The Endocrine System  Objectives: Describe the endocrine system. Identify hormones and their function in the endocrine system. The Endocrine System controls and excites growth and affects emotions and behavior in people.

The Endocrine System  Consists of glands that secrete substances, called hormones, into the bloodstream. Pituitary Gland Thyroid Gland Adrenal Gland Testes and Ovaries

Hormones  Meaning to stimulate  Hormones stimulate growth and many kinds of reactions, like activity levels and moods.  Hormones have specific receptor sites.

The Pituitary Gland  About the size of a pea  “Master Gland”  Responsible for the secretion of many hormones that affect behavior. Growth hormone Prolactin Oxytocin

The Thyroid Gland  The thyroid gland is the biggest gland in the neck. It is situated in the anterior (front) neck below the skin and muscle layers. The thyroid gland takes the shape of a butterfly with the two wings being represented by the left and right thyroid lobes which wrap around the trachea. The sole function of the thyroid is to make thyroid hormone. This hormone has an effect on nearly all tissues of the body where it increases cellular activity. The function of the thyroid therefore is to regulate the body's metabolism.

The Thyroid Gland  Produces Thyroxin that affects the bodies metabolism.  Metabolism- the rate of converting food to energy. Hypothyroidism- too little thyroxin can cause one to be overweight. Hyperthyroidism- too much thyroxin can cause excitability, inability to sleep, and weight loss.

The Adrenal Glands  Adrenal glands, which are also called suprarenal glands, are small, triangular glands located on top of both kidneys. An adrenal gland is made of two parts: the outer region is called the adrenal cortex and the inner region is called the adrenal medulla.

The Adrenal Gland  Secrete Cortical Steroids that increase resistance to stress and promote muscle development.  Cause liver to release stored sugar, making energy for emergencies.  Produce adrenaline and noradrenaline They arouse the body, enabling the person to cope with stressful situations. Adrenaline can intensify emotions like fear and anxiety. Noradrenaline can raise blood pressure.

Testes and Ovaries  Testes – male gland  Ovaries – female gland Produce hormones that affect sexuality, human development, and reproduction. Testosterone Estrogen Progesterone

Testosterone  Male Sex Hormone  Steroid (see dangerous side affects from taking steroids to enhance performance)  Important to development during prenatal and adolescent periods Prenatal development of sex organs Adolescent development of muscle and bones  Primary and Secondary Sex Characteristics

Estrogen and Progesterone  Female Sex Hormone  Important to development during prenatal and adolescent periods  Estrogen fosters development of Primary and Secondary Sex Characteristics (see examples) Linked to premenstrual syndrome  Progesterone Stimulates growth of female reproductive organs Prepares the body for pregnancy  Estrogen and Progesterone regulate the menstrual cycle