1 sensory physiology. 2 nervous system - senses general senses receptors that are widely distributed...
TRANSCRIPT
![Page 1: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/1.jpg)
1
Sensory Physiology
![Page 2: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/2.jpg)
2
Nervous System - Senses
General Senses• receptors that are widely distributed throughout the body• skin, various organs and joints
Special Senses• specialized receptors confied to structures in the head • eyes and ears
![Page 3: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/3.jpg)
3
Senses
Sensory Receptors• specialized cells or multicellular structures that collect information from the environment
• stimulate neurons to send impulses along sensory fibers to the brain
Sensation• a feeling that occurs when brain becomes aware of sensory impulse
Perception• a person’s view of the stimulus; the way the brain interprets the information
![Page 4: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/4.jpg)
4
Sensory Receptor Types
Figure 10-1: Sensory receptors
![Page 5: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/5.jpg)
5
Pathways From Sensation to Perception (Example of an Apple)
![Page 6: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/6.jpg)
6
Receptor Types
Chemoreceptors• respond to changes in chemical concentrations
Pain receptors (Nociceptors)• respond to tissue damage
Thermoreceptors• respond to changes in temperature
Mechanoreceptors• respond to mechanical forces
Photoreceptors• respond to light
![Page 7: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/7.jpg)
7
Sensory Adaptation
• ability to ignore unimportant stimuli
• involves a decreased response to a particular stimulus from the receptors (peripheral adaptations) or along the CNS pathways leading to the cerebral cortex (central adaptation)
• sensory impulses become less frequent and may cease
• stronger stimulus is required to trigger impulses
![Page 8: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/8.jpg)
8
General Senses
• senses associated with skin, muscles, joints, and viscera
• three groups
• exteroceptive senses – senses associated with body surface; touch, pressure, temperature, pain
• visceroceptive senses – senses associated with changes in viscera; blood pressure stretching blood vessels, ingesting a meal
• proprioceptive senses – senses associated with changes in muscles and tendons
![Page 9: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/9.jpg)
9
Touch and Pressure Senses
Free nerve endings• common in epithelial tissues• simplest receptors• sense itching•Ex ( nociciptor)
Meissner’s corpuscles• abundant in hairless portions of skin; lips• detect fine touch; distinguish between two points on the skin
Pacinian corpuscles• common in deeper subcutaneous tissues, tendons, and ligaments• detect heavy pressure and vibrations
![Page 10: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/10.jpg)
10
Touch and Pressure Receptors
![Page 11: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/11.jpg)
11
Touch (pressure)
Figure 10-11: Touch-pressure receptors
![Page 12: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/12.jpg)
12
Temperature Senses
Warm receptors• sensitive to temperatures above 25oC (77o F)• unresponsive to temperature above 45oC (113oF)
Cold receptors• sensitive to temperature between 10oC (50oF) and 20oC (68oF)
Pain receptors (nociceptor) • respond to temperatures below 10oC• respond to temperatures above 45oC
![Page 13: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/13.jpg)
13
Summary of Receptors of the General Senses
![Page 14: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/14.jpg)
14
Special Senses
• sensory receptors are within large, complex sensory organs in the head
• smell in olfactory organs
• taste in taste buds
• hearing and equilibrium in ears
• sight in eyes
![Page 15: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/15.jpg)
15
Sense of Smell
Olfactory Receptors• chemoreceptors• respond to chemicals dissolved in liquids
Olfactory Organs• contain olfactory receptors and supporting epithelial cells
• cover parts of nasal cavity, superior nasal conchae, and a portion of the nasal septum
![Page 16: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/16.jpg)
16
Olfactor: Sense of Smell
Figure 10-14a, b: ANATOMY SUMMARY: Olfaction
![Page 17: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/17.jpg)
17
Olfactory Receptors
![Page 18: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/18.jpg)
18
Olfactor: Sense of Smell
Figure 10-14c: ANATOMY SUMMARY: Olfaction
![Page 19: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/19.jpg)
19
Olfactory Nerve Pathways
Once olfactory receptors are stimulated, nerve impulses travel through
• olfactory nerves olfactory bulbs olfactory tracts limbic system (for emotions) and olfactory cortex (for interpretation)
![Page 20: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/20.jpg)
20Figure 10-4: Sensory pathways
![Page 21: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/21.jpg)
21
Olfactory Stimulation
Olfactory Code• hypothesis • odor that is stimulated by a distinct set of receptor cells and its associated receptor proteins
• olfactory organs located high in the nasal cavity above the usual pathway of inhaled air
• olfactory receptors undergo sensory adaptation rapidly
• sense of smell drops by 50% within a second after stimulation
![Page 22: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/22.jpg)
22
Sense of Taste
Taste Buds• organs of taste• located on papillae of tongue, roof of mouth, linings of cheeks and walls of pharynx
Taste Receptors• chemoreceptors• taste cells – modified epithelial cells that function as receptors• taste hairs –microvilli that protrude from taste cells; sensitive parts of taste cells
![Page 23: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/23.jpg)
23
Taste Receptors
![Page 24: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/24.jpg)
24
Taste Sensations
Four Primary Taste Sensations• sweet – stimulated by carbohydrates• sour – stimulated by acids• salty – stimulated by salts• bitter – stimulated by many organic compounds
Spicy foods activate pain receptors
![Page 25: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/25.jpg)
25
Taste Nerve Pathways
Sensory impulses from taste receptors travel along• cranial nerves to • medulla oblongata to• thalamus to • gustatory cortex (for interpretation)
![Page 26: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/26.jpg)
26Figure 10-4: Sensory pathways
![Page 27: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/27.jpg)
27
Taste: Chemoreceptors
![Page 28: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/28.jpg)
28
Taste: Chemoreceptors
• Salt --- Na passive • Acids– H block k channels • Sweet – Gs anhydrate cyclase – protein kinase(A) –
Phosphorylation of k channels so it will close• Bitter – Gb – phospholipasec – release of ca from ER • Depolarization –activate neurotransmitter vesicle to
diffues to membrane and release neurotransmitter
![Page 29: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/29.jpg)
29
The Ear: Hearing and Equilibrium
• The ear – receptor organ for hearing and equilibrium
• Composed of three main regions– Outer ear – functions in hearing– Middle ear – functions in hearing– Inner ear – functions in both hearing and
equilibrium
![Page 30: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/30.jpg)
30
The Outer (External) Ear• Composed of:
– The auricle (pinna)• Helps direct sounds
– External acoustic meatus• Lined with skin
– Contains hairs, sebaceous glands, and ceruminous glands
– Tympanic membrane• Forms the boundary between the external and
middle ear
![Page 31: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/31.jpg)
31
The Outer (External) Ear
Figure 16.17a
![Page 32: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/32.jpg)
32
The Middle Ear
• The tympanic cavity – A small, air-filled space
– Located within the petrous portion of the temporal bone
• Medial wall is penetrated by:– Oval window
– Round window
• Pharyngotympanic tube (auditory or eustachian tube) – Links the middle ear and pharynx
![Page 33: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/33.jpg)
33
Structures of the Middle Ear
Figure 16.17b
![Page 34: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/34.jpg)
34Figure 16.19
The Middle Ear
• Ear ossicles – smallest bones in the body– Malleus – attaches to
the eardrum – Incus – between the
malleus and stapes– Stapes – vibrates
against the oval window
![Page 35: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/35.jpg)
35
The Inner (Internal) Ear
• Inner ear – also called the labyrinth• Lies within the petrous portion of the
temporal bone• Bony labyrinth – a cavity consisting of three
parts– Semicircular canals– Vestibule– Cochlea
![Page 36: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/36.jpg)
36
The Inner (Internal) Ear
• Membranous labyrinth – Series of membrane-walled sacs and ducts– Fit within the bony labyrinth– Consists of three main parts
• Semicircular ducts
• Utricle and saccule
• Cochlear duct
![Page 37: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/37.jpg)
37
The Inner (Internal) Ear
• Membranous labyrinth (continued)– Filled with a clear fluid – endolymph
• Confined to the membranous labyrinth
– Bony labyrinth is filled with perilymph • Continuous with cerebrospinal fluid
![Page 38: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/38.jpg)
38
The Membranous Labyrinth
Figure 16.20
![Page 39: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/39.jpg)
39
The Inner (Internal) Ear
Figure 16.17b
![Page 40: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/40.jpg)
40
Cochlea
Cochlear duct• portion of membranous labyrinth in cochlea
Vestibular membrane• separates cochlear duct from scala vestibuli
Basilar membrane• separates cochlear duct from scala tympani
![Page 41: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/41.jpg)
41
The Cochlea
Figure 16.23a–c
![Page 42: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/42.jpg)
42
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 of receptor cells to bend• nerve impulse generated
![Page 43: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/43.jpg)
43
Hearing: Mechanoreceptors
Figure 10-19: Sound transmission through the ear
![Page 44: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/44.jpg)
44
Hearing: Hair Cell Transduction
Figure 10-20: The cochlea
![Page 45: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/45.jpg)
45
Hearing: Hair Cell Transduction
Figure 10-21: Signal transduction in hair cells
![Page 46: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/46.jpg)
46
![Page 47: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/47.jpg)
47
Summary of the Generation of Sensory Impulses from the Ear
![Page 48: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/48.jpg)
48
Equilibrium
Static Equilibrium• vestibule• sense position of head when body is not moving
Dynamic Equilibrium• semicircular canals• sense rotation and movement of head and body
![Page 49: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/49.jpg)
49
Vestibule
• Utricle• communicates with saccule and membranous portion of semicircular canals
• Saccule• communicates with cochlear duct
• Mucula• hair cells of utricle and saccule
![Page 50: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/50.jpg)
50
Macula
• responds to changes in head position• bending of hairs results in generation of nerve impulse
![Page 51: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/51.jpg)
51
Anatomy and Function of the Maculae
Figure 16.21a
![Page 52: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/52.jpg)
52
Semicircular Canals
• three canals at right angles• ampulla
• 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
![Page 53: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/53.jpg)
53
Crista Ampullaris
![Page 54: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/54.jpg)
54
Vestibular System & Balance
![Page 55: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/55.jpg)
55
Rotation & Gravity
![Page 56: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/56.jpg)
56
Auditory Pathway from the Organ of Corti
Figure 16.25
![Page 57: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/57.jpg)
57
Sight
Visual Accessory Organs• eyelids• lacrimal apparatus• extrinsic eye muscles
![Page 58: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/58.jpg)
58
Lacrimal Apparatus
• lacrimal gland• lateral to eye• secretes tears
• canaliculi• collect tears
• lacrimal sac• collects from canaliculi
• nasolacrimal duct• collects from lacrimal sac• empties tears into nasal cavity
![Page 59: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/59.jpg)
59
Extrinsic Eye Muscles
Superior rectus• rotates eye up and medially
Inferior rectus• rotates eye down and medially
Medial rectus• rotates eye medially
![Page 60: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/60.jpg)
60
Extrinsic Eye Muscles
Lateral rectus• rotates eye laterally
Superior oblique• rotates eye down and laterally
Inferior oblique• rotates eye up and laterally
![Page 61: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/61.jpg)
61
Structure of the Eye
• hollow• spherical• wall has 3 layers
• outer fibrous tunic• middle vascular tunic• inner nervous tunic
![Page 62: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/62.jpg)
62
Outer Tunic
Cornea• anterior portion• transparent• light transmission• light refraction
Sclera• posterior portion• opaque• protection
![Page 63: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/63.jpg)
63
Middle Tunic
Iris • anterior portion• pigmented• controls light intensity
Ciliary body• anterior portion• pigmented• holds lens• moves lens for focusing
Choroid coat• provides blood supply• pigments absorb extra light
![Page 64: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/64.jpg)
64
Anterior Portion of Eye
• filled with aqueous humor
![Page 65: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/65.jpg)
65
Lens
• transparent• biconvex• lies behind iris• largely composed of lens fibers• elastic• held in place by suspensory ligaments of ciliary body
![Page 66: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/66.jpg)
66
Ciliary Body
• forms internal ring around front of eye• ciliary processes – radiating folds• ciliary muscles – contract and relax to move lens
![Page 67: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/67.jpg)
67
Accommodation• changing of lens shape to view objects
![Page 68: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/68.jpg)
68
Iris
• composed of connective tissue and smooth muscle• pupil is hole in iris• dim light stimulates radial muscles and pupil dilates• bright light stimulates circular muscles and pupil constricts
![Page 69: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/69.jpg)
69
Aqueous Humor
• fluid in anterior cavity of eye• secreted by epithelium on inner surface of the ciliary body• provides nutrients• maintains shape of anterior portion of eye• leaves cavity through canal of Schlemm
![Page 70: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/70.jpg)
70
Inner Tunic
• retina• contains visual receptors• continuous with optic nerve• ends just behind margin of the ciliary body• composed of several layers• macula lutea – yellowish spot in retina• fovea centralis – center of macula lutea; produces sharpest vision• optic disc – blind spot; contains no visual receptors• vitreous humor – thick gel that holds retina flat against choroid coat
![Page 71: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/71.jpg)
71
Posterior Cavity
• contains vitreous humor – thick gel that holds retina flat against choroid coat
![Page 72: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/72.jpg)
72
Major Groups of Retinal Neurons
• receptor cells, bipolar cells, and ganglion cells - provide pathway for impulses triggered by photoreceptors to reach the optic nerve• horizontal cells and amacrine cells – modify impulses
![Page 73: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/73.jpg)
73
Layers of the Eye
![Page 74: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/74.jpg)
74
Light Refraction
Refraction • bending of light• occurs when light waves pass at an oblique angle into mediums of different densities
![Page 75: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/75.jpg)
75
Types of Lenses
Convex lenses cause light waves to converge
Concave lenses cause light waves to diverge
![Page 76: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/76.jpg)
76
Focusing On Retina• as light enters eye, it is refracted by
• convex surface of cornea• convex surface of lens
• image focused on retina is upside down and reversed from left to right
![Page 77: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/77.jpg)
77
Visual Receptors
Rods• long, thin projections• contain light sensitive pigment called rhodopsin• hundred times more sensitive to light than cones• provide vision in dim light• produce colorless vision• produce outlines of objects
Cones• short, blunt projections• contain light sensitive pigments called erythrolabe, chlorolabe, and cyanolabe• provide vision in bright light• produce sharp images• produce color vision
![Page 78: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/78.jpg)
78
Rods and Cones
![Page 79: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/79.jpg)
79
Visual Pigments
Rhodopsin• light-sensitive pigment in rods• decomposes in presence of light• triggers a complex series of reactions that initiate nerve impulses• impulses travel along optic nerve
Pigments on Cones• each set contains different light-sensitive pigment• each set is sensitive to different wavelengths• color perceived depends on which sets of cones are stimulated• erythrolabe – responds to red• chlorolabe – responds to green• cyanolabe – responds to blue
![Page 80: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/80.jpg)
80
Rod Cells
![Page 81: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/81.jpg)
81
Visual Nerve Pathway
![Page 82: 1 Sensory Physiology. 2 Nervous System - Senses General Senses receptors that are widely distributed throughout the body skin, various organs and joints](https://reader036.vdocuments.us/reader036/viewer/2022062422/56649ece5503460f94bdb25e/html5/thumbnails/82.jpg)
82