Recap• What is one major function of the Endocrine

System?• What is a target cell (or organ)?• Explain how negative feedback works using

any of the following examples:– Thirst– Home Heating System– Sweating– Or, your own example

The Endocrine System

Ch. 9b

Glands and Organs of the Endocrine System

• Pituitary Gland• Hypothalamus• Thyroid Gland• Parathyroid Gland• Adrenal Gland• Pineal Gland• Thymus Gland• Pancreas• Gonads

• Endocrine Glands– Ductless glands that produce hormones

that they release into the blood or lymph• Exocrine Glands

– Release their products at the body’s surface or into body cavities through ducts

Exocrine vs. Endocrine Glands

Pituitary Gland

• Attached to the Hypothalamus

• 2 lobes– Anterior lobe (Made

up of glandular tissue)

– Posterior lobe (Made up of nervous tissue)

Anterior Pituitary Gland

• There are 6 hormones released by the anterior pituitary– Growth Hormone (GH)

• Responsible for the growth of skeletal muscles and long bones

• Stimulates cells to grow and divide• Cause fats to be broken down and used for

energy

Posterior Pituitary Gland– Doesn’t make hormones, it stores hormones

made by the hypothalamus– Oxytocin

• Released during childbirth and in nursing women• Causes contractions during childbirth and milk

ejection during nursing– Antidiuretic Hormone (ADH)

• A chemical that inhibits or prevents urine production• In large amounts, can increase blood pressure

Pituitary – Hypothalamus Relationship

• The pituitary gland is known as the “Master Endocrine Gland”

• Yet, all of pituitary’s glands are controlled by the hypothalamus

Thyroid Gland

• Located at the base of the throat• Makes two hormones

– Thyroid Hormone• Body’s major metabolic hormone• Controls the rate at which glucose is converted into body

heat and energy– Calcitonin

• Decreases calcium levels in the body by causing it to be deposited in bones

Thyroid Gland

Parathyroid Gland

• Connected to the Thyroid• Makes one hormone

– Parathyroid hormone (PTH)• Most important regulator of calcium

homeostasis in the blood

Quick Quiz 1 of 2

• What gland produces the Growth Hormone (GH)?

• Where is the thyroid gland located?

Adrenal Glands• Located on the kidneys• Produces 3 major groups of steroid hormones

called corticosteroids• When stimulated by the Sympathetic Nervous

System (SNS), releases 2 hormones– Epinephrine (adrenaline)

• Increases heart rate, blood pressure, blood glucose levels

– Norepinephrine

Adrenal Glands

Pancreas• Located close to the stomach in the abdomen• 2 important hormones

– Insulin• Acts on just about all body cells and increases their

ability to transport glucose• Absolutely necessary for the use of glucose in the body

– Glucagon• Opposite of insulin• Stimulated by low blood sugar levels

Pancreas

Pineal Gland

• Located in the brain• Only secretes one hormone

– Melatonin• Levels rise and fall during the course of the day• High levels at night make us drowsy• Low levels during the daylight hours• Important in establishing the body’s day-night

cycle

Pineal Gland

Thymus Gland

• Located in the upper thorax (chest)• Decreases in size throughout adulthood• Produces one hormone

– Thymosin• Influences immunity in children

Gonads

• Hormones of the Ovaries– Located in the female pelvis– Produces two groups of steroid hormones

• Estrogens– Stimulates the development of the secondary sex

characteristics– Helps maintain pregnancy and prepare the breasts

for milk

• Progesterone

Gonads

• Hormones of the Testes– Located outside the male pelvis– Produces the male sex hormones

• Testosterone– Promotes the growth and maturation of the

reproductive system organs– Causes the development of the male’s secondary

sex characteristics

Quick Quiz 2 of 2

• What hormone is necessary for glucose use in the body?

• What is melatonin?