Section 1 Flashcards
How does a receptor send a signal to the CNS?
stimulus strength dictates AP frequency
receptor threshold dictates sensitivity to stimulus
tonic receptors
continues to send APs with continued stimulus
ex. nociceptors and prociceptors
phasic receptors
send AP with initial stimulus and with removal of stimulus
no signal with continued stimulus
ex. touch receptors
receptive field
area covered by one receptor
large -> more sensitive, less discriminatory
stretch reflex
stretch detected
afferent signal back to spinal cord
activates motor neuron of stretched (agonist) muscle
leads to muscle contraction of agonist
also activates inhibitory interneuron
inhibits activation of motor neuron for antagonist muscle
leads to relaxation of antagonist muscle
deep tendon reflex
receptor: golgi tendon organ
purpose: protect against over contraction
stimulus: tension in tendon
response: relaxation of muscle contraction (agonist), activation of antagonist muscle
flexor(withdrawal) reflex
receptors: nociceptors
purpose: move away from dangerous stimulus
stimulus: pain
response: flexor muscles cause withdrawal
taste cells
Taste receptors, not the neuron
Have several gustatory hairs (microvilli) to increase surface area
gustatory supporting cells
to give shape to taste buds
gustatory basal cells
stem cells to replace taste cells
papillae
gives rough texture
often contains taste buds
filliform
provide friction
circumvallate
form V on back of tongue
fungiform
smaller round, more abundant
anterior 2/3 of the tongue
taste buds
taste pore to let chemicals in
sweet taste
sugars, alcohol, some amino acids, and lead
salty taste
metal ions ex. NaCl
sour taste
Acids ex. H+
bitter taste
alkaloids ex. caffeine, morphine, nicotine, narangin
100x more sensitive to bitter than sour
Umami(savory) taste
amino acids(especially glutamine) meats
minty flavors
cold receptors
spicy flavors
capsacin lowers threshold for warm receptors -> feel hot in mouth and all over the body
taste pathway
specialized membrane receptors open to certain chemicals
cause depolarization(some second messenger, some directly producing action potentials)
leads to AP on sensory neurons
synapse in medulla
synapse in thalamus(integration with other sensations except smell)
ending in gustatory cortex(parietal lobe by temporal lobe)
olfactory receptor cells
bipolar neurons constant turnover(60 day lifespan)
olfactory supporting cells
surrounding olfactory cells, provide stability and shape
olfactory basal cells
stem cells for olfactory receptors
olfactory pathway
molecules bind to membrane receptor
starts second messenger system
opens ion channels
depolarize olfactory neuron
olfactory nerve stimulates nuerons in olfactory nerve(in olfactory bulb)
one tract goes to olfactory cortex of the frontal lobe
also sent to hypothalamus(emotional response) and limbic system (memory: hippocampus, emotions)
right nostril: more emotional connection
left nostril: more accurate
eyebrow function
shade and catch sweat
eyelid function
spread lubricants and protectant
tarsal gland function
secrete oily solution lubricates eye movements
conjunctiva
mucous membrane lining the inside of the eyelids
keeps eye moist
lacrimal gland
part of lacrimal apparatus
makes and secretes tears
stimulated by facial nerve VII