Neuro Flashcards
Microglial Cells
Astrocytes
glial cells in CNS
maintain the BBB and provide support to neurons
Ependymal Cells
Oligodendrocytes
form the myelin sheath in CNS
Satellite cells
PNS
cling to neurons, synaptic endings and capillaries
provide support and nutrients to the cell bodies of neurons
**NO regeneration – this is shwann
Schwann Cells
PNS
surround all peripheral nerve fibers and form meylin sheaths in thicker nerve fibers
VITAL to regeneration of damaged peripheral nerve fibers
neuron cell body
Nuclei : clusters of neuron cell bodies in CNS
Ganglia: clusders of neuron cell bodies in PNS
Neuron processes
Tract: bundle of neuron processes in CNS
Nerves: bundles of neuron processes in PNS
two types of processes:
1. dendrites
2. Axon
Resting state
all Na+ and K+ channels are closed
activation gates
open with depolarization… this allows Na+ to enter cell
inactivation gates
open at rest, blocks channel once it is open to prevent more Na+ from entering cell
Depolarization
Na+ channels open
- depolarizing local currents open the voltage gated Na+ channels…. and Na+ RUSHES INTO CELL
Na+ activation & inaction gates open
Na+ influx causes more depolarization which opens more Na+ channels
@threshold… -55 to -50 V, positive feedback causes opening of all Na+ channels
- this causes a large action potential spoke
- membrane polarity jumps to +3V
Repolarization
Na+ channels are inactivating and K+ channels open
Na+ channel inactivation gates close…
voltage gated K+ channels open
REPOLARIZATION: when membrane returns to resting membrane potential
Hyperpolarization
some K+ channels remain open and Na+ channels reset
Ca2+ entry causes synaptic vesicles to release neurotransmitter
Ca2+ causes synaptotagmin protein to react with SNARE proteins …. which control fusion of synaptic vesicles with axon membrane
sympathetic chain ganglia
collection of nerve fiber cell bodies in the Sympathetic chain
Visceral motor neurons located in the intermediolateral horn of the spinal cord from…
T1-L2
axons can take three different paths
can exit at different levels of the nerves
Splanchnic nerve
Sympathetic nerve…
coming AWAY from the sympathetic chain…
outside
Preganglionic nerves… SYMPATHETIC and PARASYMPATHETIC release….?
release Acetylcholine
Sweat glands, and certain blood vessels release…
Acetylcholine…
POST-ganglionic sympathetic nerves release…
Norepinephrine (NE)
which amino acid leads to the synthesis of Ne and EPI
tyrosine
tyrosine to NE pathway
Tyrosine… DOPA… Dopamine… Norepinephrine
alpha
located on blood vessels – vasoconstriction
beta-1
beta constrictors
force of muscle contraction
activation – increases HR and contractility
Beta-2
cause vasodilation
anything that gets upregulated
activation – bronchial dialtion, dialtion of blood vessels in skeletal muscle and glycogenolysis
Occulomotor Nerve
Fibers to pupillary pshincters and ciliary muscle
Facial Nerve
CN 7
fibers to nasal, lacrimal and submandibular gland
Glossopharyngeal nerve
CN 9
fibers to parotid gland
vagus N
CN 10
motor inputs to visceral organs
sacral segments
fibers to descending colon
rectum
bladder
and genitalia
Parasympathetic Functions
nerves release Acetylcholine (ACh) at nerve endings
these are CHOLINERGIC nerves
ALL preganglionic sympathetic nerves release acetylcholine….
ALL postganglionic sympathetic nerves release ACh…
ACh stimulates… what?
ACh stimulates nicotinic and muscarinic receptors
Nicotinic receptors
located in synapses between pre and post ganglionic neurons and at the NEUROMUSCULAR JUNCTION
part of the sympathetic nervous system
voluntary muscle coordinator
BETWEEN pre and post neurons for sympathetic and parasympathetic
muscarinic receptors
Located at ALL effectors cell stimulated by post ganglionic parasympathetic fibers
only at effector organs
adrenergic receptors
heart – beta 1
lung – beta 2
stomach – alpha
sweat gland receptors
acetylcholine
Structures of the brain
Ascending tract
Descending Tract
Brainstem questions….
are most often the medulla!
Brain Stem parts & function
Endoderm
glands, other organs,
Mesoderm
muscles, bones, connective tissues
Ectoderm
three parts:
1. Neural crest
2. Neuroectoderm (brain and spinal cord)
3. Surface Ectoderm
menstrual cycle & vision… pituitary – FSH, LH, pituitary adenoma… crosses the optic chiasm
Anterior pituitary
balances menstrual cycle
Middle Cranial Fossa
ischemia
generalized decreased blood flow
shock, cardiac arrest, hypoxic episodes
** the purkinje cells of the cerebellum and pyramidal neurons of sommer’s sector in the hippocampus – sensitive to ischemic damage and are likely to demonstrate damage
