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Y2B4 - Central Nervous System 📙 > Histology 🔬 > Flashcards

Histology 🔬 Flashcards

1
Q

Parts of spinal cord

A
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2
Q

Dorsal horn nuclei

A
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3
Q

lateral horn nuclei

A
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4
Q

Ventral horn nuclei

A
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5
Q

Structure of white matter

A
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6
Q

what are ascending tracts of spinal cord?

A
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7
Q

what are descending tracts of spinal cord?

A
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8
Q

Structures in spinal cord section at cervical levels

A
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9
Q

Structures in spinal cord section at upper thoracic levels

A
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10
Q

Structures in spinal cord section at lower thoracic levels

A
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11
Q

Structures in spinal cord section at lumbar levels

A
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12
Q

what are the parts of cerebrum?

A
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13
Q

what are the layers of the Cerebral cortex? and what is its content?

A
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14
Q

what is the structure of cerebral white matter?

A
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15
Q

Site of Cells of martinotti

A
  • throughout cerebral cortex
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16
Q

Axon of Cells of martinotti

A
  • ascend towards superficial layer
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17
Q

what are the parts of cerebellum?

A
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18
Q

what are the layers of cerebellar cortex? and what are its contents?

A
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19
Q

structure of cerebellar nuclei (From lateral to medial)

A
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20
Q

what are the functions of cerebellum?

A
  • Refines and co-ordinates voluntary muscle movement
  • maintains muscle tone
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21
Q

what are the signs of cerebellar lesion?

A
  • uncoordinated muscle movements
  • Hypotonia
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22
Q

what are the layers of the eye ball?

A
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23
Q

Definition of Cornea

A
  • It is a colorless, non-vascular and transparent layer that covers the anterior 1/6 of the outer fibrous coat.
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24
Q

LM of Cornea

A

5 Layers from outside inwards:
- Epithelium
- Bowman’s membrane
- Substantia propria
- Descemet’s membrane
- Descemet’s endothelium

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25
Q

Epithelium of Cornea

A

Str. sq. non-keratinized epi that covers its anterior surface exposed to air

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26
Q

Bowman’s membrane of Cornea

A
  • a transparent homogenous layer of collagen fibers which acts as a protective layer. Once destroyed, it is not regenerated and healing from the underlying C.T. always leaves a scar causing corneal opacity.
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27
Q

Substantia propria of Cornea

A
  • The thickest layer of the cornea. avascular layer of type I collagen fibers and fibroblasts.
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28
Q

Descemet’s membrane of Cornea

A
  • a thick basement membrane underneath Descement endothelium which is responsible for its synthesis and maintenance.
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29
Q

Descemet’s endothelium of Cornea

A
  • Simple. Sq. epi that covers the post surface exposed to the aqueous humor
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30
Q

what causes transperency of Cornea?

A

1) The continuous evaporation of water from its surface.

2) The absence of blood vessels. (Avascular)

3)The cells, fibers and matrix have the same refractive indices.

4) The regular arrangement of the fibers and cells of the substantia propria.

5)The regular arrangement of the cells of the covering epithelium.

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31
Q

Definition of Sclera

A
  • Opaque, heavily vascularized C.T that covers the post 5/6th of the eye
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32
Q

What causes opacity of Sclera?

A

1-The refractive indices of all its elements Are not equal.

2- The irregular arrangement of its C.T.fibres.

3- The presence of great amount of water.

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33
Q

Definition of Corneoscleral junction (limbus)

A
  • The junction of the opaque sclera and transparent cornea post to the limbus a circular canal called canal of schlemm
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34
Q

what is Aqueous Humor?

A
  • Clear fluid that flow from the post chamber to the ant chamber and leaves the eye through the canal of Schlemm.
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35
Q

what is Viterous Body?

A
  • Transparent gelatinous substance that fills the space between the lens and the retina.
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36
Q

Definition of Iris

A
  • Disk shaped colored diaphragm.
  • It separates the anterior and the posterior chambers.
  • It covers the anterior surface of the lens leaving an adjustable opening in the center (the pupil)
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37
Q

Structure of Iris

A
  1. Anterior surface
  2. Stroma
  3. Posterior surface
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38
Q

anterior surface of Iris

A

Discontinuous layer of fibroblasts, melanocytes and collagen.

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39
Q

Stroma of Iris

A
  • loose C.T. that differentiates into 2 layers:

( Ant stromal layer : more pigmented but less vascular. )

( Post vessel layer :More vascular but less pigmented. )

  • It contains the muscles of the iris which are arranged as follow:

✓ The dilator pupillae muscles radially arranged and lie near the back of the iris.

✓ The constrictor pupillae ms is a circularly arranged and lie at the pupillary margin of the iris.

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40
Q

posterior surface of Iris

A

covered by 2 layers of heavily pigmented cuboidal epithelial cells.

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41
Q

Function of iris

A

1) Changes the pupillary size.
2) Shares in the formation of aqueous humor.
3) Gives the color of the eye

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42
Q

Definition of Ciliary body

A

Thickened ant part of the choroid.

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43
Q

what is the interior of ciliary body formed of?

A
  • The interior of the ciliary body is made of loose C.T. rich in blood vs and melanocytes in which the ciliary ms are embedded.
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44
Q

what is ciliary muscles formed of? and what is its significance?

A
  • The ciliary muscles are formed of smooth ms fibers arranged in different directions
  • Its contraction helps in the accomodation reflex
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45
Q

what are ciliary processes?

A

Irregular processes arising from the ciliary body extending toward the lens.

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46
Q

Structure of ciliary processes

A
  • Have a loose C.T. core and numerous fenestrated capillaries.
  • They are covered by the ciliary epithelium.
  • Ciliary epi is formed of 2 layers of cubical cells
    ❖ inner is non-pigmented while
    ❖ outer layer is richly pigmented with melanin
    pigment.
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47
Q

Significance of ciliary processes

A

The ciliary processes are responsible for the formation of the aqueous humor.

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48
Q

Definition of choroid

A

It is the pigmented vascular C.T. layer which lies between the retina and the sclera

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49
Q

Structure of Choroid

A
  • Epichoroid or suprachoroid
  • The vessel layer
  • The choriocapillaries
  • Bruch’s membrane
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50
Q

Epichoroid or suprachoroid

A

It is the most outer layer consists of a loose C.T.

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51
Q

The vessel layer of choroid

A
  • A highly vascular C.T. rich in elastic fibres and pigment cells.
  • It contains tortuous choroid arteries and veins.
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52
Q

choriocapillaries

A

Single layer of fenestrated blood capillaries.

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53
Q

Bruch’s membraneof choroid

A
  • It is a thin hyaline membrane representing the inner most component of the choroid separates the choriocapillary layer from the retina
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54
Q

Function of choroid

A

1) Nutrition of the retina

2) Supports the retina and absorbs excess light.

3) Bruch’s membrane plays a significant role in limiting access of inappropriate macromolecules from the fenestrated capillaries to the adjacent part of the retina

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55
Q

what is the lens?

A

A transparent bi-convex disk composed of lens fibers that are remnants of cells filled with crystallins and surrounded by a capsule.

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56
Q

what is found on the anterior surface of the lens?

A

subcapsular cuboidal cells are present.

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57
Q

Extension of suspensory ligament of the eye

A

extend from the periphery of the lens to the ciliary processes.

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58
Q

what are the refractive media of the eye?

A
  1. cornea
  2. The aqueous humor
  3. The lens
  4. The vitreous body
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59
Q

what are the layers of Inner nervous layer (Retina)?

A
  1. Pigmented epithelium layer
  2. Rods and cones layer
  3. The outer limiting membrane
  4. The outer nuclear layer
  5. Outer plexiform (reticular) layer
  6. The inner nuclear layer
  7. The inner plexiform layer
  8. Ganglion cell layer (the 3rd order neuron)
  9. The nerve fiber layer
  10. The inner limiting membrane
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60
Q

LM of Pigmented epithelium layer

A
  • Cubical cells with rounded nuclei.
  • Cytoplasm contains melanin granules.
  • The basal region adheres firmly to Bruch’s membrane
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61
Q

EM of Pigmented epithelium layer

A
  • Apical micrvoilli.
  • Apical microvesicles and melanin granules.
  • Middle part shows rER, sER and lysosomes.
  • Basal and lateral invaginations.
  • Lateral junctional complexes.
  • Basal part shows many mitochondria
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62
Q

Function of Pigmented epithelium layer

A

1) Absorbs excess light

2) Phagocytoses old discs

3)The junction between its cells forms “a blood retinal barrier” which limits access of substances of small molecular weight from the fenestrated capillaries of the choriocapillaries to the outer part of the retina

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63
Q

what does Rods and cones layer contain?

A

It contains the dendritic processes of the rods & cones.

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64
Q

what are Rods and cones?

A

dendritic processes of the rods & cones are photoreceptors

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65
Q

Compare between Rods and cones in terms of:

  • Number
  • Structure (Outer segment, Connecting stalk, Inner segment, Cell body, Synaptic region)
  • Function
A
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66
Q

what is The outer limiting membrane?

A
  • It is a dark line which contains the junctional complexes between the processes of glial cells of Muller and the rods and cones
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67
Q

what does The outer nuclear layer contain?

A
  • Contains the cell bodies of rod and cone cells (1st order neurons)
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68
Q

what does the Outer plexiform (reticular) layer contain?

A
  • It contains the synapses between the axons (synaptic processes) of rod and cone cells and the dendrites of the bipolar and the horizontal cells
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69
Q

what does The inner nuclear layer contain?

A

Contains the cell bodies of:
- The bipolar (the 2nd order neurons)
- Horizontal
- Amacrine
- Muller Cells

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70
Q

what are the types of bipolar cells in The inner nuclear layer?

A

are of 2 types of cells (Monosynaptic and diffusebipolar)

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71
Q

what are the horizontal cells of the inner nuclear layer?

A

Are associated neurons

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72
Q

where are the horizontal cells of the inner nuclear layer?

A

lying near the outer plexiform layer.

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73
Q

what are amacrine cells of the inner nuclear layer?

A

Their processes synapse with rods and cones

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74
Q

where are the amacrine cells of the inner nuclear layer?

A

Are associated neurons

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75
Q

what do the horizontal cells of the inner nuclear layer synapse with?

A

lying close to the inner plexiform layer.

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76
Q

what do amacrine cells of the inner nuclear layer synapse with?

A

They synapse with the axons of bipolar and dendrites of ganglion cells.

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77
Q

what are muller cells?

A
  • Neuroglial cells.
  • Their processes extend from the internal to the external limiting membrane.
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78
Q

Function of muller cells

A

It supports, nourishes and insulates the retinal neurons and fibers.

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79
Q

what does The inner plexiform layer contain?

A

It contains the synapse between the axon of the bipolar nerve cells and the dendrites of ganglion cells, and the synapses of amacrine cells.

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80
Q

what does Ganglion cell layer (the 3rd order neuron) contain?

A
  • It contains the ganglion cells, which are typical nerve cells, with vesicular nucleus and basophilic cytoplasm.
  • Their dendrites synapse with the axons of the bipolar nerve cells.
  • Their axons form the fibres of the optic nerve.
  • It contains retinal blood vessels and neuroglial cells.
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81
Q

what does The nerve fiber layer contain?

A

contains:

1)The axons of the ganglion cells which pass at right angle to form the optic n

2)Neuroglial cells.

3)Retinal blood vessels.

82
Q

what is The inner limiting membrane?

A

It is a dark line formed by the terminal processes of Muller cells.

83
Q

Structures in eyelid

A
  • Skin
  • Skeletal ms
  • The tarsus
  • The Eye lashes
  • Palpebral Conjunctiva
84
Q

Skin of eyelid

A

It is a delicate which contains few fine hairs, sweat glands and sebaceous glands

85
Q

what is the tarsus of eyelid?

A

is a condensed plate of fibrous tissue that lies in the posterior part of the eyelid, it contains the meibomian glands

86
Q

skeletal msucles of eyelid

A

bundles of the orbicularis occuli

87
Q

eyelashes in eyelid

A

Are 3-4 rows of hairs projecting from the lid margin

88
Q

what are the glands in lid?

A
  • Moll Gland
  • Zeis Gland
  • The meibomian glands
89
Q

what is Moll Gland?

A
  • modified sweat glands present posterior to the eyelashes
90
Q

what is Zeis Gland?

A
  • modified sebaceous glands which are present at the roots of the hair follicles of the eye lashes
91
Q

what is a sty?

A
  • “A sty” is produced as a result of infection of either the gland of moll or the gland of Zeis
92
Q

what is meibomian glands?

A
  • Long sebacous glands in the tarsal plate.
93
Q

what characterizes meibomian glands?

A
  • They do not communicate with the hair follicles.
  • It opens on the lid margin by a duct behind the grey line
94
Q

what does obstruction of meibomian glands lead to?

A
  • Their obstruction lead to inflamed gland. “Chalazion” is an inflammatory swelling present in the eyelid as a result of the infection
95
Q

Defintion of Conjunctiva

A

A very thin transparent mucous membrane

96
Q

Structure of Conjunctiva

A

Epith:
a) Bulbar conjunctiva: str sq epith.
b) Palpebral conjunctiva: stratified squamous epith
c) Fornix: stratified columnar epith. with few goblet cells

Corium: loose C.T with blood vessels and lymphocytic infiltration.

97
Q

Function of Conjunctiva

A
  1. Lubrication and protection → secretes mucous together with the tears forms lubricant protective fluid.
  2. Defense and immunological role due to its lymphocytic infiltration
98
Q

what are the components of lacrimal apparatus?

A
  • Lacrimal gland(Tear secreting glands)
  • Lacrimal Canaliculi
  • Lacrimal Sac
  • Nasolacrimal duct
99
Q

LM of Lacrimal gland(Tear secreting glands)

A
  • It is formed of columnar shaped cells of the serous types with lightly stained secretory granules and surrounded by well developed myoepithelial cells
100
Q

Function of Lacrimal gland(Tear secreting glands)

A
  • Secrete tears which moisten the cornea and
    conjunctiva.

(The tears are rich in lysozymes which can hydrolyze bacteria.)

101
Q

what do tears drain into?

A

Lacrimal canaliculi

102
Q

Site of Lacrimal Canaliculi

A
  • Present on the medial aspect of both eyelid margins.
103
Q

what do Lacrimal Canaliculi open into?

A
  • The canaliculi open into the lacrimal sac.
104
Q

what is Lacrimal Sac? and what is it lined by?

A

it is wide tube, lined with pseudostratified columnar ciliated epithelium with motile cilia and goblet cells

105
Q

what is Nasolacrimal duct? and what does it open into?

A

is the downward continuation of the lacrimal sac. It
opens into the nasal cavity

106
Q

What are receptors for special senses?

A

Refer to GoodNotes for the next 40 questions

107
Q

what are receptors for cutaneous sensation (Extroceptors)?

108
Q

Types of (touch) mechanoreceptors

109
Q

what are receptors for deep sensations?

110
Q

what are proprioceptors responsible for?

111
Q

what are receptors of kinesthesia responsible for?

112
Q

Receptors for visceral sensations (Visceroceptors)

113
Q

Site of Nocireceptors

114
Q

Structure of Nocireceptors

115
Q

Site of Thermoreceptors

116
Q

Structure of Thermoreceptors

117
Q

what are epidermal touch receptors?

118
Q

Site of peritrichal nerve endings

119
Q

Structure of peritrichal nerve endings

120
Q

Site of merkel’s complex

121
Q

Structure of merkel’s complex

122
Q

what are receptors of dermal touch?

123
Q

Site of pacinian corpusle

124
Q

Shape & Size of pacinian corpusle

125
Q

Structure of pacinian corpusle

126
Q

Site of Meissner’s corpuscle

127
Q

Shape & Size of Meissner’s corpuscle

128
Q

Structure of Meissner’s corpuscle

129
Q

Site of Ruffini corpuscle

130
Q

Shape & Size of Ruffini corpuscle

131
Q

Structure of Ruffini corpuscle

132
Q

what is another name of Krause end bulb?

133
Q

Shape of Krause end bulb

134
Q

Structure of Krause end bulb

135
Q

what are receptors of deep sensation?

136
Q

Site of Muscle spindle (Neuro-musculae spindl)

137
Q

Size & Shape of Muscle spindle (Neuro-musculae spindl)

138
Q

Function of Muscle spindle (Neuro-musculae spindl)

139
Q

Structure of Muscle spindle (Neuro-musculae spindl)

140
Q

Capsule of Muscle spindle (Neuro-musculae spindl)

141
Q

Intrafusal muscle fibers

142
Q

Compare between nuclear bag fibers & Nuclear chain fibers

143
Q

Innevations of Muscle spindle (Neuro-musculae spindl)

144
Q

what do Tendon spindles (Neuro-tendinous end organs of golgi) differ from muscle spindles in?

145
Q

what are joint receptors?

146
Q

Function of joint receptors

147
Q

what is the ear formed of?

A

1- The external ear.
2- The middle ear (tympanic cavity).
3- The internal ear (labyrinth).

148
Q

what does the external ear consist of?

A
  • The auricle (ear pinna)
  • The external auditory meatus (canal)
  • The tympanic membrane (the ear drum)
149
Q

what is The auricle (ear pinna)?

A
  • An irregular shallow funnel.
150
Q

what does the The auricle (ear pinna) consist of?

A
  • Consists of a thin plate of yellow elastic cartilage covered by skin on both sides
151
Q

Function of The auricle (ear pinna)

A
  • Collects sound waves & directs them towards the external auditory meatus
152
Q

Structure of The external auditory meatus (canal)

A
  • Its wall is formed of yellow elastic cartilage in its outer 1/3 and of spongy bone in its inner 2/3.
153
Q

Lining of The external auditory meatus (canal)

A
  • It is lined by thin skin provided with stiff hairs in its outer part. The skin also contains sebaceous glands and ceruminous glands
154
Q

what forms ear wax (Cerumin)?

A

sebaceous glands and ceruminous glands in skin of the external auditory tube

155
Q

Structure of tympanic membrane (the ear drum)

A
  • Thin fibrous structure.
156
Q

what does the tympanic membrane (the ear drum) separate?

A

Separates the external auditory meatus from the middle ear cavity

157
Q

what is tympanic membrane (the ear drum) lined by?

A
  • Lined by skin on the surface faces the external canal .
  • Lined by single layer of cuboidal epithelium on middle ear side
158
Q

Function of tympanic membrane (the ear drum)

A
  • Transmits the vibrations of sound to the middle ear
159
Q

what is The middle ear?

A
  • Cavity in temporal bone which is lined by simple cuboidal epithelium
160
Q

Contents of The middle ear

A
  • 3 bony ossicles (malleus, incus & stapes)—>spongy bone
  • 2 muscles (tensor tympani & stapedius)
  • 2 windows (oval & round)in its medial wall
  • Chorda tympani nerve
161
Q

what does the Eustachian tube connect?

A
  • Connects the middle ear to nasopharynx.
162
Q

Function of Eustachian tube

A
  • Equalize the air pressure in the tympanic cavity & nasopharynx
163
Q

what is the internal ear (the labyrinth) formed of?

A
  • Membranous labyrinth
  • Bony labyrinth
164
Q

what is Membranous labyrinth?

A
  • Membranous tubule filled with fluid called endo-lymph.
165
Q

Site of Membranous labyrinth

A

present inside bony labyrinth

166
Q

what is Bony labyrinth?

A
  • cavities in the petrous part of the temporal bone
167
Q

what is Bony labyrinth filled with?

A

peri-lymph.

168
Q

what does Bony labyrinth consist of?

A
  • Cochlea.
  • Semicircular canals.
  • Vestibule
169
Q

what is The cochlea?

A
  • It is a spirally coiled tube which forms 2.5 turns around a central bony axis called the modiolus.
170
Q

what forms the modiolus?

A
  • The modiolus is formed of spongy bone and has a cavity in its center contains the fibres of the cochlear nerve.
171
Q

Divisions of the cochlea

A

The cochlea is divided into three compartments:

  • Cochlear duct: in the middle
  • Scala tympani: below
  • Scala vestibule: above
172
Q

what is the Cochlear duct separated from?

A
  • It is separated from the scale vestibuli by the vestibular membrane, and from the scala tympani by the spiral lamina & the basilar membrane on which the Organ of Corti is found.
173
Q

where is the organ of corti found?

A

On the basilar membrane

174
Q

Shape of CS of cochlear duct

A

Triangular in cross sections, The three sides of the triangle are:

  • The vestibular membrane and is lined by simple squamous epithelium.
  • The basilar membrane. The organ of corti rests on on this membrane
  • The stria vascularis which is in direct contact with the bony cochlea and is formed of vascular C.T. covered with pseudostratified columnar epithelium
175
Q

what is the cochlear duct filled with?

176
Q

Definition of Organ of Corti

A
  • neuro-epithelial structure on the basilar membrane of cochlear duct
177
Q

Structure of Organ of Corti

A
  • It is formed of supporting cells, hair cells and tectorial membrane
178
Q

Supporting cells of Organ of Corti

A
  1. The inner and outer pillar cells
  2. The inner and outer phalangeal cells
  3. The Hensen’s cells
  4. The border cells
  5. Cells of Boettcher
  6. Cells of Claudius
179
Q

Hensen’s cells

A

Are tall cell which form the outermost part of the organ of Corti.

180
Q

border cells of Organ of Corti

A

which form the innermost supporting cells of the organ of Corti.

181
Q

Cells of claudius

182
Q

Hair cells of Organ of Corti

A

The inner hair cells:

  • which are arranged in one row lying on the inner phalangeal cells.

The outer hair cells:

  • which are arranged in 3-5 rows lying on the outer phalangeal cells.
183
Q

what is the free surface of each hair cell provided with?

A
  • The free surface of each hair cell is provided with hair-like processes.
  • These processes are stereocilia (non-motile cilia) arranged in v-shaped array.
184
Q

What is The basal part of each hair cell surrounded by?

A
  • The basal part of each cell is surrounded by the terminal ends of the dendrites of the bipolar nerve cells of the spiral ganglia.
185
Q

Site of Tectorial membrane of organ of corti

A
  • At the medial angle of the cochlear duct
186
Q

where does the Tectorial membrane of organ of corti project from?

A
  • Projects form the bony spiral lamina above the organ of Corti.
187
Q

Structure of Tectorial membrane of organ of corti

A
  • Formed of gelatinous C.T. covered with simple squamous epithelium.
188
Q

Parts of vestibular system

A
  • The semicircular canals
  • The vestibule
189
Q

Characters of The semicircular canals

A
  • They are arranged in three different planes at right angles to each other.
  • They have 5 openings on the vestibule. Each bony semicircular canal contains a membranous canal which is filled with endolymph.
  • Each membranous semicircular canal has an expanded end called ampulla.
  • In the ampullae of the semicircular canals there is a neuroepithelial structure called the cristae ampullaris.
190
Q

Structure of Crista ampullaris

A

formed supporting cells, hair cells and copula

191
Q

Types of hair cells in Crista ampullaris

A

2 types:

  • type I cells: flask shaped
  • type II cells: columnar in shape.

(Both types are covered by tuft of long steriocilia & single kino-cilium)

192
Q

Supporting cells of Crista ampullaris

A

Columnar in shape, Covered by copula

193
Q

gelatinous membrane of Crista ampullaris

A
  • thick gelatinous membrane on the surface of crista ampullaris. The stereocilia of the hair cells are embedded in the copula.
194
Q

Function of Crista ampullaris

A
  • regulate position of body in relation to the movements of head.
195
Q

Characters of The vestibule

A
  • It contains two membranous structures: utricle and saccule.
  • The saccule is small & lies in front while utricle is larger & lies behind.
  • The utricle and the saccule are filled with endo-lymph.
  • The utricle contains a neuro-epithelial structure called macula utriculi and saccule
196
Q

Structure of Macula utriculi & Macula sacculi

A
  • formed supporting cells, hair cells and otolithic membrane
197
Q

Hair cells of Macula utriculi & Macula sacculi

A

Hair cells: 2 types:

  • Type I : flask-shaped, surrounded by afferent nerve endings, Their free surfaces are provided by stereocilia.
  • Type II: columnar. surrounded by; afferent and efferent nerve endings, They are also provided by stereocilia.
198
Q

Supporting cells of Macula utriculi & Macula sacculi

A

columnar cells.

199
Q

Gelatinous membrane of Macula utriculi & Macula sacculi

A

Otolithic membrane:
- thick gelatinous glycoprotein layer rich in calcium carbonate crystals.

200
Q

Function of Macula utriculi & Macula sacculi

A

maintain the body equilibrium in relation to gravity.

Y2B4 - Central Nervous System 📙 (8 decks)

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