Chapter 14: Autonomic Nervous System

sympathetic

"fight or flight"

parasympathetic

"rest and digest"

Vagus nerve

(X), alone provides ~75% of all parasympathetic outflow!

Dual innervation

=Many organs receive signals from both ANS divisions

excitatory

ACH binding to nicotinic receptors is always ___________.....*(nicotine binds to these and stimulate sympathetic response)

Nicotinic receptors

ACh binding to ______________is always excitatory

cooperation

ANS _______________ is best seen in control of external genitalia

ANS

Axons of ______ are a two-neuron chain: 1. preganglionic and 2. postganglionic neurons

heavily

Axons of somatic motor neurons _________ myelinated

Adrenergic receptors

Binding of epinephrine (E) or norepinephrine (NE) activates enzymes (2nd messenger systems) in cell; 2 classes- alpha and beta receptors

seconds

Effects of NT release of Sympathetic Division, last a few __________

autonomic reflexes

Even in the absence of stimuli, autonomic motor neurons maintain continuous activity; through _______________ to maintain autonomic tone

3

Generally, from adrenal medulla during SNS NT release, there is __ times more epinephrine than norepinephrine, and more beta receptors are activated, these effects last several minutes

opposite

Most often, effects of parasympathetic are ___________ to sympathetic division

epinephrine

NE and _____________ are released into blood & remain there until destroyed by the liver during sympathetic activation

norepinephrine

Neurotransmitter effects in the ANS: postganglionic fibers release ________________ or Ach and effect is either stimulatory or inhibitory

acetylcholine

Neurotransmitter effects in the ANS: preganglionic fibers release ______________

nasal decongestant

Over- the- counter drugs for colds, allergies: ________________ (ex: phenylephrine)- stimulate a1 receptors (side effect: blood pressure increases)

craniosacral

Parasympathetic (______________ division)- axons emerge from brain stem and sacral region- innervate ganglia close to (or within) target organs

vasodilation

Parasympathetic fibers cause ________________ & are responsible for erection of the penis & clitoris

Glossopharyngeal IX

Parotid salivary glands

cerebral input

Subconscious ______________ via limbic lobe connections influences hypothalamic function (psychosomatic illnesses?)

thoracolumbar

Sympathetic (___________ division):- axons emerge from thoracic and upper lumbar regions of spinal cord

parasympathetic divisions

Sympathetic Division regulates some functions not subject to ___________________, includes activity of the adrenal medulla, sweat glands, arrector pilli muscles, & most blood vessels

long lasting

Sympathetic activation is _____________ because NE: -is inactivated more slowly than ACh -IS an indirectly acting NT, using a second-messenger system

collateral ganglia

Sympathetic chain ganglia (on either side of spinal cord) & _______________ where pre- and post-ganglionic neurons synapse

ejaculation

Sympathetic fibers cause ______________ of semen in males and reflex peristalsis in females

ACh

The effect of ____binding: can be either inhibitory or excitatory; depends on receptor type of target organ

parasympathetic and sympathetic

Two main divisions of the autonomic nervous system are the __________________ nervous systems

Parasympathetic Division

Typical responses of the __________________: 1. Decreased metabolic rate 2. Decreased heart rate and blood pressure 3. Increased salivary and digestive gland secretion; increased digestive tract motility and blood flow 4. Stimulation of urination and defecation

ANS

______ output affects virtually every body system

All

______ somatic motor neurons release ACh, excitatory effect

Preganglionic

___________ (first) neuron has a lightly myelinated axon

sympathetic

___________ activation effects: -Increased alertness through reticular activating system -Feeling of energy and euphoria -Increased activity in cardiovascular and respiratory centers of medulla oblongata; increased blood pressure, heart/breathing rate -Mobilization of energy reserves: -breakdown of liver and muscle glycogen (energy) -release of adipose tissue lipids

acetylcholine

___________ excites digestive system

Atropine

____________(from Atropa belladonna)- blocks parasympathetic effects; is a competitive antagonist of the muscarinic receptors; increase heart rate, dilate pupils (eye exams). Atropine will also reverse the effects of poisoning by nerve gas

Postganglionic

_____________ (second) neuron (unmyelinated) extends to effector organ

Cholinergic Receptors

______________ (bind ACh) 2 types: nicotinic receptors and muscarinic receptors

Adrenal medulla

______________ (innervated by preganglionic neurons); center of adrenal gland, releases epinephrine and norepinephrine as hormones (prolong sympathetic response)

Unconscious

______________ ANS control can maintain homeostasis and vital physiological processes without conscious input, Ex: survival in a coma can continue for decades

parasympathetic

_______________ activation effects -constrictions of pupils and lenses focus for near vision -increased digestive organ activity -reduction in heart rate and blood pressure -stimulation and coordination of defecation -contraction of urinary bladder during urination -constriction of respiratory passageways

enteric nervous system

_________________ considered by some as a 3rd division of ANS

epinephrine and norepinephrine

_____________________ can be released during the sympathetic division NT release

Nicotine receptors

are found on: -all postganglionic neurons of both sympathetic & parasympathetic divisions -Hormone- producing cells of adrenal medulla -Motor end plates (somatic targets)

B1 receptors

cardiac muscle stimulation and increased tissue metabolism; * beta blockers bind to these (decrease heart rate, blood pressure)

Autonomic Nervous System

consists of motor neurons that: innervates smooth & cardiac muscle, glands, adipose tissue, are under subconscious control

Cranial Nerve

effector organ(s)

SNS

epi-pen

adrenaline

epinephrine

Muscarinic receptors

found on all effector cells stimulated by postganglionic cholingergic fibers in Parasympathetic n.s

a1 receptors

generally excitatory

a2 receptors

generally inhibitory

Beta receptors

generally stimulated by E, 3 classes

beta blockers

have very limited side effects

Vagus X

heart, lungs, and most visceral organs

intramural ganglia

in target organ wall

epinephrine

in the sympathetic, __________ is only a hormone, not a neurotransmitter

occulomotor III

iris of eye

S-S4

large intestine, urinary bladder, ureters, and reproductive organs

hypothalamus

master of the autonomic nervous system (control center), main integration center of ANS activity

Parasympathetic division ganglia

may be found in: terminal ganglia (near target organ), intramural ganglia (in target organ wall)

efferent

motor

terminal ganglia

near target organ

ganglion

nerve cell bodies outside CNS

enteric nervous system

network of neurons (~100 million) within walls of digestive tract, influenced by sympathetic and parasympathetic divisions, however many complex visceral activities are coordinated on a local level (without CNS instructions)

cerebral cortex

other controls come from the ___________________, the reticular formation and the spinal cord

craniosacral

parasympathetic division ganglia

Sympathetic divisions

preganglionic fibers (neurons) are short while postganglionic fibers (neurons) are long; so sympathetic ganglia (where these neurons synapse) are near spinal cord

sympathetic division

prepares body for heightened levels of somatic activity "kicks in" during exertion, stress, or emergency

Parasympathetic Division

regulation of visceral function and energy conservation

B2 receptors

relaxation of respiratory passage and blood vessel smooth muscle

B3 receptors

release of fatty acids from adipose tissue

Facial VII

salivary, nasal, and lacrimal glands

afferent

sensory

Alpha receptors

stimulated by NE and E

Sympathetic division

the ___________________ controls: thermoregulatory responses to heat; dilation of blood vessels of skin brings warm blood to surface & activates sweat glands to cool body; when temperature falls, blood vessels constrict & blood is retained by vital organs

sympathetic division

typical responses of the ___________________: 1. increased metabolic rate; activation of energy reserves; heightened mental alertness 2. reduced digestive and urinary functions 3. increased respiratory rate 4. elevated heart rate and blood pressure 5. activation of sweat glands *increase blood and energy flow to muscles