Stimuli & Responses in Humans

What is the function of the Human Nervous System?

• To control and coordinate organs and parts of the body

• To transport impulse signals

• To detect stimuli

• To send impulses back to the brain

Answer explanation

The Human Nervous System primarily functions to control and coordinate organs and parts of the body, ensuring they work together effectively. While it also detects stimuli and sends impulses, its main role is coordination.

What are voluntary actions?

• Conscious actions under our will

• Unconscious actions without prior thought

• Reflex actions

• Actions involving the medulla oblongata

Answer explanation

Voluntary actions are those that we consciously choose to perform, reflecting our will and intention. This distinguishes them from unconscious actions, reflex actions, or those solely involving the medulla oblongata.

What is the largest sensory organ in the human body?

• Skin

• Eye

• Ear

• Nose

Answer explanation

The skin is the largest sensory organ in the human body, covering the entire surface and providing the sense of touch, temperature, and pain. It plays a crucial role in protecting internal organs and regulating body temperature.

How do we smell something?

Answer explanation

We smell something when odor molecules enter our nose and bind to olfactory receptors. These receptors send signals to the brain, which interprets them as specific smells.

What is geotropism?

• Roots grow downward

• Shoot grows upward

• Roots grow toward water

• Stem moves away from water

Answer explanation

Geotropism is the growth response of plants to gravity. Roots grow downward due to positive geotropism, allowing them to anchor and access nutrients and water in the soil, making 'Roots grow downward' the correct answer.

What is the purpose of nastic movement?

• Defence mechanism against enemy and nature

• Growth towards light

• Response to gravity

• Response to water

Answer explanation

Nastic movements serve as a defense mechanism against enemies and environmental threats, allowing plants to react quickly to stimuli, such as closing leaves when touched, thus protecting themselves from harm.

What is the function of the optic nerve?

• Carry impulse from retina to brain

• Detect light

• Focus light onto retina

• Control pupil's size

Answer explanation

The optic nerve's primary function is to carry impulses from the retina to the brain, allowing us to perceive visual information. This makes 'Carry impulse from retina to brain' the correct choice.

What are the defects of sight?

• Short-sightedness

• Long-sightedness

• Astigmatism

• All of the above

Answer explanation

Defects of sight include short-sightedness (difficulty seeing far), long-sightedness (difficulty seeing close), and astigmatism (distorted vision). Therefore, the correct answer is 'All of the above'.

What is the role of the cochlea?

• Detect and convert sound vibration into impulse

• Amplify sound vibration

• Balance air pressure

• Collect sound waves

Answer explanation

The cochlea's primary role is to detect and convert sound vibrations into neural impulses, which the brain interprets as sound. This makes 'Detect and convert sound vibration into impulse' the correct choice.

What is the primary function of the retina?

• Convert light into neural signals

• Protect the eye from dust

• Regulate the amount of light entering the eye

• Focus light onto the lens

Answer explanation

The primary function of the retina is to convert light into neural signals, which are then sent to the brain for visual processing. This is essential for vision, making it the correct choice.