ANS Flashcards
Somatic NS
voluntary movement
Afferent (sensory)
Efferent (motor)
Autonomic NS
automatic; sympathetic vs parasympathetic
ANS role
regulation of cardiovascular system
regulation of homeostasis: body temp, HR, BP, intestinal activity, salivation, sweating, pupil diameter
referred to as visceral, vegetative, or involuntary NS
Afferent neurons
important in reflexes, necessary to maintain homeostasis (feedback loops)
Efferent neurons
innervate smooth muscle, cardiac muscle, exocrine glands, secretory epithelia
why do we focus more on efferent neurons for HTN treatment?
neuronal discharge directly alters function of effector organ
more is known about the neurotransmitters of the efferent side
We can manipulate pharmacologically
Sympathetic preganglionics
thoracolumbar
Spinal segments T1-L3
intermediolateral cell column (IMLCC)
Parasympathetic preganglionics
Craniosacral
Cranial Nerves 3, 8, 9, 10
Sacral segments 2-4 of spinal cord
Preganglionic neurons are ___
Postganglionic neurons are ____
myelinated; unmyelinated
The synapse between pre and postganglionic neurons both involve
nicotinic receptors and ACh as the neurotransmitter
Synapse between the postganglionic neuron and effector organ
parasympathetic: ACh and targets muscarinic receptors
sympathetic: NE and E as they target alpha and beta adrenergic receptors
The adrenal medulla is only innervated by the
sympathetic neurons
NE is synthesized from
dopamine
ACh is synthesized from
choline and acetyl CoA
What breaks down ACh?
acetyle cholinesterase