Senses and limbic system

The internal cavity of the eye is filled with fluids called

humors

Lens separates internal cavity into (_______) and (_______) segments

anterior(aqueous) and posterior(vitreous)

function of sclera

White of the eye, protects the eye and anchors extrinsic muscles

Function of cornea

Transparent, central anterior portion, helps to focus light entering the eye

Iris

-colored part of eye that contains the pupil
-regulates the amount of light entering the eye

pupil description

central opening of the iris

function of pupil

regulates the amount of light entering the eye along with the iris

retina

light-sensitive tissue lining the back of the eyeball; contains photoreceptors (rods and cones)

2 types of photoreceptors in the retina

rods and cones

Rods

dim light and peripheral vision receptors, found towards edges of the retina

Cones

bright light and detailed color, densest in the center of the retina (macula)

macula

-central section of the retina
- has high concentration of cones
- most detailed vision

Lens divides the eye into _____chambers, ________ and _______

2, anterior(aqueous) & posterior(vitreous)

aqueous humor

the clear fluid filling the space in the front of the eyeball between the lens and the cornea.
supplies oxygen and nutrients to lens and cornea

vitreous humor

soft, jelly-like material behind the lens in the vitreous chamber; helps maintain the shape of the eyeball

Lens

transparent, flexible, structure that allows precise focusing of light onto the retina

Vision pathway

cornea, pupil (through iris), lens, vitreous humor, retina (rods and cones), optic nerve, thalamus, visual cortex (occipital lobe)

Cornea and Lens are responsible for...

focusing images on the retina

Three disorders associated with the cornea or shape of the eye

Astigmatism
Myopia (nearsightedness)
Hyperopia (farsightedness)

difference between myopia and hyperopia

myopia- focal point in front of retina (nearsighted)
hyperopia- focal point behind retina (farsighted)

3 sections of the ear

external, middle, internal

The inner ear functions in both

hearing and equilibrium

semicircular canals

three fluid-filled canals in the inner ear responsible for our sense of dynamic balance (rotational movement)

endolymph

fluid responsible for movement in cochlea and semicircular canals

Receptors in the semicircular canals respond to

Dynamic movements of the head (rotation)

Receptors in the vestibule respond to

Static equilibrium (head position in relation to gravity)
Which way is up / down

Hearing pathway external ear

Auricle, ear canal, tympanic membrane

Hearing pathway middle ear

Tympanic membrane, ossicles (malleus, incus, stapes), oval window of the cochlea

Hearing pathway inner ear

Oval window, cochlea (endolymph mores hair cells), vestibulocochlear nerve

special senses include

taste, smell, sight, hearing, and equilibrium

myopia

nearsightedness
distant objects appear blurry
light is focused in front of the retina
abnormal curve of the cornea or the shape of the eye

hyperopia

farsightedness
close objects appear blurry
light is focused behind the retina
abnormal curve of the cornea or the shape of the eye

astigmatism

a condition in which the eye does not focus properly near or far
abnormal curve of the cornea or the shape of the eye

earwax glands

ceruminous glands
modified apocrine glands

tympanic membrane

Eardrum.
vibrates in response to sound waves.
transfers vibrations between the external and middle ear.

Middle ear cavity functions

Transmit vibrations from tympanic membrane to the fluids of the inner ear. Vibrations travel from the hammer to anvil to stirrup to the oval window

eustachian tube (auditory tube)

tube connecting the middle ear to the pharynx (throat)
equalizes pressure and drains fluid

Ossicle bones

malleus (hammer), incus (anvil), stapes (stirrup)

Chemorecptors

receptors for taste and smell

Olfactory receptors are located

roof of nasal cavity

gustatory cells are

taste receptors (inside taste buds) that respond to chemicals dissolved in saliva and have long hair that protrude through a taste pore.

5 basic taste sensations

1. Sweet: sugars, alcohol, some amino acids, some lead salts
2. Sour: hydrogen ions in solution
3. Salty: metal ions
4. Bitter: alkaloids just as coffee and nicotine
5. Umami: amino acids glutamate and aspartate (beefy taste of meat)

Cataracts

Vision disorder resulting from the loss of lens transparency

Somatic Senses

involve receptors from more than one place in the body general senses

mechanoreceptors

hearing, balance and touch

chemoreceptors

smell and taste

capsaicin stimulates

heat receptors

What is olfaction and where does it occur?

smelling
occurs in the upper chambers of the nasal passage

olfaction - sensory receptors respond to what?

chemical dissolved in the mucus of the nasal cavity

olfaction - when a receptor binds its specific odor molecule, where is a sensory impulse sent?

Olfactory bulb, olfactory tract, olfactory cortex and limbic system

What explains why smells trigger memories and emotions?

neural connections between the olfactory bulb and the limbic system

gustation

sense of taste

What five categories of taste can taste buds distinguish?

sweet
sour
salty
bitter
umami (savory)

What are the three functional parts of the ear?

outer ear
middle ear
inner ear

outer ear

composed of the pinna and external auditory canal, both of which capture sound waves and funnel them into the middle ear

What happens in the inner ear?

the oval window bounces in response to movement of the stapes, creating fluid waves in the cochlea

dynamic equilibrium (rotational equilibrium)

semicircular canals detect acceleration or deceleration of your head in three directions

static equilibrium (gravitational equilibrium)

physical response to gravity that tells us which direction is down

structure that detects static equilibrium

vestibule

sclera

white of the eye
provides shape and protects inner parts

There are three types of cones, each sensitive to a different wavelength of light. What are the colors of light of these wavelengths?

red
green
blue

When light enters the eye, what does the iris do?

muscles in the iris adjust the size of the pupil to let in more or less light

Olfaction

The sense of smell

Cerebral Cortex

Outer layer of the cerebrum where information is processed

Auricle picture

Tympanic Membrane picture

(vibrates)

Malleus picture

Incus picture

Stapes picture

Vestibule picture

Cochlea picture

Eustachian tube (auditory tube) picture

Vestibulocochlear Nerve picture

hair cells in cochlea

vibration of the endolymph causes them to bend and detect sound

Optic Nerve picture

Aqueous Humor picture

Vitreous Humor picture

(M)

Pupil picture

Lens picture

(E)

Iris picture

Cornea picture

limbic system physiology

responsible for memory and emotion

Limbic system structures

hippocampus, hypothalamus, amygdala, thalamus

Hippocampus

responsible for processing memory (E)

hippocampus picture

(E)

amygdala

responsible for fear responses and emotions (anxiety, fear, anger) (AE)

hypothalamus picture

hypothalamus

responsible for maintaining homeostasis

amygdala picture

(AE)

thalamus

the brain's sensory switchboard, located on top of the brainstem; relays information between lower brain areas and the cerebral cortex

thalamus picture

Conjunctivitis

inflammation or infection of the conjunctiva; pink eye

jaundice

yellowing of the skin and the whites of the eyes
can be a sign of problems with liver

glaucoma

increased pressure due to aqueous humor not draining
can damage retina/ optic nerve

colorblindness

lack of or dysfunction of cones
inability to see colors
genetic disorder more common in males

olfactory cortex

frontal and temporal lobes (smell)

gustatory cortex

parietal lobe (taste)

auditory cortex

temporal lobe (sound)

visual cortex

occipital lobe

Cerebellum

the "little brain" at the rear of the brainstem
controls equilibrium and coordinated movement