It is essential to know the target of hormones released by Endocrine glands.let us know in detail class 10 Biology chapter Control and coordination
Here's a breakdown of some endocrine glands, their hormones, and their target organs and tissues:
1. Pituitary Gland:
- Hormones: Growth Hormone (GH), TSH, ACTH, etc.
- Target Organs/Tissues: GH targets bones and muscles, TSH targets the thyroid gland, ACTH targets the adrenal cortex.
2. Thyroid Gland:
- Hormones: Thyroxine (T4), Triiodothyronine (T3).
- Target Organs/Tissues: T4 and T3 target almost all body cells to regulate metabolism.
3. Adrenal Glands:
- Hormones: Cortisol, Epinephrine, Aldosterone, etc.
- Target Organs/Tissues: Cortisol affects various tissues, Epinephrine affects the heart and blood vessels, Aldosterone targets the kidneys.
4. Pancreas:
- Hormones: Insulin, Glucagon.
- Target Organs/Tissues: Insulin targets liver, muscle, and fat cells, while Glucagon targets the liver.
5. Ovaries (in females) and Testes (in males):
- Hormones (Ovaries): Estrogen, Progesterone.
- Hormone (Testes): Testosterone.
- Target Organs/Tissues (Females): Estrogen and Progesterone target the uterus, breasts, and other reproductive tissues.
- Target Organs/Tissues (Males): Testosterone targets the male reproductive organs and secondary sex characteristics.
6. Pineal Gland:
- Hormone: Melatonin.
- Target Organs/Tissues: Melatonin influences various tissues, mainly regulating sleep-wake cycles.
7. Hypothalamus :
- Produces and controls hormones that influence the pituitary gland, which, in turn, affects other endocrine glands and their target organs/tissues.
These glands and their hormones work together to regulate and control numerous bodily functions, maintaining a balanced internal environment.
The feedback mechanism of hormone action is like a control system that helps maintain balance in the body.
There are two types of feedback mechanisms:
1. Negative Feedback:
- This is the most common type.
- It works to maintain homeostasis (a stable internal environment).
- When a hormone's level in the bloodstream rises, it triggers a response to decrease its production or release.
- Conversely, if hormone levels drop below a certain threshold, it stimulates their production or release.
- Example: Blood sugar regulation by insulin and glucagon. When blood sugar rises after eating, insulin is released to bring it down. If blood sugar falls too low, glucagon is released to raise it.
2. Positive Feedback:
- This is less common and amplifies a response.
- Instead of maintaining balance, it often pushes a process to completion.
- When a hormone's level rises, it triggers a response that further increases its production or release.
- Example: Oxytocin during childbirth. As contractions occur, oxytocin is released, which intensifies contractions, leading to birth. This continues until the baby is delivered.
These feedback mechanisms are crucial in ensuring that hormone levels stay within a narrow range, allowing the body to function optimally. They help prevent excessive hormone production and maintain stability.
1.Q. A boy runs on seeing a stray dog. His breathing becomes very fast and blood pressure also increases. Name the
hormone found to be high in his blood and the gland which produces it.
Ans. Adrenaline, Adrenal gland.
2.Q.Name the diseases by which a person is likely to suffer due to the deficiency of (a) Iodine (b) Insulin
Ans. (a) Goitre (b) Diabetes
3.Q.How does our body maintain blood sugar level?
Ans. If sugar levels in blood rises, cells of pancreas detect and secrete more insulin which leads to fall off sugar level.
4.Q.Name the hormone responsible for the regulation of
(i) metabolism of carbohydrates, fats and proteins,
(ii) balance of calcium and phosphate,
(iii) blood pressure,
(iv) water and electrolyte balance.
Ans. (i) Thyroxine
(ii) Parathormone
(iii) Adrenaline
(iv) Vasopressin or ADH (Antidiuretic hormone)
5.Q.Explain with the help of an example how the timing and amount of hormone released are regulated?
Ans. The timing and amount of hormone released are regulated by feedback mechanisms. For e.g. when there is rise
in sugar level in blood, insulin secreted by pancreas. If sugar lavel in blood fall , insulin secretion is reduced.
6. Q.Name the hormone that is secreted by our body to deal with scary situations. List any two responses shown by our
body when this hormone is secreted into the blood.
Ans. Adrenaline.
Two responses :
(i) It acts on heart due to which heart beasts faster, resulting in supply of more oxygen to our wooden.
(ii) The breathing rate increases because of the contractions of the diaphragm and the rib muscles
(iii)The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these
organs.
🎈Happy Learning!🎈
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