Biology - Nervous System Flashcards
what are the functional units of the nervous system?
nephrons
protozoa have what kind of nervous system?
NONE! (single cells)
cnidarians have what kind of nervous system?
nerve net
annelids have what kind of nervous system?
primitive central nervous system
arthropods have what kind of nervous system?
central nervous system
dendrites……information
receive
the cell body of a neuron contains the…
nucleus and controls metabolism
what kind of cells produce myelin?
glial cells
Oligodendrocytes make myelin in the ….
central nervous system
Schwann cells make myelin in the….
peripheral nervous system
the resting potential of a neuron is
-70 mV (the inside is more negative)
the Na/K pump put how many Na and K across the membrane?
3 Na+ out for every 2 K+ into the cells
when is an action potential generated?
when the inside becomes less negative…-50 mV
what is the refractory period?
time that Na+ channels recover from inactivation
what channels open in action potential?
voltage-gated Na+ channels….depolarization of that segment
what channels are open in depolarization?
voltage-gated K+ channels
stimulus intensity is coded by….
the frequency of action potentials (because it is an all-or-none-response)
what makes the backward travel of action potentials impossible?
the refractory period
what increases propagation speed?
a larger diameter and more myelination
what is the effect of curare?
inhibits postsynaptic acetylcholine receptors…leads to paralysis
what is the effect of botulism toxin?
inhibits release of acetylcholine
what are afferent neurons?
sensory information
what are efferent neurons?
motor commands
what are the two layers of the brain?
outer: grey matter of cell bodies
inner: white matter of myelinated axons
3 sections of the brain?
hindbrain, midbrain and forebrain
functions of telencepahlon
FOREBRAIN
cerebral cortex: sensory info, motor responses, creativity
olfactory bulb: odor input
functions of diencephalon
FORE BRAIN
thalamus: relays info for spine and cerebral cortex
hypothalamus: visceral functions (hunger, thirst, sex drive) and controls endocrine system
functions of the midbrain
vision, hearing and motor control
components of the hindbrain
pons, medulla and cerebellum
functions of cerebellum
motor, balance, etc.
function of pons
allows cerebellum to communicate with the cortex
function of medulla
breathing regulation, heart rate, gastrointestinal activity, etc
two divisions of the peripheral nervous system?
somatic and autonomic
what does the somatic nervous system innervate? what does it control?
skeletal muscles; voluntary movements
what does the autonomic nervous system regulate?
internal environment of the body without conscious control
the ANS innervates what?
both cardiac and smooth muscle
where are smooth muscles located?
blood vessels, digestive tract, bladder, etc.
two subdivisions of the ANS?
sympathetic and parasympathetic.
what nervous system is responsible for fight or flight?
sympathetic of the ANS
main NT of sympathetic nervous system?
norepinephrine
what does the parasympathetic system do?
restores energy after exertion (rest and digest)
main NT of parasympathetic system?
acetylcholine
main nerve of parasympathetic system?
vagus nerve
what is the sclera?
opaque layer of the eye (white of eye)
what is the choroid layer of the eye?
supplies retina with blood
what part of the eye contains photoreceptors?
retina
what part of the eye focuses light rays?
cornea
what part of the eye controls the diameter of the pupil?
iris (colored part)
what focuses the image on the retina?
the lens, whose shape and focal length is controlled by ciliary muscles.
what helps with high-acuity vision?
fovea (small part of retina)
what combine to have the optic nerve?
ganglion cells
what is vitreous humor?
jelly in eye that maintains the shape and properties of the eye
what is aqueous humor?
formed by the eye and exits through ducts
what is myopia?
nearsightedness (in front of retina)
what is hyperopia?
farsightedness (behind retina)
what causes an astigmatism?
irregularly shaped cornea
cataracts cause….
lens to become opaque
glaucoma is the…
increase of pressure in the eye because of a blockage of the outflow of vitreous humor?
path of sound through the ear:
outer ear, auditory canal, tympanic membrane (vibrates), ossicles (amplify and vibrate), oval window, inner ear receives pressure (cochlea and vestibular apparatus), hair cells are stimulated and transduce action potentials
3 bones that make up ossicles:
incus, stapes and malleus
