the endocrine glands and the hormones they secrete

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how does hypothalamus regulate the secretion of hormones from anterior lobe of pituitary gland?

-hypothalamus secretes releasing factors, which stimulate hormone secretion, -and inhibiting factors, which slow down hormone secretion -these factors travel through blood vessels to anterior lobe of pituitary gland, influencing its hormone production

How does the posterior lobe of the pituitary gland release hormones?

The posterior lobe of the pituitary gland is connected to the hypothalamus by nerve fibres. The hypothalamus produces hormones that travel along these nerve fibres to the posterior lobe, where they are stored and then released into the bloodstream. Unlike the anterior lobe, the posterior lobe does not secrete hormones but simply stores and releases them.

What hormones are released by anterior lobe from pituitary gland

gonadotropins FSH LH GH (growth hormone) TSH (thyroid stimulating hormone) ACTH (Adrenocorticotropic hormone) Prolactin (PRL)

What are the roles of follicle-stimulating hormone (FSH) and luteinising hormone (LH) in males and females?

In females, FSH stimulates the development of ovarian follicles containing eggs, while LH, triggers ovulation and the formation of the corpus luteum. In males, FSH stimulates the production and maturation of sperm, and LH stimulates interstitial cells in the testes to secrete male sex hormones. Signup and view all the answers

What is the function of growth hormone (GH) in the body?

Growth hormone (GH) stimulates body growth, particularly the growth of the skeleton. It also increases the rate at which amino acids are taken up by cells and built into proteins. GH continues to be secreted throughout life to help maintain the size of organs after maturity is reached. Signup and view all the answers

What is the role of thyroid-stimulating hormone (TSH)?

Thyroid-stimulating hormone (TSH) stimulates the production and release of hormones from the thyroid gland, which regulate metabolism and energy production in the body. Signup and view all the answers

What does adrenocorticotropic hormone (ACTH) do?

Adrenocorticotropic hormone (ACTH) controls the production and release of hormones from the cortex of the adrenal glands, which are involved in stress responses, metabolism, and immune function. Signup and view all the answers

What is the function of prolactin (PRL) in females?

Prolactin (PRL) works with other hormones to initiate and maintain milk production in females after childbirth. Signup and view all the answers

Q: Describe the pathway and process by which the hormones oxytocin and antidiuretic hormone (ADH) are produced, transported, and released by the posterior pituitary gland.

A: Oxytocin and ADH are produced in specialized nerve cells in the hypothalamus, not the posterior pituitary itself. These hormones travel down the long extensions of the hypothalamic neurons, passing through the infundibulum and reaching the posterior pituitary, where they are stored. Their release into the bloodstream is triggered by nerve impulses initiated in the hypothalamus, which are conducted along these cell extensions to the posterior pituitary. Signup and view all the answers

Q: Explain the main functions of oxytocin and ADH (also known as vasopressin) in the human body and how they affect different organs.

A: Oxytocin primarily stimulates contractions of the uterus, especially during labor, facilitating childbirth. It also promotes the release of milk from the mammary glands by causing contraction of milk ducts during breastfeeding. ADH, or vasopressin, influences the kidneys by promoting the reabsorption of water from urine back into the bloodstream, helping to maintain fluid balance in the body. At higher concentrations, ADH causes the constriction of small arteries (arterioles), which is why it is also called vasopressin. Signup and view all the answers

Q: Discuss the structural relationship between the hypothalamus and the posterior pituitary, including the specific roles of nerve cells, the infundibulum, and blood vessels in hormone storage and release.

A: The hypothalamus contains the cell bodies of nerve cells that produce oxytocin and ADH, which are transported down their long nerve extensions to the posterior pituitary through a stalk-like structure called the infundibulum. Once in the posterior pituitary, these hormones are stored until they are triggered for release. Blood vessels connected to the posterior pituitary allow the hormones to enter the bloodstream directly when released, thus reaching their target organs and exerting their physiological effects. Signup and view all the answers

what hormones does the thyroid secrete, target cells and main effects?

thyroxine–most body cells– increase metabolic rate and hence oxygen consumption and heat production triiodothyronine Calcitonin–bones, kidney– decreases calcium and phosphate levels in blood Signup and view all the answers

what hormones does the parathyroid secrete, target cells and main effects

parathyroid hormone–bones, kidney– increases level of calcium in blood Signup and view all the answers

what hormone does thymus secrete, target cells and main effects

thymosins–T-lymphocytes– stimulates development and maturation of T-lymphocytes Signup and view all the answers

what hormones does adrenal cortex produce, target cells and main effects

corticosteroids, including Aldosterone–kidney– increases reabsorption of sodium ions and excretion of potassium ions cortisol–most body cells– promotes normal metabolism; helps body deal with stress; promotes repair of damaged tissues Signup and view all the answers

hormone secreted by adrenal medulla, target cells and main effects?

Adrenaline and non-adrenaline– most body tissues– prepares the body for fight-or-flight responses; reinforces the effects of the sympathetic nervous system Signup and view all the answers

what hormones does pancreas secrete, target cells, main effects

insulin-most body cells- stimulates uptake of glucose; lowers blood glucose level glucagon-liver and fat storage tissues- stimulates breakdown of glycogen and fat; increases blood glucose level Signup and view all the answers

what hormones does testes secrete, target cells, main effects

androgens e.g. testosterone– many tissues– stimulates sperm production, growth of skeleton and muscles, and development of male sexual characteristics Signup and view all the answers

what hormones does the ovaries secrete, target cells, main effects

oestrogen–many tissues- stimulate development of female sexual characeristics; regulate the menstrual cycle progesterone- uterus and mammary glands- regulates menstrual cycle and pregnancy; prepares mammary glands for milk secretion Signup and view all the answers

Explain why people who suffer from hyperthyroidism (overactive thyroid) experience weight loss.

People with hyperthyroidism experience weight loss because the thyroid gland produces excessive amounts of thyroid hormones (like T3 and T4), which increase the body's metabolism. This heightened metabolic rate accelerates the breakdown of nutrients, causing the body to burn more calories at rest and during activity. As a result, even with normal or increased food intake, individuals may still lose weight. Signup and view all the answers

8 Explain how insulin and glucagon are able to keep blood glucose at the correct level.

Insulin and glucagon work together to regulate blood glucose levels through a negative feedback system. When blood glucose levels rise, such as after eating, the pancreas releases insulin, which facilitates the uptake of glucose into cells for energy or storage as glycogen in the liver and muscles. When blood glucose levels drop, such as between meals or during fasting, the pancreas releases glucagon, which signals the liver to convert stored glycogen back into glucose and release it into the bloodstream, keeping blood glucose within a normal range. Signup and view all the answers

10 Explain how the body is able to maintain a consistent level of calcium in the blood.

The body maintains consistent blood calcium levels through the actions of the parathyroid hormone (PTH), calcitonin, and vitamin D. When blood calcium levels are low, the parathyroid glands release PTH, which increases calcium levels by stimulating bone resorption (release of calcium from bones), enhancing calcium reabsorption in the kidneys, and activating vitamin D to increase calcium absorption from the intestine. When calcium levels are high, the thyroid gland releases calcitonin, which inhibits bone resorption and encourages calcium storage in bones, reducing blood calcium levels. These mechanisms keep calcium levels balanced. Signup and view all the answers

Hypothalamus hormone regulation

The hypothalamus regulates anterior pituitary hormone secretion via releasing and inhibiting factors carried in blood vessels.

Posterior pituitary hormone release

Hypothalamus-produced hormones travel via nerves to posterior pituitary for storage and release into bloodstream.

Anterior Pituitary Hormones

Gonadotropins (FSH, LH), Growth Hormone (GH), Thyroid Stimulating Hormone (TSH), Adrenocorticotropic Hormone (ACTH), Prolactin (PRL)