Sensory Nervous System

Question 1

sensory nervous system

Answer 1

branch of afferent peripheral nervous system (somatic and visceral nervous system)

Question 2

afferent pathway

Answer 2

starts when an internal or external sense is detected by sensory receptors adapted to detect specific senses (touch, hearing, light, hunger)

Question 3

conscious senses

Answer 3

general and special senses

Question 4

general sense

Answer 4

visceral sensations (hunger), touch, temp, pain, proprioception (location of body/limbs in space)

Question 5

special senses

Answer 5

taste, smell, hearing, equilibrium, vision

Question 6

subconscious senses

Answer 6

outside of animals awareness (muscle length, muscle tension (baroreceptors), several visceral stimuli to maintain homeostasis (BP and temp))

Question 7

hypothermia steps

Answer 7

1) activation of a sensory receptor at skin (afferent nerve) and the action potential is sent to the thalamus and hypothalamus in the brain. Internal body temp can also be detected directly at the hypothalamus
2) hypothalamus (CNS) integrates the signal to determine what physiological change needs to occur to increase body. Action potential sent through efferent nerves to arteries in the skin, muscles, and thyroid gland
3) arteries constrict to reduce heat loss and skeletal muscles contract; shivering
4) body temp is increasing back to normal levels, increase in temperature detected by hypothalamus; shuts off signal

Question 8

hyperthermia steps

Answer 8

1) activation of a sensory receptor at the skin (afferent nerve) and action potential is sent to the hypothalamus
2) thalamus and hypothalamus (CNS) integrates the signal to determine that physiological changes need to occur to lower body temp. Action potential sent through efferent nerves to the arteries in the skin, sweat gland, thyroid gland
3) arteries dilate to increase heat loss and increase secretions of the sweat glands
4) body temp decreases back to normal levels (detected by hypothalamus to shut off response)

Question 9

olfactory sense pathway

Answer 9

detection of different smells in the environment

Question 10

vomeronasal organ

Answer 10

chemoreceptor organ

Question 11

auditory sense pathway

Answer 11

conversion of sound waves to a mechanical force (fluid flow) in the inner ear that activates auditory nerves and transmit signals to integrating regions in the brain

Question 12

pinna

Answer 12

external ear, sound directed into the ear through here and the ear canal. funnels and collects sound wave vibrations and directs them to the eardrum (tympanic membrane), where they move 3 bones (ossicles) in the middle ear (malleus, incus, stapes)

Question 13

middle ear

Answer 13

transmits/amplifies vibrations, cause fluid flow in the inner ear (cochlea) that activates hair cell receptors and the auditory nerve (CN 8)

Question 14

inner ear

Answer 14

has hair cell receptors that convert mechanical vibrations into nerve impulses. important for hearing and equilibrium

Question 15

organ of corti

Answer 15

hair cells that are receptor cells for hearing with modified dendrites on the surface. tectorial membrane lies on top of the hair cells and vibrates. hair cells send action potential to the cochlear nerve (8) to the midbrain to the thalamus and auditory cortex

Question 16

equilibrium

Answer 16

maintenance of balance, mechanical receptors help maintain balance

Question 17

vestibular system

Answer 17

parts of the inner ear and eye, neurons in vestibular nuclei project their axons into the brain

Question 18

vestibulo-ocular reflex

Answer 18

compensates for head and body movements by stabilizing images on the retina and projecting images to the thalamus

Question 19

vestibular disease

Answer 19

dizziness, imbalance, vertigo, tinnitus (ear ringing), hearing loss, brain fog, visual impairment, etc

Question 20

vision

Answer 20

photoreceptor activation in retina –> activates optic nerve –> transmits action potential to integrating regions in the brain (thalamus and visual cortex)

Question 21

sclera

Answer 21

outer connective tissue layer

Question 22

choroid

Answer 22

blood vessels

Question 23

cornea and pupil

Answer 23

opening for light

Question 24

lens

Answer 24

help direct and control amount of light that reaches the retina by constricting muscles around iris

Question 25

2 types of photoreceptors

Answer 25

rods and cones, merge at optic disc at back of eye

Question 26

rods

Answer 26

light

Question 27

cones

Answer 27

color

Question 28

tapedum lucidum

Answer 28

part of choroid membrane. back of eye, reflects light back to retina to amplify amount of light reaching photoreceptors (helps night vision, causes eye to ‘glow’ in the dark)

Question 29

formation of a visual image steps

Answer 29

eye –> oculomotor nerve –> optic tract –> brain –> thalamus (most sensory tracts that reach cerebral cortex expect olfactory) –> primary visual cortex.

Question 30

Nociceptor steps

Answer 30

1) transduction - conversion of painful stimulus into action potential at end of sensory receptor
2) transmission - conduction of action potential to spinal cord
3) modulation - changes to sensory nerve impulses in the spinal cord (amplification or suppression due to amount of pain). primary target for pain management
4) perception - conscious awareness of pain in the brain, fear centers interact here

Question 31

gustatory senses

Answer 31

chemical receptors in taste buds, humans - sweet, sour, salty, bitter. Flavor testing important for food companies