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Control and Coordination - Control and coordination in animals

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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The nervous system and the endocrine system are the two main systems for control and coordination in animals.

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The Neuron is the structural and functional unit of the nervous system, consisting of the cell body (cyton), dendrites, and an axon.

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Synapse is the functional gap between two neurons where electrical impulses are converted into chemical signals using neurotransmitters to cross the gap.

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Reflex Action is a sudden, involuntary response to a stimulus, controlled mainly by the spinal cord. The pathway is called a Reflex Arc.

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The Human Brain is divided into the Forebrain (Cerebrum), Midbrain, and Hindbrain (Cerebellum, Pons, Medulla).

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The Cerebrum is the main thinking part of the brain, while the Cerebellum maintains posture and balance.

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Endocrine glands secrete hormones directly into the bloodstream. For example, the thyroid gland secretes ThyroxineThyroxine and the pancreas secretes InsulinInsulin.

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Feedback Mechanism regulates the timing and amount of hormone release. For example, the secretion of InsulinInsulin is regulated by the blood glucose levels.

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Iodine is essential for the synthesis of ThyroxineThyroxine hormone by the thyroid gland; its deficiency causes Goitre.

📐Formulae

Reflex Arc Sequence: Stimulus→Receptor→Sensory Neuron→Spinal Cord→Motor Neuron→Effector→Response\text{Reflex Arc Sequence: Stimulus} \rightarrow \text{Receptor} \rightarrow \text{Sensory Neuron} \rightarrow \text{Spinal Cord} \rightarrow \text{Motor Neuron} \rightarrow \text{Effector} \rightarrow \text{Response}

Electrical Impulse→At SynapseChemical Signal (Neurotransmitter)→Next NeuronElectrical Impulse\text{Electrical Impulse} \xrightarrow{\text{At Synapse}} \text{Chemical Signal (Neurotransmitter)} \xrightarrow{\text{Next Neuron}} \text{Electrical Impulse}

↑Blood Glucose Level→Pancreas (Islets of Langerhans)→↑Insulin secretion→↓Blood Glucose Level\uparrow \text{Blood Glucose Level} \rightarrow \text{Pancreas (Islets of Langerhans)} \rightarrow \uparrow \text{Insulin secretion} \rightarrow \downarrow \text{Blood Glucose Level}

💡Examples

Problem 1:

Why is the use of iodised salt advisable for humans?

Solution:

Iodine is required by the thyroid gland to synthesize the hormone ThyroxineThyroxine.

Explanation:

ThyroxineThyroxine regulates carbohydrate, protein, and fat metabolism in the body to provide the best balance for growth. If IodineIodine is deficient in our diet, there is a possibility that we might suffer from goitre, a disease characterized by a swollen neck.

Problem 2:

How does our body respond when AdrenalineAdrenaline is secreted into the blood?

Solution:

It prepares the body for 'fight or flight' by increasing heart rate and blood flow to muscles.

Explanation:

AdrenalineAdrenaline is secreted directly into the blood and carried to different parts of the body. The heart beats faster, resulting in a supply of more O2O_2 to our muscles. The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs, diverting the blood to our skeletal muscles.

Problem 3:

What is the difference between a reflex action and walking?

Solution:

Reflex action is an involuntary, rapid response, while walking is a voluntary action.

Explanation:

Reflex actions are controlled by the spinal cord and do not involve conscious thought (e.g., withdrawing a hand from a hot object). Walking is a voluntary action controlled by the hindbrain (Cerebellum for precision) and forebrain, involving complex coordination and conscious decision-making.