The Endocrine System

11.1- 11.2 Introduction

1. Made up of glands that produce and secrete hormones(chemical messengers)
2. Regulation of growth, metabolism, sexual development
3. Responses to stress and injury
4. Internal balance of body systems (homeostasis)



Major Glands

1. Hypothalamus
2. Pituitary
3. Thyroid
4. Parathyroid
5. Adrenals
6. Pineal Body

7. Reproductive organs (ovaries and testes
8. Pancreas

Endocrine glands =

Exocrine glands =

11.3 Hormone Action

Steroids – insoluble in water, carried in the blood and released near the vicinity of the target cell

Nonsteroid hormones - epinephrine, growth hormone

Prostoglandins – act locally, affecting only the organ where they are produced

11.4 Control of Hormonal Secretions

Negative Feedback System


Positive Feedback system


11.5 Pituitary Gland

pituitary Location:

Why is it called the master gland?

What part of the brain controls it?

Each side of the pituitary is responsible for different hormones:

---------------Anterior Pituitary Hormones--------------------

Prolactin or PRL -

Growth hormone or GH -

Adrenocorticotropin or ACTH -

Thyroid-stimulating hormone or TSH -

Luteinizing hormone or LH -

Follicle-stimulating hormone or FSH -

-------------Posterior Pituitary Hormones-----------------

Oxytocin -

What is pitocin?

Antidiuretic hormone or ADH -

*Diuretics – increase urine production

11.6 Thyroid Gland

thyroidThe thyroid is a small gland inside the neck, located in front of the (trachea)

The thyroid hormones control your metabolism, which is the body's ability to break down food and store it as energy and the ability to break down food into waste products with a release of energy in the process.

Thyroid Hormones

Thyroxin (T4) & Tri-iodothyronine (T3) - both increase the rate at which cells release energy from carbohydrates

Calcitonin – regulates the blood concentration of calcium


Thyroid Disorders

Hypothyroidism (cretinism in infants) -

Hyperthyroidism (Grave’s disease) -


11.7 Parathyroid Gland

parathyroidLocated behind the thyroid, four tiny glands that help maintain calcium and phosphorous levels

Parathyroid Hormone (PTH) - takes calcium from the bones to make it available in the blood

Hyperparathyroidism – can be caused by a tumor, increases PTH secretion; bones soften and too much calcium can cause kidney stones

Hypoparathyroidism – too little PTH, too little calcium affects nervous system


11.8 Adrenal Glands

adrenalEach adrenal gland is actually two endocrine organs located right above each kidney. The outer portion is called the adrenal cortex. The inner portion is called the adrenal medulla.

Epinephrine & Norepinephrine

Aldosterone – a mineralcorticoid, helps kidneys conserve sodium and excrete potassium, maintaining blood pressure

Cortisol – keeps blood glucose levels stable, stress hormone

Adrenal Sex Hormones - androgens (male) and estrogens (female)

Adrenal Disorders

Cushing’s Syndrome(hypersecretion of cortisol) – blood glucose remains high, retains too much sodium, puffy skin, masculinizing effects in women

Addison’s Disease (hyposecretion) – decreased blood sodium, dehydration, low blood pressure, increased skin pigmentation

11.9 Pancreas

pancreasThe pancreas is a large gland behind your stomach that helps the body to maintain healthy blood sugar (glucose) levels.
Contains islands of cells called the Islets of Langerhans which secrete glucagon and insulin

Glucagon – stimulates the liver to break down glycogen, raises blood sugar concentration

Insulin – decreases blood sugar concentrations, affects the uptake of glucose by cells

Disorders Related to the Pancreas

Diabetes Mellitus – results from insulin deficiency, blood sugar rises (hypoglycemia); excess excreted in urine.

Type I – insulin dependent diabetes mellitus or juvenile onset diabetes, often caused by inherited immune disorder that destroys pancreatic cells

Type II – mature onset diabetes (usually after the age of 40), often individuals are overweight, can be controlled with diet and exercise

Hypoglycemia – low blood sugar, can be caused by too much insulin

What are symptoms or signs of diabetes?

What is a diabetic neuropathy?

What is gestational diabetes?

11.10 Other Endocrine Glands

Pineal Gland – melatonin, sleep cycles

Thymus Gland – large in young children, gradually shrinks with age, secretes thymosins, important to immune function

Reproductive Glands – testes and ovaries – testosterone, progesterone, estrogen

What is a gonadotropin?