Autonomic Nervous System Flashcards
What is the function of the ANS
controls homeostatic mechanisms via autonomic reflexes; Operates mostly out of conscious awareness
What are the sensory afferents to the ANS
Transmitted by cranial nerves (III, VII, IX, X) to homeostatic control centers in brainstem and hypothalamus
what are the motor efferents of the ANS
sequence of two neurons project to effect tissue
what are the visceral effectors
smooth muscle, gland cells, cardiac muscle
what is the somatic motor system
- controls skeletal muscle
- local transmitter release at NMJ
- Single neuron from CNS to muscle
what is the autonomic motor system
- controls smooth muscle, cardiac muscle, and glandular tissue
- diffuse NT release
- two neurons from CNS to muscle
what are the pre ganglionic neurons in the ANS
- originate in the CNS
- Cell bodies located in brainstem and spinal cord
- Project to post ganglionic neurons
what are the post ganglionic neurons in the ANS
- Cell bodies in peripheral ganglia
- Communicate with a peripheral effector
what is the sympathetic nervous system
prepares body to face danger
active during exercise
what are the effects of the sympathetic nervous system
pupil dilation (mydriasis)
Adaption of lens for distance
bronchodilation
increased heart rate
vasoconstriction
sweating
Describe the paravertebral chain ganglia
lateral horns of spinal cord
thoracic and lumbar regions only
What are the terminations of sympathetic preganglionic neurons
1) Synapse in chain ganglion at level of entry
2) Project within the paravertebral chain to synapse in more superior or inferior chain ganglion
3) Can pass through vertebral chain to synpase on a prevertebral ganglion
Describe post ganglionic neurons of the sympathetic nervous system
Receptor: Acetylcholine
Release: norepinephrine, epinephrine
what is the adrenal medulla
receives input from sympathetic preganglionic neurons
release NE and EPI into the blood
What is the parasympathetic nervous system
rest and digest
active during quiet/resting conditions
