ANS lecture Flashcards
Which cells are adrenergic and what do they release?
release NE
most sympathetic postganglionic neurons
what does the aorticorenal ganglion innervate?
kidney and ureter
what does the inferior mesenteric ganglion innervate?
descending colon, kidneys, sex organs
Define the preganglionic neuron
cell body in the CNS extends from CNS to autonomic ganglion myelinated axon type B fiber small diameter
where are chromaffin cells located and what do they release?
the adrenal medulla and epinephrine and NE
what do the superior cervical ganglia innervate?
pineal gland, eye, lacrimal mucous membrane of the nose and palate, parotid gland, heart, and sublingal and submandibular glands
what are the sensory receptors of the ANS?
mostly interceptors (visceral sensory neurons), some somatic senses and special senses
what does the vagus nerve innervate?
heart, lungs, liver, gall bladder, stomach, pancreas, intestines
What are the ganglia in the neck?
superior, middle, and inferior cervical ganglia
major locations of A1 receptors
smooth muscle fibers in blood vessels, salivary gland cells, and sweat gland cells in thick skin
what organs control the motor output for the ANS?
involuntary control from hypothalamus, limbic system, brainstem, and spinal cord. Limited control from cerebral cortex
What effectors does the autonomic nervous system work on?
smooth muscle, glands, and cardiac muscle
what is the distribution of the parasympathetic division?
limited mainly to head and viscera of thorax, abdomen, and pelvis, some blood vessels
what is dual innervation?
organs receive impulses from both the sympathetic and parasympathetic neurons
What are the four ways axons of sympathetic preganglionic neurons can connect with postganglionic neurons?
- axon can synapse with a postganglionic neuron in the ganglion it first reaches
- an axon may ascend or descend to a higher or lower ganglion
- an axon can continue directly through the trunk to end at a prevertebral ganglion
- an axon can extend to chromaffin cells of the adrenal medulla
What does SLUDD stand for in relation to parasympathetic responses?
salivation lacrimation (tears) urination digestion defacation
what does the celiac ganglion innervate?
liver, gall bladder, bile ducts, stomach, spleen, and pancreas
How many post neurons does a parasympathetic pre neuron usually synapse with and how does that affect function?
only 4-5 all of which supply a single visceral effector, which allows parasympathetic responses to be localized to a single effector
What pattern of projection defines the sympathetic nervous system, and how does it affect function?
divergence which is why many sympathetic responses affect almost the entire body simultaneously.
what are autonomic plexuses?
tangled networks of symp and parasymp axons that lie along major arteries
How many motor neurons do (most) autonomic motor pathways have?
2, in a series one after another
What are the two divisions of the ANS?
sympathetic and parasympathetic
what is an agonist in terms of receptors?
a substance that binds to and activates a receptor and mimics the effect of a natural neurotransmitter or hormone
ex. phenylephrine
major locations of A2 receptors
smooth muscle in blood vessels, pancreatic cells, and platelets.
In terms of excitation and inhibition, what is the difference between the somatic and the autonomic?
somatic always excites, ANS can do both
Define B3 receptors
only found in brown adipose tissue and their activation causes thermogenesis
what is autonomic tone and what regulates it
the balance between sympathetic and parasympathetic activity
regulated by hypothalamus
What do Alpha 1 and Beta 1 produce?
excitation
What are the two types of neurotransmitters in the ANS?
ACh and NE
What are the 5 major prevertebral ganglion?
celiac, superior mesenteric, inferior mesenteric, aorticorenal, and renal
Where are terminal ganglia located?
close to or within the wall of a visceral organ
How do alpha and beta receptors react to NE and epinephrine?
NE stimulates alpha receptors more strongly than beta
epinephrine is a potent stimulator of both
What are the two types of autonomic neurons based on neurotransmitters?
cholinergic and adrenergic
Major locations of B1 receptors
cardiac muscle cells, kidney cells, pituitary, and adipose cells
what does the ciliary ganglion innervate?
the eye
what is the other name for the parasympathetic division?
rest and digest
where are the preganglionic neurons of the parasympathetic division?
Nuclei of cranial nerves 3 (oculomotor), 7 (facial), 9 (glossopharyngeal), and 10 (vagus), and the lateral grey matter of S2-S4. AKA craniosacral division
What are the 5 types of adrenergic subtypes?
Alpha 1 and 2
Beta 1, 2, 3
major locations of B2 receptors
smooth muscle in airways, blood vessels, and walls of visceral organs
How many preganglionic axons does the postganglionic neuron synapse with?
one or more
Where are the sympathetic ganglia found?
sympathetic trunk ganglia parallel to the spinal cord and the prevertebral ganglia
What do the cardiac plexus and pulmonary plexus supply?
heart and bronchial tree
How many neurons can a single sympathetic preganglionic fiber synapse with?
20 or more
what does the submandibular ganglion innervate?
sublingual and submandibular glands
Where are nicotinic receptors located?
plasma membrane of dendrites and cell bodies of both symp and parasymp postganglionic neurons
chromaffin cells
neuromuscular junction
Which 6 structures are only innervated by the sympathetic division?
sweat glands, arrector pili muscles, kidneys, spleen, blood vessels, and adrenal medulla.
How many cervical, thoracic, lumbar, sacral, and coccygeal ganglia are there?
3 cervical 11/12 thoracic 4/5 lumbar 4/5 sacral 1 coccygeal that is fused and on the midline rather than lateral
what does the inferior cervical ganglion innervate?
heart
where are muscarinic receptors located?
plasma membranes of all effectors
most sweat glands
what does the middle cervical ganglion innervate?
heart
Are sympathetic preganglionic axons long or short?
short because the trunk ganglia are near the spinal cord
What are the two types of cholinergic receptors that bind with ACh?
nicotinic and muscarinic
what do the pelvic splanchnic nerves innervate?
Descending colon, sigmoid colon, ureter, bladder, external genitalia, and uterus.
define the postganglionic cell
cell body in the autonomic ganglion extends from the autonomic ganglion to the effector unmyelinated type C fiber small diameter
what does ACh in muscarinic receptors cause?
can cause either depolarization/excitation or hyperpolarization/inhibition
Define autonomic reflexes
responses that occur when a nerve impulse passes through an autonomic reflex arc. reflexes play key role in regulating controlled conditions in the body such as blood pressure
What are the components of an autonomic reflex arc?
receptor, sensory neuron, integrating center (hypothalamus, brain stem, or spinal cord), motor neurons, and effector.
Why are sympathetic stimulation effects longer lasting?
1) sympathetic postganglionic axons diverge more extensively
2) NE remains in the synaptic cleft longer
3) NE and epinephrine are secreted into the blood from the adrenal medulla. Eventually destroyed in liver by enzymes
Where are the sympathetic trunk ganglia located?
lie in a vertical row on either side of the vertebral column and extend from the base of the skull to the coccyx.
What is the distribution of the sympathetic division?
wide regions of the body: skin, sweat glands, arrector pili muscles, adipose tissue, and smooth muscle of blood vessels
What does NE cause at the effector cell?
excitation or inhibition
How is the activity of NE at a synapse terminated?
NE is taken up by the axon that released it
NE is enzymatically inactivated
NE remains in the synaptic cleft longer than ACH
Which neurons are cholinergic, and what do they release?
Release ACh
- all sympathetic and parasympathetic preganglionic neurons
- sympathetic postganglionic neurons that innervate most sweat glands
- all parasympathetic postganglionic neurons
What are the four Es of sympathetic activation?
exercise, emergency, excitement, and embaressment
what are the two ways NE can be released?
a neurotransmitter by sympathetic postganglionic neurons
a hormone into the blood by chromaffin cells
epinephrine is always released as a hormone
Where are the preganglionic neurons of the sympathetic division?
lateral horns of the grey matter of T1-L2/L3 AKA thoracolumbar division
what are the two main types of adrenergic receptors?
alpha and beta and are found on visceral effectors innervated by most sympathetic postganglionic axons
what do adrenergic receptors bind to?
epinephrine or NE
what is an antagonist in terms of receptors?
a substance that binds to and blocks a receptor thereby preventing a natural neurotransmitter or hormone from exerting its effect.
ex. atropine
Are parasympathetic preganglionic axons long or short?
long
when nicotinic receptors are activated in chromaffin cells what happens?
epinephrine and NE are released
what does the celiac (solar) plexus contain?
it is the largest autonomic plexus and surrounds the celiac trunk
Contains:
2 large celiac ganglia
2 aorticorenal ganglia
stomach, kidneys, liver, and adrenal glands
what does the superior mesenteric ganglion innervate?
kidney and ureter
What is the sympathetic division also called?
fight or flight (S for stress and sympathetic)
what d alpha 2 and beta 2 produce?
inhibition
What does ACh in nicotinic receptors cause?
depolarization and excitation
what does the pterygopalatine ganglion innervate?
lacrimal gland and nasal mucosa and palate
What are the three “decreases” of the parasympathetic?
heart rate, bronchoconstriction, and constriction of pupils
what does the otic ganglion innervate?
parotid gland
what are the 4 terminal ganglia in the head?
ciliary, pterygopalatine, submandibular, and otic ganglion
