Short Notes -Class 10 -Science- Biology-Chapter 6 – Control and Coordination

Class 10 -Science- Short Notes – Biology-Chapter 6 -Control and Coordination

Introduction:

• The human body is a complex machine performing numerous functions and processes to sustain life.
• Control and coordination mechanisms enable the body to regulate movements and coordinate actions with the environment.

Movement in Organisms:

• Movement refers to the ability of organisms to move body parts.
• Locomotion occurs when organisms move from one place to another.
• Organisms exhibit movements in response to various stimuli.

Introduction to Control & Coordination:

• Organisms respond to stimuli such as light, heat, and nutrients.
• Activities in animals are controlled and coordinated by the nervous and endocrine systems.
• Hormones, secreted by endocrine glands, assist the nervous system in various functions.
• In plants, hormones coordinate movements.

The Nervous System:

• Neuron is the structural and functional unit of the nervous system.
• It comprises dendrites, cyton/soma/cell body, and axon.
• Impulses are received by dendrites, processed in the cyton/soma, and transmitted via the axon.
• Myelinated neurons transmit impulses faster.
• The central nervous system (CNS) consists of the brain and spinal cord.

Peripheral Nervous System: 

• Nerves outside the CNS constitute the peripheral nervous system (PNS).
• Includes 12 cranial and 31 spinal nerves in humans.
• Somatic nervous system controls voluntary actions, while the autonomic nervous system regulates involuntary actions.

Reflex Action: 

• Reflex action is a sudden, involuntary reaction to stimuli.
• Reflex arc involves the path of an electrical impulse during a reflex action.
• Components include receptor organ, sensory/afferent neuron, interneuron, motor/efferent neuron, and effector organ.

Protection of CNS: 

The brain is protected by the bony skull, cerebrospinal fluid, and meninges.

Plant Hormones and Movements:

•  Hormones regulate control and coordination in plants.
• Examples include auxin, cytokinin, gibberellins, abscisic acid, and ethylene.
• Movements in plants include growth-independent (nastic) and growth-related (tropic) movements.

The Endocrine System:

• Endocrine glands secrete hormones directly into the bloodstream.
• Pituitary gland is the master gland, controlling other endocrine glands.
• Thyroid gland regulates metabolism, and deficiency leads to goitre.
• Pancreas secretes insulin and glucagon to regulate blood sugar.
• Adrenal glands produce adrenaline for fight-or-flight response.
• Gonads produce testosterone and estrogen, regulating sexual characteristics and gamete production.

◆Coordination: The integrated function of various systems in the body is termed coordination.

◆Chemical Coordination: This aspect is observed in both plants and animals.

◆Plant Response: Responses and coordination in plants manifest as slow growth and turgor movements.

◆Tropic Movements: Organisms move towards or away from stimuli in tropic movements, which include phototropism (in response to light), geotropism (gravity), hydrotropism (water), chemotropism (chemicals), and thigmotropism (touch).

◆Plant Hormones: Chemical messengers called hormones regulate plant responses and growth. Key plant hormones and their functions include:

• Auxins: Promote cell elongation, cell division, etc.
• Gibberellins: Act as growth hormones in plants.
• Cytokinins: Stimulate cytokinesis.
• Abscisic Acid: Inhibits growth.

◆Animal Response: Animal response and coordination involve the sense organs, nervous system, and hormones.

◆Feedback Mechanism: Hormonal action in animals is regulated by a feedback mechanism.