Download BC SCIENCE 8 CHAPTER 2: HUMAN BODY SYSTEMS WORK

BC SCIENCE 8
CHAPTER 2: HUMAN BODY SYSTEMS WORK INDEPENDENTLY AND TOGETHER
2.1 BODY SYSTEMS
To begin: Go to pages 20-21 in the workbook. Read and answer the questions.
Then read 2.1 pp. 52-63 in your text.
I. The Characteristics of Systems
A. a system is made of individual parts that work together
B. a system is usually connected to 1 or more systems
C. if one part of the system is missing or damaged, the system will
not function properly or will not function at all
II. Introducing the Systems of the Human Body
Refer to Figure 2.3 on pp. 56 and 57.
III. Organ Systems: Putting It All Together
A. organ system: has one or more organs that perform specific body
functions
B. tissue: groups of cell that have a similar structure and function
C. organ: groups of tissue that form a particular structure
IV. Tissues: The Foundation of Body Systems
A. muscle tissue: assists in body movement; used by organs to do
their work: helps the heart pump blood
B. nerve tissue: transfers signals around the body and tells the body
how to respond to changes in its internal and external
environments
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C. connective tissue: holds together and supports other tissues;
connects, protects and insulates organs
D. epithelial tissue: covers the surface of organs and the body; lines
the inside of body parts such as the mouth, esophagus and
stomach
Now answer the questions on pp. 22-25 in the workbook. Also go
to p. 63 and answer the Check Your Understanding Questions #1
and 10.
2.2 The Digestive and Excretory Systems
To begin: Go to pages 26-27 in the workbook. Read and answer the
questions. Then read 2.2 pp. 64-81 in your text.
I. A Healthy Diet
A. nutrient: substances the body needs for growth, development,
repair and/or maintenance
1. nutrients come from our food
B. diet: the amount and type of food needed to maintain health
C. Four food groups
1. grain products
2. vegetables and fruit
3. milk products
4. meat and alternatives
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D. The food pyramid
1. try to eat foods that have the widest portions at the bottom
of the pyramid
a. for example, eat more grains than meat and beans
E. Food Availability
1. people eat food that is available at the grocery store, grown
locally, and/or is traditional for their family
F. Types of nutrients
1. Carbohydrates
a. a source of energy
b. simple carbohydrates are things like sugar or glucose
i. remember: mitochondria use glucose to provide energy
to the cell using cellular respiration
a. your body uses the energy to grow and to repair
itself
c. complex carbohydrates are made from a chain of simple
carbohydrates
i. examples include pasta, rice and other grain products
like cereals
a. your body breaks the complex carbohydrates into
simple carbohydrates
b. since this takes time and energy, this type of
carbohydrate is better for your health
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2. Proteins
a. used to build muscles, skin, hair, nails
b. also used in chemical reactions in cells
c. can be found in meat, fish, poultry, nuts, soy, and dairy
products
3. Fats
a. used to build cell membranes and for energy
b. can be stored by the body for future energy use
c. found in shortening, butter, oil, cream, and meat
d. many people eat too much fat
e. unsaturated fat is better for you
i. comes from fruits, vegetables and fish and is liquid at
room temperature
a. examples include corn oil, olive oil and other
vegetable oils
f. saturated fat is not as good for you
i. comes from animals and is solid at room temperature
a. examples include butter and lard
ii. a diet that is high in saturated fat can lead to an
increased risk of heart disease
a. fatty material called plaque builds up on the inside of
blood vessels
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b. this makes the blood vessel more narrow and blood
flow is reduced
c. leads to an increased risk of heart attack (blood
supply to the heart is cut off) and stroke (blood
supply to the brain is cut off)
4. Minerals and Vitamins
a. needed in small amounts
i. Vitamins include A, C, D etc.
ii. Minerals include calcium and iron
iii. calcium is needed to build strong bones
a. not enough calcium can lead to osteoporosis, a
disease in which people have weak bones
iv. Vitamin D is needed to help the body absorb calcium
a. not enough Vitamin D can lead to rickets, a disease
that causes the bones to weaken
b. sunlight is needed to help the body to make Vitamin D
c. drinking beverages with added Vitamin D helps people
to get enough Vitamin D
5. Water
a. is not really a nutrient but is needed by the body
b. transports nutrients and wastes
c. needed for many chemical reactions
d. used to cool the body via perspiration/sweat
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e. a person needs 3L to 5L of water per day
Now go to p. 69 in BC Science 8 and answer the Reading Check
Questions # 1 and 4. Then complete p. 28 in the workbook.
II. Digestion
A. The Four Stages of Digestion
1. digestion: the process of taking food into the body, breaking it
down, absorbing nutrients, and eliminating wastes
2. the four stages are called ingesting, digesting, absorbing and
eliminating
B. Enzymes are important for digestion
1. enzyme: a protein found in your body that helps to speed up
chemical reactions
a. without enzymes the chemical reactions would be too slow
to keep you alive
C. Digestion occurs along a big tube
1. the digestive system is one long tube that gets wider in some
parts and narrower in others
2. the beginning of the tube is the mouth and the end of the tube
is the anus
D. Stage 1: Ingesting
1. ingesting: taking in food through the mouth
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Figure 1. The digestive system.
http://www.web-books.com/eLibrary/Medicine/Physiology/Digestive/dige_tract.jpg
E. Stage 2: Digesting
*mechanical digestion is when the food is physically broken down
into smaller pieces
**chemical digestion is when chemicals are used to break down the
food into new types of molecules that are smaller than the
original food molecules
1. Mouth (mechanical and chemical digestion)
a.the teeth cut up and chew the food
b. teeth and tongue form the food into a small ball or bolus so
that it can be swallowed
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c. bolus gets covered with saliva
i. saliva made by salivary glands in the mouth
ii. saliva lubricates the bolus which helps the bolus go
down the digestive tube
iii. saliva contains amylase
a. amylase is an enzyme that breaks complex
carbohydrates (starch) into simpler carbohydrates
2. Esophagus
a. at the back of the mouth, bolus passes through pharynx
i. pharynx is where the air passage and the digestive tube
meet
b. a small flap of flesh called the epiglottis covers the opening
to the air passage
i. prevents food from going down the wrong tube
c. after the pharynx, bolus goes into the esophagus
i. esophagus connects the mouth to the stomach
d. rhythmic muscle contractions called peristalsis push the
bolus along the esophagus
3. Stomach
a. stomach is a stretchable, muscular bag
i. can hold about 2L of food or liquid
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b. inside the stomach is gastric juice
i. has hydrochloric acid (HCl), mucus and the enzyme called
pepsin
a. pepsin breaks down proteins and needs an acidic
environment to work
c. stomach walls are lined with mucus to protect the tissue of
the stomach from the acid
d. when bolus gets to the stomach, it is covered with gastric
juice and mixed around by contractions of the stomach
muscles
i. the mixture of food and gastric juice is called chyme
ii. takes between 2 and 6 hours
e. stomach has two sphincters, one between the esophagus and
the stomach and one between the stomach and the small
intestine
i. a sphincter is a found muscles that allows the tube to open
and close at certain locations
ii. vomiting and heartburn required that the sphincter
between the esophagus and the stomach is open
a. the burning feeling is from the hydrochloric acid on
the tissues
4. Small Intestine
a. is a tube that is about 6m long and 2.5cm in diameter
b. the first 1m is called the duodenum
i. the second stage of digestion is complete once the food
leaves the duodenum
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c. the pancreas and gall bladder connect to the small intestine
within the first 30cm
i. the connections are small tubes called ducts
ii. the pancreas produces digestive enzymes the will be
used in the small intestine to break down carbohydrates,
protein and fat
iii. the gall bladder stores bile from the liver and sends it
to the small intestine
a. bile breaks fat into small droplets so that the
enzymes from the pancreas can work better
F. Stage 3: Absorbing
1. Small Intestine
a. happens in the last 5m of the small intestine
b. food has been broken down into small molecules
c. the small intestine is covered in villi
i. villi are small folds in the intestine’s wall
ii. villi increase the surface area of the small intestine so
that absorption can occur more quickly
a. the total surface area of the small intestine is about
250m2, the size of a tennis court
d. food takes about 5-6 hours to pass through the small
intestine
i. peristalsis pushes the food along
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2. Large Intestine
a. a tube that is about 1.5m long and has a diameter of 5cm
b. reabsorbs water and some minerals out of the undigested
material the comes from the small intestine
i. 90% of the water is reabsorbed
c. the material is moved along by peristalsis
d. takes about 12-24 hours
3. Bacteria in digestion
a. many different bacteria live in our digestive tubes
b. beneficial bacteria help us
i. some bacteria make Vitamin K which helps blood to clot
c. sometimes we ingest bacteria such as Salmonella that can
cause food poisoning
d. a bacterium called Helicobacter pylori causes ulcers
G. Stage 4: Eliminating
1. anything left in the digestive tube is solid waste material and
called feces
2. feces is stored in the rectum and eliminated through the anus
3. the whole process (from ingestion to elimination) takes 20 to
30 hours
III. Excretion
A. excretory system removes gas and liquid wastes from the body
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Figure 2. The human urinary system.
http://missinglink.ucsf.edu/lm/IDS_101_embryology_basics/FullText.htm
B. liquid wastes are removed through the urinary tract
1. the kidneys filter blood and remove wastes
2. the urine produced by the kidneys enters tubes called the
ureters
3. the ureters carry the urine to the bladder
4. the bladder stores the urine
5. the urine is removed from the body through a tube called the
urethra
Now go to p. 76 and answer Reading Check #1-6.
IV. Nutritional Disorders-Disrupting the Digestive System
A. Obesity is too much body fat
B. more and more teenagers are obese
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C. obesity is caused by taking in more food than the body needs and
lack of exercise
D. harmful health effects of obesity include increased risk of
diabetes, heart disease, stroke and asthma
V. Eating Disorders
A. Anorexia nervosa occurs when a person severely limits his/her
food intake
1. damage to the body includes weak bones and damage to
internal organs
B. Bulimia nervosa occurs when a person eats large amounts of food
and then purposefully vomits or takes laxatives to get rid of the
food before it can be digested
2. damage to the body includes stomach and esophagus irritation
and tooth decay
Now complete pp. 29-31 in the workbook.
Next, go to p. 81 and answer Check Your Understanding # 3-9 and
15. For a bit of a challenge, you can also try # 18.
2.3 The Circulatory and Respiratory Systems
First read pp. 32 and 33 in the workbook and answer the questions.
Then read pp. 82-95 in the textbook.
VI. The Heart and Circulatory System
A. The Heart
1. the heart pumps about 4L of blood per minute and beats about
70 times per minute
2. the heart is a muscular organ about the size of your fist
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B. The Structure of the Heart
Figure 3. The human heart.
http://www.heart.com/the-human-heart.html
1. has 2 upper chambers (called atria) and 2 lower chambers
(called ventricles)
a. the atria collect blood coming back to the heart
i. they are not very muscular because they only have to
push blood to the ventricles
b. the ventricles pump blood out of the heart
i. they are more muscular than the atria because they have
to push blood to other parts of the body
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a. the left ventricle is more muscular than the right
ventricle because it has to push the blood even
further (all over the body) than the right ventricle
does (just to the lungs)
Figure 4. The path of blood through the body.
http://www.bbc.co.uk/schools/gcsebitesize/science/images/101_circulatory_system.gif
2. there is a left atrium and a left ventricle that make up the left
side of the heart
3. there is a right atrium and a right ventricle that make up the
right side of the heart
*notice that the left side of the body would be on the right
side of most diagrams and vice versa
4. there are valves between the heart’s chambers
a. valves make sure blood only flows in one direction and
prevent the blood from flowing backwards
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C. The Circulatory System
1. blood moves all around the body in blood vessels (See Figure
2.24 on p.85)
a. the total length of all your blood vessels would be about
100 000 km (around 2.8 times around the equator)
D. Types of Blood Vessels
Figure 5. Cross-sections of the blood vessels.
http://www.online.bcelearner.ca/mod/resource/view.php?id=886
1. Arteries
a. blood vessels that carry blood away from the heart
b. have thick, muscular walls and are elastic to withstand the
pressure of the blood being pumped from the heart
c. the largest artery is the aorta
2. arteries branch into smaller blood vessels called arterioles
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3. arterioles connect to tiny blood vessels called capillaries
4. capillaries have very thin walls so diffusion can occur more
easily
a. At most body cells
i. oxygen and nutrients diffuse from the blood into the cells
a. blood becomes deoxygenated
ii. carbon dioxide and wastes diffuse from the cells into
the blood
b. at the lungs (See Figure 2.28 on p.88):
i. oxygen diffuses into the blood from the lungs
a. blood becomes oxygenated
ii. carbon dioxide diffuses from the blood to the lung cells
5. blood from the capillaries goes into venules
6. venules connect to veins
7. veins bring blood back to the heart
a. veins are less muscular than arteries because the blood
pressure is lower
b. veins have valves to prevent backflow of blood
E. The Components of Blood
1. blood transports oxygen, nutrients and water to the cells and
carries away carbon dioxide and other wastes
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2. blood also has special cells that help to fight infection and heal
wounds
3. the body contains about 5L of blood
4. 55% of blood is a clear yellowish liquid called plasma
a. contains water, proteins, minerals and other substances
5. 45% of blood is red blood cells, white blood cells and platelets
a. red blood cells
i. the body has about 2 million red blood cells
ii. carry oxygen and carbon dioxide using a protein called
hemoglobin
iii. formed in the bone marrow, liver and spleen
b. white blood cells
i. fight infection and prevent the growth of cancer
ii. increase in number when you get an infection
c. platelets
i. help make the blood clot
Now go to pp. 34 and 36 of the workbook and answer the questions.
Then go to p. 89 in the textbook and answer Reading Check #1,
3-5. Next, go to p. 95 in the textbook and answer Check Your
Understanding #1-5, 14, and 18.
VII. The Respiratory System
A. the main function is to inhale/breathe in oxygen and exhale/
breathe out carbon dioxide
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Figure 6. The respiratory system.
http://www.highlands.edu/academics/divisions/scipe/biology/faculty/harnden/2122/images
/resp1.jpg
B. Breathing
1. air is inhaled through the nose or mouth
2. air is filtered by nasal hairs (in the nose), cilia (in the nasal
cavity) and mucus (in the nose and nasal cavity) and warmed
3. air goes through the pharynx, past the epiglottis, and past the
larynx or voicebox
4. air goes into a long tube made of cartilage called the trachea
5. the trachea branches into 2 tubes called the bronchi
(1=bronchus, 2=bronchi)
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6. each bronchus branches into smaller tubes called bronchioles
7. after the bronchioles, air reaches tiny sacs/bags called alveoli
(1=alveolus, 2 or more = alveoli)
C. Gas Exchange at the Alveoli
1. each alveolus is surrounded by a net of capillaries
2. the blood entering the alveolar capillaries is deoxygenated (low
in oxygen)
3. diffusion moves oxygen from the air spaces in the alveoli into
the blood
4. diffusion moves carbon dioxide from the blood into the air
spaces in the alveoli
5. the blood leaving the alveolar capillaries is now oxygenated
*the oxygen and the carbon dioxide are basically changing places
so the process is called gas exchange
Now go to p. 35 of the workbook and answer the questions. Then
go to p. 91 in the textbook and answer Reading Check #1, 4 and 5.
D. Smoking
1. smoking can cause many diseases such as lung cancer,
emphysema, and heart disease
a. emphysema causes the walls of the alveoli lose the ability
to stretch to hold air
i. makes breathing very difficult
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2. smoking destroys the cilia that line the nasal cavity so that
dirt and other particles that get trapped on the mucus cannot
be removed easily
3. some of the harmful chemicals in cigarette smoke are nicotine,
tar, carbon monoxide, formaldehyde, hydrogen cyanide and
benzene
4. 50 of the chemicals found in cigarette smoke are carcinogenic
so can possibly cause cancer
Now go to p. 95 in the textbook (again!) and answer Check Your
Understanding #7-9.
To review the whole chapter:
Answer the questions on pp. 37 of the workbook. Next go to p. 95
(one more time!) and answer #11 and 12. Finally, go to pp. 96-97
and answer questions #1-12, 17, and 22.
Don’t forget to check out bcscience.com for more review and extra
information.
Here are some animations of the processes:
1. Digestive System
a. http://www.medicalvideos.us/play.php?vid=3736
b. http://kidshealth.org/kid/htbw/_bfs_DSmoviesource.html
2. Excretory System
a. http://kidshealth.org/kid/htbw/_bfs_USmoviesource.html
3. Circulatory System
a. This is for visualizing how the heart contracts:
http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway/living/movingre
v3.shtml
b. http://kidshealth.org/kid/htbw/_bfs_CSmoviesource.html
4. Respiratory System
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a. Diffusion in the lungs:
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr/homeostasis/import
ancerev2.shtml
b. http://kidshealth.org/kid/htbw/_bfs_RSmoviesource.html
5. Here are some gross and cool things about the body:
6. http://yucky.discovery.com/flash/body/
7. Some of the effects of smoking on the body:
http://www.mydr.com.au/addictions/animation-effects-of-smoking
8. Here are some interesting facts about the heart:
http://www.pbs.org/wgbh/nova/eheart/facts.html
9. You can perform a virtual heart transplant here (don’t worry, it’s not gory at all):
http://www.pbs.org/wgbh/nova/eheart/transplantwave.html
10. Review the structure of the respiratory system with this interactive exercise:
http://www.wiley.com/college/apcentral/anatomydrill/t23/at2301_1.htm
11. Review the structure of the heart with this iinteractive exercise:
http://www.wiley.com/college/apcentral/anatomydrill/t20/at2006_1.htm
12.
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