Control and Coordination in Animals .Part 1.pptx

The PPT for the chapter "Control and Coordination" of Class 10 Biology

1. In animals control and co ordination is done by nervous system and endocrine system. Nervous System: The nervous system is an organ system containing a network of specialized cells called neurons . Types of nervous system: Central Nervous System(CNS): It includes Brain and Spinal Cord. Peripheral Nervous System(PNS): It includes a)Somatic Nervous System(SNS): It is also known as voluntary nervous system and is associated with the voluntary control of the body movements via skeletal muscles.It includes Cranial nerves and Spinal nerves Cranial nerves -12 pairs arises from the brain Spinal nerves -31 pairs arises from the spinal cord b)Autonomic Nervous System(ANS): It is also known as involuntary nervous system in which sensory and motor neurons plays an important role. It is sub divided into i)Sympathethic nervous system (for fight , flight) ii)Parasympathetic nervous system (for rest , digest).

2. Neurons(Nerves): The structural and functional unit of nervous system is called as neurons.

3. It has a cell body called cyton containing a nucleus and cytoplasm.It has several branched structures called dendrites. It has a long nerve fibre called axon which may covered by Schwann cells and a protective covering called Myelin sheath .Schwann cells are separated by a gap called as Nodes of Ranvier .Neuron ends by bulb like structure at nerve ending called as Synaptic Knob . Synaptic knob consists of several vesciles called as Synaptic vesciles , which contain the chemical for pass on the information , called as Neurotransmitters . Example . Acetyl choline.

4. Synapse : The junction between two neurons or with muscles is called synapse .

5. Nerve Impulse – Messages pass through the nerve cell in form of chemical and electrical signals called nerve impulse.The dendrites receive the information and starts a chemical reaction which produce electrical impulse which pass through axon.

6. Reflex action is a sudden , unconcious and involuntary response of the effectors to a stimulus. Ex. We suddenly withdraw our hand if we suddenly touch a hot object. In this reflex reaction , the nerves in the skin(receptor) detects the heat and passes the message through the sensory nerves to the spinal cord.Then the information passes through the motor nerves to the muscles (effector) of the hand and we withdraw our hand.

7. Reflex arc The pathway of a reflex action is called as reflex arc . In a reflex arc the stimulus is received by the receptors (sense organs) and it passes through the sensory nerves to the spinal cord. From the spinal cord the information passes through motor nerves to the effectors (muscles/glands) for the response.

8. The brain plays no action as the reflex action takes place at the level of spinal cord.But later brain is informed by the spinal cord and then later the thinking part of the action is done by brain.But brain is not active during a reflex action. Difference between Reflex action and Walking. Reflex action:It is inborn,involuntary(automatic) and require for survival and protection. Walking:It is acquire by learning , under control of brain(voluntary) and for various function.

9. The brain is the main coordinating centre in the human body. It is protected by the cranium . It is covered by three membranes called meninges filled with a fluid called cerebrospinal fluid which protects the brain from shocks. The brain has three main parts. They are fore brain, mid brain and hind brain . i) Fore brain :- consists of the cerebrum and Thalamus. It is the thinking part of the brain and controls voluntary actions.It controls touch, smell, hearing, taste, sight, mental activities like thinking, learning, memory, emotions etc . ii) Mid brain :- controls involuntary actions and reflex movements of head, neck, eyes etc . iii) Hind brain :- consists of cerebellum, pons and medulla . Cerebellum :- controls body movements, balance and posture. Pons :- controls respiration. Medulla :- controls heart beat, blood pressure, swallowing, coughing, sneezing, vomitting etc.

10. The spinal cord starts from the brain and extendsthrough the vertebral column. It has 31 pairs of spinal nerves. It carries messages to and from the brain. It also controls reflex actions.

11. Muscles are 3 types- Skeletal muscles ( Voluntary muscles /Striated muscles)- attached with bones & having alternate dark and light bands. Smooth muscles ( Involuntary muscles .Non striated muscles) present in internal body organs. Cardiac muscles- present in heart Nerve impulse reaches to muscle which resulted into muscular action.