Anatomy & Physiology IAnatomy & Physiology I

The SensesSeminar 8

Unit 8 – Senses Overview

Classification of Sense Organs General

Free Nerve Endings Encapsulated Nerve Endings

Special Eye Ear Taste Receptors Smell Receptors

Structures of Each

Classification of the Sense OrgansClassification of the Sense Organs

• General sense organs Often exist as individual cells or receptor units Widely distributed throughout the body

• Special sense organs Large and complex organs Localized grouping of specialized receptors

• Classified by presence or absence of covering capsule Encapsulated Unencapsulated (“free” or “naked”)

• Classification made by type of stimuli required to activate receptors Photoreceptors (light) Chemoreceptors (chemicals) Pain receptors (injury) Thermoreceptors (temperature changes) Mechanoreceptors (movement or deforming

of capsule) Proprioceptors (position of body parts or changes in

muscle length or tension)

Classification of the Sense Organs (cont’d.)Classification of the Sense Organs (cont’d.)

Converting a Stimulus into a SensationConverting a Stimulus into a Sensation

• All sense organs have common functional characteristics

All are able to detect a particular stimulus

A stimulus is converted into a nerve impulse

A nerve is perceived as a sensation in the CNS

General Sense OrgansGeneral Sense Organs

• Distribution is widespread; single-cell receptors are common

• Examples Free nerve endings: Sensitive to pain and crude touch Meissner corpuscles: Responsive to fine touch and

vibration Ruffini corpuscles: Sensitive to touch and pressure Krause’s end-bulbs: Touch or cold Golgi tendon receptors: Proprioception Muscle spindles: Proprioception

General Sense Receptors

Special Sense Organs

Four types Eyes Ears Nose Taste Buds

Let’s take a look at each one….

Special Sense OrgansSpecial Sense Organs

• The Eye• Function• Structure

• Three layers of the eyeball• Sclera• Choroid• Retina

Special Sense Organs (cont’d.)Special Sense Organs (cont’d.)

Conjunctiva: Mucous membrane covering the front surface of the

sclera and lining the eyelid Lens:

Transparent body behind the pupil; focuses light rays on the retina

Eye fluids Aqueous humor

Watery fluid in the anterior chamber in front of the lens

Vitreous humor Jellylike fluid in the posterior chamber behind the lens

FYI on the Iris

As the fibers of the iris contract, the pupils dilate, letting in more light.

Other fibers are circular. When they contract, the pupils constrict, letting in fewer light rays.

Normally the pupils constrict in bright light and dilate in dim light.

The Eye - Structure

Special Sense Organs (cont’d)

Visual Pathway Innermost layer of retina contains rods and

cones Impulse travels from the rods and cones through

the bipolar and ganglionic layers of the retina Nerve impulse leaves the eye through the optic

nerve; the point of exit is free of receptors and is therefore called a blind spot.

Cells of the Retina

Conditions & Surgery for the Eye

Conditions Presbyopia Cataracts Blind Spot Glaucoma

Take a look at these surgical procedures on your own…. Radial keratotomy (RK) Astigmatic Keratotomy (AK) Astigmatic Keratotomy (AK) Automated Lamellar Keratoplasty (ALK) Laser Assisted in situ Keratomileusis (LASIK) Conductive Keratoplasty (CK)

Corneal Transplant

Special Sense Organs (cont’d)

• The Ear• Function

The ear functions in hearing, equilibrium, and balance. Receptors for hearing and equilibrium are

mechanoreceptors.

Structure External Ear Middle Ear Inner Ear

The Ear

Special Sense Organs (cont’d)

Structure – Divisions of the EarExternal ear

o Auricle (pinna)o External auditory canal

•Curving canal or tube 2.5 cm (1 inch) in length•Contains ceruminous glands producing ear wax•Ends at the tympanic membrane or eardrum

Special Sense Organs (cont’d)

Middle earo Houses ear bones or ossicles

o malleus, incus, and stapeso Ends in the oval windowo The auditory (eustachian) tube connects

the middle ear to the throato Inflammation called “otitis media”

Special Sense Organs (cont’d)

Inner earo The bony labyrinth is filled with fluid called

perilympho The labyrinth is divided into the vestibule,

semicircular canals, and cochleao Membranous labyrinth is filled with endolympho Receptors for balance in the semicircular canals

are called cristae ampullariso Specialized hair cells on the organ of Corti

respond when bent by the movement of surrounding endolymph set in motion by sound waves

Inner Ear

Sound Waves

Special Sense Organs (cont’d.)Special Sense Organs (cont’d.)

• The Taste Receptors

Receptors are Chemoreceptors called taste buds

Cranial nerves VII and IX carry gustatory impulses

Six kinds of “primary” taste sensations—sweet, sour, bitter, salty, metallic, and umami (meaty)

Gustatory and olfactory senses work together

The Tongue

Special Sense Organs (cont’d.)Special Sense Organs (cont’d.)

• The Olfactory (smell) Receptors

Receptors for fibers of olfactory or cranial nerve lie in olfactory mucosa of nasal cavity

Olfactory receptors are extremely sensitive but easily fatigued

Odor-causing chemicals initiate a nervous signal that is interpreted as a specific odor by the brain

Olfactory Structures

Let’s Review!

Unit 8Chapter 9

Which of these is a special sense?

A. Pressure

B. Stretch

C. Vision

D. Temperature

E. Pain

A mechanoreceptor may detect changes in__________?

A. Temperature

B. Light intensity

C. pH

D. Pressure

E. Presence of sugars

Muscle spindles are involved in the sense of _______________?

A. Proprioception

B. Pain

C. Smell

D. Movement

E. Gravity

Most of the functional part of the ear lies deep within the:

A. Parietal bone

B. Frontal bone

C. Occipital bone

D. Temporal bone

What are the names of the three ossicles that allow sound to be transmitted through the middle ear?

:

1. Malleus, Incus, Stapes

2. Cochlear nerve, Auditory tube, Oval window

3. Ampulla, Vestibule, Semicircular Canals

4. Endolymph, Perilymph, Acoustic nerve

The layers of the eyeball are all except?

A. Sclera

B. Choroid

C. Retina

D. Cochlea

Which Division of the Ear is being described below?

The semicircular canals are filled with endolymph and are the primary organs in maintaining balance and equilibrium.

Damage or disease to this part of the ear not only affects balance but also may result in permanent hearing loss.

The transparent window of the eye is?

1. Retina

2. Iris

3. Cornea

4. Choroid

5. None of the above

The colored muscular part of the eye?

A. Iris

B. Retina

C. Sclera

D. pupil

The gland that produces tears is?

A. Endocrine

B. Lacrimal

C. Pituitary

D. Salivary

E. None of the above

What is being described below?

Sense Sweet, Sour, Salty, Bitter tastes The medical term for taste buds Papillae Part of the tongue

Nearsightedness is:

A. Myopia

B. Astigmatism

C. Presbyopia

D. Glaucoma

E. hyperopia

Which photoreceptor is responsible for Color vision?

A. Rods

B. Cones

The organ of Corti is involved in the sense of____?

A. Vision

B. Pain

C. Hearing

D. Equilibrium

E. Motion

Sensory perception occurs in the_____?

A. Receptor

B. Organ surrounding the receptor

C. Afferent neuron

D. Brain

When a person ages, the lenses of the eye lose some of their elasticity and can no longer bring near objects into focus. This is called:

A. Hyperopia

B. Myopia

C. Astigmatism

D. presbyopia

Visual interpretation occurs in:

A. The cerebellum

B. The pons

C. The medulla oblongata

D. The cerebrum

When the lens becomes hard, loses its transparency and becomes cloudy:

A. Glaucoma

B. Myopia

C. Retinopathy

D. Cataracts

E. astigmatism

Inflammation of the middle ear:

A. Otitis externa

B. Otitis interna

C. Otitis media

Question to ponder….

We have discussed the importance of maintaining homeostasis in our bodies. We have seen how the integumentary

system and muscular system contribute to homeostasis. How would you suggest

that the general and special senses contribute to homeostasis?

Answer

The general and special senses help maintain homeostasis in the body by monitoring the conditions in our environment.

For instance, heat and cold receptors help us to avoid conditions that will adversely affect temperature regulation in our body. Pain receptors tell us to avoid touching certain things.

Because of special senses such as sight and hearing, we are able to avoid many dangerous situations, which helps maintain conditions within a normal range in the body.

Our general and special senses are constantly accumulating data that are integrated with memory and reflexes to produce homeostatic responses

Review of Final Project

You are tasked with creating a PowerPoint presentation that will be used to educate a patient on a recently diagnosed condition.

Create an educational and informative piece that can be understood by the average citizen.

Details:1. Select a disease or condition that has been covered in one of the

systems discussed in this course (Chapters 1-10).

2. Describe the anatomy of the organs, physiology, pathology, and biochemistry involved in the diagnosis.

3. Include information about how other organ systems are impacted by the condition.

What you are required to include….• Be sure that you have addressed the following objectives in

your work: Identify the major anatomical regions, landmarks, directions and

cavities of the organs affected by the diagnosis. Identify the organs involved in the diagnosis. Explain the normal

functioning of the organs. Analyze the chemical basis of physiologic processes involved in

the disease. Explain how the disease or condition affects the integration of the

body systems in maintaining homeostasis. Describe the functional relationships between the body systems

and the disease process.

An APA PowerPoint

Title slide - Includes the same information as an APA paper. Introduction slide– a bulleted slide that covers the major points you will

be covering in the PPT Slides

Titles for each slide No more than 5 – 7 words for each bulleted item If you include pictures on the slide, you have to place a caption under the picture that

includes the citation in order to avoid copyright issues. 12 – 15 Slides (not including your title or reference slide)

Speaker notes This is where you will explain the bulleted items on your slide. Cite your references in proper APA format – No URLs

Conclusion slide– sum up your work Reference slide (see next slide)

References

Do not use a website address as the reference

Use a hanging indent Use proper APA reference format for each

type of material you use. Journal article Website Textbook Other….

Proper Reference for our Textbook References

Textbook Reference

Thibodeau, G., Patton, K. (2008). Structure and Function of the Body 9

(13th ed). St. Louis, MO: Mosby Elsevier Publishing

Notice the second line is indented 0.5” This is called a hanging indent

Website Examples for Citations and the corresponding References

In-text Citation example (speaker notes):

The National Osteoporosis Foundation (2004) stated, “Eighty persons of those affected by osteoporosis are women” (¶ 1).

Multiple Sclerosis affects more women than men (Copeland, 2003).

References (this is what your reference page would look like)

National Osteoporosis Foundation. (2004). Fast facts. Retrieved from

http://www.nof.org

Copeland, L. (2003). Managing Multiple Sclerosis. Journal of Neurological

Disorders, 25, 69 – 72. Retrieved from http://www.jobjournal.com

Reminder of My favorite quote…..

Don’t wait until the final day to ask for help. Favorite saying….

Lack of planning on your part, does not constitute an emergency on my part.

Yes, you can borrow this for your older children, coworkers and anyone else who meets the criteria!

Reminders & Questions

Surveys Important to new students learning Quality Improvement

Week 9 is our last Seminar No seminar in Week 10 Final Exam in Week 10 and reflective discussion

Final Project is Due at the end of Unit 9 Don’t wait until the last minute Please review for any last minute questions this weekend Send email with questions

QUESTIONS?