Revision Guide
Explore how organisms respond to stimuli and maintain homeostasis through the nervous and endocrine systems in the chapter on Control and Coordination.
Control and Coordination - Quick Look Revision Guide
Your 1-page summary of the most exam-relevant takeaways from Science.
This compact guide covers 20 must-know concepts from Control and Coordination aligned with Class X preparation for Science. Ideal for last-minute revision or daily review.
Key Points
Define reflex action with an example.
A reflex action is a rapid, automatic response to a stimulus without conscious thought. Example: Pulling hand away from a hot object.
Explain the structure of a neuron.
A neuron consists of dendrites (receive signals), cell body (processes signals), and axon (transmits signals). Synapses allow signal transfer between neurons.
State the function of the brain.
The brain controls voluntary actions, processes sensory information, regulates homeostasis, and is the center of thought and memory.
Describe the reflex arc.
A reflex arc is the neural pathway mediating a reflex action, involving sensory neurons, spinal cord, and motor neurons for quick response.
What is the role of the spinal cord?
The spinal cord transmits nerve signals between the brain and body and coordinates reflex actions independently of the brain.
Define hormones with an example.
Hormones are chemical messengers secreted by endocrine glands. Example: Insulin regulates blood sugar levels.
Explain phototropism in plants.
Phototropism is the growth of plant parts towards light, mediated by auxin hormone distribution, promoting cell elongation on the shaded side.
What is geotropism?
Geotropism is the growth response of plant parts to gravity, with roots growing downward (positive) and shoots upward (negative).
Describe the function of auxins.
Auxins promote cell elongation, root formation, and tropic movements in plants by uneven distribution in response to stimuli.
How do plants respond to touch?
Plants like Mimosa pudica respond to touch by rapid movement of leaves due to changes in turgor pressure, not growth.
State the function of adrenaline.
Adrenaline prepares the body for 'fight or flight' by increasing heart rate, blood flow to muscles, and energy availability.
What is the endocrine system?
The endocrine system consists of glands secreting hormones directly into the bloodstream to regulate body functions.
Explain the role of thyroxine.
Thyroxine regulates metabolism, growth, and development. Iodine deficiency can lead to goitre due to low thyroxine production.
Describe insulin's function.
Insulin, produced by the pancreas, lowers blood glucose levels by promoting glucose uptake in cells and storage as glycogen.
What are plant hormones?
Plant hormones (phytohormones) regulate growth, development, and responses to environmental stimuli. Examples: auxins, gibberellins.
How does the nervous system communicate?
The nervous system communicates via electrical impulses (neurons) and chemical signals (neurotransmitters at synapses).
What is the difference between voluntary and involuntary actions?
Voluntary actions are under conscious control (e.g., walking), while involuntary actions are automatic (e.g., heartbeat).
Explain the feedback mechanism in hormone regulation.
Hormone secretion is regulated by feedback loops where high levels inhibit further secretion, maintaining homeostasis.
What is hydrotropism?
Hydrotropism is the growth of plant roots towards water, optimizing water absorption for survival and growth.
Describe the role of the cerebellum.
The cerebellum coordinates voluntary movements, maintains posture, and ensures balance and muscle tone.
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