Nervous System: Senses CH 16

Describe the structure and function of the papillae of the tongue.

4 types of papillae: Fungiform- mushroom shaped, present at tip. Innervated by facial nerve. Filliform- thin,long papillae "V" shaped and most numerous. However, not involved with gustation. Foliate- ridges & grooves towards posterior roof of mouth. Innervated by facial nerve and glossopharyngeal nerve. Circumvallate- only about 10-14 on most people. Present at the back of tongue arranged in a circular row. Innervated by glossopharyngeal nerve.

Differentiate between a stimulus and a sensation.

A stimulus is the change in sensory info detected in any environment. While a sensation is our conscious awareness of incoming sensory information.

Identify areas in the brain that receive sensory input from the olfactory chemoreceptors.

Cerebral cortex-which perceive and identify smell Hypothalamus-visceral reaction to smell Amygdala-smell recognition & emotional reaction

Define Adaptation.

Decreased sensitivity to a specific stimulus continuously.

Describe accessory functions of the eye and list their functions.

Eyebrow, Eyelash, Eyelids- are to protect the eye from any potential irritant. Conjuctiva-thin-transparent membrane that covers the sclera. Helps lubricate the eye by producing mucous and tears. 6 Extrinsic Eye Muscles.

Distinguish between frequency and intensity of sound.

Frequency- the pitch, number of sound waves per second. Measured in Hertz Intensity-the loudness, the amount of energy of a vibration. Measured in decibels.

List the structures and function of the components of the eye.

Lacrimal Gland- produce tears Lateral Canthus-eyelids meet laterally Medial Canthus-eyelids meet medially Caruncle-houses glands Retina-recieve light and convert the light into neural signals that are sent to the brain for visual recognition Ciliary Body- focuses Lens-changes shape to focus on objects at various distances Suspensory ligaments- controls lens

Name the auditory ossicles and explain how they function in hearing.

Malleus- attatched to typmpanic membrane, recieves vibration from tympanic membrane and transmits to incus. Incus- receives vibrations from malleus, to which its connected laterally, and transmits to stapes, medially. Stapes- stirrup shaped bone, transmits vibration to oval window. Smallest bone in the body.

Name the components of the olfactory organs and their mode of action.

Olfactory Epithelium- specialized epithelium tissue inside nasal cavity. 3 distinct kind of cells: olfactory, supporting and basal cells. Directly responsible for detecting odors. Olfactory Tract-bundle of axons connecting to the mitral and tuffted cells of the olfactory blub to several target regions of the brain. (amygdala,piriform&entorhinal cortex) Olfactory bulb-structure within the brain that receives neural input from the nasal cavity, thus processing sense of smell. Olfactory nerve- olfactory cells are bipolar neurons which congregate to form the olfactory nerve. Receptors are located within the mucosa of the nasal cavity. Relays information to the brain.

Describe structures of outer, middle, and inner ear.

Outer: Auricle External auditory canal tympanic membrane-recieves vibration, send to ossicles Middle: Malleus Incus Stapes Auditory tube Inner: Cochlea Oval Window- "sound door" Vestibule-respond to change in position of head Semicircular canals-maintain balance, detects motion Vestibulochochlear nerve Round Window-"sound exit"

Compare and contrast the 2 general types of photoreceptors, including their photopigments.

Rods- Dim light. Most sensitive to light and dark. Cones- deal with color. Red, Blue, And Green.

Name components of cochlea and how they function in hearing.

Scala Vestibuli- perilymph filled cavity Vestibular Membrane Scala Media-endolypmh filled cavity Tectorial Membrane Organ of Corti- contains hairs that trigger hearing reaction Basilar Membrane Scala Typmani- perilymph filled cavity

6 Extrinsic eye muscles and function.

Superior rectus- up & medial Inferior rectus- Down Lateral rectus- look outward laterally(Away from nose) Medial rectus- look medially Superior Oblique- down & lateral Inferior Oblique- up & laterally

Distinguish between tonic and phasic receptors.

Tonic- sensory input adapts slowly and continuously to produce action potentials. Phasic- receptors adapt quickly.