The Endocrine System

Endocrine System- is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development and function.

-the glands are capable of synthesizing and releasing special chemical messengers - hormones

Hormoneschemical messengers created by the body. They transfer

information from one set of cells to another to coordinate the functions of different parts of the body.

Functions of the Hypothalamus

The hypothalamus controls the autonomic nervous system.

The hypothalamus contains the thirst center, the hunger center and the body's thermostat.

The hypothalamus controls thehypophysis (pituitary gland).

The hypothalamus is the site of emotions and the effect emotions can have on the body.

Pituitary Gland

- also known as the “The Master Gland.”

- is a small pea-sized lump of tissue connected to the inferior portion of the hypothalamus of the brain.

-is located at the base of the brain beneath the hypothalamus and is no larger than a pea. It is often considered the most important part of the endocrine system because it produces hormones that control many functions of other endocrine glands.

PosteriorLobe

Antidiuretic hormone (ADH)

Oxytocin

Stimulates the kidneys to conserve water

Females: causes contraction of the uterus and ejection of breast milkMales: stimulates contraction of the prostate and vas deferens during sexual arousal

Pituitary Gland

Pituitary Gland

Anterior Pituitary:

The anterior pituitary gland is the true glandular part of the pituitary gland. The function of the anterior pituitary gland is controlled by the releasing and inhibiting

hormones of the hypothalamus. The anterior pituitary produces 5 important hormones:

Pituitary Gland ****

AnteriorLobe

Growth hormoneProlactin

Adrenocorticotropic

Thyroid-stimulating

Follicle-stimulating

Luteinizing

Stimulates milk production

Stimulates the adrenal cortex to release its hormones

Stimulates the thyroid gland to release its hormones

Females: stimulates estrogen production and maturation of the ovaMales: stimulates sperm production

Females: stimulates ovulationand estrogen productionMales: stimulates testosterone production

Stimulates increase in size of muscles and bones

FUNCTION OF THE THYROID GLAND

The primary function of your thyroid gland is to secrete thyroid hormones, which are responsible for controlling your body’s metabolism. The 2 main thyroid hormones are T3 (triiodothyronine) and T4 (thyroxine). The amount of thyroid hormones secreted is controlled by another hormone, called thyroid stimulating hormone (TSH), which is released from the pituitary gland in your head.

The thyroid hormones are involved in regulating many of your bodily functions, such as your heart rate, how quickly you burn calories, and digestion. Babies and children need adequate amounts of thyroid hormones for brain development and growth.

I. ADRENAL CORTEX the outer portion of the adrenal glands, produces several

hormones that affect blood pressure and blood sugar levels, growth, as well as some sexual characteristics.

Death would result if the adrenal cortex were to stop functioning as it controls metabolic processes that are essential to life.

Main hormones secreted by the adrenal cortex: Aldosterone

- Stimulates body to retain sodium and water- Important in maintaining Blood Pressure

Cortisone- Released when stressed- Decreases protein synthesis, resulting in slowed tissue repair- Decreases inflammation

II. MEDULLA inner part of the adrenal glands, produces hormones which

regulate the "fight or flight" response in the body, the body's reaction to stressful events.

hormones produced by the medulla: EPINEPHRINE – raises blood sugar level, causes nervousness

and perspiration during acute emergencies.- It also increases muscular power and resistance to fatigue.

NOREPINEPHRINE - prepares an individual in dealing with stress and emergencies- it is also referred to as a stress hormone

There are no significant effects if this portion of the suprarenal gland is not working properly.

EXOCRINE GLANDThe exocrine gland secretes

digestive enzymes. These enzymes are secreted into a network of ducts that join the main pancreatic duct, which runs the length of the pancreas.

ENDOCRINE GLANDThe endocrine gland, which consists

of the Islets of Langerhans, secretes hormones into the bloodstream.

Endocrine/Hormonal Function: Two of the main pancreatic hormones

that are created and released directly into the bloodstream are insulin, which acts to lower blood sugar, and glucagon, which acts to raise blood sugar.

Maintaining proper blood sugar levels is crucial to the functioning of key organs including the brain, liver, and kidneys.

Structure and Function of Pancreas

Insulin is released by the beta cells which stimulate the glucose to be sent to the body’s cells and convert unused glucose to glycogen

Low

Blood sugar

Glucagon is released by the alpha cells which stimulate stored glycogen to be transformed into glucose again.

Blood sugar

Elevated

Insulin decreases blood glucose concentration and increases protein synthesis.Glucagon does just the opposite. It increases blood*** glucose and decreases protein synthesis.

Blood glucose concentrations

Protein synthesis

Blood glucose concentrations

Protein synthesis

INSULIN

GLUCAGON

TESTES Male sex hormones, as a group, are called

androgens. The principal androgen is testosterone, which is secreted by the testes. A small amount is also produced by the adrenal cortex.

Production of testosterone begins during fetal development, continues for a short time after birth, nearly ceases during childhood, and then resumes at puberty.

This steroid hormone is responsible for: The growth and development of the male reproductive

structures Increased skeletal and muscular growth Enlargement of the larynx accompanied by voice

changes Growth and distribution of body hair Increased male sexual drive

Testosterone secretion is regulated by a negative feedback system that involves releasing hormones from the hypothalamus and gonadotropins from the anterior pituitary.

TESTES

OVARIES Two groups of female sex hormones are

produced in the ovaries, the estrogens and progesterone. These

steroid hormones contribute to the development and function of the

female reproductive organs and sex characteristics

GigantismGigantism is a rare condition

that causes abnormal growth in children. It occurs when a child’s body produces too much growth hormone. Early diagnosis is important. Prompt treatment can stop or slow the changes that may cause a child to grow larger than normal. However, the condition can be hard for parents to detect, since symptoms of gigantism might first be seen as normal childhood growth spurts.

Dwarfism

Is a short stature that results from a genetic or medical condition. Dwarfism is generally defined as an adult height of 4 feet 10 inches or less (147 centimeters). The average adult height among people with dwarfism is 4 feet (122 cm).