ch 7 class 10 science notes
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Explanation:
The human body is a complex machine performing tons of functions and processes to maintain and sustain life. Explore how the body controls its movements and coordinates its actions with other parts of the body and the environment by exploring notes for Class 10 Chapter 7 Control and Coordination.
The Nervous System
Movement in Organisms
The ability of organisms to move certain body parts is movement.
When they move from one place to another, it is called locomotion.
Organisms show movements in response to stimuli.
Introduction to Control & Coordination
Organisms move in response to various kinds of stimuli like light, heat, nutrients/food, etc.
All the activities in animals are controlled and coordinated by the nervous and endocrine systems.
Hormones are chemical messengers which assist the nervous system in carrying out various functions. They are secreted by endocrine glands.
Hormones in plants coordinate the movements.
For more information on Nervous System, watch the below video
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To know more about The Nervous System, visit here.
The Nervous System
Nervous system types
Neuron
Neuron is the structural and functional unit of the nervous system.
Each neuron has three main parts: dendrites, cyton/soma/cell body and axon.
Dendrites receive impulses from other neurons.
Cyton/soma processes the impulse.
Axon transmits the impulse, either to another neuron or to muscles/glands, etc.
Axon may be myelinated or non-myelinated.
The impulse transmission is faster in myelinated neurons.
CBSE Class 10 Science notes Chapter 7 - 1
Central Nervous System
The central nervous system (CNS) is made up of the brain and the spinal cord. The functions of different parts of the brain are:
The cerebrum is responsible for reasoning, logic, emotions, speech, memory, visual processing, recognition of auditory and taste stimuli, etc.
Cerebellum regulates and coordinates body movements, posture and balance.
Pons relays signals from the hindbrain to the forebrain.
Medulla Oblongata controls all involuntary movements like vomiting, sneezing, yawning, heartbeat, breathing, blood pressure, etc.
Medulla oblongata continues as the spinal cord, which runs through the vertebral column and it controls reflex actions.
CBSE Class 10 Science notes Chapter 7 - 2
Read more: Central Nervous System
Peripheral Nervous System
The nerves coming out from the brain and the spinal cord constitute the peripheral nervous system (PNS).
There are 12 cranial nerves and 31 spinal nerves in humans.
Read more: Peripheral Nervous System
Somatic Nervous System
It forms a part of the PNS.
The nerves of PNS that control the voluntary actions of the body form the somatic nervous system.
Autonomic Nervous System
All the nerves of the PNS that control the involuntary actions in the body form the autonomic nervous system. E.g. respiration, heart rate, blood pressure, digestion, etc., are regulated by the autonomic nervous system.
Two divisions of the autonomic nervous system are the sympathetic and parasympathetic nervous systems.
The sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response, while the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high-energy functions.
Reflex Action
Reflex action is a sudden, involuntary reaction of the body in response to stimuli.
To know more about Reflex Action, visit here.
Reflex Arc
It is the path followed by an electrical impulse during a reflex action.
The impulse travels from the receptor organ to the spinal cord/brain. It is processed there, and the information is brought back to the concerned muscle to carry out the action.
Thus, the receptor organ, sensory/afferent neuron, interneuron, motor/efferent neuron and effector organ are the components of a reflex arc.
CBSE Class 10 Science notes Chapter 7 - 3
Protection of CNS
The brain is protected by 3 main layers –
The bony skull (cranium)
The cerebrospinal fluid
The meninges (Dura mater, Arachnoid and Pia mater).
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Plant Hormones and Movements
Plant Hormones
Control and coordination in plants are carried out by hormones.
Plant Hormone Function
Auxin Helps in the growth of plant tissues
Cytokinin Promotes cell division, delays ageing of cells
Gibberellins Helps in the growth of stems, initiates seed germination, promotes flowering, cell division and seed growth after germination
Abscisic acid Inhibits growth and causes wilting of leaves, promotes dormancy of buds and seeds
Ethylene This is a gaseous hormone which causes the ripening of fruits
To know more about Plant hormones, visit here.
Growth Independent Movements
The movements which are not growth related are called nastic movements. These movements occur in response to environmental stimuli but the direction of response is not dependent on the direction of the stimulus.
The movement in the touch-me-not plant is thigmonastic movement (movement in response to touch).
Thigmonasty