Chapter 12: Endocrine System

Endocrine system

A collection of glands that produce hormones to regulate body functions such as growth, metabolism, and reproduction.

Hormones

Chemical messengers secreted into the bloodstream that affect specific target organs.

Endocrine glands

Glands that secrete hormones directly into the bloodstream without using ducts.

Exocrine glands

Glands that secrete substances through ducts to body surfaces or cavities (e.g., sweat glands).

Pituitary gland

Known as the "master gland"; regulates other endocrine glands and is located at the base of the brain.

Hypothalamus

Brain structure that connects the nervous system to the endocrine system and regulates the pituitary gland.

Thyroid gland

Gland in the neck that produces thyroxine (T₄), triiodothyronine (T₃), and calcitonin.

Thyroxine (T₄)

A thyroid hormone that regulates metabolism, energy production, and growth.

Triiodothyronine (T₃)

A thyroid hormone that works with T₄ to regulate metabolism.

Calcitonin

A hormone produced by the thyroid that lowers blood calcium levels.

Parathyroid glands

Four small glands on the back of the thyroid that regulate calcium levels.

Parathyroid hormone (PTH)

A hormone that raises blood calcium levels by stimulating bone breakdown and calcium reabsorption.

Adrenal glands

Glands located above the kidneys that produce hormones involved in stress response and metabolism.

Adrenal cortex

The outer layer of the adrenal glands; produces corticosteroids like cortisol and aldosterone.

Adrenal medulla

The inner layer of the adrenal glands; produces epinephrine and norepinephrine.

Epinephrine

A hormone that increases heart rate and energy in response to stress; also called adrenaline.

Norepinephrine

A hormone that works with epinephrine to prepare the body for "fight or flight."

Pancreas

An organ with both endocrine and exocrine functions; regulates blood glucose levels.

Insulin

A hormone produced by the pancreas that lowers blood glucose levels by promoting glucose uptake in cells.

Glucagon

A hormone that raises blood glucose levels by promoting the release of glucose from the liver.

Pineal gland

A small gland in the brain that produces melatonin to regulate the sleep-wake cycle.

Melatonin

A hormone that influences circadian rhythms and sleep patterns.

Testes

Male reproductive glands that produce testosterone.

Testosterone

A male sex hormone that regulates development of male characteristics and sperm production.

Ovaries

Female reproductive glands that produce estrogen and progesterone.

Estrogen

A hormone that promotes development of female characteristics and regulates the menstrual cycle.

Progesterone

A hormone that helps regulate the menstrual cycle and maintain pregnancy.

Diabetes mellitus

A disorder in which the body has difficulty regulating blood glucose levels.

Type 1 diabetes

An autoimmune condition where the pancreas produces little or no insulin.

Type 2 diabetes

A condition where the body resists insulin or does not use it effectively.

Hyperthyroidism

A condition caused by overproduction of thyroid hormones, leading to increased metabolism.

Hypothyroidism

A condition where too little thyroid hormone is produced, leading to fatigue and weight gain.

Cushing’s syndrome

A condition caused by excessive cortisol, leading to weight gain, high blood pressure, and other symptoms.

Addison’s disease

A disorder where the adrenal glands do not produce enough hormones, causing fatigue and low blood pressure.

Gigantism

Excessive growth caused by too much growth hormone during childhood.

Acromegaly

Enlargement of extremities caused by excessive growth hormone secretion in adulthood.

isles of Langerhans

group of cells in pancreas which secrete insulin directly into bloodstream

prostaglandins

hormone-like lipids that perform many functions such as inflammation, pain, fever, clotting, and vaginal contractions

amines

class of hormones that consist of a single amino acid (includes thyroid hormones)

peptides/protein hormones

hormones made of 3+ amino acids (includes all pituitary hormones, leptin, gherlin, and insulin)

steroids

hormones converted from cholestorol

neurohormones

hormones released by neruons

negative feedback

the process by whcih the body regulates hormones

ADH and oxytocin

Which two hormones does the hypothalamus produce?