NCERT Solutions Class 10th Science Chapter – 7 Control and Coordination Notes

• Human nervous System
• Human Endocrine System (Glands)

Human nervous System 

• Central Nervous System
• Peripheral Nervous System
• Autonomic nervous system

Central Nervous System

• Brain
• Spinal cord

Peripheral Nervous System

• Cranial nervous
• Spinal nervous

Autonomic nervous system

• Sympathetic
• Para Sympathetic

Brain

• Fore Brain
• Mid Brain
• Hind brin

Hind brin

• Cerebellum
• Pons
• Medulla

Human Endocrine System (Glands) 

• Hypothalamus
• Pituitary
• Thyroid
• Parathyroid
• Thymus
• Pancreas
• Adrenal
• Ovaries
• Testes

• Plant Hormones (Phytohormones)
• Movements

Plant Hormones (Phytohormones)

• Growth Promoters
• Growth Inhibitor

Growth Promoters

• Auxin
• Gibberelin
• Cytokinin

Growth Inhibitor

• Abscisic Acid

Movements

• Nastic Movement
• Tropic Movement

Tropic Movement

• Hydro tropism
• Geotropism
• Phototropism
• Chemotropism
• Thigmotropism

• All the living organisms respond and react to changes in the environment around them.

• The changes in the environment to which the organisms respond and react are called stimuli such as light, heat, cold, sound, smell, touch etc.

• Both plants and animals respond to stimuli but in a different manner.

It is brought about in all animals with the help of two main systems:

• Nervous system
• Endocrine system

• Control and coordination are provided by nervous and muscular tissues.
• Nervous tissue is made up of an organized network of nerve cells or neurons, and is specialized for conducting information via electrical impulses from one part of the body to another.

Receptors – Are specialized tips of some nerve cells that detect the information
from the environment. These receptors are located in our sense organs.

(A) Ear

• Phonoreceptors
• Hearing
• Balance of the body

(B) Eyes

• Photoreceptors
• Seeing

(C) Skin

• Thigmoreceptors
• Heat or cold
• Touch

(D) Nose 

• Olfactory receptors
• Smell detection

(E) Tongue 

• Gustatory receptors
• Taste detection

Neuron – It is the structural and functional unit of nervous system.

(A) Dendrite – Acquires information.

(B) Cell body – Acquired information travels as an electrical impulse.

(C) Axon – Longest fibre on the cell body is called axon. It transmits electrical impulse from cell body to dendrite of next neuron.

Synapse – It is the gap between the nerve ending of one neuron and dendrite of the other neuron. Here electrical signal is converted into chemical signal for onward transmission.

Reflex action is quick, sudden and immediate response of the body to a stimulus. E.g., Knee jerk, withdrawal of hand on touching hot object.

Reflex arc – The pathway through which nerve impulses pass during reflex action is called reflex arc.

(A) Voluntary – Controlled by fore brain. E.g., talking, writing.

(B) Involuntary – Controlled by mid and hind brain. E.g., heart beat, vomiting, respiration.

(c) Reflex action – Controlled by spinal cord. E.g., withdrawal of hand on touching a hot object.

Need of Reflex Actions – In some situations such as touching a hot object, pinching etc. we need to act quickly, otherwise our body would be harmed. Here response is generated from spinal cord instead of brain.

Central Nervous System (CNS)

(i) Brain

(ii) Spinal Cord

Peripheral Nervous System (PNS)

(i) Cranial Nerves Arise from the brain

(ii) Spinal Nerves Arise from the spinal cord

Brain is the main coordinating centre of the body. It has three major parts:

(A) Fore-brain

(B) Mid-brain

(C) Hind-brain

(A) Fore-brain – It is the most complex or specialized part of the brain. It consists of cerebrum.

Functions

(i) Thinking part of the brain.

(ii) Control the voluntary actions.

(iii) Store information (Memory).

(iv) Receives sensory impulses from various parts of the body and integrate it.

(v) Centre associated with hunger.

(B) Mid brain – Controls involuntary actions such as:

•  Change in pupil size.
•  Reflex movements of head, neck and trunk.

(C) Hind brain – It has three parts:

(i) Cerebellum – Controls posture and balance. Precision of voluntary actions e.g., picking pen.

(ii) Medulla – Controls involuntary actions e.g., blood pressure, salivation, vomiting.

(iii) Pons – Involuntary actions, regulation of respiration.

(A) Brain : Brain is protected by a fluid filled balloon which acts as shock absorber and is enclosed in cranium (skull or brain box).

(B) Spinal Cord: Spinal cord is enclosed in vertebral column.

Coordination between Nervous and Muscular Tissue

(A) Electric impulse will reach only to those cells that are connected by nervous tissue.

(B) After generation and transmission of an electrical impulse, the cell takes some time to reset its mechanism before transmitting another impulse. So cells cannot continually create and transmit impulse.

(C) Plants do not have any nervous system.

Chemical Communication: To overcome the limitations of electric communication.

Movements in plants:

• Independent of growth
• Dependent on growth

(i) Independent of growth: Immediate response to stimulus. (Nastic Movement)

• Plants use electrical-chemical means to convey information from cell to cell.
• For movement to happen, cells change their shape by changing the amount of water in them, resulting in swelling or shrinking of cells.

E.g., Drooping of leaves of ‘Touch-me-not’ plant on touching it.

(ii) Dependent on growth – These movements are tropic movements e.g., directional movements in response to stimulus.

Tendrils – The part of tendril away from the object grows more rapidly as compared to the part near the object. This causes circulating of tendril around the object.

• Phototropism – Movement towards light, e.g. growth of a shoot towards light.
• Geotropism – Movement towards/away form gravity, e.g. growth of roots in soil
• Chemotropism – Movement to/away Chemicals Growth of pollen tube towards ovule.
• Hydrotropism – Movement towards water. e.g. growth of a roots towards water

(A) Auxin

• Synthesized at shoot tip
• Helps the cells to grow longer
• Involved in phototropism

(B) Gibberellin

• Helps in the growth of the stem

(C) Cytokinins

• Promotes cell division
• Present in greater concentration in fruits and seeds

(D) Abscisic Acid

• Inhibits growth
• Cause wilting of leaves
• Stress hormone

Hormones in Animals

Hormones – Hormones are the chemical substances which coordinate the activities of living organisms and also their growth.

Endocrine glands – These glands secrete their product (hormone) into the blood.

Disease in which blood sugar level increase

Cause – Due to the deficiency of insulin hormone secreted by pancreas that is responsible to control blood sugar levels.

Treatment – Injections of insulin hormone.