sympathetic nervous system

autonomic nervous system

part of nervous system responsible for regulating involuntary bodily actions

what are examples of bodily functions the autonomic nervous system helps regulate?

1. heart rate

2. digestion

3. respiratory rate

4. pupillary response

5. urination

6. sexual arousal

sympathetic nervous system

fight or flight response

what are examples of some physiological changes that would be activated by the sympathetic nervous system?

1. increased heart rate

2. dilation of pupils

3. mobilization of energy stores

parasympathetic nervous system

rest and digest; conserve energy

enteric nervous system

a complex network of neurons within the gastrointestinal tract that regulates digestion, secretion, and motility independent of the CNS

nonepinephrine

neurotransmitter released by sympathetic nerves that plays a key role in the fight or flight response

what actions in the body does nonepinephrine help with?

1. increasing heart rate

2. constricting blood vessels

3. mobilizing energy stores

epinephrine is produced by

hormone and neurotransmitter produced by adrenal glands

what is the function of epinephrine?

powerful sympathomimetic agent that stimulates both alpa and beta adrenergic receptors

cholinergic receptors

receptors that bind to acetylcholine. including nicotinic and muscarinic receptors

where are nicotinic receptors found?

in autonomic ganglia

where are muscarinic receptors found?

found in target organs

adrenergic receptors

bind to norepinephrine and epinephrine; mediate the response of the sympathetic nervous system

alpha-adrenergic receptors

GPCR found on the postsynaptic membranes of effector cells innervated by the sympathetic nervous system

beta-adrenergic receptors

GPCR found on the post synaptic membranes of effector cells innervated by the sympathetic nervous system

sympathomimetic drugs are also known as…

adrenergic agonists

what are the effect of sympathomimetic drugs?

• mimic the action of norepinephrine and epinephrine

• activate adrenergic receptors

• stimulate sympathetic nervous system

what are sympatholytic drugs also known as?

adrenergic antagonists

what are the function of sympatholytic drugs?

inhibit the action of norepinephrine and epriphrine at adregenic receptors therefore blocking sympathetic activity

ganglion

a cluster of nerve cell bodies located outside the central nervous system

what is the function of ganglia in the autonomic nervous system?

relay points for transmitting signals between the central nervous system and target organs

sympathetic chain ganglia

paired structures located lateral to the vertebral column that are responsible for relaying sympathetic signals to target organs

prevertebral ganglia

ganglia located anterior to the vertebral column that innervate specific abdominal functions; digestion and urination

what is the longest cranial nerve?

vagus nerve

what subtype of the autonomic nervous system does the vagus nerve predominantly work with?

parasympathetic

what is the function of the vagus nerve?

innervate organs in the thoracic and abdominal cavities

mydriasis

dilation of the pupil of the eye

hypertension

abnormally high blood pressure

baroreceptor

specialized sensory receptors that detect changes in blood pressure and help regulate by adjusting heart rate and vascular tone

pupil

the opening in the center of the iris that regulates the amount of light entering the eye

what stimulation of the pupil would cause pupil dilation?

sympathetic stimulation

what stimulation of the pupil would cause pupil constriction?

parasympathetic stimulation

adrenergic neuron

neurons that release norepinephrine as a neurotransmitter

where are adrenoreceptors located?

1. on the neuron (presynaptic)

2. effector organ (post synaptic)

what triggers the release of norepinephrine?

action potential triggers calcium ion influx that will cause release into synaptic cleft via exocytosis

what are alpha-1 AR agonists commonly used for?

hypotension

where does epinephrine come from?

adrenal medulla

what pre-synaptic adrenergic receptor is linked to inhibition of norephinephrine release?

alpha-2 AR

what are the functions of the somatic nervous system?

voluntary control of the skeletal muscle function

what does the autonomic nervous system regulate?

functions of internal organs and adapts them to the needs of the moment

where is the stimulus coming from for the autonomic nervous system?

internal environment

where is the stimulus coming from for the somatic nervous system?

external environment

what is important about the collaboration of the parasympathetic and sympathetic systems of the autonomic nervous system?

they are complimentary to one another; THEY ARE NOT ANTAGONISTS

where do the preganglionic neurons originate from in the sympathetic ANS?

central nervous system's thoracolumbar region

where do neurons start their journey for the sympathetic ANS?

intermdiolateral gray matter of spinal cord

what is the ratio of preganglionic fibers to postganglionic fibers in sympathetic division?

1:20

what are the different ways preganglionic neurons can leave the spinal cord to activate post-ganglionic cells?

1. paravertebral chain

2. prevertabral chain

route of signal transmission in sympathetic ANS

1. neuron starts journey in gray matter of spinal cord

2. preganglionic neuron leaves spinal cord through ganglion chain

3. establish synapsis with postganglion neuron

4. postganglion fiber innervate target cells

all preganglionic neurons (sympathetic and parasympathetic) are .

cholinergic

what does it mean to be cholinergic?

synthesize and release acetylcholine as their primary neurotransmitter

what does it mean for the cholinergic receptor to be "nicotinic"?

the chromaffin cells in the adrenal medulla will release epinephrine into the blood stream

what does it mean for postsynaptic neurons to be largely adrenergic?

synthesize and release norepinephrine as their primary neurotransmitter