NCERT Class 10 Science Chapter 6 – Control and Coordination

NCERT Class 10 Science Chapter 6 – Control and Coordination explains how living organisms regulate and manage their body activities to survive in changing environments. This chapter focuses on how animals use the nervous system and hormones, while plants depend on chemical signals for coordination.

In animals, control is carried out through the Brain, Spinal Cord and Nerves. The structural and functional unit of the nervous system is the Neuron, which carries information in the form of electrical impulses. Reflex actions are quick and automatic responses mainly controlled by the Spinal Cord. The reflex pathway follows: Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector.

The Human Brain is divided into three main parts. The Forebrain (Cerebrum) controls thinking, intelligence and voluntary actions. The Midbrain handles reflex activities related to vision and hearing. The Hindbrain (Cerebellum and Medulla) regulates balance and involuntary functions like breathing and heartbeat. The brain is protected by the Cranium, Meninges and Cerebrospinal Fluid (CSF).

In plants, coordination occurs without a nervous system. Plants respond through Tropisms (directional growth movements) and Nastic Movements (non-directional responses). For example, Phototropism is the growth of shoots towards light, and Mimosa pudica folds its leaves when touched. Plant hormones such as Auxin regulate these growth responses.

Hormonal control in animals is carried out by Endocrine Glands. The Pituitary Gland is known as the master gland. The Thyroid Gland secretes thyroxine (requires iodine), the Adrenal Gland releases adrenaline during emergencies, and the Pancreas secretes insulin to regulate blood sugar levels. Hormonal control is slower than nervous control but produces long-lasting effects.

NCERT Class 10 Science Chapter 6 is important for CBSE board exams and foundation-level competitive exams because it builds conceptual clarity in nervous regulation, plant movements and endocrine control. Students should refer to the official NCERT website at for authentic textbooks and syllabus updates.

For structured preparation of NCERT Class 9–12 for UPSC, BPSC and State PCS examinations, strengthen your basics with our complete NCERT Book Notes PDF for Class 9-12, available inside the NCERT foundation course level-2.

Access Complete NCERT Book Notes PDF

6.1 Animals – nervous system

• Animals respond to environmental changes called Stimuli through a specialised Nervous System that provides fast and accurate control over body activities.
• The structural and functional unit of the nervous system is the Neuron (Nerve Cell), which has three main parts — Cell Body (Cyton), Dendrites, and Axon, as shown in the neuron diagram in the textbook.
• Dendrites receive impulses from receptors or neighbouring neurons, while the Axon transmits electrical impulses away from the cell body towards muscles or glands.
• Information travels as Electrical Impulses in a fixed direction: dendrite → cell body → axon → nerve ending, ensuring proper signal flow.
• Neurons communicate through tiny gaps called Synapses, where impulses are passed using Chemical Substances (Neurotransmitters), as illustrated in the synapse figure.
• The nervous system is divided into the Central Nervous System (CNS) consisting of Brain and Spinal Cord, and the Peripheral Nervous System (PNS) made up of nerves connecting the CNS to the rest of the body.
• Specialised cells called Receptors located in sense organs detect changes like heat, light, pain and sound and convert them into electrical signals for transmission to the CNS.
• The nervous system coordinates with Muscles and Glands to produce suitable responses, helping the body maintain control, protection and adaptation.

6.1.1 What happens in Reflex Actions?

• A Reflex Action is a rapid, automatic and involuntary response to a stimulus such as withdrawing the hand from a hot object.
• Reflex actions are mainly controlled by the Spinal Cord, enabling an immediate response without waiting for instructions from the brain.
• The pathway followed during a reflex action is called a Reflex Arc, as shown in the textbook diagram.
• A typical Reflex Arc consists of Receptor, Sensory Neuron, Interneuron (Spinal Cord), Motor Neuron and Effector (Muscle or Gland).
• When a receptor detects a stimulus like heat or pain, it generates an Electrical Impulse that travels through the sensory neuron to the spinal cord.
• The spinal cord processes the signal and sends an impulse through the motor neuron to the effector organ, causing muscle contraction or gland action.
• The Brain is informed after the reflex action occurs, which is why awareness of pain happens slightly later.
• Reflex actions are essential for Protection, Rapid Response and Survival in harmful situations.

6.1.2 Human Brain

• The Human Brain is the main coordinating centre of the body and forms a part of the Central Nervous System (CNS) along with the spinal cord.
• It receives sensory information from different receptors, processes it and sends appropriate motor responses to muscles and glands.
• The brain is divided into three main parts: Forebrain, Midbrain and Hindbrain, as shown in the labelled diagram in the textbook.
• The Forebrain includes the Cerebrum, which controls thinking, memory, intelligence, emotions and voluntary actions such as writing and speaking.
• The Midbrain controls reflex movements related to vision and hearing and helps in coordination of sensory input.
• The Hindbrain consists of the Cerebellum, Pons and Medulla Oblongata, which regulate balance, posture and involuntary actions like breathing and heartbeat.
• The Cerebellum maintains body balance and precision of movements, while the Medulla controls vital activities such as blood pressure and respiration.
• The brain ensures proper Control and Coordination of both voluntary and involuntary functions of the body.

6.1.3 How are these Tissues protected?

• The Brain is protected by a hard bony box called the Cranium, which prevents mechanical injury.
• Inside the cranium, the brain is covered by three protective membranes called the Meninges, which provide additional cushioning.
• A fluid-filled space between the meninges contains Cerebrospinal Fluid (CSF) that acts as a shock absorber and reduces friction.
• The Spinal Cord is protected by the Vertebral Column, which forms a strong bony canal around it.
• The vertebral column prevents damage while allowing flexibility and movement of the body.
• The presence of CSF around the spinal cord also helps in cushioning and protection from sudden jerks.
• These protective structures ensure the safety of delicate Nervous Tissues, which are highly sensitive and cannot regenerate easily if damaged.

6.1.4 How does the Nervous Tissue cause Action?

• Nervous tissue generates an Electrical Impulse in response to a stimulus, which travels through neurons to reach the target organ.
• At the end of the axon, the impulse triggers the release of Chemical Substances (Neurotransmitters) across the Synapse.
• These chemicals pass the signal to the next neuron or directly to an Effector Organ such as a muscle or gland.
• When the impulse reaches a Muscle Fibre, it causes contraction by changing the chemical composition of muscle cells, leading to movement.
• In case of glands, the impulse stimulates secretion of specific substances required for body functions.
• The conversion of electrical signals into chemical signals ensures controlled and coordinated body responses.
• This mechanism enables precise Control and Coordination of voluntary and involuntary activities.

6.2 Coordination in plants

• Plants do not have a Nervous System, yet they show control and coordination through chemical substances called Plant Hormones.
• Plants respond to external stimuli such as light, gravity, touch and water, although their responses are slower than animals.
• Coordination in plants occurs mainly through growth movements and changes in turgor pressure.
• The tips of roots and shoots detect environmental changes and produce chemical signals that regulate growth.
• Plant movements are generally of two types: Immediate Responses and Growth-Related Movements.
• Unlike animals, plant coordination depends on Chemical Regulation rather than electrical impulses.
• These mechanisms help plants survive and adapt to changing environmental conditions.

6.2.1 Immediate Response to Stimulus

• Some plants show rapid movements in response to stimuli without growth, such as folding of leaves in Mimosa pudica (Touch-me-not) when touched.
• These movements are caused by sudden changes in Turgor Pressure in specific plant cells.
• When touched, water moves out of cells at the leaf base, causing them to lose turgidity and the leaf to droop.
• This movement does not involve growth and is therefore reversible once normal conditions are restored.
• Such responses are examples of Nastic Movements, which are independent of the direction of stimulus.
• Immediate plant responses help in Protection and Survival, especially against grazing animals or environmental stress.

6.2.2 Movement Due to Growth

• Plants show directional growth movements called Tropisms, which occur in response to environmental stimuli such as light, gravity and water.
• Growth movements are slow and irreversible because they involve cell division and elongation.
• Phototropism is the movement of shoots towards light, caused by unequal distribution of the hormone Auxin.
• Geotropism (Gravitropism) refers to root growth towards gravity and shoot growth away from gravity.
• In roots, auxin accumulates on the lower side and slows growth, causing downward bending.
• In shoots, auxin promotes cell elongation on the shaded side, resulting in bending towards light.
• Growth-related movements ensure better absorption of Water, Minerals and Light, helping plants survive efficiently.

6.3 Hormones in animals

• Hormones are chemical messengers secreted by specialised glands called Endocrine Glands, which coordinate body functions.
• Hormones are released directly into the bloodstream and act on specific Target Organs to regulate growth, metabolism and reproduction.
• The Endocrine System works along with the nervous system to maintain proper Control and Coordination in the body.
• The Pituitary Gland is known as the Master Gland because it controls the secretion of hormones from other endocrine glands.
• The Thyroid Gland secretes Thyroxine, which regulates metabolism and requires sufficient Iodine; deficiency can cause Goitre.
• The Adrenal Gland secretes Adrenaline, also called the “emergency hormone”, which prepares the body for stress by increasing heart rate and blood pressure.
• The Pancreas secretes Insulin, which regulates blood glucose levels; deficiency of insulin leads to Diabetes.
• Hormonal control is slower than nervous control but produces long-lasting effects in the body.

Exam Oriented Facts

• The basic structural and functional unit of the nervous system is the Neuron, consisting of Cell Body (Cyton), Dendrites and Axon.
• The junction between two neurons is called a Synapse, where transmission occurs through Neurotransmitters (chemical substances).
• A Reflex Arc follows the sequence: Receptor → Sensory Neuron → Interneuron (Spinal Cord) → Motor Neuron → Effector.
• Reflex actions are controlled by the Spinal Cord, while voluntary actions are controlled by the Brain.
• The brain is divided into Forebrain, Midbrain and Hindbrain; the Cerebrum controls intelligence and voluntary actions, while the Medulla Oblongata controls breathing and heartbeat.
• The brain is protected by the Cranium, Meninges and Cerebrospinal Fluid (CSF); the spinal cord is protected by the Vertebral Column.
• Plant movements are of two types: Nastic Movements (non-directional, e.g., Mimosa pudica) and Tropic Movements (directional growth movements).
• Phototropism is growth towards light; Geotropism is growth in response to gravity; both are regulated by the hormone Auxin.
• Auxin promotes cell elongation in shoots but slows growth in roots when present in higher concentration.
• Plants lack a nervous system and coordination occurs through Plant Hormones and growth regulation.
• Hormones are chemical messengers secreted by Endocrine Glands and released directly into the bloodstream.
• The Pituitary Gland is called the Master Gland because it regulates other endocrine glands.
• The Thyroid Gland secretes Thyroxine; deficiency of iodine leads to Goitre.
• The Adrenal Gland secretes Adrenaline, known as the Emergency Hormone, increasing heart rate and blood pressure.
• The Pancreas secretes Insulin; deficiency causes Diabetes Mellitus.
• Nervous control is rapid and short-lasting, whereas hormonal control is slow but long-lasting.

Understanding NCERT Class 10 Science Chapter 6 – Control and Coordination builds a strong foundation in biology. This chapter connects directly with human physiology and hormonal regulation topics in higher classes and competitive exams.

Continue reading NCERT Class 10 Science Chapter 7 – How do Organisms Reproduce? to understand reproduction and genetic continuity.

FAQs

Q1. What is control and coordination?
It is the process by which organisms regulate body functions and respond to stimuli.

Q2. What is the structural unit of the nervous system?
Neuron.

Q3. What is reflex action?
A quick, automatic response controlled mainly by the spinal cord.

Q4. Which gland is called the master gland?
Pituitary gland.

Q5. Why is Chapter 6 important for exams?
It explains nervous system, hormones and plant coordination, which are frequently asked in CBSE exams.

---