Feedback Mechanism in Hormones
The conditions inside the hormones are altered in response to a stimulus. The hormones are responsible for regulating the internal body temperature. A feedback mechanism tends to speed up or inherit a procedure. Among most of the hormones, this loop usually provides negative feedback.
Negative Feedback Mechanism
Negative feedback mechanism occurs when the original effect of the stimulus is less by the output.
Negative feedback mechanisms smoothen things when they start becoming too extreme. Example of a negative feedback mechanism is the thyroid gland that is regulated by a negative feedback mechanism.
The hormone secreted by the hypothalamus stimulates the pituitary gland to release thyroid stimulating hormone.
In turn, the thyroid stimulating hormone triggers the thyroid gland to release its hormones.
When there is an increase in the thyroid levels, the hormones put a hold on the secretion of TRH by the hypothalamus and secretion of TSH by the pituitary gland by the feedback mechanism.
The hormone secretion by the thyroid gland is inhibited without the stimulation of TSH.
The thyroid hormone levels fall very low.
The secretion insulin by the pancreas is also being controlled by the negative feedback mechanism.
Positive Feedback Mechanism
It takes place when the original effect of the stimulus is enhanced by the output.
The conditions become extreme in this mechanism.
When milk is secreted by a mother’s mammary glands that is an example of a positive feedback mechanism.
While suckling, the nerve sends signals from the nipple to stimulate the pituitary gland to secrete prolactin.
In turn, prolactin triggers the mammary glands to secrete milk.
As the baby suckles more milk, more prolactin is secreted and more milk is produced.
What are Hormones?
The essential chemicals that are secreted from our body for the smooth functioning of the body are called Hormones. These chemicals are secreted from a gland known as the Endocrine Glands which are distributed throughout the body. These chemicals control many functions like physiological and psychological. Hormones are very important for maintaining a balance in the body.
Functions of Hormones
Some of the important functions of hormones are the following -
It helps in food metabolism.
It helps in the growth and development of the body
Helps in controlling the thirst and hunger.
Maintaining body temperature.
Regulating mood and cognitive functions.
Initiating and maintaining sexual development and reproduction.
List of Important Hormones
Estrogen- Also, termed as the sex hormone in women, this hormone helps in bringing out puberty, prepared the uterus and body for pregnancy and also helps in regulating periods. As the level of estrogen changes in women during menopause, they might feel a little uncomfortable.
Progesterone – This hormone is also a female sex hormones which functions for the regulation of the menstrual cycle leading to pregnancy and embryo genesis.
Cortisol – This is the hormone that is present in our body and shows symptoms when we are tensed, called the Stress Hormones. This hormone increases the blood sugar, increases the heart rate and makes the body shiver.
Melatonin – Primarily circadian rhythm or sleep cycles are controlled by this hormone.
Testosterone – The feeling of sex that is caused during pubery in men is caused by Testosterones. muscle mass growth, and strength, increase in bone density and facial hair growth, all are controlled by this hormone in men.
FAQs on Feedback Mechanism in Hormones
1. What is a feedback mechanism in the context of hormones?
A feedback mechanism is a biological regulatory system where the body uses the output of a process to control its own operation. In the endocrine system, this means the level of a specific hormone in the blood can either inhibit (negative feedback) or stimulate (positive feedback) its own further release, ensuring hormone levels are maintained within a precise range for proper bodily function.
2. What is the main difference between positive and negative feedback mechanisms in the endocrine system?
The main difference lies in the response to the stimulus. A negative feedback mechanism counteracts the original stimulus to restore balance (homeostasis); for instance, high blood sugar triggers insulin release, which lowers blood sugar. A positive feedback mechanism, which is much rarer, amplifies the original stimulus, pushing the body further from its normal state to complete a specific process, such as the release of oxytocin during childbirth.
3. Can you give a classic example of a negative feedback mechanism involving hormones?
A classic example is the regulation of thyroid hormones. Here’s how it works:
The hypothalamus releases TRH (Thyrotropin-releasing hormone).
TRH stimulates the pituitary gland to release TSH (Thyroid-stimulating hormone).
TSH travels to the thyroid gland and stimulates the release of thyroid hormones (T3 and T4).
When T3 and T4 levels in the blood rise, they inhibit the release of both TRH from the hypothalamus and TSH from the pituitary. This shutdown prevents overproduction and maintains stable hormone levels.
4. What is a key example of a positive feedback mechanism in the human body?
The most common example of positive feedback is the release of oxytocin during labour. When the baby's head presses against the cervix, nerve impulses are sent to the brain. This stimulates the pituitary gland to release oxytocin, which causes stronger uterine contractions. These stronger contractions push the baby's head further, triggering even more oxytocin release. This amplifying cycle continues until the baby is born, which removes the initial stimulus.
5. How is the timing and amount of hormone release regulated in the body as per the CBSE 2025-26 syllabus?
According to the CBSE syllabus for the 2025-26 session, the timing and amount of hormone secretion are precisely regulated by feedback mechanisms. The body continuously monitors hormone levels and the conditions they control. If a hormone level deviates from the set point, the endocrine glands are signalled to either increase or decrease secretion until balance is restored, ensuring hormones are released only when needed and in the right quantity.
6. Why is the negative feedback mechanism more common for hormone regulation than the positive feedback mechanism?
Negative feedback is more common because its primary function is to maintain homeostasis—a stable internal environment. It acts like a thermostat, correcting any deviation from a set point. Positive feedback, on the other hand, is destabilising as it pushes the body away from its normal state. It is only useful for specific, short-term events like childbirth or blood clotting, where a rapid, amplifying process is needed to reach a conclusion.
7. How does the hypothalamus-pituitary axis use a feedback loop to act as a 'master controller'?
The hypothalamus-pituitary axis is a central command centre. The hypothalamus secretes 'releasing' or 'inhibiting' hormones that control the pituitary gland. The pituitary, in turn, releases tropic hormones (like TSH or ACTH) that target other endocrine glands (like the thyroid or adrenal gland). The hormones produced by these target glands then feed back to the hypothalamus and pituitary, inhibiting their activity. This hierarchical control and feedback loop allows the brain to precisely manage multiple complex hormonal pathways throughout the body.
8. What would happen if the negative feedback mechanism for insulin failed?
If the negative feedback for insulin failed, it would lead to a serious metabolic disorder like Type 2 diabetes. Normally, high blood glucose after a meal triggers insulin release, which then lowers glucose levels, and this drop in glucose stops further insulin release. If this feedback loop breaks, either the body's cells become resistant to insulin or the pancreas doesn't produce enough. Consequently, blood glucose levels would remain dangerously high (hyperglycemia), as there is no effective signal to absorb glucose from the blood or to shut down glucose production by the liver.
