Control and coordination

All the living organisms respond and react to change in the environment around them. The changes in the environment to which the organisms respond and react are called stimuli. The living organisms so response to stimulus as light heat smell test pressure pain water and force of gravity. Sense of organisms to us in the form of some movement of their body part. For example, if a man touches a very hot utensil accidentally, he quickly pulls his hand away from the hot utensil.

Control and coordination in plants

The plants do not have an nervous system and sense organs like eyes, ears, or nose, etc, like the animals but they can still sense things full stop the plans can sense the presence of stimuli like light, gravity, chemicals and water and respond to them. The plans can send things like light gravity chemicals water and touch by the action of hormones in them. The plants co-ordinate their behaviour against environment changes by using hormones.

Animals use both nervous system and hormones for coordination of their activities full stop plants have no nervous system so plants use only hormones for coordination. Thus, the reaction of plants to different stimuli like light gravity water and touch is due to the effect of hormones. The plants respond to various stimuli very slowly by growing. So in most of the cases response of a plant cannot be observed immediately.

The function of control and coordination in plants is formed by the chemical substances called plant hormones.

Plant hormones or phytohormones

The control and coordination in plants is is done by plants hormone. There are four major types of plant hormones which are involved in the control and coordination in plants.

These are:

1). Auxins

2). Gibberlins

3). Cytokinins

4). Abscisic Acid

• auxins are the plant hormones which promote cell enlargement and cell differentiation in plants full stop auxins also promote fruit growth. Auxin hormone controls a plants response to light and gravity. In other words oxin hormone is responsible for the phototropic and geotropic responses of plants.

• Gibberlins  are plants hormones which Pramod sale enlargement and cell differentiation in the presence of auxins. Gibberlins help in breaking the dormancy in seeds and buds. They also promote growth in fruits.

• cytokinins are the plant hormones which promote cell division in plants. Cytokinins also help in breaking the doormancy of seeds and buds. They also delay the aging in leaves. Cytokinins promote the opening of a stomata . Promote fruit growth.

• Abscisic acid is a plant hormone which functions mainly as a growth inhibitor. Abscisic acid promotes the doormancy in seeds and birds. It also promotes the closing of stomata. Abscisic acid promotes the wilting and falling of leaves.

Tropism or tropic movements

Agrote moment of a plant part in response to an external stimulus in which the direction of stimulus determines the direction of response is called tropism. The stropism is a directional movement of the parts of a plant caused by its growth. The growth of a plant part in response to a stimulus can be towards the stimulus or away from the stimulus due to which we can have a positive tropism or negative tropism.

Types of tropism

• the moment of a plant in response to light is called photo tropism. In other words the response of a plant to light is called phototropism full stop if the plant at moves away from light then it is called negative phototropism. The stem of a growing plant bends towards light so the stem of a plant so positive phototropism. On the other hand the routes of a plant move away from light so the roots of a plant so negative phototropism.

• the movement of a plant part in response to gravity is called geotropism full stop in other words that response of a plant to gravity is called geotropism full stop if the plant part moves in the direction of gravity it is called positive geotropism. On the other hand if the plant parts move against the direction of gravity it is called negative geotropism. Now, the roots of a plant move downwards in the direction of gravity so the roots of a plant show positive geotropism. The other hand, the stem of a plant moves upward against the direction of gravity so the stem of a plant shows negative geotropism.

• The moment of a plant part in response to a chemical stimulus is called chemotropism. If the plant part shows movement towards the chemical it is called positive chemotropism. On the other hand if the plant part so movement away from the chemical then it is called negative chemotropism.

•  The moment of a plant part in response to water is called hydrotropism. If the plant part moves towards water it is called positive hydrotropism. And if the plant part moves away from the water then it is called negative hydrotropism. The roots of a plant always go towards water roots are positively hydrotropic. 

•  The directional growth movement of a plant part in response to the touch of an object is called thigmotropism. The climbing parts of the plants such as tendrils grow towards any support which they happened to touch and wind around that support. So tendrils of a plants are positive ly thigmotropic.

NASTIES or Nastic movements

The movement of a plant part in response to an external stimulus in which the direction of response is not determined by the direction of stimulus is called a Nastic movement. Nastic movements of plants are also called nasties. The Nastic movements of plants are induced by stimuli such as heat light touch etc. The main difference between tropic and Nastic movements is that tropic movement is a directional movement of a plant part but Nastic movement is not a directional movement of the plant part with respect to the stimulus.

• Thigmonasty

Dhannoon directional movement of a plant part in response to the touch of an object is called  Thigmonasty. The sensitive plant has bad like swelling called pulveni at the base of each leave. The pulveni contain a lot of water in their cells . Due to the internal water pressure in them all the full winning are very form and hold the leaves above them upright. The folding up of the leaves of a sensitive plant on touching is due to the sudden loss of water from pad like swelling called pulveri present at the base of all leaves of the sensitive plant which make the pull we need loose their famines causing the leaves to drop and fall.

• Photonasty

Non directional movement of a plant part petals of flower in response to light is called photo nasty. 

   Coordination in animals

   The multicellular animals have a specialised cell called nerve cell to respond to stimuli and co-ordinate their activities full stop system made up of nerve cells is called nervous system. The coordination in simple multicellular animals takes place through nervous system the control and coordination in higher animals called vertebrates takes place through nervous system as well as hormonal system called endocrine system. A receptor is a cell or a group of cell in a sense organ which is sensitive to a particular type of stimulus are a particular type of change in the environment such as light sound smell test heat pressure etc.

Different types of receptors: 

Photoreceptors - Detect light

Phonoreceptors- Detect sounds

Olfactory receptors- Detect smell

Gustry receptors- Detect taste

Thermo receptors- Detect heat or cold

There are two system of coordination of activities in humans. These are: 

1). Nervous system

2). Endocrine system

Human Nervous system
The function of nervous system is to co-ordinate the activities of our body. It is the control system for all our action thinking and behaviour. The nervous system helps all other system of our body to work together. The nervous system is like a manager inside our body. It's job is to control and coordinate the parts of our body so that they work together doing their job at the right time full stop the human nervous system receives information from the surrounding process it enterprets it and then response accordingly.

The unit of nervous system: Neuron

The units which makeup The nervous system are called nerve cell or neurones. So neurone is the structural and functional unit of The nervous system. We can now say that nervous system is made up of special cell called neurones is the largest cell in the body which looks like an electric wires contain the same basic part as any other animal cell but their structure is specially adapted to be able to carry massages over large distences in the body quickly.

A neuron has three components:

•Cell body

• Dendrites

• Axon

Any two neurones in The nervous system do not join to one another completely. There is always a very small gap between the two neurones. This gap is called a synapse. The nerve impulses are carried over this small gap between a pair of neurones by means of chemical substances called a neurotransmitter substance. We cannot say that a microscopic gap between a pair of adjacent neurones over which nerve impulses pass when going from one neurone to the next is called a synapse.

The organs of human nervous system

The man organs of The nervous system are brain spinal cord and nerves full stop the sense organs like eyes ears tongue nose and skin can be considered to be other organ of the nervous system because they help in the functioning of the nervous system. The main organs of The nervous system in the given figure.

The brain and spinal cord are connected to all the sense organs and other parts of a body by millions of nerves. There are many two types of nerves in our body: Cranial nerve and Spinal nerve.

The nerves which carry messages from the body parts to the brain are called sensory nerves and the nerves which carry messages from the brain to the body parts for action are called motor nerves.

The parts of the nervous system

Banaras system can be divided into two main parts:

• central nervous system

• peripheral nervous system

The peripheral nervous system

All the nerves of the body together make up the peripheral nervous system (PNS). They all enter our leave the central nervous system. The three types of nerves which make up the peripheral nervous system are spinal nerves, cranial nerves, and visceral nerves

.

Reflex action and reflex arcs

The simplest form of response in the nervous system is reflex action. This is a rapid automatic response to stimulus which is not under the voluntary control of the brain. It is describes as an involuntary action full stop does a reflex action is one which we perform automatically full stop it is a comparatively simple form of behaviour in which the same stimulus produces the same response every time. If we Unknowingly touch a hot plate, we immediately move our hand away from it. So moving our hand away on touching a hot plate is an example of reflex action. Similarly moving our food away when we step on something sir is also an example of reflex action.

Reflex Arc

The pathway aur root taken by nerve impulses in a reflex action is called the reflex are. Reflex arcs allow rapid response. Reflex action is an automatic response to stimulus. The reflexes of this type of which involves only the spinal cord are called spinal reflexes full stop those reflex action which involved brain are called cerebral reflexes. The contraction of people of our eye automatically in the presence of bright light is an example of cerebral reflex.

Central nervous system

The central nervous system (CNS) consist of the brain and the spinal cord. Like a telephone exchange with in going and outgoing wires it is responsible for the coordination and control of the activity of The nervous system. The work of central nervous system is to direct incoming messages to the motor neurones that have connected to the part of the body which will respond to stimulus. In complicated response central nervous system is involved. If you pick up a very hot plate in the kitchen without knowing that it is very hot then our reflex action produced by the spinal cord alone says that we should pull away our hand full stop and break into pieces now it is here that the central nervous system involving brain steps in full stop when the message from our finger saying that the plate is to hot arrives at our central nervous system there is already another message saying don't drop it. This is due to the intelligence of the brain. The job of the central nervous system is to collect all the information from all the receptor in our body. This information is added together before massages are sent out to the effectors. 

Brain

Brain is the highest coordinating centre in the body. The brain is located inside the skull of our body full stop it is protected by a Bony box in the skull called cranium. The brain is surrounded by three membrane called meninges, which help to protect it. The space between the membrance is filled with cerebros spinal fluid which protects the brain from mechanical shock. 

The brain is broadly divided into three regions: forebrain, midbrain, hindbrain.

The four brain consist many of cerebrum full stop the mid brain does not have any further divisions full stop the Hind brain consists of 3 centres called pones cerebellum and medulla.

The cerebrum is the main thinking part of the brain. It is the site of our faculty such as learning reasoning intelligence personality and memory. Our memory is stored in area called hippocampus. All our thoughts sensations actions and movement are controlled by the cerebrum full stop the cerebrum has different areas for performing different functions. There are association areas and cerebrum which control thinking and memory. This association areas also store information and expressions. There are sensory areas where information is receive from the sense organ like I earn nose tongue and skin and we give us the sensation or feeling. Similarly cerebrum has motor areas from which instructions are sent to muscles to do various types of jobs all the voluntary action of the body are co-ordinated by the cerebrum. Sensory information through the recepter of sense organs. In the light of previous expression and take a decision which it things is right full stop it then sends out instruction to the motor areas so as to make voluntary muscle move to bring about the appropriate responses. The pones takes part in regulating respiration. The cerebellum helps in maintaining posture and balance of the body. It also enables us to make precise and accurate movements. The cerebellum coordinate smooth body movement such as walking dancing riding a bicycle etc. Medulla is also the controlling centre for reflexes such as swelling coughing sneezing secretion of saliva and vomiting.

Spinal cord

Spinal cord is a cylindrical structure. The spinal cord begins in continue with medulla and extend downwards full stop it is enclosed in a bunny cage chord vertebral column full stop spinal cord is also surrounded by membrane called mannings full stop as many as 31 pairs of nerves arises from the spinal cord first of the spinal cord isned with spinal reflex action and the coordination of no impulses and from the brain.

Hormones

Hormones are chemical substances secreted in very small amounts by specialised tissue in the body called endocrine glands this hormones co-ordinate the activity of living organisms and also their growth. So we can say that hormones are the chemical substances which co-ordinate the activities of living organisms and also their growth. Hormones are made inside the body of an organism in very small amount. The various characteristic of hormones are given below:

•the hormones are secreted in a small amounts by the endocrine glands

•the hormones are Ford directly into the blood and carrot throughout the body by blood circulatory system.

•the hormones have their effect at the sides different from the sides where they are made. So they are also called chemical messengers.

•the hormones act on a specific tissue or organ called target organs.

•the hormones co-ordinate the cavity of the body and also its growth.

The endocrine system

A group of endocrine glands which produces various hormones is called an endocrine system. The endocrine system is also called hormonal system. The endocrine glands present in the human body are: pineal gland; hypothalamus gland; pitutory gland; thyroid gland; parathyroid gland; thymus; pancreas; adrenal glands; testes; ovaries. 

The hormones produced by endocrine glands act as messengers between the nervous system and the organ of our body full stop there are two adrenal glands in our body one on top of each kidney. The adrenal glands make adrenaline hormone. 

The complete coordination in the human body is achieved by the nervous system and endocrine system working together full stop the main centres in the body for the coordination of the two system of control at the hypothalamus and pituitary gland. The hypothalamus place and important role in collecting information from other reasons of the brain and from blood vessels pressure and allows more glucose to go into the blood to give us a lot of energy quickly to fight or run away. Adrenal glands are often called glands of emergency.

1. Hypothalamus

Hypothalamus gland is present in the brain. Hypothalamus produces releasing hormones and inhibitory hormones full stop the function of hypothalamus is to regulate the secretion of hormones from pituitary gland is hypothalamus controls the pituitary hormones.

2. Pituitary gland

Gland is present just below the brain. The patriotic gland secretes a number of hormones. One of the hormone secreted by pituitary gland is growth hormone or human growth hormone full stop the growth hormone control the growth of the human body. For example growth hormone controls the development of bones and muscles full stop a person having a deficiency of growth hormone in childhood dreams very short and becomes a dwarf.

3. Thyroid gland

Thyroid gland is attached to the wind pipe in our body. Thyroid gland make a hormone called thyroxine full stop the function of thyroxine hormone is to control the rate of metabolism of carbohydrates fats and proteins in the body full stop iodine is necessary for the making of thyroxine hormone by thyroid gland there for a deficiency of iodine in the diet can cause a deficiency of thyroxin hormone in the body full stop the deficiency of iodine in the diet of a person produce less thyroxine hormones and causes a disease known as guiter. The main symptoms of goitre is that the neck of the person appears to be swelling due to the enlargement of thyroid gland located in the neck full stop people are advise to use iodise salt for cooking food so as to prevent goitre disease.

4. Parathyroid Glands

There are four small parathyroid glands which are embedded in the thyroid gland. parathyroid gland secret of hormone called parathormone. The function of parathormone is to regulate calcium and phosphate levels in the blood.

5. Thymous gland

Thymus gland lies in the lower part of the neck and upper part of chest. Thomas gland secrets thymous hormone which place are role in the development of the immune system of the body. Thomas gland is large in young children but shrinks after puberty or sexual maturity.

6.. pancreas

The pancreas is just below the stomach in the body. And curious secret the hormone called insulin. The function of insulin hormone is to lower the blood sugar level or blood glucose level. Deficiency of insulin hormone in the body causes a disease known as diabetes full stop diabetes disease is characterized by large quantities of sugar in the blood. The insulin hormone controls the metabolism of sugar. Pancreas does not produce and secrete sufficient amount of insulin into blood then the sugar level in the blood rises. The high sugar level in the blood can cause many harmful effects to the body of a person.

7. Adrenal glands

There are two adrenal glands which are located on the top of two kidneys. The adrenal glands secret adrenaline hormone. The function of adrenaline hormone is to regulate heart rate breathing rate blood pressure and carbohydrate metabolism. Adrenaline hormone is secreted in small amounts all the time but in large amounts when a person is right and or excited . when adrenaline is secreted in large amount it prepare a body for action. Eat spirits of heartbeat and breathing rises blood pressure and allow more glucose to go into the blood to give us a lot of energy quickly to fight our flight. Adrenal glands are often called glands of emergency.

8. Testes

Testis are the glands which are present only in male full stop taste is makes male sex hormone call testosterone. The function of testosterone hormone is to control the development of male sex organs and male features such as people voice moustache beard and more body hair. All this changes caused by testosterone are associated with male poverty which the boys at 10 at 10 age of 13 to 14 years full stop the test is also makes the mail gametes called sperms.

9. Ovaries

Overseas are the glands which are present only in females. Over is make two female sex hormone called oestrogen and progesterone. The function of oestrogen hormone is to control the development of female sex organs and female features such as feminine voice soft skin and mammary glands. All this changes caused by estrogen are associated with female poverty which the girls attend at an age of 10 to 12 years. The function of progesterone hormone is to control the uterus changes in menstrual cycle. It also helps in the maintenance of pregnancy. The ovaries also make the female gammates called ova or eggs.

Feedback mechanism

The excess or deficiency of hormones has a harmful effect on our body. For example the deficiency of insulin hormone result in a disease called diabetes where as excess of insulin in the body can lead to coma. So, it is necessary that the hormones are secreted by the glands in our body in presides quantities which are required for the normal functioning of the body. This means that there should be some mechanism to regulate the production and release of hormones in the body. The timing and amount of hormones released by various glands are controlled by the feedback mechanism which is inbuilt in our body. For example if the sugar level in the blood rises too much they are detected by the cells of pancreas which respond by producing and secreting more insulin into blood. And as the blood sugar first to a certain level the secretion of insulin is reduced automatically.