Bio 102 - Lession 18 Sensory Organs

Senses convert a ______ into an electrical signal in the NS

stimulus

whats the process called where senses convert a stimulus into an electrical signal

sensory transduction

Membrane potentual

difference in electrical charge across a cell membrane due to the differential distribution of ions

action potential

a rapid, temporary change in the electrical potential of a neurons membrane that is used to transmit signals down an axons

depolarization

interior of the cell is temporarily less negative that the outside

sensory receptors

structures or cells that respond to internal or external stimuli

each sensory receptor is modified for the type ______

of stimulus it detects

________ of stimulus determines frequency of action potentials in neuron

intensity

what is the most fundamental function of a sensory system?

translation of a sensory signal to an electrical signal in the nervous system

Perception

interpretation of sensory system input by the brain

action potentials from different sensory receptors are linked to ________

specific regions of the brain that are dedicated to a particular stimulus

what are the 5 main categories of receptors

• mechanoreceptors

• chemoreceptors

• electromagnetic receptors

  • photoreceptors

• thermoreceptors

• pain receptors

Mechanoreceptors

detects physical deformation

in mammals ____ and _____ are closely linked and facilitated by mechanoreceptors in ear

hearing, equilibrium

when a force disrupts the mechanoreceptors membrane ___________

it initiates a change in membrane potential

equilibrium is the

sensory system for maintaining balance

ear divided into 3 regions

outer ear, middle ear, inner ear

outer ear is made of

pinna and auditory canal

pinna

external part of ear

auditory canal

tube in outer eat that links pinna to tympanic membrane

What does the Pinna do

transport vibrations to tympanic membrane

tympanic membrane (eardrum)

thin tissue that separates outer ear from middle ear

what are the 3 bones in the middle ear

malleus, incus, stapes

vibrations from outer eat are transmitted through _________

the tympanic membrane and bones to inner ear

middle ear contains eustachian tube and it connects to ______

the pharynx and equalizes pressure in ear

Inner ear contains the

cochlea

cochlea

coiled, fluid filled organ that has special mechanoreceptors known as hair cells

hair cells

mechanosensory cells that have hair-like projections and facilitate sensory transduction for hearing and equilibrium

vibrations from the middle ear are trasmitted through ___________

the tympanic membrane and ear bones to cochlea

what causes the hair-like structures in the cochlea to bend

liquid waves

bending in one direction ________

depolarizes hair cells & increase neurotransmitter release

bending in another directions _______

hyper polarizes hair cells & reduces neurotransmitter release

cochlear implants

surgically implanted device that bypass damaged hair cells

chemoreceptors (smell)

sensory receptor that responds to chemical stimulus

odorants

molecule that can be detected by sensory receptors of the olfactory system

olfaction

sense of smell

how do odorants diffuse?

through mucus and bind to specific chemoreceptors on olfactory neurons

brain integrates input from multiple odorants into __________

single sensation or “smell”

taste

any chemical that stimulates the sensory receptors in a taste bud

gustation

sense of taste

taste bud

modified epithelial cells that contain multiple tasting cells

what are the 5 different tastes that mammals can detect

• sweet

• sour

• salty

• bitter

• umami (savory)

taste buds have _____________ that are designated to finding one of the five different tastes

specialized taste chemoreceptor cells

flavor is determined by ________

a combination of 5 sense as well as the smell and texture of food

electromagnetic receptor

responds to electromagnetic energy such as visible light, electricity or magnetism

electromagnetic receptors are used by animals for _______

vision, navigation, and detection of electrical fields

iris

colored, muscular part of the vertebrae eye

pupil

opening in the iris, which admits light into the interior of the vertebrate eye

lens

transparent structure behind the iris that focuses light rays onto the retina

retina

innermost lauyer of the vertebrate eye, containing electromagnetic receptors

photoreceptors

specialized electromagnetic receptor that detects visible light

what are the two types of photoreceptors that humans have?

rods & cones

rod

type of photoreceptor in retina (enable low-light, night, and peripheral vision)

cones

type of photoreceptor in retina (enables color vision in high-light environment)

different wavelengths activate _______

different cones

thermoreceptor

receptor stimulated by either heat or cold

pain receptor

sensory receptor that responds to noxious or painful stimuli

skeletal muscle

responsible for the voluntary movements of the body

smooth

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