Nervous System: Efferents Flashcards
Three types of neurons
- Afferent -????
- Efferent - lead from brain/spinal cord to effector
- Interneuron (association) - contained w/in the CNS
CNS
- Brain
- Spinal cord
PNS
- Efferent
- Afferent
Efferent
- Autonomic
- Somatic
Afferent
- Visceral
- Sensory
Autonomic
- Parasympathetic
- Sympathetic
Somatic Nervous System
- cell bodies lie w/in the CNS
- direct connection to skeletal muscle
- Ach released at neuromuscular junction onto nicotinic receptor
- always excitatory (allow more Na+ in than K+ out = depolarization)
Autonomic NS
- innervates all tissue except skeletal muscle
- two neurons b/t CNS & effector
—1st neuron’s soma w/in CNS
—NT at synapse always Ach onto nicotinic receptors - either excitatory or inhibitory (effect
Sympathetic
Ganglia lie close to CNS
- Utilize NorEpi at postganglionic synapse
- Adrenergic receptor at postganglionic synapse
Parasympathetic
Ganglia close to innervated tissue
- Utilize Ach at postganglionic synapse
- Muscarinic receptors at postganglionic synapse
Tissue: Bronchial
Sympathetic:
*Beta 2
- Increases strength
Parasympathetic:
*M
- Contract
Dual innervation
Many tissues affected by both sympathetic & parasympathetic NS
Tissue: Heart
Sympathetic:
*Beta 1
- Increases rate
- Increases strength
Parasympathetic:
*M
- Decreases rate
Initially treated asthma patients w/ Epi…
But targeted ALL adrenergic receptors
- need a target response towards Beta 2 (Beta 2 agonist)
Synapses in the Autonomic Neurons
- Many autonomic neurons lack traditional bouton endings at a synapse
- Instead, swellings called VARICOSITIES influence effectors cells
- AP initiates neurotransmitter released into ECF
- NT impact a larger area (not limited to cleft region)
- Effector response is slower acting but for longer duration
Fascicle
Bundle of neurons
- wrapped with CT
Perinerium
Binds fascicle
Epineurium
Surrounds nerve
- blood vessels present to provide nutrients
Everything (afferent) goes into spinal cord _______
Dorsally aka posterior
Everything (efferent) comes out of spinal cord ______
Ventrally aka anterior
Ganglion
Collection of cell bodies
Gray matter
unmyelinated
White matter
Myelinated
43 pairs of nerves
- 12 cranial (brain)
- 31 peripheral (comes out spine)
— cranial nerve #1 comes out above bone #1 and so on…
— thoracic nerves comes out below
Homeostasis is?
Dynamic balance between the autonomic branches
- with very precise control
Rest-and-digest
Parasympathetic activity dominates
Fight-or-flight
Sympathetic activity dominates
Adrenal cortex is a?
true endocrine gland
Adrenal medulla is a?
modified sympathetic ganglion
- Epi comes from here
The adrenal gland also acts as part of the?
?????missing
Betas use?
cAMP
Parasympathetic NS originates from?
Craniosacral region
Sympathetic NS originates from?
Thoracolumbar region
