The Autonomic Nervous System and Higher-Order Functions Flashcards
Autonomic nervous system
Adjusts our basic life support systems without conscious control
ANS
Coordinates cardiovascular, respiratory, digestive, urinary, and reproductive functions
Preganglionic neurons
- CNS
- Send axons to synapse on ganglionic neurons in autonomic ganglia outside the CNS
Sympathetic division
- Fight or flight
- Made of preganglionic fibres from T1-L2, ganglionic neurons in ganglia near vertebral column and neurons in adrenal glands
Parasympathetic division
- Rest and digest
- Made of preganglionic fibres leaving the brain and sacral segments
2 types of sympathetic ganglia
Sympathetic chain ganglia and collateral ganglia
Sympathetic chain ganglia
Anterior roots in spinal segments in T1-L2 give rise to myelinated white ramus communicans which in turn leads to the sympathetic chain ganglia
Postganglionic fibres
Target structures in the body wall and limbs rejoin the spinal nerves and reach their destinations by way of the posterior and anterior rami
Splanchnic nerves
Formed from preganglionic fibres that innervate the collateral ganglia
Celiac ganglion
Innervates the stomach, liver, gallblader, pancreas, and spleen
Superior mesenteric ganglion
Innervates small intenstine and initial segments of the large intestine
Inferior mesenteric ganglion
Innervates the kidneys, urinary bladder, terminal portions of the large intestine and the sex organs
Adrenal medulla
Preganglionic fibres entering the adrenal gland synapse within the adrenal medulla
Sympathetic activation
- In crisis, the entire sympathetic division responds
- Increased alertness, energy and euphoria, increased cardiovascular and respiratory activites, elevation in muscle tone, mobilisation of energy reserves
Stimulation of sympathetic division
Secretion of:
- ACH or norepinephrine (NE) at specific locations
OR
- Epinephrine (E) and NE into the general circulation
Varicosities
Sympathetic ganglionic neurons end in telodendria studded with varicositites containing neurotransmitters