Chemical Coordination (Animal Hormones) MCQs Quiz | Class 10
This quiz is designed for Class X Science students (Code 086), focusing on Unit II: World of Living. Specifically, it covers the topic of Chemical Coordination (Animal Hormones), including an overview of the endocrine system and the basic roles of various hormones. Test your knowledge on these fundamental concepts and download a detailed answer PDF for revision.
Educational Content: Chemical Coordination in Animals
Chemical coordination in animals is primarily achieved through the endocrine system, which consists of ductless glands that secrete chemical messengers called hormones directly into the bloodstream. These hormones travel to target organs or cells, regulating various physiological processes like growth, metabolism, reproduction, and stress responses.
The Endocrine System: An Overview
The endocrine system works alongside the nervous system to control and coordinate body functions. While the nervous system provides rapid, short-term responses, the endocrine system provides slower, long-lasting effects. Key components include:
- Endocrine Glands: Specialized organs (e.g., pituitary, thyroid, adrenal, pancreas, gonads) that produce and secrete hormones.
- Hormones: Chemical substances that act as messengers, carrying signals from one part of the body to another to influence specific target cells.
- Target Cells/Organs: Cells or organs that have specific receptors for particular hormones, allowing them to respond to the hormonal signal.
Major Hormones and Their Roles
Here’s a basic overview of some important hormones and the glands that produce them:
| Gland | Hormone(s) | Primary Role(s) |
|---|---|---|
| Pituitary Gland | Growth Hormone (GH), TSH, FSH, LH, Prolactin | Regulates growth and development; controls other endocrine glands (master gland). |
| Thyroid Gland | Thyroxine | Regulates metabolism, growth, and development. Requires iodine for synthesis. |
| Adrenal Gland | Adrenaline (Epinephrine), Cortisol | Prepares body for ‘fight or flight’ response (stress hormones); regulates metabolism. |
| Pancreas | Insulin, Glucagon | Regulates blood sugar levels. Insulin lowers blood glucose, Glucagon raises it. |
| Testes (Males) | Testosterone | Responsible for male secondary sexual characteristics and sperm production. |
| Ovaries (Females) | Estrogen, Progesterone | Responsible for female secondary sexual characteristics and menstrual cycle regulation. |
Feedback Mechanism
Hormone secretion is tightly regulated by feedback mechanisms. Most commonly, negative feedback loops are involved. For example, when the level of a hormone in the blood rises, it inhibits further release of that hormone, preventing overproduction. Conversely, low levels stimulate further release.
Quick Revision Points
- Endocrine glands are ductless glands.
- Hormones are chemical messengers.
- Pituitary is the ‘master gland’ controlling others.
- Thyroxine requires iodine.
- Adrenaline prepares the body for emergencies.
- Insulin and Glucagon maintain blood sugar balance.
- Testosterone and Estrogen control sexual development.
- Feedback mechanisms regulate hormone levels.
Extra Practice Questions
- Which gland is often referred to as the ‘master gland’ because it controls the functions of many other endocrine glands?
- A person is suffering from diabetes. Which hormone is deficient in their body, and which organ produces it?
- What is the role of adrenaline in the human body, especially during stressful situations?
- Why is it important for our diet to contain iodine?
- Name the two hormones produced by the pancreas and state their opposing functions regarding blood sugar regulation.
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