PHAR 2002: Chapter 15 - The Special Senses (Part 1; Olfaction, Gustation, Visualization)

Special senses (5);

Olfaction, Gustation, Vision, Hearing, Equilibrium

Olfactory organs are located in...

the nasal cavity

The olfactory epithelium is located on...

the superior nasal conchae

Olfactory receptor cells are located within a layer of __________________ epithelium.

Pseudostratified

Describe olfactory receptor cells (neurons) with three words...

bipolar, ciliated, chemoreceptors

True or false; olfactory epithelia are amitotic, much like skeletal muscle.

false

Olfactory pathway; Olfactory receptor cells are stimulated by; a) UV light b) ligands c) chemicals d) ions

c

Olfactory pathway; Olfactory receptors have ____________ proteins which activate a...

G-linked, secondary messenger system

Olfactory pathway; Olfactory receptor cell axons penetrate the...

cribiform plate

Olfactory pathway; After penetrating the cribiform plate, olfactory axons synapse with...

olfactory bulb

Olfactory pathway; Axons leaving the olfactory bulb travel to the __________ cortex found in the ___________ lobe.

olfactory, temporal

Olfactory pathway; After reaching the olfactory cortex, input is transmitted to (2)...

frontal lobe, thalamus, limbic system

The relay of olfactory input through the ________________ explain the emotional and behavioural responses smell can elicit.

limbic system

Gustation, the sense of...

taste

Gustatory cells; specialized cells located in ______________ that respond to chemicals dissolved in...

taste buds, saliva

True or false; individual taste buds respond most effectively to one of five primary tastes.

true

The five primary tastes;

sour, sweet, bitter, salty, umami

Gustatory cells turnover every...

7-10 days

Compounds that produce a sweet taste...

sugar, saccharin, alcohols, amino acids, lead salts

Compounds that produce a sour taste...

hydrogen ions

Compounds that produce a salty taste...

metal ions

Compounds that produce a bitter taste...

alkaloids

Compounds that produce a umami taste...

glutamate, aspartate

Which cranial nerves transmit sensory information from the tongue (2)?

VII/Facial, IX/Glossopharyngeal

How do gustatory cells transmit information to other cells?

Vesicles with neurotransmitter

Sensory input from the 7th and 9th cranial are relayed via the ____________ to the _________.

thalamus, insula

Sensory information regarding the texture and temperature of foods are transmitted via which cranial nerve?

V Trigeminal

The eyelids are lined with mucous membranes called (Eyelids)...

palpebral conjunctiva

The palpebral conjunctiva are continuous with the _________ conjunctiva that cover the ________ of the eyes (not the cornea) (Eyelids).

bulbar, whites

The corners of the eye where upper and lower eyelid join is called the (Eyelids)...

Canthus

Within the canthus is the ____________________; containing sebaceous and sweat glands (Eyelids).

lacrimal caruncle

The ________________ is made up of connective tissues and supports the __________________ which produces oily secretions (Eyelids).

tarsal plate, tarsal gland

Function of oily secretions from the tarsal gland (Eyelids)...

lubricate eyelid

The space between the eyelid and globe is called the (Eyelids)...

conjunctival sac

Which structure produces the watery component of tears (Lacrimal apparatus) ?

lacrimal glands

Contained within the watery-fluid produced by the lacrimal glands are (2) (Lacrimal apparatus)...

antibodies, lysozyme

Name the channels that drain tears into lacrimal sacs (Lacrimal apparatus);

Lacrimal canaliculi

The openings of the lacrimal canaliculi are called (Lacrimal apparatus)...

Lacrimal puncta

Lacrimal sacs are located in (Lacrimal apparatus) ...

a groove of the lacrimal bone

Nasolacrimal ducts extend from the lacrimal sac into the ____________________ (Lacrimal apparatus).

inferior meatus

There are two types of eye muscles...

Intrinsic, extrinsic

Intrinsic eye muscles are composed of ___________ muscle and extrinsic eye muscles are composed of ___________ muscle.

smooth, skeletal

What type of eye muscle are the iris and ciliary muscles?

intrinsic

The iris regulates...

size of pupil

The ciliary muscle controls...

shape of lens

Which eye-muscle type attaches to the bones of the orbit; intrinsic or extrinsic?

extrinsic

Two sub-categories of extrinsic eye muscles...

rectus, oblique

Types of rectus muscles (4)...

superior, inferior, medial, lateral

Types of oblique muscles (2)...

superior, inferior

All extrinsic muscles of the eye are controlled by cranial nerve III (Oculomotor) except (2)...

lateral rectus, superior oblique

The globe of the eye is composed of three layers, also called __________. List them from outer to inner;

tunics, fibrous, vascular, neural

The globe of the eye has two fluid-filled segments;

anterior chamber, posterior chamber

The fluid filled segments of the globe (anterior/posterior chamber) are named in respect to...

the lens

The two major portions of the fibrous (outer) tunic;

sclera, cornea

_________ is a tough white tissue that covers all but the _______________ of the eyeball.

sclera, anterior 1/6th

The sclera of the fibrous tunic is composed of what type of tissue?

fibrous connective

The ____________ forms the transparent anterior portion that lies over the iris.

cornea

The cornea is _____________ with the sclera.

continuous

The cornea has plenty of _______________ but no _________.

nerve endings, veins

What does the cornea do to light as it enters the eye?

bends it

What's the name of the junction between sclera and cornea?

limbus

Found at the junction of sclera and cornea, is the __________________________.

sceral venous sinus

The Vascular (middle) tunic contains lots of (2)...

blood vessels, pigment

Functions of the Vascular tunic (2);

produce aqueous humor, supply nutrients

Components of the vascular tunic (3);

Iris, ciliary body, choroid

The coloured part of the vascular tunic...

Iris

The iris consists of two _____________ (smooth or skeletal?) muscle layers;

smooth, circular, radial

The circular muscle ______________ the pupil, and the radial muscle __________ the pupil.

constricts, dilates

True or false; the iris can contain either blue, brown, or green pigments.

false, brown only

Fitting between the margin of the retina and iris is the...

ciliary body

The ciliary muscle, controlled by the cranial nerve _____, changes the lens to adjust for...

III, near and far vision

What is the name of the folds in the ciliary body that produce aqueous humor?

Ciliary processes

Posterior continuation of vascular tunic...

choroid

Functions of the choroid (2)...

supply oxygen and nutrients to retina, absorbs light to prevent scattering

There are two types of humors (fluids) in the eye: ___________ humor; a clear, watery filtrate of blood and _______________; a permanent semisolid material.

aqueous, vitreous

Aqueous humor fills both chambers of the ______________________, and is drained out by the _______________________.

anterior segment, scleral venous sinus

Vitreous humor fills the ____________ segment.

posterior

What is the main function of aqueous humor?

supply nutrient to lens and cornea

What are the main functions of the vitreous humor (2)?

maintain intraocular pressure, holds retina against choroid

The lens functions to focus...

incoming light on retina

The lens is enclosed in a capsule of...

elastic fiber

The lens is produced from _______________ on its ___________ surface.

epithelium, anterior

Epithelial cells differentiate into _____________; cells that contain few _______________and are packed with proteins called _____________.

lens fibers, organelles, crystalline

True of false; production of lens fibers ceases around age 65.

false, it continues throughout life

The ciliary muscle is arranged ____________-like around the lens, allowing controlled _________ of vision.

sphincter, focus

The ________________ nervous system relax' ciliary muscle, which ____________ the ligaments and flattens the lens for _____ vision.

sympathetic, tightens, far

The ______________________ nervous system stimulates the ciliary muscle, which ____________ the ligaments and allows the lens to bulge for ______ vision.

parasympathetic, loosens, near

The Neural (inner) tunic is composed of two layers;

pigmented retina, neural retina

The pigmented retina is a ________ (single, bi, or multi?) celled layer that is adjacent to the ___________ and covers the _____________ part of the ciliary body.

single, choroid, posterior

Functions of the pigmented retina (2);

absorb excess light, phagocytises old photoreceptors

The neural retina is composed of (2)...

neurons, supportive cells

Structures of the retina (3);

optic disc, macula lutea, fovea centralis

The optic disc is formed by collections of _________ from the ganglion cell ___________ the eye. This area produces a...

axons, exiting, blind spot in vision

Which structure of the retina is responsible for acute vision?

Macula lutea

The macula lutea is an area of acute vision due to high concentrations in _________.

cones

The small depression in the macula which light directly strikes photoreceptors...

fovea centralis

What kind of neurons are found in the retina (3)?

Photoreceptor cells, bipolar cells, ganglion cells

There are two types of photoreceptors; _________ and _________, both of which respond to...

rods, cones, light

Ganglion cells generate ___________________ and the axons of ganglion cells collect to form the _____________ (recall optic disc).

action potentials, optic nerve

Which neuron-type forms the bridge between ganglion cells and photoreceptors?

Bipolar cells