Biomed II Part 3

What is the main function of the endocrine system?

To regulate body processes by releasing hormones that act as chemical messengers through the bloodstream.

What is the hypothalamus and what does it do?

A gland in the brain that links the nervous and endocrine systems; it controls the pituitary gland and regulates hunger, thirst, sleep, and emotions.

What does the pituitary gland do?

Known as the “master gland,” it secretes hormones that control other endocrine glands and regulate growth, water balance, and reproduction.

What does the pineal gland do?

Secretes melatonin, which regulates sleep and wake cycles.

What does the thyroid gland do?

Controls metabolism, energy production, and growth through hormones like thyroxine (T4) and triiodothyronine (T3).

What does the thymus do?

Produces thymosin, which helps develop white blood cells (T-cells) important for immunity, especially before puberty.

What do the adrenal glands do?

Produce hormones such as cortisol and adrenaline that control stress responses, metabolism, and blood pressure.

What does the pancreas do?

Releases insulin and glucagon to regulate blood sugar levels.

What do the ovaries do?

Produce estrogen and progesterone, which regulate the menstrual cycle, reproduction, and secondary female sex characteristics.

What do the testes do?

Produce testosterone, which regulates sperm production and male secondary sex characteristics.

What controls the pituitary gland?

The hypothalamus.

What are hormones?

Chemical messengers that travel through the blood to target organs, altering their activity.

What happens when you eat a lot of sugar?

Blood glucose rises, causing the pancreas to release insulin, which helps cells absorb glucose and lowers blood sugar levels.

What happens when you haven’t eaten in a while?

Blood sugar drops, prompting the pancreas to release glucagon, which signals the liver to release stored glucose into the bloodstream.

What is Type 1 Diabetes?

An autoimmune disease where the body’s immune system destroys insulin-producing cells in the pancreas, requiring insulin injections.

What is Type 2 Diabetes?

A metabolic disorder where the body’s cells become resistant to insulin, often linked to diet and lifestyle factors.

What is glucagon and when is it released?

A hormone released by the pancreas when blood sugar is low to raise glucose levels.

What is insulin and when is it released?

A hormone released by the pancreas when blood sugar is high to lower glucose levels.

What is a negative feedback loop?

A process where the body reverses a change to maintain homeostasis, such as lowering blood sugar after it rises.

What is a positive feedback loop?

A process where the body amplifies a change, such as during childbirth when oxytocin increases contractions.

Give an example of a negative feedback loop.

Regulation of blood sugar by insulin and glucagon.

Give an example of a positive feedback loop.

Release of oxytocin during labor to intensify uterine contractions.