peripheral nervous system - afferent division

stimulus

internal or external changes, graded potentials in the receptor, alters receptor permeability

wha are afferent neuons

sensory neurons from peripheral → CNS

What is sensory transduction?

the process of converting external stimuli into a cellular response

photoreceptors

respond to light waves

hair cells

in the ear, respond to sound waves

mechanoreceptors

respond to pressure, touch (tactile receptors)

thermoreceptors

some warm: detect above body temp

some cold: detect below body temp

osmoreceptors

in hypothalamus, detect composition of blood in terms of tonicity (how much water is lost in retained in the kidneys)

chemoreceptors

in hypothalmus, blood electrolytes

nocireceptors

pain singal gets turned into action potential in order for it to reach the brain

A stimulus alters the receptors permeability leads to a ....

Graded potentials may initiate action potentials, Confrontation detected by receptors is conveyed via sensory neurons to the CNS to be interpreted

receptor potentials may initiation _______ in the afferent neuron

action potentials

occipital lobe

vision

temporal lobe

hearing

parietal lobe

somatosensory processing, sensations from the surface of the body, such as touch, pressure, heat, cold, and pain

frontal lobe

primary motor cortex, controls skeletal muscles, personality, decision making, motor strip

acuity

how sharp or clear vision is

what is the receptive field

specific area within the visual field that, when stimulated by light, will cause a particular neuron in the visual system to fire an action potential

what is perception and what is it derived from

ability to interpret the visual would around you, how close or far you think something may be, derived from thalamus and visual cortex

what is important about pain

beings conscious awareness to tissue damage that is occurring, storage of painful experiences in memory helps us avoid potential harmful events in the future

delta fibers

myelinated, fast pain, cold, mechanical stimuli

C fibers

unmyelinated, slow pain, heat, cold, mechanical stimuli

stimulation of nociceptors will

turn pain signla into action potential in order for it to reach the brain

fast pain

well-localized, sharp, ex: paper cut

slow pain

diffuse, generalized area, dull, achy, ex: abdominal cramping or lactic acid build up in calves

What does it mean when the brain has an analgesic system?

the brain contains a network of neurons and neurotransmitters that can actively suppress pain signals

outer protective mechanisms of the eye

eyelids and eyelashes, tears and lacrimal gland

inner protective mechanisms of the eye

sclera/cornea, choroid, ciliary muscle (body), iris, retina, vitreous humor and aqueous humor front of eye

what are the three layers which enclose the fluid filled cavity

sclera/cornea

choroid, ciliary muscle, iris

retina

what contols the amount of light entering the eye

iris

why would the eye refract entering light

to focus the image on the retina

chorid of the eye

blood supply to the brain

ciliary muscle of the eye

wraps around the lens, relaxes and contracts causes shape changing of the lens (accommodation)

what does accommodation help acomplish

increase the strength of the lens for near vision, strength of the lens depend son its shape, regulated by the ciliary muscle

rods

indisitict gray vision at night, good for night vision

cones

sharp color vision during the day

rods have high ___ and low ___

sensitivity, acuity

cones have high ____ and low ____

acuity, sensitivity

color vision depends on

the rations of stimulation of red, blue, and green

the sensitivity of the eyes can vary through

changes in light conditions

what will the thalamus and visual cortex elaborate

augment the visual image

what is the pupillary reflex

a series of automatic responses that control the size of the pupil in your eye to adjust to different amounts of light

what is binocular vision

The left visual field of each eye is projected to the visual cortex on the right side of the brain, and the right visual field is projected to the left visual cortex

3 components of the ear

external, middle, inner

sound waves

traveling vibrations of air

Describe the tympanic membrane and the external ear plays a role in what?

turn sound waves into vibrations, sound localization

What is the function of the middle ear?

The middle ear bones convert tympanic membrane vibrations into fluid movements in the inner ear

bones found in the middle ear

malleus, incus, stapes

cochlea

a fluid-filled, spiral-shaped cavity found in the inner ear that plays a vital role in the sense of hearing and participates in the process of auditory transduction

corti

sense organ for hearing, tranduce fluid movements into neural signals

Describe the pathway of the auditory system

• Sound waves strike tympanic membrane and become vibrations 

• Sound wave energy is transferred to 3 bones of the middle ear which vibrate 

• The stapes is attached to the oval window

• The oval window creates fluid waves within the cochlea 

• Fluid bends the hair cells creating an electrical signal that alters neurotransmitters to release 

• Neurotransmitters release onto sensory neurons which create action potentials that go through the cochlear nerve to the brain

what is important for detecting head positions and motion

vestibular apparatus

equilibrium pathway

• Vestibular apparatus 

• Vestibular branch of the vestibulocochlear nerve 

• Cerebellum or vestibular nuclei of medulla 

  • If vestibular nuclei of medulla: 

    • Either somatic motor neurons controlling eye movements 

    • Or 

    • Reticular formation 

• From reticular formation to thalamus 

• Cerebral cortex