Control and Coordination

This set of flashcards include the whole CLASS Xth[2025 Syllabus] Chapter Control & Coordination

What is Control and Coordination?

It is the process that helps living things control body activities and respond to changes around them. It is important for survival, growth, and balance inside the body.

What is the Human Nervous System?.

It is the body’s command center that controls voluntary and involuntary actions with the help of special cells called neurons.

What are Neurons?

Neurons are nerve cells. They have 3 parts

Dentrites

receive messages

Cyton

processes messages

Axon

sends messages to other neurons, muscles, or glands

What are the main types of Nervous System?

1. Central Nervous System (CNS)

2. Peripheral Nervous System (PNS)

3. Autonomic Nervous System (ANS)

4. Somatic Nervous System (SNS)

What is the Central Nervous System (CNS) made of?.

Brain + Spinal cord.

How is the CNS protected?

1. Bony skull (cranium)

2. Cerebrospinal fluid

3. Meninges (Dura mater, Arachnoid, Pia mater)

What is the Peripheral Nervous System (PNS)?

.

Nerves from the brain and spinal cord that connect with the rest of the body. It includes 12 cranial nerves and 31 spinal nerves.

What is the Somatic Nervous System (SNS)?.

Part of PNS that controls voluntary actions (things we do by choice, like walking or writing).

What is the Autonomic Nervous System (ANS)?.

Part of PNS that controls involuntary actions (automatic actions like heartbeat, digestion).

What is a Synapse?

The junction (gap) between two neurons or between a neuron and muscle/gland where messages pass using electrical/chemical signals.

What is the Forebrain ?

The largest part of the brain. It controls thinking, memory, emotions, voluntary movements, and senses.

What are the main parts of forebrain ?

1. Cerebrum

2. Hypothalamus

What is the function of the Cerebrum?

Controls memory, problem-solving, decision making, emotions, and voluntary actions (like writing, dancing, playing).

What is the function of the Hypothalamus?

Maintains body temperature, hunger & thirst, sleep, mood, and links nervous system with hormones.

What is the Midbrain?

Middle part of the brain that controls reflexes of eyes, head-turning toward sounds, and helps maintain balance.

What is the Hindbrain ?

Lower part of brain (near neck) that manages balance, posture, breathing, and heart rate.

What are the 3 parts of the Hindbrain?

1. Cerebellum → balance & smooth movements

2. Pons → breathing, sleep, facial expressions

3. Medulla oblongata → heartbeat, breathing, swallowing

What is the Spinal Cord?

A long bundle of nerves extending from the brainstem to the lower back. It connects the brain with the body and controls reflex actions.

How is the spinal cord protected?

By the vertebral column (backbone) and 3 protective layers called meninges.

What are the functions of the Nervous System?

1. Collects information from sense organs

2. Processes and interprets the data

3. Sends commands to muscles/glands

What is a Reflex Action?

An automatic, quick, and involuntary response to a stimulus (e.g., pulling hand away from something hot).

What is a Reflex Arc?

The pathway of signals in a reflex action. It includes receptor → sensory neuron → interneuron (spinal cord) → motor neuron → effector (muscle).

Why are reflex actions important?

They protect us from harm by giving quick responses without waiting for brain decisions.

What is the Endocrine System?

A system that controls body functions using chemical messengers called hormones, made by glands and carried in blood.

What are the main glands of the Endocrine System?

1. Adrenal gland

2. Thyroid gland

3. Pituitary gland

4. Gonads (testes & ovaries)

5. Pancreas

6. Pineal gland

7. Hypothalamus

8. Parathyroid glands

What is the function of Adrenal Glands?

Located above kidneys.

• Cortex → makes cortisol, aldosterone

• Medulla → makes adrenaline (fight/flight hormone for stress, danger, excitement).

What is the function of the Thyroid Gland?

Found in neck, makes thyroxine (needs iodine). Controls metabolism of carbs, proteins, and fats.
Deficiency → Goitre (swollen neck).

What is the Pituitary Gland?

Called the “master gland.” Makes many hormones like growth hormone, TSH, FSH, LH, etc. Controls growth, reproduction, and other glands.

• Less growth hormone → dwarfism

• Too much → gigantism

What are Gonads and their hormones?

• Female (Ovaries) → Oestrogen (female puberty changes), Progesterone (menstrual cycle & pregnancy)

• Male (Testes) → Testosterone (male puberty changes like deep voice, body hair)

What is the role of the Pancreas?

Makes insulin & glucagon to control blood sugar.

• Lack of insulin → Diabetes mellitus

What is the Pineal Gland?

Small gland in the brain that makes melatonin (controls sleep-wake cycle, reproduction, seasonal changes).

What is the Hypothalamus (as an endocrine gland)?

Links nervous system with hormones. Makes hormones like Somatostatin & Dopamine.

What are Parathyroid Glands?

Small glands behind the thyroid. Make parathormone which controls calcium and phosphate levels in blood & bones.

• Less hormone → Tetany

• More hormone → Osteoporosis

What is the Thymus Gland?

Found in front of the heart. Makes thymosin, which helps T-lymphocytes mature (important for immunity).

How do plants coordinate without a nervous system?

Using hormones (phytohormones) and movements (tropisms) to respond to environment.

What are Tropic Movements in plants?

Growth movements toward or away from a stimulus.

• Phototropism → towards light

• Geotropism → towards gravity

• Hydrotropism → towards water

What are Plant Hormones (Phytohormones)?

Chemical messengers in plants. Main types:

1. Auxins

2. Gibberellins

3. Cytokinins

4. Abscisic Acid (ABA)

What is the role of Auxins?

Control directional growth. Make stems bend towards light and help root growth.

What is the role of Gibberellins?

Act as growth boosters → cause stem elongation and seed germination.

What is the role of Cytokinins?

Promote cell division, prevent early aging, keep leaves green and healthy.

What is the role of Abscisic Acid (ABA)?

Stress hormone → helps plants during drought, closes stomata to save water, and keeps seeds dormant until right conditions.

What is a Feedback Mechanism in the endocrine system?

It controls the release of hormones to keep balance in the body.

Example:

• If blood sugar rises → pancreas releases more insulin.

• If blood sugar falls → insulin release decreases.

What is Cerebrospinal Fluid (CSF)?

A protective fluid around the brain & spinal cord. It cushions against shocks and supplies nutrients.

Give one example of Phototropism.

Sunflowers turn their heads toward the sun.

Give one example of Reflex Action.

Pulling your hand back quickly after touching a hot pan.

Why is the Medulla called the “automatic pilot”?

Because it controls basic life functions automatically → heartbeat, breathing, swallowing.

What is the dual role of the Hypothalamus?

• As part of Forebrain → controls hunger, thirst, body temperature, emotions.

• As part of Endocrine system → releases hormones (like Somatostatin, Dopamine) and controls pituitary gland.

Why are Reflex Actions faster than normal actions?

Because the spinal cord makes the decision directly without waiting for the brain.

What are the functional types of neurons?

1. Sensory (afferent) neurons

2. Motor (efferent) neurons

What is a Sensory (afferent) neuron?

It carries messages from sense organs/receptors to the spinal cord or brain.
Example: receptors in skin send “hot” or “pain” messages to the brain.