Observe the illustration and answer the following questions. How impulses are generated in these cells when light rays fall on it?

Photoreceptors can be characterised as specialized cells that are found in the retina of the eye. The receptors of the eyes are extremely specialized neuroepithelial cells. There are two types of photoreceptors present in the eyes of the human. These are rod and cone cells. Cone cells help in colour vision. When light falls on cone cells, the photopsin in them dissociates into retinal and opsin. Rod cells help in dim light or low light vision. When light falls on rod cells, the pigment rhodopsin in them dissociates into retinal and opsin. This chemical change creates impulses and sends signals to the brain through the optic nerve for the processing of images.

Observe the illustration and answer the following questions. Explain the role of these cells in making vision possible.

Photoreceptors can be characterised as specialized cells that are found in the retina of the eye. The receptors of the eyes are extremely specialized neuroepithelial cells. There are two types of photoreceptors present in the eyes of the human. These are rod and cone cells. Cone cells help in colour vision. When light falls on cone cells, the photopsin in them dissociates into retinal and opsin. Rod cells help in dim light or low light vision. When light falls on rod cells, the pigment rhodopsin in them dissociates into retinal and opsin. This chemical change creates impulses and sends signals to the brain for the processing of images.

Observe the illustration and answer the following questions. Name the cells (A) and (B).

Photoreceptors can be characterised as specialized cells that are found in the retina of the eye. The receptors of the eyes are extremely specialized neuroepithelial cells. There are two types of photoreceptors present in the eyes of the human. These are rod and cone cells. In the given diagram A represents rod cells and B represents cone cells.

Redraw the picture given below. Identify the name indicated and label the parts The part that adjusts its size as the intensity of light varies.

The human eyes play an essential role in the formation and processing of the image in the brain of the human. This sensory organ is composed of different parts. The pupil can be characterised as a small opening in the iris. The pupil adjusts its size according to the intensity of the light. The pupil’s function is to adjust the amount of light entering the eye.

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The size of the pupil is regulated by the action of

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Important Questions on Nervous System

EASY

Science>Biology>Nervous System>Sense Organs

How do conjunctiva and tears protect the eye?

MEDIUM

Science>Biology>Nervous System>Sense Organs

Choose between the two options to answer the question specified in the brackets for the following.

An example is illustrated below.

Example: Corolla or Calyx (Which is the miter whorl?) Answer: Calyx

Sclerotic layer or choroid layer (Which one forms the iris?)

EASY

Science>Biology>Nervous System>Sense Organs

Fill the blanks in the statement.
"Three types of cone cells are present in human eye. This is due to the chänge in _____ in the Opsin molecule"

EASY

Science>Biology>Nervous System>Sense Organs

Membranous labyrinth in the inner ear is filled with perilymph.

EASY

Science>Biology>Nervous System>Sense Organs

Certain hormones released from the anterior lobe of pituitary gland are given.
Thyroid Stimulating Hormone (TSH)
Adreno Cortico Tropic Hormone (ACTH)
Gonado Tropic Hormone (GTH)

Write the common feature of these hormones.

EASY

Science>Biology>Nervous System>Sense Organs

Observe the illustration and answer the following questions.

Question Image

How impulses are generated in these cells when light rays fall on it?

EASY

Science>Biology>Nervous System>Sense Organs

Name the following:

The layer of the eyeball that provide nourishment to the eye.

EASY

Science>Biology>Nervous System>Sense Organs

Observe the illustration and answer the following questions.

Question Image

Explain the role of these cells in making vision possible.

EASY

Science>Biology>Nervous System>Sense Organs

Certain hormones released from the anterior lobe of pituitary gland are given.
Thyroid Stimulating Hormone (TSH)
Adreno Cortico Tropic Hormone (ACTH)
Gonado Tropic Hormone (GTH)

Write one function of ACTH and TSH.

EASY

Science>Biology>Nervous System>Sense Organs

Reflex actions occur when the following incidents happen in the everyday life of a human. Give the importance of these two reflex actions:

(i) When food particles enter into the trachea

(ii) When foreign particles enter inside the nasal cavity

EASY

Science>Biology>Nervous System>Sense Organs

Vitreous humor is formed from blood, and is reabsorbed by blood.

MEDIUM

Science>Biology>Nervous System>Sense Organs

Mention the exact location of the following:
(iii) Malleus