Neurobiology 4 Flashcards
Structure of peripheral nerves:
- axons - can be myelinated or unmyelinated
- CT: endoneurium (around axons), perineurium (around bundles axons), epineurium (around nerves)
- schwann cells - myelinate axons
- blood vessels
how do you differentiate a nerve from an artery?
- solid and do not stretch, arteries are hollow and stretchy
what are the parts of the peripheral nervous system?
- somatic and autonomic
- autonomic: enteric, sympathetic, parasympathetic
What is the autonomic nervous system?
- regulates involuntary physiological processes: heart rate, bp, respiration, digestion, sexual functioning
- sympathetic, enteric, parasympathetic
discuss somatic nervous system
- conscious sensation and voluntary movement
- effects skeletal muscle
- motor pathways: one neuron, one cell body in CNS
discuss autonomic nervous system
- visceral sensation, cardiac and smooth muscle contraction, gland secretion
- effects smooth muscle, glands, cardiac muscle
- motor pathway: 2 neurons that synapse outside CNS
what is the function of sympathetic?
response to stress
what is the function of parasympathetic?
maintenance of homeostasis
response time of sympathetic
- fast
response time of parasympathetic
- slower
location of ganglia in sympathetic?
- chain parallel to spinal cord
location of ganglia in parasympathetic
in or near target organ
What is the origin of the sympathetic?
- lateral horns of thoracic and lumbar spinal grey matter
what is the origin of the parasympathetic
brainstem nuclei and sacral spinal grey matter
length of sympathetic axons
short pre, long postganglionic
length of parasympathetic axons
long preganglionic, short postganglionic
neurotransmitter released by presynaptic neuron in sympathetic?
acetylcholine
what is the neurotransmitter released by presynaptic neuron in parasympathetic?
acetylcholine
What is the neurotransmitter released by post-synaptic neuron in sympathetic?
norepinephrine
what is the neurotransmitter released by postsynaptic neuron in parasympathetic?
acetylcholine
discuss sympathetic
- fight, flight, or fright (imagine running from bear)
- activated in stress
- increased heart rate, resp rate, blood flow to muscles
- dec digestive process
- innervates almost every tissue in body
- ganglia in chain next to cord
motor pathways of sympathetic
preganglionic neuron: short axon, cell bodies in intermediolateral cell column, synapses in sympathetic ganglion, acetylcholine
postganglionic neuron: long axon, cell bodies in sympathetic ganglion, synapses on effector organ, norepinephrine
sensory pathway of sympathetic:
cell bodies in dorsal root ganglion
adrenal gland
- craniomedial to kidney
- endocrine gland - releases chem msgs to blood
- cortex: controlled by pituitary
- medulla: controlled by sympathetic nerves, releases epi or norepi
discuss parasympathetic
- rest and digest
- dec heart rate, bp, inc digestion
- ganglia located in or near target organ
motor pathways parasympathetic
- preganglionic neuron: long, cell bodies in brain and cervical spinal cord, synapse in ganglia near or in target organ, acetylcholine
- postganglionic neuron: short, cell bodies in parasympathetic ganglia, synapse on effector organ, acetylcholine
sensory pathway of parasympathetic
- similar to cranial and spinal nerves (sacral and brain)
- follow cranial nerves III, VII, IX, X
enteric nervous system
- web-like series of neurons located in wall of intestine
- vagus and sympathetic
