Grade 8 Science Unit 4 Cells Tissues Organs

Grade 8 Science Unit 4: “Cells, Tissues, Organs & Organ Systems” Chapter 12: The health of the body depends on the health of its interdependent systems.

How Body Systems are Connected. . . All the cells of the body have the same basic needs. • Energy • Nutrients • Oxygen • Removal of wastes

Body systems work together to provide cells with what they need.

Example: Cellular Respiration • A chemical process that releases energy that is stored in glucose.

Organ systems that are directly involved with cellular respiration include: • Respiratory system • Digestive system • Circulatory system • Excretory system

More Connections Between Systems include. . . 1. Circulatory & Respiratory 2. Circulatory & Digestive 3. Nervous & Muscular

Circulatory & Respiratory • The blood picks up oxygen from the lungs and delivers it to the body cells. • The blood picks up carbon dioxide and delivers it to the lungs to be exhaled.

Circulatory & Digestive • The digestive system breaks down food into glucose and other nutrients. • Nutrients enter the blood from the small intestine. • The blood carries the nutrients to the body cells.

Nervous & Muscular • Help to keep your body temperature stable. • The nervous system monitors conditions outside the body through temperaturesensing cells in the skin. • The information that is sent to the brain causes the brain to send nerve signals to different parts of the body, including the muscles. • Ex. If cold, the muscles will relax and contract rapidly i. e. Shiver.

Questions in Textbook • Page 445: #s 1 -7 and Pause and Reflect

Body Systems & Health • Maintaining the health of each body system keeps the network of systems, and the whole body healthy. • Factors that affect the health of the body systems include: 1. Diet 2. Exercise 3. Stress

The Balance of Body Systems Can be affected by both: • Genetic factors • Lifestyle factors

Genetic Factors • Things you inherit from one or both birth parents. • Out of your control

Lifestyle Factors page 449 • Within your control Include: • Diet • Smoking • Drugs and alcohol • Lack of exercise

To support healthy organs and body systems, we all have the same basic needs. • Clean air and water • A nutritious and wellbalanced diet • Exercise • Restful sleep

Scientific Technologies • 1. Insulin pump: a device that can be programmed to deliver a specific dose of insulin at specific times during the day. Worn at all times (Diabetes) – used to help out the pancreas

2. Artificial Heart: used when a donor heart is unavailable. It is difficult for humans to stay alive for any length of time using hearts from other species.

Core STSE Artificial Organs

“The Effect of Activity on Heart Rate and Breathing Rate”

Examples of Careers in Health • Lab technician • X-ray technician • Physiotherapist • Nutritionist • Coaches • Doctor

• Public health nurse

Making Informed Decisions: Ideas for research. . . • Insurance companies • Fitness equipment • Use of sunscreen • Food additives • Steroids • Other?

Questions in Textbook • Page 457 #s 1 -9

p. 445 1. Cells need oxygen in order to perform cellular respiration, which is a chemical reaction that provides the cell with energy. 2. The blood (circulatory system) picks up oxygen from the lungs (respiratory system) and delivers it to the body cells. Also the blood (circulatory system) picks up carbon dioxide from the body cells and delivers it to the lungs (respiratory system). 3. The blood (circulatory system) picks up nutrients from the small intestine (digestive system) and delivers them to the body cells. The blood supplies oxygen and carries away carbon dioxide to enable cellular respiration to take place in the stomach muscles, so that they have the energy they need to function. 4. If the body gets too cold, the nervous system instructs muscle cells to contract and relax repeatedly, causing shivering.

p. 445 5. (a) The blood vessels of the circulatory system near the surface of the skin expand. This increases blood flow near the body surface so heat can be lost to the outside, cooling the body. (b) The nervous system is the key system working with the circulatory system to cool the body. 6. The wastes that need to be filtered by the kidneys are carried in the blood in the circulatory system. Blood vessels must enter and leave the kidneys so that the wastes come in contact with the filtering units.

p. 445 7. (a) Substance in Blood chloride glucose urea uric acid calcium Amount in Urine 6 g 0 g 20 g 0. 5 g 0. 15 g (b) Glucose should not be found in urine because the chart indicates that all of it is returned to the bloodstream. Glucose is used by cells. It is not a waste product. (c) One benefit is that individuals do not have to keep eating to maintain the glucose in their bodies. By returning it to the body for use by the cells, the body is reducing the amount that needs to be consumed.

p. 445 Pause and Reflect Answer Carbon dioxide from all cells in the body leaves the same way: The carbon dioxide crosses the cell membrane and enters into the blood in the capillaries of the circulatory system. The blood is carried through veins to capillaries in the lungs. The capillaries encase the alveoli of the lungs, and gas exchange occurs here. The carbon dioxide leaves the blood in the capillaries and is exhaled when you breathe out.

p. 457 1. • Positive: diets low in fats and cholesterol; regular exercise • Negative: smoking and consuming drugs and alcohol, not exercising, eating a high fat diet 2. Fluids that are more viscous are more resistant to flowing. They require more energy to keep them moving. Since the heart provides that energy, it must work harder. 3. (a) Technology can be used to support or even replace the function of an organ or organ system. (b) Students should describe two of the following: artificial pacemaker: releases electrical charges that stimulate heart muscle cells to beat with a steady rhythm insulin pump: delivers a specific dose of insulin at specific times of the day to help cells absorb glucose from the blood artificial heart: pumps blood in the circulatory system while a person is waiting for a real heart to become available for a transplant kidney dialysis machine: filters waste products from the blood in a person whose kidneys are not able to do that 4. Smoking is a double threat because the nicotine in cigarettes causes the blood vessels to constrict, increasing heart rate and raising blood pressure. As well, the carbon dioxide in smoke competes with oxygen in the lungs, reducing the ability of the blood to carry oxygen.

p. 457 5. Homeostasis is the ability of the body to maintain an internal balance. 6. Genetic factors are out of the control of the individual, whereas lifestyle factors are choices that can be adjusted. 7. A high-fat diet can cause fatty deposits that clog blood vessels, reducing the flow of blood through blood vessels. 8. Drugs and alcohol can either be classified as stimulants, which temporarily increase the rate of life functions, or as depressants, which decrease the rate of life functions. 9. A: the respiratory system, which exchanges oxygen and carbon dioxide in the lungs, and works with the circulatory system to carry the oxygen and carbon dioxide to and from the site of gas exchange B: the heart (circulatory system), which is the pump that moves the blood through the circulatory system C: the digestive system, which breaks down food and releases nutrients into the circulatory system where they are carried to the cells D: the excretory system, which takes wastes carried in the circulatory system and filters them out into the urine