The Senses & Accessory Organs

Sclera

"white of the eye" (anterior), protects and covers 5/6 of the eyeball

Cochlea

(spiral shapped) - hairs cells on Organ of Corti generate NI when movement of Endolymph, set in motion by soundwaves, bend them. - impulses are sent through the Cochlear cortex

We are in the Vasceral Layer (middle)...

- Choroid - Ciliary Body - Iris

Pancreas

- Deep to the stomach - head is hugged by duodenum - Exocrine and Endorcine gland - contains Bicarbonate (neutralizes stomach acid)

Visual Pathway (vision process)

- Let there be light! - light enters through pupil - light is refracted or bent so that it is focused on the retina (stimulus) - Retina creates nerve impulse (rods and cones create synapse) - NI leaves eye through Optic Nerve (posterior surface of eyeball) - enters brain and into visual cortex (occipital loeb) - We have vision!!! (CN II, Optic)

How many primary taste sensations?

- Sweet - Salty - Bitter - Sour

What does the orbit of the eye contain?

- eyeball - optic nerve - ocular muslce - fascia - nerves - vessels - fat - lacrimal gland and sac

Smell Receptors (olfactory, CN I)

- found in small area of epithilial tissue, in upper part of nasal cavity - Each olfactory cell has a # of cilia that senses different chemicals = NI - NI travels through Olfactory bulb and tract - NI then enters thalamic and olfactory centers of brain - they are closely associated with areas of brain for emotion and memory

Stimulus to Sensation for General SO

- not Speciallized - normally bare or encapsulated nerve ending - found in almost every part of body - mostly found in skin, leads to: vibration, pressure, pain, temperature

Bile

- produced by liver for export to duodenum - fat emulsifier (contains cholestorol and bile salts)

Stimuli of Special Senses Organs

- taste receptors of tongue - visual receptors of eye - auditory receptors of ear - olfactory receptor of nose

External Ear consists of two parts;

1. Auricle 2. External Auditory Canal

Ear is divided in three parts:

1. External Ear 2. Middle Ear 3. Inner Ear

The two categories of Sense Organs:

1. General Sense Organs 2. Special Sense Organs

Accessory organs of Digestive System:

1. Teeth 2. Salivary Glands 3. Liver and Gallbladder 4. Pancreas 5. Veriform Appendix

Eyeball has 3 layers:

1. fibrous layer (outer) 2. vascular layer (middle) 3. retina (inner layer)

Converting Stimulus to Sensation (all sense organs have this in common)

1. sense or detect stimuli or change 2. stimulus changed to electrical or nerve implulse 3. nerve impulse sent via sensory nerve pathway to CNS

How many Taste Receptors do we have?

10,000 avg.

Middle Ear is comprised of:

3 Bones (malleus, incus, stapes)

Salivary Glands

3 pairs which prodce and secrete most of our saliva

How many teeth do we have?

32

Types of teeth

8 incisors (cutting) 4 canines (tearing and piercing) 8 premolars (grinding and crushing) 12 molars (grinding and crushing)

Auricle (aka Pinna)

Appendage on side of head (the ear)

CN for Smell

CN I, Olfactory

CN for Vision

CN II, Optic

CN responsible for Secretion of saliva

CN IX Glossopharyngeal

CN for teeth

CN V, Trigeminal

Which Cranial Nerve/s are for Taste Receptors?

CN VII & IX

CN for taste

CN's VII (Facial) & IX (Glossopharyngeal)

Ciliary Body

Connects choroid and circumference of iris, is muscular and vascular

Which Cranial Nerve is for Hearing

Cranial Nerve VIII, Vestibulocochlear

Ceruminous Glands

Creats Earwax: may block canal and impair hearing

External Auditory Canal

Curving tube about 1" in length (temporal bone to ear drum)

General Sense Organs

Detect stimuli such as; pain, pressure, vibration, temperature, touch, or stretch (in muscle or tendon)

Ampulla

Dilated area found on each Semicircular Canal

Sclera and Cornea are found in which layer of eye?

Fibrous Layer (outside)

We are the speciallized cells in taste buds that generate nerve impulses...

Gustatory Cells

The ear is not only for sound, what else is its purpose?

Hearing Equilibrium Balance

Special Sense Organ

Large and complex organs (e.g. eye, or are localized into groups of specialized regions such as nasal mucosa or tongue.

Organ of Corti (organ of hearing)

Lies in the Cochlea, surrounded by Endolymph, which fills the cochlear duct

Liver and Gallbladder

Liver's right and left ducts join to form common hepatic duct. Gallbradder has Cystic duct ...together they are joined and form Common Bile Duct which descends to Duodenum

Duodenum

Major Duodenal Papilla is meeting place into Duodenum from Common Bile duct (liver and gallbladder) and pancreas

Endolymph

Membranous Labyrinth (internal to Bony Labyrinth) containing thick fluid found

Can you taste when you have a cold?

Most likely no, and if so, you cannot smell either. They are connected.

Conjunctiva

Mucus membrane lines eyelid and covers Sclera.

Middle Ear Infection

Often caused by a soar throat, large amounts of liquid and pus in the Pharyngotympanic (auditory) tube does not drain or pools.

Liver

One of the most important and is the largest in body Right and Left hepatic ducts

Cataract

Over-exposure to radiation or sunlight, lense becoms hard, no longer transparent, milkyin appearance.

3 Pairs of Salivary Glands

Parotid - largest, lie anterior to ears at angle of jaw Submandibular - lie along medialaspect of mandible body Sublingual - lie anterior to submandibular gland, under tongue

The Bony Labyrinth consists of:

Perilymph (watery fluid) and... 1. Vestibule 2. Semicircular Canals 3. Cochlea

Retina (inner layer of eye) contains what?

Photoreceptor cells called Rods and Cones

Choroid

Prevents the scattering of incoming light rays. Brown membrane found between sclera and retina.

Crista Ampullares

Receptor found in Ampulla which generates nerve impulse when you move your head

Proprioceptors

Receptors found in muscles and tendons; when stimulated, they provide information on the position or movement of body parts, length, extent of contraction and tension in skeletal muscle

Middle Ear breakdown

Sound waves are transmitted and amplified by ear bones, vibration onto Oval Window causes movement of fluid in the inner ear. - Eardrum attached to Malleus - Malleus head attached to Incus - Incus attached to Stapes - Stapes presses against membrane covering Oval Window (seperates middle and inner ear)

Cones

Stimulated by bright light (daytime vision)

Rods

Stimulated by dim light (night vision)

Gallbladder

Storage tank for bile (GB posterior to Liver)

Chemical Receptors that generate nervous impulse resulting in sense of taste?

Taste Receptors (taste buds) (CN VII & IX)

Which organ is the same size from the time you are born until you are no longer?

The eye

Pupil

Transmitts light, varies in size regulating amount of light

Vermiform Appendix

Worm-shaped process projecting from Cecum. Part of Lymphatic system

When focusing on a near object, ciliary muscle contracts and lense is:

bulging and more curved

Cornea

covers 1/6 of the eyeball and is transparent

Iris

lies around the anterior surface of the lens, directly behind pupil

When we look at distant objects, the ciliary muscle is relaxed and the lense is:

slightly curved shape