Chapter 4b: Auditory, Taste, and Olfactory systems

Pinna

the visible portion of the ear made up of folded cartilage; gathers and transmits sound into the ear canal

Ear canal

A narrow tube following the pinna that amplifies certain sound frequencies and transmits them to the eardrum

Eardrum

A thin piece of tissue separating the ear canal from the inner ear that amplifies certain frequencies and passes them to the ossicles

Ossicles

A set of 3 tiny bones that amplifies certain frequencies and relays them to the cochlea

Cochlea

A coiled, bony structure in the inner ear that is filled with fluid and contains the basilar membrane

Basilar membrane

A strip of tissue inside the cochlea that contains the hair cells that transduce sound

Hair cells

A type of mechanoreceptor situated in the basilar membrane that are stimulated by vibrations in the fluid in the cochlea, this is transduced into a neural signal that is sent to the brain

What happens to sound when it moves through the ear?

Sound loses a lot of amplitude when it moves from air to fluid

Tonotopic map

A spatial arrangement of neural structures (such as hairs) in which locations are organized based on the frequency of sound they encode

What is the frequency of the inner and out ear?

Outer hair cells= 20,000 Hz

Inner hair cells= 200 Hz

Primary Auditory Cortex (A1)

A region in the temporal lobe of the cortex that is first to receive auditory information in the cortex; responds to pitch and rhythm

Sound waves, frequency (wavelength), amplitude

Olfaction

Sense of smell; chemicals travelled through the air

Gustation

sense of taste; chemicals ingested in mouth

Taste buds

Structures on the surface of the tongue that contain the sensory receptors for the taste

What are the 5 kinds of taste buds?

Sweetness, sourness, saltiness, bitterness, and savory (umami)

Gustatory path

Primary gustatory cortex receives information from the gustatory sensory system; it is on the lateral sulcus (deep fissure that divides both the frontal and parietal lobes to form the temporal lobe)

Olfactory path

Olfactory epithelium: a strip of tissue in the nasal cavity that contain the chemical sensory receptors that support the sense of smell

Olfactory bulb: specialized brain structure at the bottom of the forebrain that receives the information