Control and Coordination - Class 10 Notes

Introduction

• The human body is a complex machine performing functions to sustain life.
• Control and coordination involve the body's movement and interactions with the environment.

The Nervous System

Movement in Organisms

• Movement: Ability to move certain body parts.
• Locomotion: Movement from one location to another.
• Movements occur in response to stimuli.

Components of Control and Coordination

• Stimuli: Light, heat, nutrients, etc.
• Controlled by the nervous and endocrine systems.
• Hormones: Chemical messengers, secreted by endocrine glands, assist the nervous system.

Neuron

• Basic unit of the nervous system.
• Consists of dendrites, cyton/soma, and axon.
• Dendrites: Receive impulses.
• Cyton/Soma: Processes impulses.
• Axon: Transmits impulses.

Central Nervous System (CNS)

• Composed of the brain and spinal cord.
• Brain functions:
  • Cerebrum: Reasoning, emotions, memory.
  • Cerebellum: Movement coordination, balance.
  • Pons: Signal relay.
  • Medulla Oblongata: Controls involuntary actions.

Peripheral Nervous System (PNS)

• Nerves from brain and spinal cord.
• 12 cranial nerves, 31 spinal nerves.

Somatic and Autonomic Nervous Systems

• Somatic: Controls voluntary actions.
• Autonomic: Controls involuntary actions (e.g., heart rate, digestion).
• Divided into sympathetic (fight-or-flight) and parasympathetic (relaxation).

Reflex Action and Reflex Arc

• Reflex Action: Sudden, involuntary body response to stimuli.
• Reflex Arc: Pathway of impulses during reflex actions.

Protection of CNS

• Brain protected by skull, cerebrospinal fluid, and meninges.

Plant Hormones and Movements

Plant Hormones

• Control and coordination in plants done by hormones:
  • Auxin: Growth of plant tissues.
  • Cytokinin: Promotes cell division.
  • Gibberellins: Stem growth, seed germination.
  • Abscisic Acid: Inhibits growth, wilting.
  • Ethylene: Fruit ripening.

Movements in Plants

• Nastic Movements: Non-growth related, response to stimuli.
• Tropic Movements: Growth-related, direction-dependent on stimulus.
  • Phototropism: Light-dependent.
  • Geotropism: Gravity-dependent.
  • Hydrotropism: Water-dependent.
  • Chemotropism: Chemical-dependent.
  • Thigmotropism: Touch-dependent.

The Endocrine System

Exocrine and Endocrine Glands

• Exocrine: Secrete through ducts.
• Endocrine: Ductless, secrete directly into bloodstream.

Major Endocrine Glands

• Pituitary: Controls other glands, secretes Growth Hormone.
• Thyroid: Secretes Thyroxine, regulates metabolism.
• Pancreas: Produces insulin and glucagon, regulates blood sugar.
• Adrenal: Secretes adrenaline for fight-or-flight.
• Gonads: Testes (testosterone) and ovaries (oestrogen, progesterone).

Other Endocrine Organs

• Include hypothalamus, parathyroid, pineal, thymus glands.

FAQs

Function of CNS

• CNS controls body and mind functions.

Facts about the Human Brain

• 60% fat, 100 billion neurons.

Parts of the Human Eye

• Consists of 7 parts.