Chapter 8 Lesson 7 "How the Endocrine System Controls the Body"

Materials:

• The Endocrine System sheet.
• The Notes Sheet

Objective:

• .Students will explain what hormones do.
• Students will explain how a feedback loop works.
• Students will describe the stress response.

Alaska Content Standards:

• SCI A-10 Students will understand that living things are made up mostly of cells and that all life processes occur in Cells (Cells)
• SCI A-12 Students will distinguish the patterns of similarity and differences in the living world in order to understand the diversity of life and understand the theories that describe the importance of diversity for species and ecosystems.

Anticipatory Set:

Teacher Input: Introduce the students to the idea of a hormone. Hormones are chemical messengers secreted into blood or extracellular fluid by one cell that affect the functioning of other cells. Show this picture of a homone talk to the students about how these substances produced by one cell can affect other cells. The chemical known as a hormone can travel through tissues or it can travel through the blood system. Here is a picture of a hormone affecting only certain cells.

Your body regulates hormones much like you regulate the speed of a car. As you want to go faster you push the accelerator. This causes gas in another part of the car to flow above the pistons. The trick is to keep a steady speed of 55 whether going up hills or down.

When your body needs a substance to be created the endocrine system sends out a hormone. The hormone causes cells in another part of the body to create the substance when there is enough of the substance the the Endocrine System stops secreting the hormone then the cells in the other part of the body stop making the substance.

The main gland is the pititary gland. The pituitary gland is a pea-sized gland located at the base of the skull between the optic nerves. The pituitary gland secretes hormones. The pituitary is sometimes referred to as the "master gland" as it controls hormone functions such as our temperature, thyroid activity, growth during childhood, urine production, testosterone production in males and ovulation and estrogen production in females. In effect the gland functions as our thermostat that controls all other glands that are responsible for hormone secretion. The gland is a critical part of our ability to respond to the environment most often without our knowledge.

Guided Practice Remind the students of their notes sheet and they may want to complete it during the next 10 minute discussion.

The Thyroid gland, With the help of the thyroxine hormone secreted by the thyroid gland, 100 trillion cells are individually organized to function according to a certain rhythm and at a certain rate of speed. This hormone determines how quickly nutrients are converted into energy and how efficiently food burns in the body. This gland can increase or decrease your temperature.

In the thymus gland lymphocytes become specialized. The thymus plays an important role in lymphocyte specialization and immunity. Lymphocytes are the white blood cells that fight infections.

The pancreas is part of both the endocrine system and the digestive system. As an endocrine gland, it releases the hormone insulin into the blood. As a gland of digestive system, it secretes digestive enqymes into the small intestine.

When you are in trouble the nerve systems tells the adrenal glands in or above your kidneys to release special chemicals* into the blood.These chemicals prepare your body to fight or to run away "fight or flight". They make your breathing deeper and faster. They turn off the blood flow to your stomach and send it to the muscles in your arms and legs. They make the pupils of your eyes grow larger (dilate). When you are in danger your sight sharpens and you become more aware of everything around you. Your sense of pain goes down. Your immune system gets ready for action.

The ovaries are a pair of female reproductive organs. They are located in the pelvis, one on each side of the uterus. The ovaries are connected to each other by the Fallopian tubes. Each ovary is about the size and shape of an almond. The ovaries have two functions: they produce eggs (also called ova) and female hormones. (estrogen and progesterone). These hormones control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.

The Testies make sperm, male reproductive cells; nourish the sperm; and make the male hormone testosterone, which Enhances Sexual Drive, Heightens Sexual Performance, Increases Energy Levels, Enhances Mood, Promotes Bone and Muscle Growth.

Modeling Students will watch the ADAM CD to see the parts of the endocrine system.

Check for Understanding: Go through the question on P198 with the students help them with ideas that are difficult for them.

Closure: Not all glands are part of the endocrine system. Endocrine glands secrete hormones into the bloodstream. The secretions of exocrine glands move through ducts, or reach cells directly. Teh pancreas also is considered an endocrine gland because it secretes the hormones insulin and glucagon. Insulin lowers blood glucose levels, while glucagon raises blood glucose levels.

Independent Practice: Students will complete their notes sheet, the Endocrine Systems sheet and take the quiz on Lesson 7.

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).