L24 - reflexes and senses

Question 1

reflex pathway in arm

Answer 1

• output provided to agonist muscle to contract so lower part of arm lifts up
• antagonist muscle

Question 2

main inhibitory NT in CNS

Answer 2

GABA

Question 3

flexor/ extensor reflex

Answer 3

• step on something you don’t want to
• leg lifts up
• mechanoreceptor activated in foot causes A.P to go to spinal cord
• neurones triggered to cause legs to flex or extend muscles

Question 4

other types of reflexes

Answer 4

changes in pupil size due to light or focus

Question 5

do reflexes have to involve spinal cord?

Answer 5

no

Question 6

cranial nerves

Answer 6

nerves go in and out of brain instead of spinal cord

Question 7

the eye

Answer 7

• iris sphincter muscle controls diameter of pupil
• cillary muscle controls thickness of lens to focus light in retina

Question 8

how does eye work?

Answer 8

photons of light being focused to back of eye

Question 9

rodes

Answer 9

helps you see in low light and in ur periphery

Question 10

cones

Answer 10

for colour perception, respond to different wavelength of light.

Question 11

pupil constriction reflex

Answer 11

shine bright light in eye, reflex action to restrict pupil as iris gets bigger, protects back of eye from being exposed to light

Question 12

what does the optic tract do?

Answer 12

innverates the brain stem (area called pretectal nucleus), which in turn innervates the oculomotor nerve

Question 13

association cortex / areas

Answer 13

• interprets what visual cortex tells brain what eyes see
• neuronal input from auditory cortex is interpreted (allowed us to have language) - frontal lobe involved in what it means

Question 14

touch receptors

Answer 14

nerve endings that respond to mechanical stimulation (skin moving), this opens ligand gated ion channels open, so Na+ enter cell, depol, A.P triggered

Question 15

receptive field of touch receptors

Answer 15

• pacinian corpusle
• receives touch from wide area of skin

Question 16

sense of taste

Answer 16

• specialised cells in taste buds which have receptors which respond to chemicals in food
• 5 taste receptors
• sweet, salt, sour, bitter, umami

Question 17

sense of smell

Answer 17

chemicals in air activate G protein coupled receptors in nose. 300 diff smell receptors which respond to different chemicals. sense of smell more diverse than taste.

Question 18

the ear

Answer 18

sound waves go into ear and activate the ear drum (tympanic membrane), this vibrates at same frequency as sound wave, vibration passes into inner ears, causing hair cells in inner ears to bend (receptors that respond to mechanical stimulation)