Human Anatomy - PowerPoint PPT Presentation

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Human Anatomy

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Title: BIO 1414 Human Anatomy & Physiology II Author: Preferred Customer Last modified by: Eee PC Created Date: 9/5/2000 8:24:24 PM Document presentation format – PowerPoint PPT presentation

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Title: Human Anatomy


1
Human Anatomy
  • Senses

2
Conjunctiva
3
Conjunctiva
  • Covers the inner surface of the eyelids and the
    anterior surface of the eye.
  • Membrane which produces mucous that lubricates
    the eye and prevents dryness.
  • Protects the eye.

4
Fibrous Tunic
5
Fibrous Tunic
  • Cornea Functions
  • Transparent window for light entry
  • Refracts light
  • Sclera Functions
  • Protects eye
  • Shapes eye
  • Anchors eye muscles

6
Vascular Tunic
7
Vascular Tunic
  • Choroid Functions
  • Provides nutrients to all eye tunics.
  • Absorbs light preventing reflecting scattering
    of light within the eye.
  • Ciliary Body Functions
  • Ciliary processes secrete aqueous humor.
  • Suspensory ligaments hold lens in place.
  • Ciliary muscles pull on the ligaments to change
    the thickness of the lens.
  • Iris Functions
  • Constricts or dilates to adjust the amount of
    light entering the eye.

8
Vascular Tunic
Ciliary Muscles
Ciliary Processes
9
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10
Aqueous Humor
  • Helps support the eye internally due to the
    intraocular pressure it produces inside the eye.
  • Supplies nutrients oxygen to the cornea, lens
    and portions of the retina.
  • Carries away metabolic wastes from the cornea,
    lens and portions of the retina.

11
The iris constricts or dilates to adjust size of
the pupil.
The pupil allows light to enter the posterior
segment of the eye.
12
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13
Vitreous Humor
  • Transmits light within the posterior segment.
  • Supports the lens posteriorly.
  • Holds the retina in place.
  • Contributes to intraocular pressure.

14
Sensory Tunic
15
Retina
  • Pigmented Layer
  • Absorbs light
  • Carries out phagocytosis
  • Stores Vitamin A
  • Neural Layer
  • Contains photoreceptors (rods and cones) for
    visual perception
  • Contains bipolar cells ganglion cells for
    visual impulse transmission

16
Retina
  • Fovea Centralis
  • Contains only closely packed cones
  • Provides acute color vision in bright light
  • Macula Lutea
  • Contains more widely spaced cones
  • Other areas of Retina
  • Contain only rods
  • Provide night, dim light peripheral vision
  • Shades of grey only
  • Optic Disc
  • Contains no receptors
  • Blind spot

17
Retina
Optic Disc
18
Photoreceptors
19
Cones
  • Are located in macula lutea but are most highly
    concentrated in the fovea centralis.
  • Are sensitive to bright light (daylight)
    situations in which light is very intense.
  • Each cone synapses with a single bipolar cell
    which synapses with a single ganglion cell.
  • The axons of ganglion cells form the optic nerve
    to conduct visual images to the brain.
  • Provide acute (sharp) color images (vision).

20
Cones
21
Photoreceptors
22
Rods
  • Most highly concentrated in the retina outside
    the macula lutea
  • Many rods synapse with a single bipolar cell
  • Many bipolar cells may synapse with a single
    ganglion cell which carries stimuli to brain
  • More sensitive function only in dim light,
    night and peripheral vision
  • Images are blurry and only in shades of gray

23
Visual Pigments
  • Composed of two components
  • Retinal - light absorbing molecule (made from
    Vitamin A)
  • Opsin (four types made from protein)
  • Opsin combined with retinal visual pigment
  • Depending on the type of opsin retinal is bound
    to, each of the four pigments will only absorb
    certain wavelengths of light.

24
Visual Pigments RODS
  • Retinal Opsin Rhodopsin (visual purple)
  • Absorbs light throughout entire visible light
    spectrum (most sensitive to green)
  • Functions only in dark, dim light peripheral
    vision
  • Light causes Retinal to change shape separate
    from opsin causing nerve impulse
  • Regenerate only in dark or dim light situations

Impulse
25
Visual Pigments Cones
  • Retinal Red, Green or Blue Opsin Red, Green
    or Blue visual pigments
  • Each Opsin absorbs light only in the area of the
    visible light spectrum it is sensitive to, ie,
    red cones, green cones blue cones
  • Function only in bright light (daylight)
  • Provide sharp color images

Impulse
Impulse
26
Lens
  • Refracts (bends) light
  • Focuses precise image on the retina (fovea)
    through accommodation (changing thickness)

27
Myopia (Nearsighted)
  • Eyeball too long
  • Distant objects focused in front of retina
  • Image striking retina is blurred
  • Correction
  • Concave lens or
  • laser surgery to slightly flatten the cornea

28
Hyperopia (Farsighted)
  • Eyeball too short, lens too thin or too stiff.
  • Nearby objects are focused behind retina.
  • Image striking the fovea is blurred.
  • Correction
  • Convex lens

29
Astigmatism
  • Irregular Curvature in parts of the cornea or
    lens
  • Causes blurry image
  • This may be corrected by specially ground lenses
    which compensate for the irregularity or laser
    surgery.

30
Cararact
  • Clouding of lens due to aging, diabetes mellitus,
    heavy smoking, frequent exposure to intense
    sunlight or congenital factors

Treatment Lens Implant
31
Conjunctivitis
  • Inflammation of the conjunctiva by
  • Bacteria, fungi or viruses
  • Trauma

32
Glaucoma
  • Most common cause of blindness.
  • Increasing intraocular pressure compresses
    retina, optic nerve blood vessels.
  • Late symptoms include blurred vision halos
    around bright objects

33
Glaucoma
34
Color Blindness
  • Congenital lack of one or more cone types
  • Deficit or absence of red or green cones most
    common
  • Sex-linked trait
  • Most common in males

What numbers can you see in each of these?
35
Night Blindness
  • Impaired vision at night or in dim light
    situations
  • Rhodopsin deficiency affecting rods
  • Most common cause - prolonged Vitamin A
    deficiency
  • Rods degenerate

36
Macular Degeneration
  • Most common cause of vision loss after 65.
  • Progressive deterioration of macula causing loss
    of central vision
  • Dry Form - due to accumulation of pigments in
    macula due to reduced phagocytosis of cone debris
    by pigmented layer
  • Wet Form - due to invasion of macula with new
    blood vessels from choroid causing scarring
    retinal detachment

37
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38
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39
Middle Ear
40
Middle Ear
41
Inner Ear
Vestibule
42
Vestibule
Utricle
Saccule
43
Maculae
  • Monitors position of head in space
  • Responds to straight-line changes in speed
    direction
  • Receptors for static equilibrium

44
Macula
Receptor for Static Equilibrium
45
Inner Ear
Semicircular Canals
46
Semicircular Canals
47
Semicircular Canals
  • Christa ampularis - receptor for dynamic
    equilibrium
  • Responds to rotational (angular) movements
  • Changes in rotatory velocity movements

48
Semicircular Canals
Dynamic Equilibrium
49
Inner Ear
Oval Window
50
Inner Ear
Cochlea
51
Cochlea Unrolled
Sprial Organ of Corti
52
Spiral Organ of Corti
  • Receptor organ of hearing
  • Different frequencies of vibrations (compression
    waves) in cochlea stimulate different areas of
    Organ of Corti
  • Interpreted as differences in pitch

53
Inner Ear
Round Window
54
Cochlea
Oval Window
Round Window
55
AcknowledgementsMost of the figures used in this
presentation came from the Benjamin Cummings
Digital Library Version 2.0 for Human Anatomy
Physiology, Fifth Edition. Other figures came
from public domain internet sources and software
in the possession of the author.
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