Unit 11: Endocrine System

Endocrine System

A system made up of glands that produce and secrete hormones to regulate growth, metabolism, sexual development, stress response, and maintain homeostasis.

Hormones

Chemical messengers produced by glands that act on target cells.

Negative Feedback System

A control mechanism that regulates hormone levels by secreting hormones to raise or lower them when they go above or below a set point.

Positive Feedback System

A mechanism that increases the production of a substance in response to its own actions, e.g., oxytocin during childbirth.

Pituitary Gland

Often called the 'master gland', located below the brain, it controls all other glands.

Hypothalamus

A brain structure that regulates the pituitary gland's actions.

Prolactin (PRL)

A hormone that stimulates milk production from a woman's breasts after childbirth.

Growth Hormone (GH)

A hormone that stimulates growth during childhood and helps maintain muscle and bone mass.

Adrenocorticotropin (ACTH)

A hormone that stimulates the production of cortisol by the adrenal glands.

Cortisol

A stress hormone vital for maintaining blood pressure and glucose levels.

Thyroid-Stimulating Hormone (TSH)

A hormone that stimulates the thyroid gland to produce thyroid hormones, regulating metabolism and energy.

Follicle-Stimulating Hormone (FSH)

A hormone that promotes sperm production in men and stimulates egg release in women.

Luteinizing Hormone (LH)

A hormone that regulates testosterone in men and estrogen in women.

Oxytocin

A hormone that causes milk letdown in nursing mothers and contractions during childbirth.

Antidiuretic Hormone (ADH)

A hormone that regulates water balance in the body.

Thyroid Gland

A gland responsible for regulating metabolism through thyroid hormones such as thyroxine (T4) and triiodothyronine (T3).

Calcitonin

A hormone that regulates blood calcium levels by taking calcium from the bones.

Parathyroid Hormone (PTH)

A hormone that increases blood calcium levels by taking calcium from the bones.

Adrenal Glands

Glands located at the top of the kidneys that produce hormones including adrenaline and cortisol.

Cushing's Disease

A condition caused by excessive cortisol production, leading to symptoms like increased thirst and obesity.

Addison's Disease

A condition resulting from hyposecretion of cortisol, leading to low blood pressure and other symptoms.

Insulin

A hormone that decreases blood sugar levels by promoting glucose uptake by cells.

Glucagon

A hormone that increases blood sugar levels by stimulating the liver to break down glycogen.

Diabetes Mellitus

A condition characterized by insulin deficiency, leading to high blood sugar levels.

Hypoglycemia

A condition of abnormally low blood sugar levels.

Diabetes Insipidus

A condition where the kidneys are unable to conserve water, leading to excessive thirst and urination.

Melatonin

A hormone secreted by the pineal gland that helps maintain circadian rhythms.

Thymus Gland

A gland that secretes thymosins, important for immune function, and is larger in children than in adults.

Gonadotropins

Hormones that affect the gonads (testes and ovaries) in reproductive processes.

Myostatin

A protein that inhibits muscle growth, with potential inhibitors being developed for treating muscle-wasting diseases.

Thyroid Hormones

Hormones (T4 and T3) that control the rate at which cells release energy from carbohydrates.

Goiter

An enlargement of the thyroid gland, often caused by iodine deficiency.

Hyperthyroidism (Grave's Disease)

A condition where the thyroid gland produces too much hormone, leading to weight loss and other symptoms.

Hypothyroidism

A condition where the thyroid gland produces too little hormone, leading to weight gain and fatigue.