Anatomy & Physiology Chapter 8: Special senses

The Middle layer of the eye the Vascular layer has what 3 regions

1. Choroid 2. Ciliary body 3. Iris

The inner ear is filled with membraneous sacs name the three

1. Cochlea - auditory system 2. Vestibule - located between cochlea & Semicircular canals 3. Semicircular canals - vestibular system - Balance

Secretions ( Tears) contain what 4 things

1. Dilute salt solution 2. Mucus 3. antibodies 4. Bacteria destroying lysozymes

The eye has 4 major accessory structures name them

1. Eyelids and eyelashes 2. Conjunctiva 3. Lacrimal apparatus 4. Extrinsic ( External ) Eye muscles

The dorsal surface of the tongue is covered in small projections called papillae list the three forms

1. Filiform papilla - sharp w/ no taste buds 2. Fungiform papilla - rounded w/ taste buds 3. Circumvallate papilla - large w/ taste buds

The ear is divided into 3 major regions name them

1. Outer or external ear 2. Middle ear 3. Inner, or internal ear

The outer external ear is made of 2 parts name them

1. Pinna aka auricle 2. External acoustic meatus aka external auditory canal

Eyelids and eye lashes name 5 points on them

1. Protect the anterior eye 2. Meet at the MEDIAL & LATERAL corners, or CANTHUS of the eye ( Corners of the eye) 3. Have eyelashes projecting our from them 4. Contain SEBACEOUS Glands (Tarsal) OIL Lubricates 5. Also contains sweat glands, ( Ciliary) between Eye lashes

We have 5 senses name them

1. Smell 2. Taste 3. Sight 4. Hearing 5. Equilibrium

The sense of taste is taken with 10,000 taste receptors or taste buds that are scattered through out the oral cavity most on the tongue list the two areas

1. Soft palate 2. Cheeks

What are the two functions of the organs of equilibrium - (Movement and position of body)

1. Static equilibrium 2. Dynamic equilibrium

There are 4 basic taste sensations list them and their corresponding stimulation

1. Sweet = responds to sugars, saccharine & some amino acids OH 2. Sour = responds to the acidity of solution H 3. Bitters = responds to alkaloids 4. Salty = responds to metal ions in solution

Two points about the Olfactory receptors

1. They are very sensitive 2. they are also very adaptable

What are the 2 steps sound takes to travel

1. an action potential starts in the cochlear nerve, 2.which impulses travel to the temporal lobe

The middle ear is a small air filled space in the temporal bone, between the eardrum and the bony wall with what 2 openings

1. opening from the auditory canal is covered by the tympanic membrane 2. the auditory tube connecting the middle ear w/ the throat - equalizing pressure by yawning / swallowing other wise collapsed

Describe the Pinna of the external ear -3-

1.The shell shaped structure surrounding the auditory canal opening 2. What most of us refer to as the ear 3. In many animals, it still directs sound waves into the ear - largely lost in humans

The main focusing part the LENS is supported upright and divides the eye cavity into how many chambers

2

Structures of the eye are that the eye is a hollow sphere its wall is made up of how many layers

3

There are how many types of cones each being most sensitive to specific wavelengths of light

3

How many Extrinsic (external) eye muscles are there

6. Attached to the outer surface of the eye

Eye and Vision uses what % of sensory receptors in the eye

70%

Dynamic equilibrium respond to what movements -2-

Angular or rotary which are located in the semicircular canals

The lens has 2 segments name them

Anterior - Outside Posterior - Inside

Rods are most dense at the edge of the retina and decrease in # towards the

Center

The external acustic meatus - aka the external auditory canal is described as a short and narrow, skin lined chamber within the skull, the skin lined walls contain what glands

Cerminous glands which excrete earwax or cerumen.

Chemical senses: taste and smell or olfaction are called

Chemoreceptors because they respond to chemicals in solutions

The nerve cells (neuron) or olfactory receptor cells have long

Cilia, now called Olfactory hairs that protrude from the nasal epithelium

The Lens of the eye is held upright by

Ciliary zonule attached to the ciliary body

The iris is also modified and pigmented to give eyes

Colour

Cones allow us to see sharply in

Colour in bright light and in our central line of vision

The central anterior part is a transparent "window" or known as the

Cornea through which light enters

Conjuctiva fuses with

Corneal epithelium at the edge of the cornea

Cones are densest in the center and decrease in # towards the

Edge

The Outermost layer of the eye is

Fibrous

The inner ear is composed of three parts and has a cavity filled with

Fluid - perilymph

Static equilibrium uses Maculae receptors explain how these work with otolithic membranes

Hair cells are embedded in the otolithic membrane- Otoliths ( tiny stones) float in a gel around the hair cells - movement causes these stones to bend the hair cells

The inner (internal) ear (Aka, osseous or bony labyrinth is for what two functions

Hearing and Equilibrium or balance

Lacrimal apparatus is made up of

Lacrimal glands and the ducts that drain its secretions into the nasal cavity

Pathway of light is the image formed on the retina is a real image, real images are reversed from

Left to right, upside down and smaller than the object

The lens focuses what entering the eye onto the retina

Light

Static equilibrium uses what receptors

Maculae receptors which report on the position of the head plus send info via vestibular nerve

The Iris of the eye is anterior and interior to ciliary body

Meaning the most front of the inside of the eye

Electric impulses leave the eye through the retina & go via the optic ......... to the Optic cortex ( the brain)

Nerve

Each eye has over a million

Nerve fibers

There are 1000s of smell receptors or other wise called

Olfactory receptors found in a small area in the roof of each nasal cavity

Air entering the nasal cavities must make a sharp turn to enter the respiratory tract below so sniffing, which causes more air-flow across the

Olfactory receptors intensifies smell

Visual fields and pathways have optic chiasma where the optic nerves cross, fibers from the medial side of each eye cross over to the

Opposite side of the brain

Rods & cones are NOT distributed evenly but there are None in the -2-

Optic disc or blind spot

Lacrimal apparatus has three functions name them

Protects moistens lubricates the eye

The iris is formed by differently arranged .......... muscle fibers

Smooth

The taste receptor cells or gustatory cells are surrounded by

Supporting cells in the taste bud

Lacrimal glands release

Tears ( A dilute salt solution) Onto the anterior eye - surface through tiny Lacrimal gland ducts

What is the only part of the body tissue that can translated with our rejection ( no blood vessels)

The Outermost layer

The Middle layer of the eye is known as the

Vascular layer

Posterior (inside) to the lens contains

Vitreous humor ( back side of eye - thicker more jell like humor. Floaters

The outermost layer of the eye is thick white connective tissue called the sclera known as the

White of the eye

Lacrimal glands are located

above the lateral end of the eye

The ability to focus specifically for close objects is called

accommodation

Anterior (Front part) to the lens

aqueous humor (watery)

Cochlear nerve attached to hair cells transmits to

auditory cortex on temporal lobe

The retina respond to light and send electrical impulses via 2 neuron- chains name them

bipolar neurons ganglion cells

Taste has 4 types of receptors, smell can differentiate a large range of

chemicals

The Gustatory cells respond to

chemicals dissolved in the saliva

The Dynamic Equilibrium is a tuft of the hair covered with .... and explain how to works

cupula - if the head moves, the cupula drags against the endolymph

The External acoustic meatus runs from the external opening to the

ear drum or tympanic membrane - causes it to vibrate

The inner ear is located behind the

eye sockets and composed of 3 parts

Protection of the eye is enclosed in a bony orbit plus a cushion of

fat that surrounds most of the eye

Continued stimulation can lead to adaption means:

firing of nerves, noises you hear all the time the brain doesn't sent it to your consciousness if the noise is new then the body will send it to your consciousness.

The eye ball is filled with what 2 things

fluids, or humours

Rods allow us to see in

greys in dim light and in our peripheral vision

Mechanism of hearing is through Vibrations from sound waves move tectorial membrane which means

hair cells are bent by the membrane

receptors are made of

hair cells on the basilar membrane, which a gel like tectorial membrane is capable of bending hair cells

The middle ear contains THREE the tiniest bones (ossicles) that transmit eardrums vibrations that move the

happer - anvil - stirrup to the inner ear

Outer external ear is for what only

hearing

Middle ear aka tympanic cavity is for what only and is filled with what

hearing. air

Tears wash across the eye into what three areas

lacrimal canaliculi medically Lacrimal sac nasolacrimal duct ( empties into the nasal cavity)

The Choroid in the most further back position contains a dark pigment that prevents

light scattering in the eye

Importantly they have long

microvilli now called gustatory hairs

The long cilia of the olfactory receptor hairs are coated in

mucous that is secreted by underlying glands

Conjuctiva Secretes

mucous to lubricate the eye

The ciliary body of the eye is described as modified smooth

muscles, attached to the lens

The Ciliary body is more Anterior meaning it is located

near the most front

The Outermost later of the eyeball has lots of

nerve-endings, especially pain fibers ( Increased blinking, tears)

The Choroid contains blood and thus

nutrition rich

The interpretation of odors occurs in the

olfactory cortex - a odor snapshot is taken

Extrinsic eye muscles produce large muscle movements for example

our ability to follow a moving object

Conjuctiva are a membrane covering what

part of the outer surface of the eye and lining the eyelids

This innermost layer the Retina contains what three things

photoreceptores rods cones

Eyes are photo receptors that

pick up light

The iris has a rounded opening the called the

pupil that constricts or dilates to regulate amount of light entering

The Innermost layer is the sensory layer called the

retina ( light -sensitive part of the eye)

Lateral to the blind spot is a tiny pit containing only cones the Fovea centralis this is our area of

sharpest vision

Smell and taste also respond to many of the same

stimuli and complement one another

these Microvilli hairs called Gustatory hairs protrude through a hole called a

taste pore

What part of the eye is the most exposed and thus vulnerable area of the eye (but regenerates well)

the Outermost layer - Fibrous

Organs of hearing the organ of corti is located in

the cochlea

The middle ear contains the Eustachin tube that connects

the middle ear and the throat

The Choroid in the middle layer of the eye is the most posterior meaning

the most further back in position