Control & Co-ordination ppt

  

                

 Control and coordination

Class 10th Science

TOPICS I N THIS CHAPTER : -

1. NERVOUS SYSTEM

2. COORDINATION IN PLANTS

3. HORMONES IN PLANTS

4. HORMONES IN ANIMALS

5. IMPORTANCE OF IODINE

6. DIABETES

INTRODUCTION :-

• All the living organism respond and react to changes in the environment around them.
• "The changes in the environment to which an organism react and respond are called stimuli such as light, heat, touch,smell,cold, sound etc."
• Both plants and animals respond to stimuli but in a different manner.
•  the nervous system and hormonal system are responsible for control and co¬ordination.

What is Control & Co-ordination ?

Synchronization between the different organs of the body so that they can work

together in harmony to perform the vital activities of life.

Control and coordination in animals is done with the help of two main systems:

1. Nervous System

2. Endocrine System

NERVOUS 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
•  neuron is specialized for conducting information via electrical impulses from one part of the body to another.

Functions of the nervous system 

• Nervous system receives information from the environment. 
•  To receive the information from the various body. 
• To act according to through muscles and glands.

                                                       click on video to watch👇

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

1. Ear- It acts as phone receptors (receiving sound).
2. Eyes- It acts as photoreceptors (receiving light).
3. Skin- Itacts as thermoreceptors (feels temperature). 
4. Nose- It acts as olfactory receptors (sense of smell).
5. Tongue- It acts as Gustatory receptors (sense of taste}.   

NEURON

"It is the structural and functional unit of nervous system. It consists of cell body,dendrites , nucleus, axon and nerve ending. It is the largest cell in the body."

Cell body- The central portion of the neuron that contains nucleus is called a cell body.

"Dendrites- The cell extensions which are shorter,branched and more numerous are called dendrites. They receive information from other neuron and transmit it towards the cell body."

Axon- It conducts the message away from the cell body and transmits to another cell.

Myelin sheath: There is an insulator cover around the axon. This is called myelin sheath. The myelin sheath insulates the axon against nerve impulse from the surroundings.

"Synapse- It is the gap between two nerve cells or neuron. Here,electrical signa ls are converted into chemical signals for onward transmission."

REFLEX ACTION

"Reflex action is quick,sudden and immediate response of the body to a stimulus. Example: knee jerk,withdrawal of hand on touching hot objects."

Stimulus:It is a observable or detectable change in the external or internal environment to which an organism reacts.

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

reflex arc. 

                                                                                           click on video to watch👇

Three types of responses:

"(i)  Voluntary action: These actions require thinking & are performed consciously.These actions are controlled by fore brain. Example- walking, talking,writing." 

"(ii)  Involuntary actions: these are automatic response to stimulus which are not under the control of brain.These are controlled by mid and hind brain. Example- heart beat, vomiting, respiration."

"(iii) Reflex action: It is an spontaneous, response of a part of body messages are sent to brain from muscles, glands to a stimulus,which is controlled by spinal cord. Example­ withdrawal of hand on touching a hot object."

"Need for 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 to brain. In this way time for taking action is reduced which save us from"

injury.

HUMAN NERVOUS SYSTEM

The nervous system in humans can be divided into three main parts 

1. Central Nervous System: The central nervous system is composed of the brain and the spinal cord. The brain controls all the functions in the human body. The spinal cord works as the relay channel for signals between the brain and the peripheral nervous system. 

2. Peripheral Nervous System: The peripheral nervous system is composed of the cranial nerves and spinal nerves. There are 12 pairs of cranial nerves. The cranial nerves come our of the brain and go to the organs in the head region. There are 31 pairs of spinal nerves. The spinal nerves come out of the spinal cord and go to the organs which are below the head region.

 3. Autonomous Nervous System: The autonomous nervous system is composed of a chain of nerve ganglion which runs along the spinal cord. It controls all the involuntary actions in the human body. 

The autonomous nervous system can be divided into two parts : 

 Sympathetic nervous system. 

 Parasympathetic nervous system. 

Central nervous system consists of 

1. Brain 
2. Spinal Cord.

• Peripheral nervous system consists of Cranial Nerves which arise from brain and Spinal Nerves which arise from the Spinal cord.

HUMAN BRAIN

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

(i)  Fore - brain 

(ii) Mid - brain 

(iii) Hind - brain

 Fore - Brain: It is the most complex or specialized part of the brain. It consists of

cerebrum.

Functions of Fore-brain:- 

• Thinking part of the brain.
• Controls the voluntary actions.
• Stores information (Memory).
• Receives sensory impulses from various parts of the body and integrate it.

 Mid - Brain:-

"lt controls Involuntary actions such as change in pupil size and reflex movements of head, neck and trunk."

Hind - Brain:- It has three parts:

"1.Cerebellum: It is responsible for precision of voluntary actions and maintaining the posture and balance of the body. Example- riding a bicycle,picking up a pencil."

"2.Medulla: It controls involuntary actions such as blood pressure,salivation & vomiting. 

3.Pons: It controls involuntary actions, regulation of respiration."

Protection of Brain and Spinal Cord:-

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

Spinal Cord - Spinal cord is enclosed in vertebral column.

                                                                click on video to watch👇

COORDINATION IN PLANTS

These are two different types of movements in plants:

(i)   Independent of Growth 

(ii)  Dependent on Growth

Independent of Growth:- Independent growth has immediate response to the stimulus and here no growth involved. 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."

Example: Drooping of leaves of 'Touch-me-not' plant on touching it.

Dependent on Growth: - These movements are tropic movement i.e. directional movement in

response to stimulus.The part of the 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.

             

   

•   Geotropism: Movement towards/away from gravity.

                      

•  Chemotropism: Growth of pollen tube towards ovule.

•  Hydrotropism: Movement towards water.

PLANT HORMONES

"These are the chemical compounds which help to  growth, development and responses to the environment."

Main plant hormones are:

Auxin: This hormone is synthesized at shoot tip.It helps the cells to grow longer and involved in phototropism (response towards light).

Gibberellin: It helps in the growth of the stem.

Cytokinins: It promotes cell division. This is present in greater concentration in fruits and seeds.

Abscisic acid: It inhibits growth. It also causes wilting of leaves and also known as stress hormone.

HORMONES IN ANIMALS

Hormones are the chemical substances which coordinatethe activities of living organism and also their growth.

Endocrine glands: - These glands secretes hormones into the blood.

The list of endocrine glands with the hormone names and their functions are given below:

"•  Thyroxine: This hormone is secreted by thyroid gland.The thyroid is located in neck/throat region. It regulates the metabolism of carbohydrates,fats and proteins."

•   Growth hormone: This is secreted by Pituitary (Master gland). This gland is located in mid-brain. It regulates growth and development.

•  Adrenaline: This hormone is secreted by Adrenal gland. The Adrenal gland is located

"above both the kidneys. It regulates blood pressure, heart beat, carbohydrate metabolism."

•  Insulin: This hormone is secreted by Pancreas. The Pancreas is located above stomach. It reduces and regulates blood sugar level.

•  Sex hormone:

{i)  Testosterone: This hormone is secreted by Testis. The testis is located in genital areas. Its changes associated with puberty(sexual maturity).

{ii) Oestrogen: This hormone is secreted by Ovaries. The ovaries are located in lower abdomen area. Its changes associated with puberty (sexual maturity).

IMPORTANCE OF IODINE

"Iodised salt is necessary because iodine mineral is essential part of thyroxine hormone secreted by thyroid gland.Thyroxine regulates metabolism of carbohydrates, fats and proteins. So, we must consume iodised salt which is necessary for proper working of thyroid"

gland. It's deficiency causes a disease called goitre {swollen neck).

DIABETES

Diabetes is a disease in which blood sugar level increases. Causes of Diabetes: The disease is caused due to the deficiency of insulin hormone secreted by Pancreas that is responsible to control blood sugar levels.

Treatment of Diabetes: It can be treated by taking injections of insulin hormone.