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The Sensory Mechanism > Eyes > Flashcards

Eyes Flashcards

1
Q

What is a Sensory Receptor?

A

A sensory receptor is a special part of a neuron that detects changes (stimuli) in the environment and converts them into electrical signals.

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2
Q

What is a stimulus?

A

A stimulus is a form of energy.

(e.g., light, sound, heat)

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3
Q

How do receptors convert energy?

A

Receptors change one type of energy (like light or sound) into electrical signals that the brain can understand.

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4
Q

What are sensory neurons?

A

They are modified ends of sensory neurons, specialized parts of nerve cells that can detect specific stimuli.

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5
Q

What is the function of sensory receptors?

A

They amplify energy to ensure the stimulus is strong enough to trigger a response in the nervous system.

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6
Q

What are photoreceptors?

A

Photoreceptors (in eyes) convert light energy into electrical signals.

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7
Q

What are mechanoreceptors?

A

Mechanoreceptors (in skin, ears) convert pressure or sound waves into electrical signals.

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8
Q

What are chemoreceptors?

A

Chemoreceptors (in nose, tongue) convert chemical signals into electrical signals.

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9
Q

What is a neural impulse?

A

A neural impulse is an electrical signal that travels through neurons to carry information.

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10
Q

How do neural impulses function?

A

They carry messages from sensory receptors (like your eyes or skin) to the brain.

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11
Q

What are sensory neurons compared to perception?

A

Sensory neurons act like messengers, delivering raw information, while perception is how the brain interprets those signals.

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12
Q

Where do sensory neurons send signals?

A

Sensory neurons send signals to the brain from sensory organs (eyes, ears, skin, etc.).

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13
Q

What is the cerebral cortex’s role in perception?

A

Perception happens in the cerebral cortex of the brain.

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14
Q

What are primary receptor cells?

A

Primary receptor cells are directly connected to nerve pathways.

Example: Olfactory cells (smell).

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15
Q

What are secondary receptor cells?

A

Secondary receptor cells need helper cells to pass signals to neurons.

Example: Retina cells (vision).

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16
Q

What are the four categories of sensory receptors?

A
  1. Photoreceptors – Detect light (eyes).
  2. Chemoreceptors – Detect chemicals (taste and smell).
  3. Mechanoreceptors – Detect touch, pressure, vibration, and sound (skin, ears).
  4. Thermoreceptors – Detect temperature (skin).
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17
Q

What is a biological transducer?

A

A biological transducer is a cell or organ that converts one form of energy into another inside the body.

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18
Q

How does a biological transducer work?

A

It receives a stimulus (like light, sound, or heat) and converts it into an electrochemical signal (a neural impulse).

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19
Q

What is sensory adaptation?

A

Sensory adaptation occurs when a receptor becomes accustomed to a stimulus over time.

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20
Q

What is an example of sensory adaptation?

A

When you first step into a room with a strong smell, you can smell it strongly, but after a while, you may stop noticing it.

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21
Q

What is the importance of vision?

A

Vision supplies 80-90% of the important information that reaches the brain.

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22
Q

What is the structure of the eye?

A

The eye is a fluid-filled, hollow ball about 2.5 cm in diameter.

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23
Q

What wavelengths can the human eye detect?

A

The human eye detects electromagnetic radiation (light) with wavelengths between 350 - 800 nm.

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24
Q

What are the three layers of the eye?

A
  1. External Layer – Sclera & Cornea.
  2. Intermediate Layer – Choroid.
  3. Internal Layer – Retina.
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25
What is the function of the sclera?
The sclera is a tough, white, fibrous layer that protects the eye and helps maintain its shape.
26
What is the function of the cornea?
The cornea is a transparent bulge that refracts light as it enters the eye.
27
What is the conjunctiva?
The conjunctiva is a thin, transparent membrane that covers the cornea and protects it from dust and microorganisms.
28
What is the choroid layer?
The choroid layer contains a pigmented cell layer that prevents light from reflecting inside the eye and is rich in blood vessels.
29
What is the function of the iris?
The iris controls the amount of light that enters the eye by adjusting the diameter of the pupil.
30
What are the ciliary muscles?
Ciliary muscles change the shape of the lens to help focus light onto the retina.
31
What is the retina's role?
The retina is the innermost layer of the eye where photoreceptors convert light into electrical signals.
32
What are rods and cones?
Rods are sensitive to light intensity and help in low-light conditions, while cones detect colors and function in bright light.
33
What is the fovea centralis?
The fovea centralis is a small area in the retina that contains only cones, providing the sharpest, clearest vision.
34
What is the optic nerve?
The optic nerve connects the retina to the visual cortex of the brain.
35
What are rods?
Rods detect light intensity (brightness) and help in dim light.
36
What are cones?
Cones detect colors and function in bright light.
37
What is the fovea centralis?
The fovea centralis is a small, central area in the retina that contains only cones.
38
What is the purpose of the fovea centralis?
It provides the sharpest, clearest vision because cones are responsible for detailed and color vision.
39
How do rods and cones convert light energy?
Both rods and cones convert light energy into electrochemical nerve impulses.
40
What is the pathway of impulses from rods and cones?
1. Rods and cones convert light into electrical signals. 2. Signals are passed to bipolar neurons in the retina. 3. Bipolar neurons pass impulses to the optic nerve, which transmits signals to the brain.
41
What is a blind spot?
The blind spot is a small area in the visual field of each eye where no image is detected.
42
Why does the blind spot exist?
The optic disk, where the optic nerve exits the eye, has no photoreceptors, resulting in a gap in the visual field.
43
What is accommodation?
Accommodation is the process by which the eye adjusts its focus to see objects clearly at different distances.
44
What role does refraction play in accommodation?
Light entering the eye must be refracted for the image to be properly focused on the photoreceptors in the retina.
45
How does the lens adjust for near objects?
The lens becomes rounder to increase refraction and focus light more strongly.
46
How does the lens adjust for far objects?
The lens becomes flatter to reduce refraction, allowing light to focus properly.
47
What is the role of ciliary muscles in accommodation?
Ciliary muscles contract to reduce tension on the suspensory ligaments, allowing the lens to become fatter.
48
What happens when the lens becomes fatter?
It increases its ability to refract light, helping to focus light from near objects on the retina.
49
What happens when ciliary muscles relax?
It increases tension on the suspensory ligaments, pulling the lens into a thinner shape.
50
What is astigmatism?
Astigmatism occurs when the cornea or lens has an uneven shape, causing light to bend in different directions.
51
How does astigmatism affect vision?
It causes images to appear blurred or distorted because light does not focus properly on the retina.
52
What is glaucoma?
Glaucoma is a condition caused by an increased build-up of aqueous humor, leading to increased pressure in the eye.
53
How does glaucoma damage vision?
Increased pressure collapses blood vessels in the retina, reducing oxygen and nutrients, which can lead to blindness.
54
What is a cataract?
A cataract occurs when the lens of the eye becomes opaque, resulting in blurry or dimmed vision.
55
How are cataracts treated?
The cloudy lens is removed and replaced with a plastic intraocular lens (IOL).
56
What is myopia?
Myopia occurs when the eyeball is elongated, causing light to focus in front of the retina.
57
How is myopia corrected?
It is corrected with concave lenses that diverge light.
58
What is hyperopia?
Hyperopia occurs when the eyeball is short, causing light to focus behind the retina.
59
How is hyperopia corrected?
It is corrected with convex lenses that converge light.
60
What are rods and cones?
Rods and cones are specialized photoreceptor cells in the retina that help detect light and color.
61
What is rhodopsin?
Rhodopsin is the light-sensitive pigment in rod cells, made up of opsin and retinene.
62
How does rhodopsin work?
When light strikes rhodopsin, it splits into opsin and retinene, activating the rod cell.
63
What is iodopsin?
Iodopsin is the light-sensitive pigment found in cone cells.
64
What is the trichromatic theory of color vision?
It states that three types of cones (red, green, and blue-sensitive) work together to help us see a wide range of colors.

The Sensory Mechanism (1 decks)

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