1. Anatomy and Physiology
Marieb’s Human
Anatomy and Physiology
Marieb w Hoehn
Chapter 13 – General Sensory Receptors
Chapter 15 - Special Sensory Receptors
Lecture 22
55 slides, 155 min. (1 -> 26, 80 min; 28 -> end, 75 min.)

2. Lecture Overview Introduction to the senses and sensation
Types of sensors
Classification of sensory receptors
Anatomy of the ear
Physiology of hearing/equilibrium
Anatomy of the eye
Physiology of vision
Video 1
Video 2
Video 3

3. Special Senses
sensory receptors are within large, complex sensory organs in the head
hearing and equilibrium in ears
sight in eyes
smell in olfactory organs
taste (gustation) in taste buds
(Video 2)*
(Video 3)
Not covered in video – see master slide set

4. Overview of the Ear

5. External Ear auricle (pinna) external auditory meatus
collects sounds waves
external auditory meatus
lined with ceruminous glands
carries sound to tympanic membrane
terminates at tympanic membrane
tympanic membrane
vibrates in response to sound waves

6. The Middle Ear (Tympanic Cavity)
Typanic (attenuation) reflex: Elicited about 0.1 sec following loud noise; causes contraction of the tensor tympani m. and stapedius m. to dampen transmission of sound waves

7. Auditory Tube Eustachian, auditory, or pharyngotympanic tube
connects middle ear to throat
helps maintain equal pressure on both sides of tympanic membrane
usually closed by valve-like flaps in throat
When pressure in tympanic cavity is higher than in nasopharynx, tube opens automatically. But the converse is not true, and the tube must be forced open (swallowing, yawning, chewing).

8. Inner Ear 3 Parts of Labyrinth cochlea semicircular canals vestibule
functions in hearing
semicircular canals
function in equilibrium
vestibule
functions in equilibrium
utricle and saccule
Labyrinth

9. Cochlea Scala vestibuli upper compartment
Cochlea as it would look ‘unwound’
Tympano = in relation to, in connection with
Oval window = base of scala vestibuli (vestibular duct); round window = base of scala tympani (tympanic duct).
Scala vestibuli and s. tympani are filled with perilymph (like interstitial fluid ad CSF); cochlear duct (s. media) is filled with endolymph (unique comp., but similar to intracellular fluid)
Scala vestibuli
upper compartment
leads from oval window to apex of spiral
part of bony labyrinth
Scala tympani
lower compartment
extends from apex of the cochlea to round window
part of bony labyrinth

10. Organ of Corti group of hearing receptor cells (hair cells)
on upper surface of basilar membrane
different frequencies of vibration move different parts of basilar membrane
particular sound frequencies cause hairs (stereocilia) of receptor cells to bend
nerve impulse generated

11. Physiology of Hearing Know pathway for exam
Figure from: Marieb, Human Anatomy & Physiology, Pearson, 2013
Know pathway for exam
Tympanic membrane  malleus  incus  stapes  oval window  scala vestibuli  scala tympani  round window

12. Auditory Nerve Pathways
Accessory Nerve (CN XI)
Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004
(pons)

13. Vestibule
Utricle
communicates with saccule and membranous portion of semicircular canals
Saccule
communicates with cochlear duct
Macula
contains hair cells of utricle (horizontal) and saccule (vertical)
Utricle and saccule provide sensations of: 1) gravity and 2) linear acceleration
These organs function in static equilibrium (head/body are still)

14. Macula responds to changes in head position
bending of hairs results in generation of nerve impulse

15. Semicircular Canals
three canals at right angles
ampulla (expansion)
swelling of membranous labyrinth that communicates with the vestibule
crista ampullaris
sensory organ of ampulla
hair cells and supporting cells
rapid turns of head or body stimulate hair cells
Acceleration of fluid inside canals causes nerve impulse
These organs function in dynamic equilibrium (head/body are in motion)

16. Crista Ampullaris
Semicircular canals respond to rotational, nonlinear movements of the head

17. Pathways for Equilibrium Sensations
For vestibulo-ocular reflex
80 min to this point.
Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004 *

18. Please Take the Short Quiz
Remember to take the brief quiz now to see if you’ve gotten the major concepts from the video.
You can always go back and review the video as many times as you like – and can retake the quiz, as well.