CONTENT LIST
CONTROL & CORDINATION
Introduction
Living organism respond various detectable change in internal/external environment such as heat, light, cold, touch etc. This responses are termed as Stimuli.
• You feel hunger so you eat some food.
• An animal feels cold so it moves into the sun.
• A dog feels hot so lies in the shade
• If you touch something hot, your hand moves away quickly.
• In a cold day, the small hairs stand on our body.
• Snakes, hares, squirrels flee as soon as they feel someone around them.
In all above cases, Living organism responded when they detect change in environment around them.
The body works in control and coordinated manner with the help of
1. Nervous system
2. Endocrine system
The nervous system and the endocrine system work together as a team.
ANIMALS – NERVOUS SYSTEM
Nervous system
• Nervous system is also called as your body's command centre.
• Neuron is the the functional unit of nervous system
• It consists of brains, spinal nervous system and network of nerves.
• It is responsible for control, command and coordination in our body.
• It receive the information from the environment and respond various body parts accordingly through muscles and glands.
Need of Nervous system
• It control and harmonises all voluntary muscular activity. Such as walking, holding a book, etc.
• It regulates involuntary activities. Such as thinking, breathing, heart beating, etc.
The Human Nervous system is consist of two parts, known as
1. Central Nervous Systems (CNS),
2. Peripheral Nervous System (PNS)
Central sensory system (CNS): The Central Nervous System (CNS) consists of the brain and the spinal cord. It manages every exercises of the body.
Peripheral sensory system (PNS):
The peripheral nervous system consists of the nerves Which are branch out from the brain and spinal cord.
These nerves form the communication network between the CNS and the body parts.
The peripheral nervous system is subdivided into the (a) somatic nervous system and (b) the autonomic nervous system
What happens in Reflex Actions?
Reflex action is a automatic & rapid response of an stumulus .
It a kind of involuntry action cause by reflex arc formed in spinal cord.
It protects the body from potentially dangerous situations like touching something hot.
Stimuli:- Stimuli is a respond by a living organism in which they detect various internal and external change in the environment.
Resepters:- It sense the change in environment around any living organism and transmit the information or signal to CNS.
Effectors:- Effectors execute the responses received from CNS.
Responses:- Responses are the actions of the effectors to cope-up the change in environment.
Neuron / Nerve cell
Neurons are the structural and functional unit of the nervous system. It main function is to recieve and transmit signal and information to different parts of the body.
Neuron Types
There are three kind of neurons
1. Sensory Neurons
2. Motor Neurons
The sensory neurons carry information from the sensory receptor cells, which are present throughout the body to the brain.
Sensory neurons are activated by sensory input from the environment. Example, when you touch any hot surface with your fingertips, the sensory neurons present at fingertip get activated and produce signals and sending off signals to the rest of the nervous system about the information they have received.
The motor neurons carry information from the brain to the muscles. It is part of the central nervous system (CNS) and connect to muscles, glands and organs throughout the body. They directly control all of our muscle movements.
A neuron varies in shape and size according to function and location.A typical neuron consists of three main parts:-
1) Soma or cell body is a compact structure contains nucleus and Nissl's granules. Dendrites and axon are ejected from it.
2) Dendrites help in receiving and the processing of the information.
3) Axon is a tube-like structure which carries electrical impulse from the cell body to the axon terminals and thus pass the impulse to another neuron.
Human Brain
Human brain is situated inside a brain box called cranium (skull) which protect the brain from mechanical injury. It is also surrounded by three membrane called meninges.
Human brain is made up of three major parts
- Forebrain: It is anterior part of the brain, consists of Cerebrum, Hypothalamus and Thalamus. It is main thinking part of the brain. It is the area of the brain specialised for hearing, smell and sight.
- Midbrain: It is the smaller and central part of the brainstem, consists of Tectum and Tegmentum.
- Hindbrain: It is the central region of the brain, composed of Cerebellum, Medulla and Pons
Human Brain
How does the Nervous Tissue cause Action?
Nervous tissue is made up of neurons, which transmit impulses with the suport neuroglia (which help in propagation of the nerve impulse as well as provide nutrients to the neuron).
Nervous tissue send signals to the brain through spinal cord and receive stimuli.
Human brain produced nerve impulse (reflex arc) in spinal chord.
When this nerve impulse reaches the muscle,the muscle fibre must move by changing their shape. This happens because muscle cells have special proteins which change both their shape and arrangement in the cell in response to nervous electrical impulses.
Nervous tissue has point called axons that transfer the brains message to the relative muscle and carry out the action. The human brain send the message through the tendons and axons to the the point in action.
COORDINATION IN PLANTS
Any type of movement which is found in plant is known as plant movement.
The movement in plants are not as apparent as in case of animals.
Movement is plant is very slow.
The higher plants are fixed to the substartum by means of root.
They can not move from one place to another.
They show movement of their organs only.
Plants have 2 kind of movement in response to various stimuli:
i) Movement independent of growth
ii) Movement dependent on growth
There are no nervous system, muscles and sense organs in plants but they still respond to various environmental stimuli such as light, water, gravity, touch, chemicals etc.
Plants coordinate their responses against environmental stimuli with the help of hormones.
Hormones coordinate in plant in 2 ways:
i) For the growth of plant and as a result part of plant show movement
ii) For the shape of plant cell by changing amount of water in them (shrinking or swelling)
Immediate Response to Stimulus
Plant Movement - Tropic movement
Directional movement of any specific part of the plant in response to external stimuli is called tropism. The directional movements are very slow. The movement of plant part can be towards or away from stimulus. If the movement of plant is towards stimulus, it is called tropic stimulus. It is also called positive stimulus.
If the movement of plant is away from stimulus, it is called negative stimulus.
Movement Due to Growth
Phototropism:- Phototropism is a kind of tropic movement in which plants move towards light stimulus.
If the movement in plant is towards the direction of light, it is called positive phototropism.
Ex: Stem or Shoot
If the movement in plant is away from the direction of light, it is called negative phototropism.
Ex: Roots
Geotropism:- Geotropism is a kind of tropic movement in which plants move in realtion to gravity.
If the movement in plant is towards the direction of gravity, it is called positive phototropism.
Ex: Roots
If the movement in plant is away from the direction of gravity, it is called negative phototropism.
Ex: Stem or Shoot
Chemotropism:- Chemotropism is a kind of tropic movement in which plants move in realtion to chemical. Ex: Movement of pollen tube and funal hyphase
Hydrotropism:- Chemotropism is a kind of tropic movement in which plants move in realtion to water. Ex: Roots of seedlings
Thignotropism:- Thignotropism is a kind of tropic movement in which plants move in realtion to contant or support. It is also know as haptotropism. Ex: Tendrils, Haustoria and Cuscuta
HORMONES IN ANIMALS
Gland
The special tissues or organs present in our body which secretes chemcial that control and coordinate the activity throughout the body are called glands.
There are two kinds of gland:-
i) Exocrine glands
ii) Endocrine glands
Exocrine glands:- Exocrine glands are the glands that secrete their product into a duct. Ex:- Salivary gland
Endocrine glands:- Endocrine glands are the glands that secrete their product directly into the blood. Ex:- Pituitary gland
Major Endocrine Glands
Pituitary gland:- Pituitary gland is a pea shaped gland located at the base of brain. It is considered as master of gland that secretes many hormones to regulate organs as well as the other glands.
Thyroid gland:- Thyroid gland is located in the neck region near larynx. It is the largest endocrine gland present in our body. It secretes thyroxine hormones. Thyroxine hormones regulates the metabolism of carbohydrates, protiens and fats in our body. Over secretion of thyroxine hormone leads to goitre disease in adults. Goitre is caused due to defection of iodne in food.
Parathyroid gland:- Parathyroid gland is composed of four small glands that are located behind the thyroids in the neck. They affect the calcium levels in the body by producing a hormone called Parathyroid Hormone. When the gland produces excess parathyroid hormones, it can develop negative effects such as brittle bones and kidney stones.
Adrenal gland:- Adrenal gland are found on top of each kidney. Adrenal gland help in increasing blood sugar levels, blood supply to the muscles, dilating the pupils, increasing the heart rate and tightening the jaw muscles.
Pancreas:- Pancreas is exocrine as well as an endocrine gland that sits behind the stomach. It is roughly 6 inches long and rather flat. It helps in producing digestive enzymes and producing hormones such as insulin and glucagon.
Hormones
The chemical substance secreted by the glands is called hormones.
Characteristics of hormones are:-
- Hormones which are secreted by endocrine glands are in very small amount.
- Hormones which are secreted by endocrine glands are directly secreted into blood and travel thoughout the body with the help of circulatory system.
- Hormones have their effect on the basis of the sites from where they are made.
- Hormones act as a specific tissues or organs.
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