Chapter 18

Reproduction and Heredity

The Endocrine System

• Endocrine glands- glands that produce and release chemicals

• Hormones- chemical substances produced by endocrine glands.

The Pituitary Gland

small gland at the base of the brain

Controls growth rate, metabolism, and reproduction

Called the “master gland” because it regulates many other endocrine glands

Hypothalamus

Controls the pituitary gland

Regulates body temperature, use of water, and blood pressure

Oversees many of the hormone levels in the body

Adrenal Glands

Produce hormones that affect the functioning of your kidneys, your metabolism, and your response to stressful situations

Adrenaline – hormone important in the fight or flight response

Thyroid Gland

Releases a hormone that regulates metabolism

Releases a hormone that regulates the amount of calcium in the blood

Parathyroid Gland

4 tiny glands attached to the back of the thyroid that regulates levels of calcium and phosphorus.

Pancreas

Located behind the stomachPart of two systems –

digestive and endocrineIn the endocrine it controls

the level of sugar in the blood.

Improper function can cause: Diabetes—level of sugar too high or Hypoglycemia—level of sugar too low.

Thymus

Function not thoroughly understood.

Plays a role in developing some of the body’s defenses against infection.

Reproduction and the Endocrine System

• Ovaries – reproductive glands in females• Testes – reproductive glands in males

• Follicle-stimulating hormone (FSH)• Luteinizing hormone– Two hormones produced by the pituitary gland

that begin that process of sexual maturation in adolescents

Reproduction and the Endocrine System

• In males, testosterone and FSH control production of sperm, the male sex cells.

• Testosterone is also responsible for developing and maintaining other male traits such as deepening voice and body hair

• In females, two female sex hormones, progesterone and estrogen are produced by the ovaries.

• They are responsible for developing other female traits such as breast development and widening of the hips

• In addition, progesterone and estrogen work with FSH and LH to produce ova or eggs.