January 22, 2022

Class 10 Science Chapter 7 Control and Coordination

Class 10 Science Chapter 7 Control and Coordination. As we already learn in the previous chapter about the life process which has the main function i.e. to control the function of the body. As we learned that all the things which show movement is alive and all those movements are because of growth.

Not every movement happens because of growth. So, some of the movements are because of the response due to change of environment. Now, we have to control all of these movements in response to the environment. To perform these control and coordination movements every organism has specialized tissues.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about the animal nervous system.

# Animals – Nervous System

In animals, control, and coordination is done by nervous and muscular tissue.

Q. How do we detect that we are touching a hot object?

In our body, we have some special tips in the nerve cells which detect all the changes in our environment.

However, we have different receptors in our body such as:

  1. Olfactory Receptors – In our Nose
  2. Thermore Receptors – In our Skin
  3. Gustatory Receptors – In our Tongue
  4. Photo Receptors – In our eyes

The endpoint of the nerve cell called dendrite capture the information, after that this converts it into an electrical impulse and now it travels inside the cell body. Now, it goes from axon to nerve ending. So, at the end of the axon, a chemical is released and this chemical covers the gap between axon or nerve ending and new neuron’s dendrite called the synapse.

Synapse: The gap between the ending of an axon and the dendrite of another neuron.

So, now the information passes to the next neuron and information passes by until it reached the brain which gives us the signal of different things while we touch them. Such as hot, cold, wet, dry, etc.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about reflex actions.

# Reflex Actions

If there is any change in the environment, then the action that we take suddenly in response to it is called reflex action. Like when we touch something hot, we take our hands away immediately. Also, we do this without thinking and we have no control over it.

If we perform the reflex action based on thinking then it will take a lot of time because for thinking nerve impulses have to interact with nerve neurons and after that, the message will go to the thinking tissue, and then we will know that message in our whole body. So if we spend this much time in a reflex action, then our hands will burn.

So to do this work immediately, there are 2 types of nerves in our body. One that will help detect heat and one that will give information to the muscles that you have to move. So if we can somehow connect these two nerves without going to the brain, then this action of ours will be completed soon. So this type of connection is called the reflex arc.

Reflex arc: It is the shortest route that can be taken by an impulse from the receptor to an effector.

The flow of this reaction is given below:

Stimulus → Receptor → CNS (by Sensory Neuron) → Effector (by Motor Neuron) → Response

Reactor: These are the dendrites of the nerve cells that respond to the stimulus and convert it into impulses in a sensory neuron.

Effector:  It is an organ (muscle or gland) that responds to motor nerve impulses.

Whatever nerves are there, they are found in our spinal cord and this information is carried to the brain. Although the reflex arc is formed on the spinal cord, the information that is there also goes to the brain. And this reflex arc is also developed in animals because the thinking process of animals is not fast enough.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about the human brain (Fore and Mid).

# Human Brain

So far we have seen that the spinal cord is made up of nerves and it supplies information to think. Our nervous system is made up of 2 types, one is the central nervous system and the other is the peripheral nervous system.

1. Central Nervous System: So the brain and spinal cord together are called the central nervous system and their job is to receive and integrate information from the whole body.

Q. Name the 2 main organs of our central nervous system? Which one of them plays the major role in sending commands to muscles to act without involving the thinking process?

The 2 main organs are the Brain and Spinal Cord. The major muscle is the Spinal Cord which acts without thinking.

2. Peripheral Nervous System: Mainly nerves come in this which are of 2 types. First cranial nerve and second spinal nerve. The cranial nerves are derived from the brain. and spinal nerves are derived from the spinal cord. It creates communication between the central nervous system (CNS) and other body parts.

Voluntary action: These are the actions that you perform by thinking and these are in your control. Like you are reading, drinking water, etc.

Involuntary action: This is the action that is done by your body without thinking and it is not under your control. Like your heartbeat, Blood flow in your body, etc.

Now, let’s learn about the brain, it is divided into 3 parts Fore-brain, Mid-brain, and Hind-brain.

1. Fore-Brain

So, the combination of the cerebrum, Hypothalamus, and Pituitary Gland is called Fore-Brain. This part is responsible for our thinking process. It enables us to think, reason out, invent, plan and memorize. It is also the seat of intelligence, consciousness, and willpower.

Whatever sensory impulse comes from the sense organs, it receives it. Different areas are made in it for different work like hearing, smelling, sight, etc. Whatever we see, like a picture of a thing, such as the picture of a lion, so it does the job of interpreting it on the basis of past information and let us know that it is a lion.

It performs all the voluntary actions in the body. This also produces the sensation of hunger and the feeling of fullness.

2. Mid-Brain

It connects the two hemispheres of the brain and controls whatever reflexes are attached to the eyes and ears. It controls some of the involuntary actions.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about the human brain (Hind-Brain).

3. Hind Brain

It has 3 parts i.e. Ponds, Medulla, and Cerebellum. Also, the medulla further becomes the spinal cord. Part of it controls some of the involuntary actions such as vomiting, salivation, blood pressure, etc all these are controlled by the medulla.

It is responsible for the precision of the voluntary action, that is, it takes care of how well these actions will be performed. Like riding a bicycle properly, walking in a straight line, etc. These all works are done by the cerebellum. Also, it helps to maintain the posture and balance of the body.

# How are these tissues protected?

Our brain is protected by a bony box there is also a fluid present in this box named cerebrospinal fluid. This fluid protects the brain from any kind of shock. The spinal cord is inside the bone cage named the vertebral column.

# How does the nervous tissue cause action?

When there is an impulse comes from a motor neuron that reaches the muscle, then muscle fibers have to move. So, for the movement of muscle fiber, the muscle cells have to change their shape and make themselves short.

So, muscle cells have a special protein and they can change their shape and arrangement. So, due to this new arrangement happens and muscle cells get a shorter form.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about coordination in plants.

# Coordination in Plants

Firstly, the plant doesn’t have any nervous system or muscles. So, how do they respond? Like when we touch a leaf of Touch-me-not it closes. So, this is a quick response and independent from the growing movement. Plant includes another movement i.e. dependent on growth.

1. Movement independent on growth

So, how do they detect the touch with nerves or muscles? Now, if we observe that where are we touching the plant and where does plant actually move. So, you will notice that information of touch must be communicated in the plant.

So, they use electrical chemical means from cell to cell or diffusion. But they don’t have specialized tissue. So, instead of specialized protein, they change the shape by changing the amount of water in them. Due to this they can swell and shrink their shape.

2. Movement dependent on growth

There are some plants like pea which can climb on the other plants with the help of tendrils. Also, the tendril is sensitive to touch so, whenever the tendril touches the surface its growth of that particular part stops and the part which doesn’t touch the surface will accelerate its growth and due to this the tendril bends and encircle the whole surface.

Environmental triggers such as light, gravity can change the direction of a plant’s growth. So, there are 2 types of movement i.e. towards or away from the stimulus. They are also known as a directional or tropic movement.

Tropic movement / Tropism: The growth movement of plants in response to any stimuli, either towards or away from stimuli is called tropism. So, there are different types of tropism i.e. Phototropism, Geotropism, Hydrotropism, and Chemotropism.

  1. Phototropism: Movement towards the light.
  2. Geotropism: Movement towards gravity.
  3. Hydrotropism: Movement towards the water.
  4. Chemotropism: Movement towards the specific chemical.

Q. Give an example of chemotropic?

Growth of pollen tubes towards ovules.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about coordination in plants and plant hormones.

So, as we see there are slow and fast response is there. Now, if you want to have a fast response, then we need fast information transfer and hence we have to use a fast medium of transfer.

For fast response, we need electric impulse but there are 2 limitations:

  1. They only reach those cells which are connected to the nervous tissue.
  2. Once an impulse is transmitted in a cell, then it will take some time to reset itself for a new impulse that means the cell can’t transmit electrical impulses continuously.

That’s why most multi-cellular organisms use another way i.e. chemical communication which uses hormones. This chemical compound uses diffusion to transmit but it is a slow process that reaches all of the cells of the body and it can be done continuously.

Plant Hormones

These are the chemical substances that help towards their growth, development, and response in our environment.

# Types of Plant Hormones

There are mainly 4 types of hormones present in the plants:

1. Auxin

When a growing plant detects light, then at its tip of the shoot auxin starts generating which helps plants cells to grow longer. Its function is to diffuse in shady parts of the plant where light doesn’t reach and hence, the plant starts to bend towards the light.

2. Gibberellins

It helps in the growth of the stem.

3. Cytokinins

It helps cell division. They are present in seeds and fruits where rapid cell division is needed.

4. Abscisic acid

It inhibits growth or we can say that resists growth. Also, it is responsible for the willingness of leaves.

Class 10 Science Chapter 7 Control and Coordination

In this section of Class 10 Science Chapter 7 Control and Coordination, we are going to learn about Animal hormones.

# Hormones in Animals

When animals face a dangerous situation in their body, a chemical signal is released and in the case of humans and some animals, this work is done by adrenaline. There are 5 different types of hormones present in animals and humans lets discuss all of them.

1. Adrenaline Hormones

It is released by the adrenaline glands. They are directly released into the blood, these hormones are a part of the endocrine system. Also, it is known as ductless glands. Its target organ is the heart by this more oxygen supply to our muscles and increases in a heartbeat.

So, blood supply is reduced in our digestive system and skin due to the contraction of muscles. It also diverts the blood to our skeletal. So, because of the contraction of the diaphragm and rib muscles our breathing rate increases.

2. Thyroxin Hormones

Iodine is necessary for the thyroxine gland to make this hormone. In our body, the proper breakdown of carbohydrates, proteins, and fats is done by this. This affects your weight gain and loss. If there is a lack of iodine in your body you may suffer from goiter, in this you face the disease of the swollen neck.

3. Growth Hormones

It is released by the pituitary gland. It is responsible for the height of your body. If there is a lack of this hormone, it can make you into a dwarf.

4. Testosterone and Oestrogen

Our complete body changes around the age of 10-12 due to these hormones. In boys testosterone is responsible and in girls, oestrogen is responsible for all the changes.

5. Insulin

It is produced by the pancreas and its main function is to regulate the blood sugar level. If the sugar level rises you may face problems like blindness, kidney diseases, etc.

So, all of these hormones in the body are released at the correct time and in the correct amount and all this is decided by the feedback mechanism which is present in our body.

Check Also: Class 10 Science Chapter 7 Control and Coordination Blueprint 2021-22

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