Lesson 1: Endocrine System

Endocrine System

Made up of organs and glands that produce, store, and release hormones.

Hormones

Chemicals used to increase or decrease activity of specific target cells.

• Aids body in homeostasis.

Exocrine Glands

Release hormones into a duct to target cells.

Endocrine Glands

Release hormones directly into bloodstream.

Negative Feedback Loop

Hormone release stops in response to decrease in stimulus.

Positive Feedback Loop

Action of hormone release continues if stimulus is present.

Pituitary Gland

Master gland of the endocrine system

Myxedema

Swelling of the skin and underlying tissues, seen in severe hypothyroidism.

Endocrine System Functions

• Regulates chemical reactions in cells

• Control functions of the organs, tissue, and other cells.

What are the 3 features that the endocrine system relies on?

• Glands

• Hormones

• Trillion of cell receptors

How many glands are located in the brain?

3

How many glands are located throughout the body?

7

Anterior Lobe of Pituitary Gland secretes…

• Growth hormone

• Thyroid Stimulating Hormone (TSH)

• Follicle Stimulating Hormone (FSH)

• Luteinizing Hormone (LH)

• Prolactin

Posterior Lobe of Pituitary Gland secretes…

• Antidiuretic Hormone (ADH)

• Oxytocin

Growth Hormone

• Anterior Lobe

• Body growth

Thyroid Stimulating Hormone (TSH)

• Anterior Lobe

• Regulates thyroid gland

Follicle Stimulating Hormone (FSH)

• Anterior Lobe

• Growth of ova and sperm

Luteinizing Hormone (LH)

• Anterior Lobe

• Stimulated ovulation and testosterone in males

Prolactin

• Anterior Lobe

• Causes the breasts to grow and make milk during pregnancy and after birth.

Antidiuretic Hormone (ADH)

• Posterior Lobe/Hypothalamus

• Stimulates reabsorption of water by the kidneys

Oxytocin

• Posterior Lobe/Hypothalamus

• Stimulates uterine contractions during labor and release of breast milk.

Hypothalamus

secretes antidiuretic hormone (ADH) and oxytocin

Pineal Gland

Secretes melatonin

Melatonin

Regulates onset of puberty, biological clock/sleep.

Thyroid Gland

Base of the neck, located below the Adam’s apple.

Thyroid Gland secretes…

• T3 and T4

• Calcitonin

T3 and T4

• Thyroid Gland

• Regulates metabolism

Calcitonin

• Thyroid Gland

• Increase bone calcium

Thymus

• Posterior to the sternum

• Secretes Thymosin

Thymosin

• Thymus

• Development of cells in the immune system

Parathyroid Glands

• Located on thyroid

• Secretes Parathyroid Hormone

Parathyroid Hormone

• Parathyroid Glands

• Regulates Calcium

Pancreas

• Behind the stomach & in front of spine.

• Both endocrine and exocrine functions

• Secretes Alpha Cells (Glucagon) and Beta Cells (Insulin)

Alpha cells (Glucagon)

• Pancreas

• Increases blood sugar

Beta Cells (Insulin)

• Pancreas

• Lowers blood sugar

Adrenal Glands

Located on top of both kidneys

Adrenal Glands secrete…

• Cortisol

• Aldosterone

• Epinephrine

• Norepinephrine

Cortisol

• Adrenal Glands

• Regulates carbohydrates; prolonged stress inhibits the body’s immune response.

Aldosterone

• Adrenal Glands

• Regulates electrolytes and fluid volume

Epinephrine

• Adrenal Glands

• Fight or flight response

Norepinephrine

• Adrenal Glands

• Vasoconstriction (narrowing of blood vessels), which increases blood pressure

• Recovering from stress

Ovaries

• Female Reproductive System

• Secretes estrogen and progesterone

Estrogen

• Ovaries

• Development of secondary sex, regulates menstrual cycle

Progesterone

• Ovaries

• Prepares the body for pregnancy

Testes

• Male Reproductive System

• Secretes Testosterone

Testosterone

• Testes

• Sperm production, secondary sex characteristics in males

Diabetes Mellitus

Chronic disease characterized by elevated blood glucose levels

Diabetes Mellitus: Type 1

• Body stops making insulin; usually born with disorder.

• Requires Insulin replacement.

Diabetes Mellitus: Type 2

Associated with obesity; genetic predisposition

Diabetes Mellitus: Gestational

Occurs during pregnancy, usually temporary.

Polycystic Ovary Syndrome (PCOS)

• Irregular menstrual periods;

• Elevated hormone levels;

• Cysts on ovaries

Gigantism Acromegaly

Results from an excess of growth hormone from the pituitary gland.

Hyperthyroidism (Graves Disease)

• Autoimmune disorder

• Excessive thyroid hormone.

• Weight loss, heat tolerance, anxiety, increased heart rate

Hypothyroidism

• Underactive thyroid gland

• Weight gain, fatigue, slow heart rate

• Myxedema: swelling of the skin and underlying tissue

Cretinism

Severe physical and mental retardation due to iodine deficiency, and specifically due to deficiency of thyroid hormones during early pregnancy.

Cushing’s Syndrome

High levels of the hormone cortisol from the adrenal glands over long periods of time

Goiter

• Irregular growth of the thyroid gland.

• Treated with iodine or surgery