Perceptual processes ch 2

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Questions and Answers

Which of these options best describes the process by which light is redirected when it strikes a surface?

Scattering

Refraction

Absorption

Reflection (correct)

Which part of the eye is responsible for regulating the amount of light entering the eye?

Cornea

Iris (correct)

Pupil

Lens

What is the transparent fluid that fills the anterior chamber of the eye, providing nutrients and oxygen to the cornea and lens?

Optic nerve

Crystalline lens

Aqueous humor (correct)

Vitreous humor

What is the condition caused by a buildup of aqueous humor in the front of the eye, potentially leading to damage of the optic nerve?

Angle-closure glaucoma (D) Signup and view all the answers

What is the transparent layer over the surface of the eye that provides protection?

Cornea (A) Signup and view all the answers

Which of the following is NOT a way that light interacts with matter?

Conduction (C) Signup and view all the answers

What is the clear, gelatinous substance that fills the posterior chamber of the eye, helping to maintain its shape?

Vitreous humor (A) Signup and view all the answers

What is the ovoid structure located behind the pupil that focuses light onto the retina of the eye?

Crystalline lens (C) Signup and view all the answers

Which of these accurately describes the reason that a camera lens moves back and forth to adjust focus, while the human eye's lens changes shape?

The human eye's length cannot change, but the camera can be made longer or shorter. (A) Signup and view all the answers

What structure in the human eye acts as the equivalent of a camera's aperture?

The iris (D) Signup and view all the answers

In the analogy of the eye as a camera, what would the human eye's retina be equivalent to?

The camera's film (C) Signup and view all the answers

How is the human eye's retina different from camera film?

All of the above (D) Signup and view all the answers

What is the term for the tool used to view the back of the eye, also known as the fundus?

Ophthalmoscope (C) Signup and view all the answers

What is the name of the pigmented region near the center of the retina, which is responsible for sharp central vision?

Macula (C) Signup and view all the answers

What part of the eye is considered the 'blind spot'?

Optic Disc (A) Signup and view all the answers

The retina's photoreceptor cells are named for their shape, but what other characteristic do they possess?

They transduce light energy into neural energy. (A) Signup and view all the answers

What are floaters?

Bits of biodebris floating in the vitreous humor of the eye (C) Signup and view all the answers

What is the primary function of the embryonic hyaloid vasculature in the developing eye?

To provide nutrients for the development of the lens (D) Signup and view all the answers

What is persistent hyperplastic primary vitreous?

A disorder caused by a failure of the embryonic hyaloid vasculature to regress (A) Signup and view all the answers

Which of the following structures in the eye is primarily responsible for refracting light?

Cornea (B) Signup and view all the answers

What is accommodation in the context of the eye?

The process of changing the shape of the lens to focus light on the retina (D) Signup and view all the answers

What is emmetropia?

The condition of experiencing no refractive error (B) Signup and view all the answers

Which of the following conditions results in difficulty focusing on near objects due to age-related loss of accommodation?

Presbyopia (B) Signup and view all the answers

What is the condition where light is focused in front of the retina, resulting in difficulty seeing distant objects?

Myopia (C) Signup and view all the answers

Which of the following is NOT a segment of a photoreceptor cell?

Axon terminal (D) Signup and view all the answers

What happens to a photoreceptor when it senses light?

It becomes hyperpolarized, resulting in the closure of calcium channels. (D) Signup and view all the answers

During light adaptation, why does the sensitivity of photoreceptors decrease?

Photopigments are regenerated more slowly than the rate of light entering the eye. (C) Signup and view all the answers

Which of these events occurs FIRST in the process of light detection?

Light absorption by the chromophore (B) Signup and view all the answers

Why does a photoreceptor cell become desensitized after bleaching?

The photopigment needs to regenerate before it can process another photon of light. (C) Signup and view all the answers

Which part of the photoreceptor is primarily responsible for producing and storing the photopigment?

Both inner and outer segments. (C) Signup and view all the answers

What is the primary function of the synaptic terminal in a photoreceptor?

To transmit the electrical signal to other neurons. (B) Signup and view all the answers

How does the light-induced isomerization of the chromophore result in a signal being sent to the brain?

The isomerization triggers a series of enzymatic reactions that alter the photoreceptor's membrane potential, ultimately leading to a signal being transmitted to the brain. (D) Signup and view all the answers

What type of retinal cell is responsible for pooling signals from multiple photoreceptors?

Bipolar cells (D) Signup and view all the answers

Which type of retinal cell is described as the 'gossip cells' due to its widespread connections and signal transmission?

Amacrine cells (D) Signup and view all the answers

What is the primary function of lateral inhibition in the retina?

Enhancing contrast perception (B) Signup and view all the answers

Which of the following best describes the relationship between photoreceptors and bipolar cells?

Photoreceptors transmit signals to bipolar cells, which then relay the information to ganglion cells. (D) Signup and view all the answers

Which of the following is NOT a characteristic of ganglion cells?

They are specialized for either rods or cones, not both. (A) Signup and view all the answers

What is the primary function of ON-center ganglion cells?

Detecting edges and boundaries (A) Signup and view all the answers

How does the pooling of signals by bipolar cells contribute to peripheral vision?

It allows for greater sensitivity to detect faint light in the periphery. (B) Signup and view all the answers

The statement that 'amacrine cells receive signals from bipolar cells and other amacrine cells' implies that they are involved in:

Horizontal pathways within the retinal layers (D) Signup and view all the answers

What is the primary reason for using a logarithmic scale to display the electromagnetic spectrum?

To highlight the visible spectrum's relatively small range within the entire electromagnetic spectrum. (A) Signup and view all the answers

What is the primary function of the 'double slit experiment'?

To showcase the wave-like nature of light by demonstrating interference patterns. (A) Signup and view all the answers

What happens to light energy when it is 'absorbed' by a material?

The energy is converted into another form, such as heat. (A) Signup and view all the answers

Which statement accurately describes the nature of light?

Light can be described as both a wave and a stream of particles called photons. (C) Signup and view all the answers

Which of these phenomena is NOT a way light can interact with matter?

Conduction (D) Signup and view all the answers

Study Notes

Light: A Physical Perspective

Light is a narrow band of the electromagnetic spectrum, it can be a wave or a stream of photons.
A wave is a disturbance in a medium travelling from one point to another without permanent displacement.
Photons are a quantum of electromagnetic radiation exhibiting both particle and wave properties.

Light and the Visible Spectrum

The visible spectrum is a small portion of the full electromagnetic spectrum.
The spectrum's length has been compressed for easier visualization in a log scale.

Light Interactions

Light can be absorbed, scattered, reflected, transmitted, or refracted.
Absorption is when light energy is taken up and not transmitted.
Scattering describes the irregular dispersal of light.
Reflection is the redirection of light when it hits a surface.
Transmission is the passage of light through a surface.
Refraction is the bending of light as it passes into a different medium.

The Eye as a Camera Analogy

Aperture (iris/pupil): regulates the amount of light entering the eye.
Focus (lens): changes shape to adjust focus.
Film (retina): records an image.
While there are similarities, the eye is not a perfect camera analogue. The retina adapts to changing light settings and the lens physically molds to refocus light. A camera's lens moves, not the eye's.

Eye Anatomy and Function

Cornea: transparent protective outer layer (responsible for 80% of light refraction.)
Aqueous humor: watery fluid filling the anterior chamber providing nutrients and removing waste.
Crystalline lens: ovoid structure bending light to focus on the retina.
Vitreous humor: transparent gel-like substance filling most of the eye

Eye Conditions

Angle-closure glaucoma: a disease resulting in optic nerve damage caused by excess aqueous humor buildup in the eye.

The Iris & Pupil

Iris: muscular diaphragm regulating light entry through pupil dilation/constriction.
Pupil: A circular opening in the center of the iris. It's response to light conditions helps the visual system adapt to ambient light levels.

Retina Structure and Function

Retina: the light-sensitive membrane at the back of the eye.
Photoreceptors: Rods and cones located at the back of the retina responsible for the initial transducing of light into neural energy.
Rods: specialized for night vision and low-light conditions, not color-sensitive.
Cones: specialized for daytime vision, color vision, and sharp details; high light conditions.
Optic Disc: the area where the optic nerve leaves the eye, known as the blind spot.
Fovea: The point of highest visual acuity located near the center of the macula.
Macula: pigmented region near the center of the retina
Retinal Pigmented Epithelium: opaque cells needed for rods and cones to function.

Retinal Topography

Retinal Geography: the distribution of rods and cones (cones are concentrated for sharper vision).

Visual Angle

Vision scientists use visual angle for determining size estimations of objects and stimuli.

Light Detection and Adaptation

Photoreceptors have 3 parts: outer and inner segments, and synaptic terminal.
Photoreceptors sense light in 6 steps: light absorption, isomerization, deactivation, phototransduction, electrical transmission, visual perception.
Adaptation is the system's changing responsiveness to differing light conditions.
Two key adaptation mechanisms: Pupil dilation and photoreceptor adaptation (bleaching, desensitizing or regenerating)
Retinal ganglion cells are responsible for the processing of light and sending signals to the brain. P- and M-type cells are responsible for different parts of our visual experience for object recognition and motion.

Receptive Fields

Receptive fields are the regions of the retina that affect the firing rate of a neuron.
Ganglion cells contain ON-center and OFF-center receptive fields (excitable when the center area is triggered, and inhibited by the surrounding areas).

Persistent Hyperplastic Primary Vitreous, Glaucoma and other conditions

It's a congenital disease of the eye
Certain conditions increase the risk of glaucoma, cataracts, retinal detachment and interocular hemorrhage (which can lead to some forms of blindness (loss of vision).

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Description

Test your understanding of eye anatomy and the interaction of light with different surfaces. This quiz covers key terms and conditions related to vision, including the functions of various eye components and how light behaves when it strikes them. Perfect for students studying biology or optics!