Hormones
Master Chemical Coordination in Minutes: Explore how our body communicates over long distances using slow but long-lasting chemical signals. Learn about the major endocrine glands, their hormonal secretions, deficiency disorders, and the precision tuning of the feedback loop mechanism.
1.0Learning Outcomes
After completing this lesson, you will be able to:
- Define hormones and list the properties of the endocrine system.
- Contrast nervous system control with chemical (hormonal) coordination.
- Map major human endocrine glands, their target functions, and corresponding health disorders.
- Explain the physical mechanism of the "fight-or-flight" emergency response triggered by adrenaline.
- Describe how the homeostasis mechanism self-regulates blood sugar levels through a negative feedback loop.
2.0Introduction
Hormones are chemical messengers in your bloodstream. They are secreted by glands to regulate different physiological activities, including growth, metabolism, mood, reproduction and more. Hormonal imbalance can lead to several health conditions, which is why it is important to understand their functions and effects.
Hormones maintain homeostasis, the internal balance of your body. Each of them has a specific role, but it is their collective action that ensures your body functions smoothly. Read on to learn more about the hormones meaning, their functions, and more.
3.0Types of Hormones
Hormones, produced by endocrine glands, travel through the bloodstream to reach your organs and tissues. They influence bodily functions such as appetite, sleep, mood, reproduction, and others. These hormones bind to a specific receptor to interact with the target cells, which triggers changes in gene expression or cell behaviour.
Based on their function or chemical structure, they can be classified into the following types:
4.0Functions of Key Hormones
Almost every biological process is influenced by hormones. Let’s take a look at a few of the essential hormones and their roles:
Prolactin Hormone
Secreted by the pituitary gland, the prolactin hormone is responsible for producing milk in females after childbirth. In addition to this, it also affects immune system regulation and male fertility.
Any imbalance in this hormone can lead to reproductive dysfunction and galactorrhea (milk secretion without pregnancy).
Cortisol Hormone
Also known as the stress hormone, Cortisol is secreted by the adrenal glands. It is responsible for reducing inflammation, regulating metabolism, and responding to stress.
If you have a high level of cortisol hormone, it can result in weight gain, high blood pressure, and anxiety.
Estrogen Hormone
The estrogen or female sex hormone is produced by the ovaries and plays an important role in female reproductive health. It is also found in males in small amounts.
Low estrogen levels can cause hot flashes, irregular periods, and osteoporosis.
Growth Hormone
You need the growth hormone for your physical development. Produced by the anterior pituitary gland, it helps with tissue growth, metabolism, and cell regeneration.
In children, the deficiency of growth hormone can lead to dwarfism, while excess can cause acromegaly or gigantism.
Parathyroid Hormone
Secreted by the parathyroid glands, this hormone regulates phosphate and calcium levels in your blood and bones.
Imbalance in parathyroid hormone can result in muscle spasms, kidney stones, or bone fragility.
5.0Difference Between Happy Hormones and Stress Hormones
Hormones have an impact on both our physical and emotional well-being. Certain hormones help you feel joy and calm, and there are others that prepare you for stressful situations. Let’s take a look:
Happy Hormones
These hormones are responsible for regulating positive emotions, such as love, pleasure, motivation, and overall well-being. These include:
- Dopamine: Enhances pleasure, attention, and motivation. It's like a reward system for your brain.
- Serotonin: Improves your appetite, sleep, and mood. Low levels of serotonin have been linked to anxiety and depression.
- Oxytocin: Oxytocin, or the love hormone, promotes emotional closeness, trust, and bonding.
- Endorphins: Endorphins are natural painkillers and mood boosters. They are commonly released during exercise.
To elevate the happy hormones, you need to engage in activities like exercise, meditation, laughing, listening to music, and more. It improves your overall mental health.
Stress Hormones
These hormones are released in response to danger or perceived threats. While they are essential for survival, prolonged elevation can have a negative impact on health.
- Cortisol: Known as the primary stress hormone, it increases blood sugar and energy availability but can contribute to anxiety and fatigue when persistently high.
- Adrenaline: Prepares the body for immediate action, increasing heart rate and alertness in a “fight-or-flight” response.
Maintaining a balance between happy and stress hormones is crucial for emotional stability and overall well-being.
6.0Diseases Caused by Hormonal Imbalances
Even slight changes in hormone levels can disrupt the body's internal balance and lead to various health conditions. Some of the most common hormone-related disorders include:
- Diabetes Mellitus: Triggered by either a lack of insulin or the body’s inability to utilise it effectively, this condition results in elevated blood sugar levels. It is primarily a disorder of the pancreas.
- Hyperthyroidism: Caused by an overactive thyroid gland, it speeds up the body's metabolism. Symptoms include rapid heartbeat, unintended weight loss, irritability, and restlessness.
- Hypothyroidism: When the thyroid is underactive, metabolism slows down. Individuals may experience fatigue, weight gain, dry skin, and sensitivity to cold.
- Osteoporosis: Often associated with reduced levels of estrogen or testosterone, this condition weakens bones and increases the risk of fractures, especially in older adults.
- Acromegaly: This condition occurs when growth hormone is produced in excess during adulthood, resulting in enlarged facial features, hands, and feet.
- Gigantism: A rare disorder caused by too much growth hormone during childhood, resulting in excessive growth and abnormal height.
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8.0Supporting Study Materials
This study material CBSE Notes and NCERT Solutions for the Chapter "Control and Coordination" on Hormones Topics is designed according to the latest CBSE Class 10 Science syllabus and NCERT guidelines. It provides clear explanations of key concepts, definitions, examples, and important questions to help students understand animal hormones (endocrine system), plant hormones (phytohormones), and feedback mechanisms, and prepare effectively for examinations.reactions, corrosion, and rancidity, and prepare effectively for examinations.
9.0PREVIOUS YEAR QUESTIONS (PYQs)
Q1. Why is the use of iodized salt specifically advised by medical professionals? Explain the biological reason. (CBSE Board)
Answer
- The use of iodized salt is highly advised because iodine is an indispensable element required by the thyroid gland to manufacture the hormone thyroxine.
- Thyroxine plays a vital role in regulating carbohydrate, fat, and protein metabolism, ensuring balanced physical and mental growth in the human body.
- If our daily diet is deficient in iodine, the thyroid gland cannot produce adequate thyroxine. Consequently, the gland swells up in an attempt to capture more iodine, causing a clinical condition called goitre, which is characterized by a noticeably swollen neck.
Q2. How does our body respond internally when adrenaline is suddenly secreted into the bloodstream? (CBSE Board)
Answer: When adrenaline is secreted into the blood during an emergency, it initiates a "fight-or-flight" mechanism through several concurrent steps:
- Heart Rate Spikes: The heart beats much faster, increasing the delivery of oxygen and glucose to active skeletal muscles.
- Blood Diversion: Smooth muscles surrounding small arteries in the digestive organs and skin contract. This action curtails local circulation and diverts the bulk of the blood flow to the limbs to facilitate immediate physical action.
- Breathing Accelerates: The respiration rate climbs significantly due to rapid movements of the diaphragm and rib cage muscles, maximizing oxygen intake.
- Energy Mobilization: Glucose is quickly released from liver reserves into the blood, providing the necessary energy to handle the emergency situation.
10.0Recommended Next Topics
- Central Nervous System (Brain and Spinal Cord anatomy)
- Reflex Action and the Reflex Arc pathway
- Coordination in Plants (Tropic Movements and Phytohormones)
- Human Reproduction and Pubertal Hormonal Shifts