sensory systems Flashcards
sensory receptor
special proteins in sensory cells embedded in sensory organs
sensory transduction
something in the environment is the signal (chemo, mechano, photo)
chemoreceptors
a molecule in the environment we can bind to which signals to ion channels to open
mechanoreceptors
membrane bound protein with cuticle (shield) that detects pressure and changes shape so ion channels open up
photoreceptors
protein membrane bound is able to detect light which sends signal to brain, closes ion channels and hypoerpolarizes the cells in the eyes
electroreceptors
detects changes in charges, common in fish
thermoreceptors
detect changes in temperature
nociceptor
detects pain
lateral inhibition
enhances edge and border detection by reducing excitation of adjacent interneurons
G protein coupled receptor
G proteins have extracellular receptor, causes conformational change, has units that move intracellularly when G protein becomes phosphorylates (cascade of effects)
olfactory epithelium
a collection of olfactory nerves
olfactory sensory neuron
connects directly with stimuli, no sensory cell
chemo-sensitive hair
odorants bind to these and detect a sense of smell
taste bud
made up of taste sensory cells and has microvillli coming off of it to detect taste
5 basic flavors
sweet, bitter, savory, salty, sour (acidity)
how does sweet send signals
GPCR
how does bitter send signals
GPCR
how does savory send signals
GPCR
how does salty send signals
Na+ depolarize cell opening voltage gated Ca2+ channels (sodium from food can depolarize)
how does sour send signals
depolarize via H+ ion channels and inhibits K+ channels
transformation of force through the ear
air wave –> mechanical force –> liquid force
pinna
outer ear
tympanic membrane
ear drum
bones in the middle ear (in order)
malleus, incus, stapes
oval window
space between middle ear and cochlea/semicircular canals
vestibular system
senses motion and gravity, includes the ear
process of hearing
- amplification from pinna to eardrum to malleus, 2. 3 bones hit oval window and convert sound vibrations to mechanical and then fluid waves, 3. mechanoreception by hair cells in organ corti, 4. sends signals to brain of sounds
stereocilia
hair like cells in the inner ear
statocyst
group of sensory cells in shrimp
stalolith
structure in statocyst which allows organisms to detect motion and gravity (in shrimp)
tectorial membrane
membrane where hair cells are disturbed from fluid waves
basilar membrane
where hair cells are located on, initially at rest, pushes up into tectorial membrane and bends stereocilia
organ of corti
where hair cells are
how do hair cells depolarize?
pushing against the tectorial membrane from the fluid wave causes K+ to rush into the cell, and the downward motion of the basilar membrane resets the hair cell and they repolarize
cornea
transparent shield over the eye
iris
surrounds the opening where light is focused through the lens
fovea
lots of cones and connected to optic nerve in back of eye
optic nerve signaling
phototransduction to the brain
pupil
hole
lens
reads light and sends it to fovea
ciliary muscle
contract and relax to adjust lens, contract to focus close (lens is rounder), relax for focusing far (flatten lens)
rods
peripheral vision and dark/light, surround fovia, slow
cones
color, fovea, fast
sensory cell (discs)
contain either conopsin or rhodopsin
what happens when discs are activated
when light hits them, retinal is activated (goes from trans to cis) which leads to activation of G protein, activated G protein activates PDE, PDE hydrolyzes cGMP reducing its concentration (increasing G protein), closes Na+ channel and hyperpolarizes cell
how do the Na+ ion channels close in the eye
cGMP was bound to the ion channels keeping them open but then it is turned into GMP which closes the channels
on bipolar cells
the first cell the signal is sent to, on bipolar cells do the opposite (if there is a signal they will not send it, if there is not they will send it)
off bipolar cells
the first cell the signal is sent to, off bipolar cells do what they are signaled to do
ganglion cells
also have on and off versions, same as bipolar
horizontal cells
connect rods and cones and sharpen vision (cause lateral inhibition)
amacrine cells
connect bipolar cells and adjust for motion and brightness
forebrain
cerebral cortex, thalamus, hypothalamus
midbrain
midbrain is part of brain stem
hindbrain
pons and medulla, cerebellum
cerebellum
integrates motor and sensory information which allows for complex motor tasks
medulla oblongata
center for respiration and circulation
pons
neural pathway from cortex to the medulla and cerebellum
cerebrum
cerebral cortex
thalamus
relay center
hypothalamus
links nervous system and endocrine system via the pituitary gland
function of the folds in the cerebral cortex
increases the surface area and therefore the number of neurons and increased cognitive ability
grey matter
soma/dendrites
white matter
myelin sheath
frontal lobe
decision making, taste, and smell; contains olfactory and gustatory cortices and primary motor cortex
parietal lobe
body/spatial awareness; contains primary somatosensory cortex
occipital lobe
processes visual information; contains visual cortex
temporal lobe
process sound and speech; contains auditory complex
limbic system
amygdala and hippocampus; behavior, instincts, emotions, and motivation; long term memory formation
ventral termental area (VTA)
amygdala, N. accumbens, hippocampus, prefrontal cortex; sends dopamine to all of these places and diff stimuli can activate this pathway dif amounts
cognition
ability to be cognizant and self aware, being able to understand the world around you
synaptic plasticity
a synapse is not static and can be strengthened or weakened
ways to strengthen synapses
increase ligand gated ion channels, grow new dendrites, expand current dendrites
long term potentiation
a way of strengthening connections, creates long term memories
electroencophalogram (EEG)
monitors electricity in brain and different wavelengths associated with different sleep stages
