Biology Flashcards
synapses can be both…
chemical and electrical
inhibitory synapses cause the release of….
neurotransmitters that cause an influx of negative ions or an efflux of positive ions leading to hyper polarization, inhibiting the action potential
Multiple sclerosis is a
neurodegenerative disease in which immune cells attack the myelin sheaths surrounding axons in the central nervous system (CNS).
Huntington’s disease
is an autosomal dominant genetic neurodegenerative disease in which neuronal loss occurs in extensive regions of the brain, including the basal ganglia.
in the CNS, gray matter is composed of
neuronal cell bodies
in the CNS, white matter is composed of
axons that allow long-distance communication between neurons
In the white matter of the spinal cord, afferent axons carry
sensory information to the brain
in the white matter of the spinal cord, efferent axons carry
motor commands to the body.
the glial cells of the CNS are
oligodendrocytes, astrocytes and ependymal cells, microglia
oligodendrocytes
form myelin sheaths around axons to reduce ion leakage and increase action potential propagation speed
astrocytes
support, blood-brain barrier, interstitial space
ependymal cells
epithelial cells that line the compartments of the CNS and secrete CSF
Glial cells in the PNS
Schwann cells (myelin)
satellite cells (structural support + nutrients to near cell bodies)
microghlia
macrophages of the CNS
the blood brain-barrier is composed of
endothelial cells held together by tight junctions to regulate transport through four routes
route 1 to BBB
paracellular transport (between cells) is limited for hydrophilic molculces
route 2 to BB
transcellular route will allow small, lipophilic molecules in by passive transport (diffusion), including
non polar gases (e..g diatomic, CO2)
steroid hormones
route 3 to BBB
carrier-mediated transport which uses facilitated diffusion and active transport allows large or hydrophilic molecules like amino acids or nucleosides
route 4 to BBB
through endocytosis to transport molecules in bulk
aldosterone
secreted by the adrenal cortex, increases na absorption to increase water retention in the kidneys to increase blood pressur/volume
norepinephrine and epinerine from the adrenal medulla
mobilize body under extreme stress including changes to blood vessel diameter
vasoconstriction
higher BP but lower nutrients delivered to tissues
vasoconstriction
lower BP but more nutrients delivered to tissues
adrenal cortex makes
steroid hormonesad
adrenal medulla
makes peptide hormones
an endogenous substance is
one that is produced in the body e.g. endogenous cortisol
myelin sheath has nodes of ranvier where charges can leak across the swath and back into the extracellular space.
when AP flows down from node to node
saltatory conduction
