Autonomic Nervous System Flashcards
Efferents of the Autonomic Nervous System: Preganglionic cell bodies
in CNS
Efferents of the ANS: Postganglionic cell bodies
in peripheral ganglia
Sympathetic Nervous System efferents
Short pre-ganglionic neurons (T1-L2)
Long post-ganglionic neurons (near spinal cord)
Organ/Tissue involvement in Sympathetic Nervous System activity
sympathetic nerve activity to multiple tissues can be increased simultaneously
Parasympathetic Nervous System efferents
Longer pre-ganglionic neurons (cranial nerves and sacral nerves)
Short post-ganglionic neurons (in or near the target tissue)
Organ/Tissue involvement in Parasympathetic Nervous System Activity
parasympathetic nerve activity to each tissue is usually under SEPARATE control
Sympathetic effect: Saliva production
decrease
Parasympathetic effect: Saliva production
increase
Sympathetic effect: Heartrate
increase
Sympathetic effect: Intestinal mobility
decrease
Sympathetic effect: Glucose release
increase
Sympathetic effect: Urination
decrease
Sympathetic effect: Relaxes/Dilates airway
increase
Sympathetic effect: Nasal Secretion
decrease
Sympathetic effect: Blood Pressure
increase
Parasympathetic effect: Heartrate
decrease
Parasympathetic effect: Intestinal mobility
increase
Parasympathetic effect: Glucose release
decrease
Parasympathetic effect: Urination
increase
Parasympathetic effect: Relaxes/dilates airway
decrease
Parasympathetic effect: nasal secretions
increase
Parasympathetic effect: blood pressure
small decrease
When do the sympathetic and parasympathetic systems NOT antagonize each other
Sexual function:
Parasympathetic- Erection
Sympathetic- Ejaculation
T/F There is a lot of parasympathetic innervation of blood vessels
FALSE. decreases in blood pressure are mediated mostly by sympathetic withdrawal
Parasympathetic: NT and receptor
Acetylcholine
Muscarinic receptor
Sympathetic: NT and receptor
Norepinephrine
Alpha or Beta adrenergic receptors
(some sympathetic postganglionic neurons release acetylcholine i.e. sweat glands)
Adrenal Medulla: NT and receptor
Acetylcholine
Epinephrine (80%)
Norepinephrine (20%)
Blood vessels
Pre-ganglionic NT and receptor in both
Acetylcholine
Nicotinic receptor
Adrenergic receptor: Alpha- 2 subtypes
contractile effects of norepinephrine/epinephrine
blood vessels, urogenital, sphincters
Adrenergic receptor: Beta- 3 subtypes
B1- stimulatory effects of norepinephrine/epinephrine in the heart
B2- relaxing effects (epinephrine > norepinephrine)
GI tract, urogenital system, airway, some blood vessels
The controlled elimination of urine
micturition
leaking urine
incontinence
T/F There is parasympathetic, sympathetic, and somatic control of bladder function
TRUE
Control of Bladder: Parasympathetic Stimulation
contraction of bladder wall (Detrusor)
relaxation of internal sphincter
Control of Bladder: Sympathetic Stimulation
relaxation of bladder wall
contraction of internal sphincter
Control of Bladder: Alpha Motor Neuron
contraction of external sphincter
Detrusor muscle
(smooth) relaxed: filling
contract: emptying
Internal sphincter
(smooth) contracted: filling
relaxed: emptying
External Sphincter
(striated, like skeletal muscle) contracted: filling
relaxed: emptying
Spinal Reflex- Autonomic Afferent (urination)
What reflex activation is expressed?
stretch receptors in the bladder wall are activated when the bladder is stretched (filled);
parasympathetic nerves to the bladder walll, causing it to contract
Supra-spinal reflexes (urination)
What reflex activated is expressed?
Sympathetic- brain stem (micturition center) that causes reflex relaxation of the sphincters allowing urine to leave bladder
Activation of the sympathetic nervous system increases blood pressure by:
- Contracting vascular smooth muscle around blood vessels to decrease their diameters and therefore increase total peripheral resistance
- Increasing heart rate, cardiac contractility (SV), and therefore, cardiac output
Activation of the parasympathetic nervous system can decrease blood pressure by _____.
decreasing heart rate
Arterial baroreceptor reflex inhibits what and activates what?
inhibition of sympathetic efferents and activation of the parasympathetic efferents so that BP returns to NORMAL
Where are baroreceptors located?
carotid sinus and aortic arch (goes to brain stem)
Hypothalamus functions
coordinated regulation of visceral function by ANS and the endocrine system
