Class 10 Chapter 6 Long Qans Science Ncert

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Extra long-answer questions from the Chapter:6 Control and Coordination chapter of Class 10 CBSE Science, along with detailed answers.

Explain the human nervous system in detail

Answer:

The human nervous system controls and coordinates body functions.

It is divided into:

Central Nervous System (CNS)

– Brain and Spinal Cord.

Peripheral Nervous System (PNS)

– Cranial and Spinal nerves.

Brain Parts:

Cerebrum

: Controls voluntary actions, intelligence, memory.

Cerebellum

: Maintains balance and posture.

Medulla Oblongata

: Controls involuntary actions like heartbeat, breathing.

What is reflex action? Explain with an example and draw a reflex arc.

Answer:

Reflex action is a

quick, automatic, and involuntary

response to a stimulus.

Example:

Pulling hand away after touching a hot object.

Reflex Arc Components:

Receptor

– Detects stimulus (skin).

Sensory neuron

– Sends signal to spinal cord.

Interneuron

– Processes response in spinal cord.

Motor neuron

– Sends impulse to muscle.

Effector

– Performs action (muscle withdraws hand).

Describe the structure and functions of a neuron.

Answer:

Neuron is the

structural and functional unit

of the nervous system.

Parts of a Neuron:

Dendrites

– Receive impulses.

Cell body

– Contains nucleus and cytoplasm.

Axon

– Transmits impulses away from cell body.

Axon terminals

– Pass signals to the next neuron.

Functions:

Transmits nerve impulses.

Controls body responses.

Coordinates reflex actions.

Differentiate between voluntary, involuntary, and reflex actions with examples.

Answer:

Voluntary Action

Under

conscious control

(e.g., writing, walking).

Controlled by the

cerebrum

Involuntary Action

Occurs

without consciousness

(e.g., digestion, heartbeat).

Controlled by the

medulla oblongata

Reflex Action

Quick automatic response

(e.g., blinking, knee jerk).

Controlled by

spinal cord

Explain the role of the brain in control and coordination.

Answer:

The brain is the

control

centre

of the nervous system.

Main Parts & Their Functions:

Cerebrum

: Thinking, memory, intelligence, voluntary actions.

Cerebellum

: Balance and coordination.

Medulla Oblongata

: Involuntary actions (breathing, heartbeat).

It processes information and sends

appropriate responses

to different body parts.

What is the role of the spinal cord in the human nervous system?

Answer:

connects the brain to the body

via nerves.

It controls

reflex actions

Acts as a

pathway for nerve impulses

Explain synapse and its role in nerve impulse transmission.

Answer:

Synapse

: The gap between two neurons where impulses are transmitted.

Role:

Electrical signal triggers

neurotransmitters

Neurotransmitters cross synapse, starting an impulse in the next neuron.

Describe the Peripheral Nervous System (PNS).

Answer:

PNS consists of

cranial nerves

(from brain) and

spinal nerves

(from spinal cord).

It connects the CNS to body parts.

Differentiate between central nervous system and peripheral nervous system.

Answer:

Feature	CNS	PNS
Components	Brain, Spinal Cord	Nerves
Function	Processes and sends signals	Connects CNS to organs
Voluntary/Involuntary	Controls both	Carries impulses

Describe the structure and function of the human brain.

Answer:

Parts of the Brain:

Cerebrum

Cerebellum

Medulla Oblongata

11. How do plants respond to external stimuli? Explain different types of plant movements with examples.

Answer:
Plants respond to external stimuli through tropic movements and nastic movements:

A) Tropic Movements (Directional Growth Response)

Phototropism

– Growth towards light.

(Example: Sunflower bends towards the sun.)

Geotropism

– Growth in response to gravity.

(Example: Roots grow downward, stems grow upward.)

Thigmotropism

– Growth in response to touch.

(Example: Climbing vines like Pea plants.)

Hydrotropism

– Growth towards water.

(Example: Roots grow towards a water source.)

Chemotropism

– Growth in response to chemicals.

(Example: Pollen tube growing towards the ovule.)

B) Nastic Movements (Non-Directional Response)

Seismonastic

Movement

– Response to mechanical stimuli like touch.

(Example: Mimosa

pudica

(Touch-Me-Not) folds leaves when touched.)

Nyctinasty

– Response to light and darkness.

(Example: Flowers of Moonflower bloom at night.)

12. How does the brain coordinate different functions of the body? Explain the role of different parts of the brain.

Answer:
The brain is the control centre of the body and coordinates all voluntary and involuntary actions.

A) Main Parts of the Brain & Their Functions

Cerebrum (Largest part)

Controls

voluntary actions

, intelligence, memory, and learning.

Divided into two hemispheres.

Controls thinking, emotions, and problem-solving.

Cerebellum

Maintains

balance and posture

Coordinates muscle movements.

(Example: Walking, running.)

Medulla Oblongata

Controls

involuntary actions

like heartbeat, breathing, digestion, and blood pressure.

Hypothalamus

Regulates

body temperature, hunger, and emotions

Pituitary Gland

Secretes

hormones

and controls other endocrine glands.

B) How the Brain Coordinates Body Functions

receives and processes signals

from sense organs.

It sends commands to muscles and glands for an appropriate response.

It ensures balance, reflex actions, and voluntary control.

13. Compare and contrast the nervous system and endocrine system in humans.

Answer:

Feature	Nervous System	Endocrine System
Mode of Action	Uses electrical impulses	Uses chemical hormones
Speed	Fast (milliseconds)	Slow (takes minutes to hours)
Duration of Effect	Short-lived	Long-lasting
Pathway	Travels through neurons	Travels through bloodstream
Control	Controls voluntary and reflex actions	Regulates growth, metabolism, and hormones
Example	Reflex actions (pulling hand from fire)	Insulin secretion for sugar control

Conclusion: Both systems work together to maintain homeostasis (balance in the body). The nervous system ensures immediate responses, while the endocrine system ensures long-term regulation.

14. What is homeostasis? How do the nervous and endocrine systems work together to maintain homeostasis?

Answer:
Homeostasis is the process of maintaining a stable internal environment in response to external changes.

A) Role of the Nervous System in Homeostasis

Detects changes through

sensory receptors

Sends

signals to the brain

, which processes the information.

Sends

motor responses

to muscles or glands to correct imbalances.

(Example: If body temperature rises, sweat glands are activated to cool the body.)

B) Role of the Endocrine System in Homeostasis

Regulates hormones

to maintain balance.

Example:

Pancreas releases insulin

when blood sugar is high.

Thyroid gland secretes thyroxine

to control metabolism.

Adrenal gland secretes adrenaline

in stress situations.

C) How They Work Together

Example 1: Blood Sugar Control

Pancreas releases

insulin

when sugar is high.

Nervous system signals hunger when sugar is low.

Example 2: Body Temperature Regulation

Nervous system detects

high temperature

→ Sweat glands activated.

Endocrine system releases

thyroxine

to regulate metabolism.

Thus, both systems cooperate to maintain internal stability.

15. What are the different types of hormones in humans? Explain their functions.

Answer:
Hormones are chemical messengers secreted by endocrine glands to regulate body functions.

A) Major Endocrine Glands & Their Hormones

Endocrine Gland	Hormone	Function
Pituitary Gland	Growth Hormone (GH)	Controls growth and development.
Thyroid Gland	Thyroxine	Regulates metabolism and energy production.
Pancreas	Insulin	Lowers blood sugar levels.
Adrenal Glands	Adrenaline	Controls stress response ("fight or flight").
Ovaries (Females)	Estrogen & Progesterone	Regulates menstrual cycle and pregnancy.
Testes (Males)	Testosterone	Regulates male reproductive functions.

B) Importance of Hormones

Help in

growth & development

Maintain

blood sugar & metabolism

Control

mood, emotions, and stress

Regulate

sexual and reproductive functions

Conclusion:
Hormones play a vital role in the coordination of body activities, ensuring smooth functioning of all organs.