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?