletal muscles controlled by somatic nerves e.g. phrenic innervates the diaphragm
How does the ANS affect the GIT/heart?
GI Tract: circulation reduced when inactive to increase the volume of blood to other organs and muscles
What are the effects of the autonomic NS on heart rate?
sympathetic - increases heart rate and. contraction force
parasympathetic - decreases
What is the metabolism connection to ANS?
parasympathetic NS - stores energy
sympathetic NS - makes energy available to organs
What is the ANS effect on the iris (radial and sphincter muscles)?
parasympathetic - contraction
sympathetic - contraction
What is the ANS effect on ciliary muscle?
parasympathetic - contraction
sympathetic - relaxation
What is the ANS effect on salivary glands?
parasympathetic - copious, watery
sympathetic - viscous, low volume
both cause secretion but of different qualities
What is the ANS effect on lacrimal glands?
parasympathetic - secretion
sympathetic - none
What is the ANS effect on nasal glands?
parasympathetic - secretion
sympathetic - none
What is the ANS effect on blood vessels?
sympathetic - alpha 1 receptors cause constriction, beta 2 receptors cause dilations
parasympathetic - none
What neurotransmitter acts on the parasympathetic nervous system?
acetylcholine
What neurotransmitter(s) acts on the sympathetic nervous system?
acetylcholine between pre and postganglionic neurons and noradrenaline at postganglionic
Why does noradrenaline have different effects on different organs?
due to different receptors
What are the two different types of receptors and what system do they belong to?
parasympathetic - cholingeric - involves acetylcholine
sympathetic - adrenergic - involves noradrenaline
What does the alpha ANS receptor do?
A1 - contraction of smooth muscle, glands and organs, peripheral blood vessels
A2 - inhibits at pre-synaptic terminals to reduce sympathetic effects
What do the beta ANS receptors do?
B1 - stimulate heart and juxtaglomerular cells, increases HR, BP and contraction
B2 - relaxation of smooth muscle, glands and organs, relax bronchioles and airways
What do beta blockers do?
beta-blockers, block beta-1 receptors only so their effects are restricted to the heart, propranolol for anxiety
What do many local anaesthetic preparations contain?
adrenaline which is used as a vasoconstrictor
What are the two types of cholinergic receptors?
muscarinic, nicotinic
Where is a muscarinic receptor?
post-ganglion, neuro-effector junctions blocked by atropine
What are the effects of atropine?
increases the heart rate, reduces fluid by blocking the parasympathetic influences on the heart.
Where is a nicotinic receptor?
pre-ganglion, post-ganglion, neuromuscular junctions
What transmitter works on the sympathetic system and where?
acetylcholine at the synapse of pre-ganglionic and post-ganglionic neurons and noradrenaline at the effecter organ
What is the different receptor effects of noradrenaline on smooth muscle?
Alpha Receptor
contraction of smooth muscle in blood vessels (vasoconstriction)
Beta Receptor
relaxation of smooth muscle in smooth muscle in bronchi (bronchodilation)
What are alpha and beta receptors a part of?
adrenergic (sympathetic)
What are the types of adrenergic receptors and what is their effect?
Alpha 1, Beta 1 = Excitatory effect
Alpha 2, Beta 2 = inhibitory effect
Where is each of the adrenergic receptors found?
Alpha 1 = smooth muscle, glands, organs
Beta 1 = heart, kidneys
Alpha 2 = pre-synaptic (ganglion) inhibition
Beta 2 = smooth muscle, glands, organs
What are the two types of cholinergic receptors and where are they found?
nicotinic = found in the pre-ganglionic synapse of both sympathetic and parasympathetic systems
muscarinic = found at the post-ganglion where the effector organ is
