Chapter 15 - ANS Flashcards
skeletal muscles – Skeletal muscle – Conscious and reflex movement – Skeletal muscle contracts with nerve stimulation (only stimulation of targets) – One synapse from CNS to target
Somatic
viscera (internal organs)
– Smooth & cardiac muscle, and glands
– Unconscious regulation & reflexes
– Target tissues stimulated or inhibited with nerve stimulation
– Two synapses from CNS to target
• Autonomic
Neurotransmitter: Acetylcholine
– Receptor: Nicotinic cholinergic
Somatic
Neurotransmitters: Acetycholine & Norepinephrine (also epinephrine – hormone)
– Receptors: Nicotinic & muscarinic cholinergic; α & β adrenergic
Autonomic
“fight/fright/flight”
Sympathetic division
Increase heart activity – Shift blood flow – to skeletal muscles & heart, – away from kidney & digestive organs, – maintain flow to brain – Focus on distance
Sympathetic responses
“relax and live” or “rest and digest” or “relax/rest/connect”
Parasympathetic division
Slow down heart
– Digest food
– Make urine
– Shift focus to near objects like baby in arms
Parasympathetic responses
a nervous system within the digestive tract;
Enteric nervous system
digestive tract coordination & regulation
• both sympathetic and parasympathetic divisions connect to it
• spinal and brainstem parasympathetic and sympathetic reflex arcs help regulate enteric
system
• contains internal reflex arcs with ganglia in digestive tract to coordinate digestive activity
Enteric nervous system
neurotransmitter acetylcholine released onto
nicotinic cholinergic receptor for both
Motor neuron to ganglionic neuron (pre-ganglionic)
norepinephrine onto adrenergic receptor
Sympathetic
acetylcholine onto muscarinic cholinergic receptor
Parasympathetic
adrenergic receptors will cause smooth muscle contraction or inhibition
α
adrenergic receptors will cause smooth muscle relaxation or stimulation
β
in brainstem and spinal cord control much of the minute to minute
activity of visceral organs, glands, and blood vessels
Autonomic reflexes
influence autonomic reflex activity.
• The hypothalamus and higher brain centers
influence activities of enteric nervous system
through autonomic reflexes
Sympathetic and parasympathetic divisions
can function independently of CNS through local reflexes
• Typically inputs from cerebral cortex or other limbic structures influence ANS centers in the
hypothalamus.
Enteric nervous system
send fibers to the brainstem areas (midbrain, pons,
or medulla) to influence pattern generating or regulatory centers for many functions.
The hypothalamic centers
limbic system structures (ties to emotion) typically connect to
hypothalamus
Cerebral Cortex
coordinates ANS outputs with satiety/hunger, salt craving, thirst,
libido, biological clock and other cycles, etc.; outputs sent from hypothalamus to
brainstem areas
Hypothalamus
into regulatory centers here (heart, breathing, salivary
glands, GI secretions, bladder control, pupil constriction/dilation, etc.)
Hypothalamus input
is affected by ANS centers in the
hypothalamus and influences ANS output centers in the cortex and
hypothalamus
Reticular formation (RAS)
for regulation of many ANS outputs along cranial nerves
Brainstem reflex arcs
reflex arcs regulate the following and more: • Urination • Defecation • Erection • Ejaculation
Spinal cord
– regulated by having more or less sympathetic signal sent to the smooth
muscle; said to have sympathetic tone
Blood vessels
– regulates glucose release from glycogen
liver
regulates release of fatty acids from triglyceride breakdown
Adipose cells
– regulates release of an enzyme called renin
Kidney
