2.5 - Efferent Branch of PNS Flashcards
What are the 2 divisions of the PNS?
- autonomic division
- somatic division
TRUE OR FALSE:
The autonomic division is made of 1 single neuron while the somatic division is made of 2 neuron chains
FALSE:
Autonomic: 2 neuron chains
somatic: single neuron
What does the autonomic division innervate?
- smooth and cardiac muscle
- glands
- some adipose tissue
What is another term for the autonomic division?
involuntary division
What does the somatic division innervate?
skeletal muscle fibers/cells
What is another term for the somatic division?
voluntary division
What are the different branches of the autonomic division?
sympathetic
- fight or flight response
- physical activity and stress
parasympathetic
- rest and digest
the sympathetic and parasympathetic divisions are _____ to one another
antagonistic/opposite responses
Where does the sympathetic ganglia run?
close to the spinal column or along the descending aorta
SYMPATHETIC GANGLIA: TRUE OR FALSE
long nerves project into target tissues
short post ganglionic axons, long pre ganglionic axons
TRUE
FALSE:
Short pre ganglionic, long post ganglionic axons
Where do the parasympathetic ganglia originate?
- in brain stem, axons leading in cranial nerves
- in sacral region to control pelvic region
TRUE OR FALSE: PARASYMPATHETIC GANGLIA
long pre ganglionic axons, short post ganglionic axons
TRUE
Pre ganglionic neurons of the sympathetic and parasympathetic neurons release ____ onto ____
ACh, cholinergic muscarinic receptors
Post ganglionic neurons of the sympathetic and parasympathetic neurons release ___ onto _____
Sympathetic: N.E. onto adrenergic receptors
para: ACh onto muscarinic receptors
What are varicosities?
swollen areas at distal ends of the synapse in the autonomic nervous system
How do NTs get secreted from varicosities?
- voltage gated Ca2+ channels open up allowing Ca2+ to enter the cell to trigger the exocytosis of NTs
How is NT action terminated in autonomic pathways?
- diffusion
- metabolism
- active transport back into cells near synapse
What are the 2 types of receptors for regulation of body systems?
- adrenergic receptors = for E and NE
- cholinergic receptors = for ACh
What are some adrenergic receptors for E and NE?
Alpha 1: found on most tissues = NE > E
Beta 1: heart muscle and kidneys NE=E
BETA 2: blood vessels, smooth muscle: E>NE
B1 and B2 stimulate ______ production
cAMP
A1 receptors increase ____ levels in the cytoplasm
Ca2+
Nicotinic receptors are stimulated by ________ while muscarinic receptors are stimulated by _____
nicotinic: ACh and nicotine (agonist)
muscarinic (ACh and muscarine)
Where are nicotinic receptors found?
on skeletal muscle motor end plates and sympathetic and parasympathetic ganglia
TRUE OR FALSE:
Both nicotinic and muscarinic receptors are always excitatory
FALSE:
nicotinic: always excitatory
muscarinic: can be either excitatory or inhibitory
Nicotinic receptors act via _____ while muscarinic receptors act via ____
ion channels, G proteins
What is the effect of NE and ACh on heart rate?
NE: increases heart rate
ACh: decreases heart rate
What are the 2 parts of the adrenal gland?
adrenal medulla
- associated with sympathetic pathway
- special cells called chromafin cells secrete E to travel in blood
adrenal cortex:
- secretes steroid hormones in bloodstream
TRUE OR FALSE:
The somatic division controls both muscle excitation and inhibition
FALSE
controls only excitation
in the neuromuscular junction of the somatic divisions, the _____ contains ACh
presynaptic axon terminal, filled with NTs vesicles containing ACh
The post synaptic membrane of skeletal muscle fibers contain _____ receptor channels
nicotinic ACh
