Autonomic Nervous System Flashcards
How is Homeostasis maintained?
balance between ANS, Endocrine system and behavioral systems
What are the three Homeostatic Control Centers?
- Hypothalamus
- Pons
- Medulla
What is the Parasympathetic NS?
Rest and Digest (PNS Dominates)
What is the Sympathetic NS?
Fight/Flight (SNS Dominates)
ANS’s Antagonistic Control
Both PNS and SNS can act as agonist’s or antagonists but they always oppose one another, like a dance
SNS origin in the CNS
thoracic and lumbar spine
SNS Ganglion Location
within the spinal cord
SNS Neuron Pathways
1st = short
2nd = long
PSNS Origin in CNS
brainstem and sacral spine
PSNS Ganglion Location
close to target organ
PSNS Neuron Pathways
1st = long
2nd = short
SNS Neurotransmitters
- Acetylcholine
- Norepinephrine
SNS Receptor
- Adrenergic receptor
PSNS Neurotransmitters
- Acetylcholine twice
PSNS Receptors
- Muscarinic Receptors
Synapses at Target Cells
Called Neuroeffector Junctions
1. Autonomic Varicosities release nt’s over the surface of target cells
2. branch out and innervate a large area of tissue
Adrenal Medulla
- Specalized part of the SNS
- two parts, cortex and medulla
Adrenal Cortex
- true endocrine gland that secretes hormones
Adrenal Medulla
- modified sympathetic ganglion made up of chromaffin cells
Nicotinic Acetylcholine Receptor Details
- binds two ACh molecules
- opens and allows K+ and Na+ to enter and leave
- Na+ enters more rapidly and depolarizes the tissue
SNS Target Cell Receptors
- Alpha and Beta
- All GPCR’s with a different response and different affinity for NE and E
PSNS Target Cell Receptors
- 5 different types of Muscarinic receptors
- All are GPCR’s with different ICF response
