Anatomy Chapter 15 The Special Senses

Front 1

Lacrimal Apparatus

Back 1

- Facial Nerve (CN 7) Innervates

Tears: Salt, lysozyme (antibacterial), mucus, ions

Flows into nasolacrimal duct into the nose

Front 2

Eyelid with Tarsal Plate

Back 2

- Glands that secrete sebum to lubricate eyes

- Inflammation and subsequent blockage of the glands lead to chalazion (cyst)

Front 3

Conjunctiva

Back 3

- Deep to eyelid

- Loosely bound sac attached to sclera on inner surface of eyelid

- With mucus membrane and blood vessels for lubrication

Front 4

Oculomotor CN 3

- Superior Rectus (Elevates, medial)

- Inferior Rectus (Depresses, medial)

- Medial Rectus (Medial)

- Inferior Oblique (Elevates, lateral)

Trochlear CN4

- Superior Oblique (Depresses, lateral)

Abducens CN 6

- Lateral Rectus (Lateral abduction)

Back 4

6 Extrinsic Eye Muscles

- Cranial Nerve

- Action

Front 5

Cornea

Sclera

Back 5

Fibrous Layer Components (2)

Front 6

Also called Uvea

- Iris

- Choroid

- Ciliary body

Back 6

Vascular Layer Components (3)

AKA?

Front 7

AKA Retina

- Pigmented Part

- Neural Part

Back 7

Nervous Neural Layer Components (2)

AKA?

Front 8

Sclera

Back 8

- Collagen and elastic fibers

- Covers most of surface of eye

- Innervated and blood vessels

- Supports/protects

- Extrinsic eye muscle tendons insert into here

Front 9

Cornea

Back 9

- Collagen

- Clear part of eye covering iris and pupils

- Trigeminal Nerve CN 5 - Sensory

- No blood vessels: gets nourishment from tears flowing over surface of eye and from aqueous humor in back

- Most sensitive

Front 10

Choroid

Back 10

- Contains melanin, helps to absorb excess light

- Blood vessels - Provide nourishment to retina

Front 11

Ciliary Body

Back 11

- Process: Secretes aqueous humor to fill anterior and posterior chamber in front of eye

- Muscle: Smooth muscle to control shape of lens

Front 12

Iris

Back 12

- Blood vessels

- Pigment cells

- Dilator pupillae muscle innervated by sympathetic nerve fibers

- Constrictor pupillae muscle (CN 3) Oculomotor nerve

Front 13

Retina

Back 13

From back to front

- Pigment epithelium: Simple squamous

- Photoreceptors

Rods: Dim light vision

Cones: Color and visual acuity, project to fovea centralis

- Bipolar neurons: Synapse with rods and cones

- Ganglion cells: Synpase with bipolar neurons and processes from other end form Optic Nerve CN 2

Front 14

Rods: 125 million, located around periphery of retina

Cones: 6 million, more close to center, most are at region called fovea with sharpest vision

Back 14

Are there more rods or cones?

Location?

Front 15

Canal of Schlemm

Back 15

Aqueous humor from ciliary body leaves posterior chamber through pupil into anterior chamber and through this canal

Front 16

Refraction

Back 16

Bending of light rays by lens onto surface of the retina

Front 17

Focal Point

Focal Distance

Back 17

_____________ is where the light rays from an object intersect on the retina and the _____________ is between the center off the lens and that point.

Front 18

Lens

Back 18

- Made of protein to give elasticity

- Ciliary muscles (smooth) surround lens and are attached to via the suspensory ligaments

Front 19

Accomodation

Back 19

Changing the shape of the lens to keep the focal distance constant

Front 20

Distant Vision

Back 20

- Lens is flattened for distance vision

- Ciliary muscle relaxes and pulls on suspensory ligaments attached to lens

Front 21

Close Vision

Back 21

- Lens bulge

- Ciliary muscle contracts, suspensory ligaments relax, lens is not pulled on

Front 22

Emmetropic Eye

Back 22

- No vision problems, not too short or too long.

Front 23

Glaucoma

Back 23

- When there is not enough absorption of the aqueous humor

- Build up puts pressure on the back of the eye and damages the nerves that make up the optic nerve

Front 24

Medial Retina Fibers

Back 24

- Fibers cross over to other side at optic chiasm, for peripheral view

Front 25

Lateral Retina Fibers

Back 25

- Fibers do not cross over, responsible for receiving light from medial side

Front 26

Auricle/Pinna

External auditory canal/meatus

Tympanic Membrane

Back 26

3 Parts of External Ear

Front 27

Auricle/Pinna

Back 27

- Collect sound waves and funnel them to external auditory canal

Front 28

External auditory canal

Back 28

- In temporal Bone

- Cerumen glands: Produce cerumin (earwax - antibacterial properties)

- Otitis Externa: An infection of this region is called swimmer's ear. Antibacterial drop treatment

Front 29

Tympanic Membrane

Back 29

- Stratified squamous epithelium on external surface

- Simple cuboidal internal surface

- Elastic fibers between these two epithelial layers

- Sound comes in causing these elastic fibers to vibrate, which cause parts of middle and inner ear to vibrate

Front 30

Malleus

Incus

Stapes

Eustachian Tube

Back 30

4 Parts of Middle Ear

Front 31

Malleus

Back 31

- Attached to tympanic membrane

Front 32

Incas

Back 32

- Between malleus and stapes

- Synovial fluid exist between the spaces between malleus and ______

Front 33

Stapes

Back 33

- Attached to oval window

- Synovial fluid between incus and ________

- Conduct vibrations to cochlea inner ear

Front 34

Eustachian tube

Back 34

- Connects middle ear to nasophayrnx (Throat)

- Functions to equalize pressure in middle ear

- Bacteria in middle ear can cause infection called (Otitis Media)

Front 35

Antrum

Back 35

The cavity that holds malleus, incus and stapes

Front 36

Cochlea

Back 36

* Fluid filled chambers

- Sound waves - Stapes - Oval window membranous entrance

- Scala Vestibule (Superior chamber) - Scala Tympani (Inferior Chamber) - Sound stops at round window

- Vibrations in the two chambers go to Perilymph and endolymph (cochlear ducts - Internal chambers)

- Receptors located in Organs of Cortii with cilia (Hair cells - machenoreceptor)

- Auditory vestibulocochlear nerve CN 8 carries sound to brain

Front 37

Vestibule

Back 37

- Contains utricle and saccule that sit at right angles to each other

- These contain hair cells with stones called otoliths on top

- Utricle and saccule filled with endolymphs (cochlear ducts - internal chambers)

Front 38

Static Equilibrium

Back 38

- As head it tilted, otoliths push down on hair cells in utricle and saccule

- Send action potential to Auditory Vestibulocochlear CN 8 to brain

Front 39

Semicircular Canals

Back 39

Contain Crista ampularis

- Hair cells surrounded by endolymph

- When body moves, hair cells move

- Balance while moving

- Dynamic equilibrium

Front 40

Conduction Deafness

Back 40

- Anything that causes damage to the structures of external, middle or inner ear (Pinna, external acoustic canal, malleus, incus, stapes)

- Cannot hear

- Cause: Something blocking passageway infects the structures to not move as well as they should

Front 41

Sensorineural deafness

Back 41

- Damage to the sensory pathway to cause deafness

- Auditory vestibulocochlear nerve CN 8 - medulla - inferior colliculli (midbrain) - thalamus - temporal lobe

Front 42

Olfaction

Back 42

Location:

- Superior part of nasal epithelium

- Olfactory epithelium

- Bipolar neuron extensions synapse on olfactory bulb

- Sensitive, threshold

- Adaptation: Repeated odors can cause decrease in stimulation

Front 43

Olfactory Cortex

Back 43

- Pathway bypasses the thalamus, ______________, hypothalamus, part of limbic system involved in memory and emotions

Front 44

Taste

Back 44

Location:

- Papillae, chemoreceptors

Nerves:

- Facial Nerve 7

- Glossopharyngeal Nerve CN 9 (Ingestion)

- Vagus Nerve CN 10