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
6g
0g
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