Unit 3 Flashcards
Dendrites
receive information and put it toward the cell body
Axons
transmit signals away from the cell body, usually longer and have fewer branched extensions
Axon hillock
where signals that are coming into the cell body are tallied
Action potential
nerve impulse - brief electrical signal that is sent down the axon
Axon terminal
lies close to an adjacent cell, almost touching but not quite
Chemical synapse
communication pathway
Synaptic cleft
the space between two cells where the communication pathway lies
Presynaptic cell
the cell giving out the neurotrnasmitters
Postsynaptic cell
the cell receiving the neurotransmitters
Neurotransmitter
chemical messenger
Receptors
Channels that let in ions, but instead of responding to changes in voltage, they are binding to neurotransmitters - ligand-gated channel
Glial cell
support cell for neurons
Astrocyte
specialized glial cell, helps maintain the blood/brain barrier
Schwann cells
insulate motor and sensory neurons
Oligodendrocytes
insulate brain and spinal cord
Myelin sheath
Schwann cells and oligodendrocytes
Nerve signal
a change in the voltage across the plasma membrane of a neuron
Voltage
change in the electrical signal between two points
Ion
charged molecule or simple element
Membrane potential
the charge that is held across the plasma membrane of a cell
Refractory period
the time it takes the cell to reset to fire again
Action Potential
a rapid change in the voltage across a cell membrane that occurs when a cell is activated by a stimulus
Speed is affected by
diameter of axons and myelination
Nodes of Ranvier
axon spaces between adjacent myelin internodes
Saltatory Conduction
signals hopping from one node to the next
Electrical Synapse
two cells directly connected by a gap junction, signals can go from one to the next immediately
Chemical Synapse
Nerve and muscle cells, narrow gap with no physical connection, allows for a variable reponse
Receptors
proteins in the postsynaptic membrane that bind to neurotransmitters and cause electrical responses in the postsynaptic cell
Ligand-gated Channels
proteins in the cell membrane that open and close in reponse to a chemical messenger
Acetylcholinesterase
an enzyme that breaks up down acetylcholine
Acetylcholine
a neurotransmitter that carries chemical messages between nerve cells and other cells in the body
EPSP = Excitatory Post-Synaptic Potential
Depolarizing; closer to threshold and more likely to fire (sodium channels are opened)
IPSP = Inhibitory Post-Synaptic Potential
Repolarizing; potassium channels are opening
Summation
Addatory effect of post-synaptic potentials; the cumulative effect of multiple electrical impulses on a neuromuscular junction, which is the junction between a nerve cell and a muscle cell
Temporal Summation
Firing multiple times from the same axon
Spatial Summation
Multiple different axon firing once
Sensory transduction
changes the form of a signal
Chemoreceptors
molecule binding to a membrane on a protein which is caused by a chemical change in the environment
Taste buds
a group of chemoreceptors
Papillae
the bumps on your tongue (these have taste buds on them)
Microvilli
extensions off of sensory cells (on the tongue) that create more surface area
5 different kinds of taste
sweet, salty, sour, savory (umami), bitter
Mechanoreceptors
hair cells (stereocilia)
Statocyst
sensory organ that contains the statolith
Statolith
position stone, moves and depresses stereocilia which provides gravity detection
Outer ear consists of
pinnae, external auditory ear canal, tympanic membrane
Pinnae
capturing and funneling sound, helps with directionality
External auditory canal
tube that goes toward the brain
Tympanic membrane
ear drum, vibrates when sound hits it
Middle ear consists of
ear ossicles, malleus, incus, stapes, pharyngotympanic tube (non human animals), eustachian tube (humans)
Malleus
hammer (1st); amplifies sound and transfers to middle ear
Incus
anvil (2nd); amplifies sound and transfers to middle ear
Stapes
stirrup (3rd); amplifies sound and transfers to middle ear
Eustachian tube
connects middle ear to throat and nose and is responsible for pressure equalization
Inner ear
Oval window, vestibule, semi-circular canals, cochlea
Oval window
where the stapes hook to the inner ear
Vestibule
bony chamber in the ear that helps maintain balance and coordinate eye movement
Semi-circular canals
three fluid-filled tubes that help you sense head movement and maintain balance
Cochlea
spiral cavity containing the organ of Corti, which produces nerve impulses in response to sound vibrations
Utricle
assists in horizontal orientation
Saccule
assists in vertical orientation
Otoliths
ear stones, pick up on acceleration and movement of head
Organ of corti
organ of hearing
Basilar membrane
thin, flexible membrane that moves and pushes cells upward against the tectorial membrane when pressure waves move it
Tectorial membrane
rigid membrane covering the stereocilia
Planeria
flatworms that have light detection organs called ocelli
Compound eyes
mostly seen in insects, have light detectors called ommatidia
Single-lens
better at forming an image than detecting motion
Sclera
whites of your eyes, go around your head
Cornea
made of similar compunds as the sclera but is clear, protects the eye, starts to bend light waves coming into the eye
Choroid
mostly layer of blood vessels, bring nutrients and oxygen to the eye as well as take away waste products
Iris
ring of muscle with different pigments, controls how much light is getting into the eye
Pupil
hole in the middle of the iris
Lens
opening behind the iris, focuses light onto the retina
Ciliary muscles
attached to the lens and change shape as they contract/relax
Aqueous humor
fluid inside the eye
Vitreous humor
thicker than aqueous humor and helps maintain shape of the eye
Retina
sheet of photoreceptors and interneurons, this is where the light is being sensed, the part that is sending signals
Fovea
sharpest region of acuity in the eye, takes the form of an indentation in the eye, packed with photoreceptors
Optic nerve
connects photoreceptors to the brain
Presbyopia
“old man eyes”, refractive error that makes it difficult to see things close up
Rods
respond to light not color, good for responding to movement, dendrites on the end are photoreceptors
Rhodopsin
photosensitive molecule embedded in rod membranes
Opsin
protein, connected with vitamin A
Retinal
explain the picture in your notes
Cones
respond to different colors, opsin aborbs different wavelengths of light
Tetanus
fused, smooth summation
Motor Unit
motor neuron and all of the fibers it integrates
Partial Pressure
pressure exerted by a certain gas within a mixture of gases
Respiratory surface is everted
gills
Respiratory surface is inverted
lungs
Gills are housed in cavities and protected by…
operculum
Gill arches
Bony struts that hold up each gill and provide base for each side
Gill filaments
arches with filament create sieve, fleshy part of a fish’s gills that allow it to breathe underwater by O2 and CO2 with water
Gill lamellae
site of gas exchange, forces blood to go in one direction
