Unit 2 The Circulatory System
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- Slide 1: Science Interactive LTD Copyright 2005
Science Interactive LTD
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GCSE SCIENCE
Unit 1: The Digestive System Unit 20: Crude Oil and its Products
Unit 2: The Circulatory System Unit 21: Rock Cycle
OCR
Unit 3: Healthy Body and Immunity Unit 22: Elements, Molecules and Compounds
EDEXCEL
AQA
Unit 4: The Respiratory System Unit 23: Ionic and Covalent Compounds
Unit 5: Nervous System and the Senses Unit 24: The Halogens, their Uses and Compounds
Unit 6: Human Homeostasis Unit 25: The Noble Gases, their Properties and Uses
Unit 7: Hormones and the Endocrine System Unit 26: Rates of Reaction
Unit 8: Drugs and Bad Body Maintenance Unit 27: Energy
Unit 9: Photosynthesis in Green Plants Unit 28: Generating Electricity and its Domestic Use
Unit 10: Water Transport in Plants Unit 29: Electricity
Unit 11: Flow of Energy and Elements through the Environment Unit 30: Light and the Electromagnetic Spectrum
Unit 12: Mitosis and Meiosis Unit 31: Radioactivity
Unit 13: Inheritance and Selection Unit 32: Newton's Forces and the Effects of Forces
Unit 14: Evolution and Human Impact Unit 33: Earth and Space
Unit 15: Genetic Engineering Unit 34: The Earth and Plate Tectonics
Unit 16: The Periodic Table and its Elements Unit 35: The Alkaline Earth Metals
Unit 17: The Alkali Metals Unit 36: Sound and Hearing
Unit 18: Metals and their Properties Unit 37: Natural Forces
Unit 19: The Transitional Metals Unit 38: Cells, Tissue, Organs and Organs systems
- Slide 2: Science Interactive LTD Copyright 2005
Unit 2
The Circulatory System
- Slide 3: Unit 2: The Circulatory System Science Interactive LTD Copyright 2005
Understand: Keywords:
The role of the cardiovascular system and its key
1. Blood, Tissue, Red blood cells, White blood
organs. cells, Platelets, Antibodies, Cardiovascular,
That blood is a moving tissue containing blood
2.
System, Heart, Arteries, Capillaries, Veins,
cells, oxygen, carbon dioxide, nutrients,
Oxygen, Transport, Systole, Diastole,
hormones and waste products.
Haemoglobin, Microbes, Bacteria, Viruses,
The role of red blood cells and how haemoglobin
3.
Disease, Scab, Immunity, Lymphocytes,
aids oxygen transport.
Neutrophils, Clotting, Antibodies, Vaccines,
The anatomy and function of the heart as a four
4.
chambered pump. Vaccination & Arthrosclerosis.
The role of arteries, veins and capillaries.
5.
The heart cycle including systole and diastole.
6.
What lifestyle factors contribute to the
7.
development of arthrosclerosis and the key
events of a heart attack.
That the genetic blood disorder, sickle cell
8.
anaemia affects oxygen transport to cells.
How maintaining fitness leads to a healthy body.
9.
10. The clotting response and scab formation.
11. The role of white blood cells, platelets and
antibodies in protecting us against infection by
bacteria and viruses.
Click mouse to begin
- Slide 4: Science Interactive LTD Copyright 2005
The cardiovascular system
The cardiovascular system, like any other organ system is a collection of specialised cells, tissues
and organs. Its role is to transport useful substance like o________, amino acids and glucose to
respiring tissues whilst removing waste substances like c______ dioxide and urea. Your blood
also transports hormones produced by the endocrine glands, for example adrenalin. W______
blood cells, antibodies and platelets are also transported by the blood and help prevent infection
caused by viruses and bacteria. Why does a unicellular organism like an Amoeba not need a
cardiovascular system ?
Overview of the cardiovascular system: Word bank: oxygen carbon white
Blood cells Blood vessels Heart Cardiovascular system
Diagram
Red and white blood Blood vessels range The heart continuously The cardiovascular system
Notes
cells are transported from almost 1 cm in pumps blood around the is the human body’s
around the body by diameter to a fraction body, beating around 70 transport system. It moves
network of tubes. of a millimetre. There times a minute for almost oxygen, carbon dioxide,
These cells are made are over 50,000 km of 80 years. It is an nutrients, hormones and
in the soft marrow of blood vessels in the incredible example of immune cells around a
the long bones. human body. bio-engineering. network of tubes.
- Slide 5: Science Interactive LTD Copyright 2005
Your blood
The human body has about five litres of blood which is continuously p______ around a network
of arteries, capillaries and v______. Blood is a moving, liquid tissue that contains many types of
cells, each which a unique function. Red blood cells transport oxygen around the body. White
blood cells help fight disease. P________ are cell fragments which help scabs to form to prevent
bleeding and microbial infection after injury to the skin. The yellow liquid called plasma
transports nutrients like glucose and waste products like carbon dioxide and urea. How would you
separate the yellow plasma from the red and white blood cells ?
Human blood: Word bank: pumped veins platelets
Blood volume Transfusions Blood plasma Blood cells
Diagram
An average human has Blood transfusions are Plasma can also be given One of the specialised
Notes
five litres or eight pints often performed during surgery or cells of blood is the red
of blood circulating during surgery or after following dehydration. blood cell or erythrocyte.
around the body. When a major accident. Plasma contains salts, It is highly specialised to
you donate blood, Blood is vital for life water, nutrients like sugar transport oxygen around
doctors only take one and needs to be and amino acids and the many arteries veins
pint or half a litre. replaced quickly if hormones like adrenalin. and capillaries.
lost.
- Slide 6: Science Interactive LTD Copyright 2005
Red blood cells and their function
There are over four million red blood cells in every mm3 of blood. Their function is to transport
o_________ from the l______ surface, through the capillary network to every living cell in your
body. Red blood cells are well designed to transport oxygen, having no n_________ and a
dumbbell shape to increase s_________ area. They are also rich in haemoglobin, which binds
oxygen during its transport from the lungs around the entire body. How does having no nucleus
help red blood cells to transport oxygen ?
Red blood cells: Word bank: oxygen lung nucleus surface
What's in blood Blood plasma Red blood cells Haemoglobin
Red blood cell
Diagram
Plasma
Platelets
Red blood cells
A single drop of blood Over half the liquid in Red blood cells contain Red blood cells are rich in
Notes
contains many millions blood is clear plasma. a red pigment called the protein haemoglobin
of red blood cells. This Nutrients from the haemoglobin. They and iron, which transport
represent just under digestive system are have no nucleus and are oxygen from the lung
half the total number of dissolved in plasma as biconcave in shaped to surface to billions of
cells found in human well as waste products help transport oxygen respiring cells in the
blood. like urea. around the body. human body.
- Slide 7: Science Interactive LTD Copyright 2005
Other components of blood
White blood cells are larger than r____ blood cells, but there are fewer of them. For every
one white blood cell there are over 500 red blood cells. Their main function is to protect
the body against m_______ infection. There are two main types of white blood cells.
Lymphocytes produce antibodies which bind bacteria and viruses before there are
engulfed by the other type of white blood cell, neutrophils. Platelets, which are not whole
cells, help scab formation when you cut your skin. This prevents further blood loss. What
is the disease called when your blood fails to clot ?
Other components of the blood: Word bank: red microbial
Lymphocytes & neutrophils Platelets Other blood components
Diagram
lym ne
ph utr
oc op
yte hil
s
s
Both lymphocytes and neutrophils are Platelets are not true If you analyse your blood, you will
Notes
part of the immune system. They roam whole cells, but cell also find dissolved in the plasma
the body and ‘search and destroy’ any fragments. When you cut nutrients like glucose, amino acids,
invading microbes (bacteria & viruses.) yourself, platelets help fatty acids and glycerol, which are
Lymphocyte cells produce antibodies scab formation preventing the products of digestion. Hormones
which help clump bacteria together so further blood loss and are also transported from their site
they can be engulfed by neutrophils. microbial infection. of production to their target tissues.
- Slide 8: Science Interactive LTD Copyright 2005
Arteries, veins and capillaries
The heart does not work alone to deliver oxygen and n_______ to the entire body. Blood is
pumped around a highly complex system of blood vessels measuring over 50,000 km in the
average human. There are three types of blood vessels: Arteries, Veins and Capillaries. Arteries
carry blood at the highest pressure away from the h_____ and therefore have the thickest elastic
muscle wall of all of the different types of blood tubes. From the descriptions below describe any
similarities of differences ?
Blood tubes of the cardiovascular system: Word bank: nutrients heart
Arteries Capillaries Veins
Valve
Elastic fibres
Elastic fibres
Thick muscle
Thin muscle
Outer wall
Outer wall
Arteriole Venule
Capillaries
Arteries carry blood away from the Fine capillaries cover the human Veins carry blood towards the heart
heart under high pressure. They have a body in a network of tubes. These under low pressure. They have a thin
thick muscle and elastic layer which capillaries are extremely thin and muscle and elastic layer and valves
stretch every time the heart beats. They narrow, measuring over 50,000 which prevent blood flowing
contract back and force blood forwards. km in the human body. You need backwards. Blood flow back towards
This can be felt as your pulse ! a microscope to see capillaries. your heart is also helped by your
- Slide 9: Science Interactive LTD Copyright 2005
Blood cells at the capillary
Blood capillaries have a very small d______ allowing only one red blood cell through at a
time. Blood flows very slowly through your capillaries. The capillaries are extremely thin
walled, which allows o______ and plasma which contains nutrients to diffuse to the tissue
bed and cells. Also waste products like urea and carbon dioxide can pass from the cells
back to the capillary. Why are red blood cells unable pass through the capillary walls ?
Understanding your capillaries: Word bank: diameter oxygen
Blood capillaries Gaseous and nutrient exchange at the capillary bed
Diagram
Net pressure
Carbon
dioxide Urea Wastes
Glucose Water
Oxygen Amino acids
Cells
Notes An electron micrograph Oxygen and nutrients including glucose diffuse from the blood, across
of a single capillary. the capillary wall to the cells. These are used for cellular respiration.
Notice the narrow Waste products including carbon dioxide and urea are transported back
diameter allowing only
in the plasma for transport to the lungs and kidneys.
one blood cell through.
- Slide 10: Science Interactive LTD Copyright 2005
Blood circulation
The circulation of blood through the heart, lungs and other major organs keeps the human
body supplied with the o______ and nutrients that it requires for cellular respiration,
growth and repair. This transport system also carries the white blood cells, platelets and
antibodies around the body defending us against microbial infection. What lifestyle
factors can prematurely age your cardiovascular system ?
Circulation in the body: Word bank: oxygen
Capillary exchange in detail
Red Blood Cell
Red Blood Cell
CO2 CO2
Tissue
O2 O2 O2 O2
Oxygen is exchanged for carbon dioxide at the tissue
surface. Oxygen diffuses across the capillary wall into
the cells or tissue. Oxygen is combined with glucose
during cellular respiration. Waste products including
carbon dioxide and urea are transported in the plasma
to the lungs and the kidneys.
- Slide 11: Science Interactive LTD Copyright 2005
Oxygen transport by blood haemoglobin
Red blood cells contain the protein, haemoglobin which is responsible for binding oxygen
at the l______ tissue (alveoli) and delivering it to every r____________ tissue or cell via a
huge capillary network which can be up to 50,000 km in length in the human body.
Haemoglobin also contains the mineral i_____ to help oxygen transport. Why is iron
important in the diet and why do females require greater quantities of this mineral ?
Oxygen transport: Word bank: lung respiring iron
At the alveoli Haemoglobin In the tissues
Haemoglobin
Diagram
O2
O2
CO2 CO2
CO2
O2 O2
O2
O2
O2
Oxyhaemoglobin
Notes Air contains 21% oxygen which is Haemoglobin is a protein found Oxygen diffuses across the thin
taken to the alveoli tissue by the in the red blood cell. It contains capillaries walls to the cells. It
bronchioles. Oxygen dissolves Iron (Fe2+) and is able to bind travels form a high concentration
across the thin alveoli surface and oxygen at several sites. Why do inside the capillary to a low
binds to red blood cells found females require more iron than concentration. Carbon dioxide
inside the lung capillaries. males ? moves to the blood.
- Slide 12: Science Interactive LTD Copyright 2005
The human heart
The heart, a four chambered pump is a collection of s__________ tissues which work together to
pump blood to the lungs, picking up oxygen and excreting carbon dioxide and then to the body
delivering oxygen and nutrients to every respiring cell, via a network of arteries, veins and
capillaries. The ventricles create sufficient p_________ by squeezing to send blood either to the
lungs (right ventricle) or the rest of the body (left ventricle) A number of valves between the
connecting chambers stops any unwanted backflow of blood. Why is the left ventricle thicker than
the right ventricle ?
Main features of the human heart: Word bank: specialised pressure
Human heart Heart valves Blood pressure
Diagram
The human heart is about the size of Valves between the four The difference in blood
Notes
a adult fist. Its function is to pump chambers (Atria and Ventricles) pressure in the arties and veins
blood to the lungs (RA, RV) and to open and close to prevent blood allows blood to flow around the
the rest of the body (LA, LV). Look from being forced backed when body. This pressure is created
at the picture of the four chambers. the ventricles contract. by the ventricles contracting.
- Slide 13: Science Interactive LTD Copyright 2005
The heart cycle one
If you look at the diagram below and follow the arrows, you can trace the path of blood around
the heart. Deoxygenated blood flows from the b_____, entering the right atria. It then travels to
the right ventricle where its is pumped to the l______ to pick up oxygen and excrete carbon
dioxide. Oxygenated blood enters the left atria, where it travels to the left ventricle. Here blood is
pumped to the rest of the body via the aorta.
Circulation around the heart: Word bank: body lungs
Arrow Action (Draw numbered arrows on the diagram)
Deoxygenated blood enters the heart into the right atrium.
1
Right ventricle contracts and pumps blood to the lung.
2
Blood loses carbon dioxide and picks up oxygen.
Lungs
Oxygenated blood enters the heart into the left atrium.
3
Blood moves into the left ventricle.
4
Blood is forced through the largest artery and into the blood.
5
Blood delivers oxygen and nutrients to all cells.
6
The diagram above shows the structure of the human heart. The pumping action of your heart is produced by
the muscle walls of the left and right ventricles. When the ventricles contract, blood is squeezed at pressure into
the arteries that supply the lung or the entire body. The valves only allow blood to flow in one direction. Draw a
flow diagram to help explain how blood is pumped around your lungs and body ?
- Slide 14: Science Interactive LTD Copyright 2005
The heart cycle two
The heart is supplied by electrical impulses through the vagus nerve. At rest, the heart
beats approximately 72 beats per minute (b.p.m.) When we e_________, our heart rate
increases to supply the exercising muscles with additional oxygen and nutrients. In a
trained athlete what are the differences in how their hearts perform during exercise ?
The heart cycle: Word bank: exercise
Stage One Two Three Four
Diagram
ECG
Notes The beating cycle of the heart lasts just under a second. It is controlled
by the vagus nerve. If we monitor the electrical activity of the heart it
gives a typical profile as shown left. The peak electrical activity triggers
the contraction of the left ventricle, the largest ventricle which forces
oxygenated blood around the body.
- Slide 15: Science Interactive LTD Copyright 2005
Understanding blood pressure
Blood pressure is caused by the ventricular muscles contracting during every heart cycle. This
pressure forces blood through the vast network of arteries, capillaries and veins. High blood
pressure, caused by narrowed arteries and high salt diets can damage your vascular system and in
extreme cases, lead to a heart a______.
Blood pressure in humans: Word bank: attack
One Two Three Four Blood pressure
Diagram You can take your blood
pressure. A normal adult
should have a reading of
120/80 (mmHg)
Notes
Pressure (mmHg)
- Slide 16: Science Interactive LTD Copyright 2005
The heart and aerobic respiration
If you view animals cells under a m__________, you can see tiny dots in the cytoplasm. These are
mitochondria. Cellular respiration occurs in the mitochondria, releasing energy from the
breakdown of glucose using oxygen. All living things give out carbon dioxide, a waste product of
cellular respiration. It is the role of the heart to supply sufficient oxygen to and remove waste
carbon dioxide from all cells in the Human body.
Respiration and mitochondria: Word bank: microscope
Mitochondria Notes
Diagram Cellular respiration is the breakdown of glucose with
oxygen providing cellular energy. This happens in the
C6H12O6 6H2O
cell’s mitochondria.
Cellular respiration equation:
Energy
Mitochondria
C6H12O6 + 6O2 6H2O + 6CO2
6O2 6CO2
Cells
Glucose Oxygen Water Carbon dioxide
Muscles Transport Digestion Nerve messages Body temp (oC) Building cells
Use
Diagram
- Slide 17: Science Interactive LTD Copyright 2005
Oxygen debt during anaerobic respiration
When muscles are working hard, they begin to respire glucose without oxygen. This is called
anaerobic respiration. Lactic acid produced during anaerobic respiration builds up and slowly poisons
your muscles. When your body can’t supply sufficient oxygen to your muscles, this is called oxygen
debt. When you stop vigorous exercise, your heart and lungs continue to supply extra oxygen to allow
the muscle to breakdown l____ acid. This repays the oxygen debt.
Oxygen debt: Word bank: lactic
Oxygen debt in muscles Lactic acid production in muscle
Diagram Oxygen supply
2.5 2.5
Oxygen demand (litres)
Oxygen supply (litres)
Lactic
Oxygen demand
C6H12O6
2.25 2.25
acid
2.0 Oxygen debt 2.0
Sugar
b
1.75 1.75
1.5 1.5
1.25 1.25
a B C
1.0 1.0
c
A
0.75 0.75
0.5 0.5
6O2 Carbon
0.25 0.25
dioxide
0
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Time (Minutes)
Notes During rest (a) the supply of oxygen to the muscles meets demand. During anaerobic respiration, less
During hard vigorous exercise (b), demand increases above supply energy is produced respiring glucose
and the muscle have to continue respiring glucose without oxygen. without oxygen. Lactic acid builds
Anaerobic respiration leads to the oxygen debt and formation of up and begins to damage your
lactic acid. This oxygen debt is repaid when exercise stops (c) by muscles, giving you the sensation of
the lungs continuing to oversupply the muscles with the lungs. the ‘burn.’
- Slide 18: Science Interactive LTD Copyright 2005
Complete fitness
Athletes require their key organ systems to work together so that they can exercise and
play their sport. Fitness is a measure of how well you body w_____ and exercises.
Athletes require ‘total fitness’ so that they can win and excel at their s______. The
cardiovascular, respiratory and skeletal-muscle system all work together to supply the
oxygen and nutrients to your muscles. How would you devise a training programme to
increase your overall fitness ?
Essential organ systems: Word bank: works sport
Athlete Cardiovascular Respiratory Muscle
Diagram
Professional athletes The cardiovascular Your respiratory system The skeletal-muscle
Notes
like runners and system is the human is constantly working to system works to move
footballers work hard body’s transport system. exchange oxygen for the body during sport.
to be fit for their sport, It moves oxygen, carbon carbon dioxide between An elite sprinter
but ideas of fitness dioxide, nutrients, the alveoli and the requires the fastest
vary according to their hormones, and immune pulmonary capillaries in contracting muscles
sport. cells around a network of the lung. during a 100 m race.
tubes.
- Slide 19: Science Interactive LTD Copyright 2005
Maintaining fitness
Athletes work hard to achieve total fitness, but what does being fit mean ? If you are fit,
you will have a low resting heart rate which recovers quickly after e_________. Your
lungs efficiently exchange oxygen and carbon dioxide at the alveoli tissue and your
skeletal m________ system moves you quickly, without tiring during a race or a game.
Exercising (running, weights & gym work) helps us to achieve fitness and improve our
ability to compete and win.
Fitness and the five ‘S’ Word bank: exercise muscle
Strength Stamina Skill Suppleness Speed
Diagram
Notes The five ‘S’ strength, stamina, skill, suppleness and speed are all improved by
repetitive training and exercise. Regular exercise also helps prevent people becoming
overweight and developing heart disease and diabetes. Nearly 25% of all adults are
now considered obese with almost 50% of all pupils of secondary school age not
taking enough exercise.
- Slide 20: Science Interactive LTD Copyright 2005
Atherosclerosis and heart disease
A high f____ diet over many years, lack of e__________, too much alcohol and smoking
leads to arthrosclerosis and general heart disease. Arthrosclerosis reduces the diameter of
the aorta and other major arteries, therefore increases blood p_______. Eventually a heart
attack may follow because of a clot in the coronary arteries. How can we educate people to
reduce their risk of developing atherosclerosis ?
Atherosclerosis: Word bank: fat exercise pressure smoking
Factor Alcohol Drugs Smoking Exercise
Diagram
Process Risk factors Normal Veins or Arteries Atherosclerosis Heart attack
Alcohol
S________
Drugs
No exercise
All these risk Healthy arteries allow red Fatty deposits block veins The heart starved of
Notes
factors contribute blood cells to flow freely and arteries reducing oxygen suffers a heart
to heart disease. through the heart tissue. blood flow. attack.
- Slide 21: Science Interactive LTD Copyright 2005
Understanding heart attacks
During a heart attack, the arteries supplying the heart and its muscular ventricles become
blocked with f______ deposits that have become detached from the lining of the coronary
arteries. Any heart muscle ‘downstream’ of the blockage is starved of o_______ and dies.
The heart can withstand losing about 50% of its muscle function. A fatal heart attack is
where the blockage deprives over 50% of heart muscle of their essential oxygen and
nutrients. What ‘lifestyle factors’ increase the risk of a heart attack ?
Heart attack: Word bank: fatty oxygen
Blocked arteries Heart attack Heart bypass Mechanical heart
Diagram
A high fat diet may During a heart attack, If your coronary arteries A final option, if the heart
Notes
lead to fatty deposits the muscle tissue is become blocked, you becomes damaged beyond
blocking your arteries. starved of oxygen and can opt for a triple repair, is to have a
These can break free nutrients because of a bypass, where veins mechanical heart. Post
causing a blockage in blockage in the from your leg replace operative survival rates
the arteries supplying coronary arteries. The the blocked arteries for this procedure are
the heart. muscle tissue then dies. supplying the heart. relatively low.
- Slide 22: Science Interactive LTD Copyright 2005
Sickle cell anaemia
Sickle cell anaemia is a genetic disease of the blood that affects African populations. The
disease is passed through faulty genes carried by the paternal s_____ or maternal eggs. In
humans who have the disease, red blood cells are sickle shaped with a reduced
s_________ area, which reduces the amount of o________ carried to the cells and tissues.
This disease is normally fatal. How can genetic counselling help parents and families who
carry the faulty gene for sickle cell anaemia make choices when having children ?
Sickle cell anaemia: Word bank: sperm surface oxygen
Normal blood Sickle cell Oxygen transport
Diagram Normal cell Sickle cell
O2 O2
O2
O2 O2 O2
O2 O2
O2 O2
O2
O2 O O2 O2 O2
2
Oxygen
Oxygen
Oxygen Oxygen
Normal red blood cells Faulty genes inherited Less oxygen than normal reaches
Notes
have no nucleus and are from one or both parents the tissues and cells. The sickle
biconcave in shape to help cause sickle cell disease. shaped red blood cells are not able
transport oxygen around The surface area of the to carry sufficient oxygen because
the body. sickle cell is reduced. of their reduced surface area.
- Slide 23: Science Interactive LTD Copyright 2005
Disease causing microbes
Bacteria, v_________ and fungi are all microbes which are able to cause disease in humans. Not
all diseases are caused by microbes, for example heart disease is caused by a number of lifestyle
factors like a high fat diet, smoking or excessive a________ intake. Microbes can be found
anywhere, in the air, the soil, on food, or on unclean surfaces and in water. A particular risk of
infection is associated with sharing unclean needles. Blood born viruses like HIV and hepatitis
can be passed on from person to person. Why are intravenous drug users who inject drugs like
heroin or crack at particular risk at contracting viruses like HIV and hepatitis?
Microbes: Word bank: viruses alcohol
Bacteria Viruses Fungi Needles
Diagram
A bacteria is a single Viruses are extremely Some types of fungi can Blood borne viruses
Notes
celled organism. All the small. Viruses are not cause disease or including and
HIV
bacteria in the world whole cells. Their infections in humans. hepatitis can be passed
weigh more than any genes are found in a Athlete’s foot is caused from person to person by
other class of species. protective protein coat. by a fungi. They needle sharing. Drug
They are the most They reproduce inside reproduce by producing users have a high risk of
successful species. other cells. spores. contracting HIV.
- Slide 24: Science Interactive LTD Copyright 2005
Transmission of bacterial disease one
Bacteria can be found in every living o_________, on every surface and even in the air we
breathe. Some bacteria are very useful, whilst other cause diseases like cholera and
dysentery. There are a number of ways in which bacteria can enter your body. By
understanding how disease enters our body, we can reduce our risk of contracting or
spreading the disease. Explain why most infections caused by bacteria are entirely
avoidable in humans ?
Bacterial infecting people: Word bank: organism
Food Touching Sewage Surfaces
Diagram
Fresh food and drink Touching an infected Water containing human Surfaces in kitchens and
Notes
can be infected with person can lead to the waste is full of bacteria. bathrooms can be home
bacteria. Some foods transmission of the Before water is fit to to many thousands of
contain bacteria that disease causing bacteria. drink it is filtered, unwanted and harmful
can only be destroyed Bacterial infections cleaned and sterilised bacteria. Always keep
by cooking. How does causing nausea can be using chlorine which is these surfaces clean by
this destroy bacteria ? spread by touch. antiseptic. using disinfectants.
- Slide 25: Science Interactive LTD Copyright 2005
Transmission of bacterial disease two
Bacteria has to enter our bodies before they can cause d________. They can enter via the
digestive system, the nose or cuts in our s____. Our lifestyles determine our risk to
infection. In refugee camps, where there is little or no treatment of sewage, poor nutrition
and many people living in unsanitary conditions, disease spreads rapidly killing many
people. We all have a personal responsibility for how we live and how clean we are.
Explain how modern intensive farming can lead to the transmission of viruses like ‘bird
flu’ or ‘mad cows disease: BSE’ in humans ?
Bacteria infecting people: Word bank: bacteria skin
Animals Washing hands Sneezing Waste
Diagram
Animals are a potential Washing your hands Using a tissue and Human waste is another
Notes
source of infection. before meals or after covering your nose source of bacterial
Most farm raised going to the toilet prevents you from infection. Decaying fruit,
animals are given huge reduces the risk of infecting other people. meat and vegetables play
amounts of antibiotics infection from bacteria Millions of microbes are host to many different
to control their levels found in human waste expelled from your nose bacterial colonies. Why
of disease and bacteria. like faeces. every time you sneeze. do we treat our waste ?
- Slide 26: Science Interactive LTD Copyright 2005
Human immunity
You can have two types of immunity: Innate and acquired immunity. Innate immunity is
your body’s response to an i_________. When you are infected by a microbe, your white
blood cells will respond by engulfing the microbes and produce the right sort of
antibodies. Acquired immunity can come from vaccinations, breast feeding or booster jabs.
During breast feeding, your mother’s milk contains a__________ which can help you fight
any disease until your own immune system develops. Can you remember any of the
vaccinations that you have been given ?
Types of immunity: Word bank: infection antibodies
Innate immunity Vaccination Breast feeding Boosters
Diagram
Plasma Red Blood Cells
Neutrophils
Blood
Lymphocytes
Cells
Notes White blood cells find and destroy We can acquire immunity in three ways: During vaccination,
microbes, reducing our risk of vaccines are given to us when we are young to protect us against
dying from infection. Although less diseases like smallpox. Breast feeding allows the newborn to have all
numerous than red blood cells, there the same antibodies as their mothers. Boosters are given when there
are an essential part of our immune is an outbreak of a disease or to the young and old. These are given
system. by injection.
- Slide 27: Science Interactive LTD Copyright 2005
Blood fighting infection one
Blood also contains white blood cells, platelets and antibodies that are all part of the immune system
which is responsible for fighting disease. White blood cells are a collection of cells that help
recognise, fight and destroy foreign material like b________ and viruses. Lymphocytes produce
antibodies which help clump bacteria together so they can be engulfed by neutrophils (also called
phagocytes) When a new m_________ enters the body, new antibodies are made which recognise only
that microbe. After the microbe has been destroyed, these antibodies remain in the blood, giving you
immunity to that microbe. Why do babies have the same immunity as their mothers ?
Immune response in blood: Word bank: bacteria microbe
Stage one Stage two Stage three Stage four
Diagram
Microbes enter your Microbes use the blood Antibodies produced by Phagocytes or
Notes
body from sources like and other tissues to lymphocytes in response neutrophils begin to
unclean hands or food begin to multiply. They to a specific microbe are search, and destroy
that has not been have a ready source of able to recognise and microbial cells. They
cooked or handled oxygen and nutrients. If clump together these release enzymes which
properly. Describe the microbes continue to invaders. It takes about 2 rip open and destroy the
four other ways of multiply, the toxin they – 5 days for lymphocytes microbes. They also
microbial transmission produce would kill you. to make these antibodies. neutralise any microbial
- Slide 28: Science Interactive LTD Copyright 2005
Blood fighting infection two
The skin is the largest o______ in the body. One of its main functions is to act as a ‘physical
barrier’ to the entry of microbes. If cut, you are at risk of infection caused by the entry and
subsequent multiplication of microbes in the circulatory system. Once cut, the skin rapidly heals
to prevent further blood loss and the entry of microbes into the b______ stream. Healing and
scab formation is helped by the clotting response. This is where platelets and fibrinogen, both
carried in the blood, form a tightly knitted scab that closes the wound. What role do plasters play
in helping us avoid infection from microbes ?
Forming a scab: Word bank: organ blood
Human skin Stage one Stage two Stage three
Diagram
A key role of the skin is to help
Notes When you cut healthy skin, a three stage response occurs before
maintain core body temperature scab formation takes place. One: The skin is cut, bleeding
at 37oC. The skin also has many occurs. Two: Platelets are pumped to the injury site. Three:
other roles. It protects your body
Platelets and fibrinogen form a scab which prevents further
against disease and bacterial
bleeding and closes the wound. White blood cells are also
infection by acting as a physical
rushed to the injury site to destroy what ?
barrier
- Slide 29: Science Interactive LTD Copyright 2005
Blood fighting infection three
White blood cells (neutrophils) constantly roam around the circulatory system. Unlike red blood
cells, they do not carry o_______, but form part of your immune system. Neutrophils are able to
find, attach and engulf m_______. When the invading microbes are fully engulfed, they are
digested and destroyed by enzymes inside the cell. These white blood cells are also able to
neutralise any microbial toxins, therefore preventing these toxins from poisoning your body. HIV
affects your white blood cell count...how does this leave you vulnerable to other diseases ?
Neutrophils engulfing bacteria: Word bank: oxygen microbes
Components of the blood Neutrophils (Phagocytes) in action
Diagram
Plasma Red Blood Cells
Neutrophils
Blood
Lymphocytes
Cells
An essential role of blood is to fight disease. Images of a neutrophil (phagocyte) in action. They
Notes
Lymphocyte antibodies and neutrophils search and have long thread like features which literally trap the
destroy microbes. Without an immune system we bacteria and draw them in to be engulfed by the
couldn't survive in our environment. neutrophil. HIV destroys these cells !
- Slide 30: Science Interactive LTD Copyright 2005
Blood fighting infection four
Despite millions of neutrophils, which search and destroy microbes that enter the bloodstream,
some microbes are difficult to find and evade detection by these immune cells. The other white
blood cells, lymphocytes produce a__________ which are specific to an individual microbe.
They work by binding onto the surface of the microbe and clumping them together. This makes
their detection by neutrophils easier. Your body also remembers this microbe and continue to
produce antibodies for the rest of your life, ready for the next time. Why do they say that you
never catch the same cold twice ?
Antibodies in your blood: Word bank: antibodies
Bacterial infection Producing antibodies How antibodies work
Diagram
Bacteria enter and multiply in Several days after infection, Antibodies are able to clump
Notes
the blood. They spread out and your lymphocytes start to together microbes in the blood
try to avoid detection by your produce large numbers of by binding themselves to the
neutrophils. What happens if antibodies which roam around their surface. This aids their
they are left to continue to the bloodstream looking for detection by neutrophils which
multiply in the bloodstream ? invading microbes. then destroy them.
- Slide 31: Science Interactive LTD Copyright 2005
Microbes and your health
When microbes like viruses or bacteria enter your body, you develop s_________ alongside the
disease. These symptoms are a result of either toxins produced by rapidly multiplying bacteria or
viruses destroying your cells found in organs like your lung. Your body temperature rises, you
may feel generally unwell, sleepy and experience a____ or pains. During the illness period, your
body begins to make new antibodies and neutrophils to search and destroy the microbes. Look at
the graph and see how you body responds to illness or disease caused by microbes.
Microbes and your health: Word bank: symptoms aches
Notes
incubation illness recovery
Measurements of body
temperature, microbes and
antibody levels were taken
Antibodie s
during a 14 days period.
1: How long would you have
felt ill during the 14 days ?
2: How many days did the
Microbe
microbe replicate itself in the
body before your immune
system kicked in ?
3: Why did the number of
microbes start to decrease after
Body temp
5 days ?
normal 4: Explain why the level of
37o C
antibodies in your blood remain
6 time days 8
0 2 4 10 12 14 high, even during recovery ?
- Slide 32: Science Interactive LTD Copyright 2005
Extension questions and homework
1. Define the following terms: Blood, Immunity, Microbe, Bacteria, Virus, Fungi, Immunity, Antibodies & Vaccine.
2. Look at the diagram of the three types of microbes. Complete the table.
Microbe Examples How are they spread What symptoms do they produce
Bacteria
Viruses
Fungi
12. Name three cells types contained in the blood and give a function for each. What’s the role of the clear plasma
fluid found also in blood.
13. Using the diagram of the circulatory system answer the following questions: (a) Which blood vessels carry blood
away from the heart. (b) Which blood vessels carry blood to the heart. (c) Name the blood vessel through which
blood enters the heart from the body (d) Describe the path blood takes from the lung surface to the liver.
14. Complete the following table:
Arteries Capillaries Veins
Carries blood ___ the heart. Connects arteries and _______. Carries blood to the heart.
Has a ______ wall carrying Has a _____ wall and carries blood Has a _____ wall carrying blood at
blood at ______ pressure. The at _____ pressure to allow gas ______ pressure. Contains valves to
aorta is the biggest example. exchange. stop back flow.
- Slide 33: Science Interactive LTD Copyright 2005
6: Look at the information in the table below. It shows the patient’s temperature when suffering from a bacterial
infection:
Day 0 2 4 6 8 10 12 14 16 18
Body temperature 37oC 37oC 38oC 39oC 39oC 40oC 40oC 38oC 37oC 37oC
a) What symptom of the disease is shown by the data.
b) How long was the incubation period.
c) What caused the fever and how long did it last.
7: a) What is an antibiotic and how was the first antibiotic discovered.
b) In hospitals, patients are treated for bacterial infection by doctors using antibiotics. Some of the bacterial strains
become resistant to antibiotics like penicillin. How might this happen.
8: What is the difference between the following;
a) An antiseptic and a disinfectant.
b) An antibody and an antibiotic.
c) A vaccine and vaccination.
9: Explain why you should:
a) Never share a bath towel with someone.
b) Always wash your hands before handling food.
c) Always wash your hands after going to the toilet.
d) Always refrigerate food and throw away after the ‘use by’ date.
e) Always cook meat thoroughly.
f) Never share needles and always practice safe sex using the barrier method e.g. condoms.
- Slide 34: Science Interactive LTD Copyright 2005
10: The movement of blood through the circulatory system of a mammal is described as a double circuit (a) Explain
how the structure and the tissues of the heart maintains the double circulation blood pressure (b) Why is the muscle
wall of the left ventricle thicker than that of the right (c) Explain the role of the bicuspid, tricuspid and semi-lunar
valves.
11: Give a function for each tissue of the heart.
Part Function Part Function
Left ventricle R_____ A______ Receives blood from body
Right ventricle Left atrium
A______ Takes blood to body Pulmonary vein
Smooth heart lining Pulmonary artery
12: A high altitude there is less oxygen in the air. People who live at high altitude make more red blood cells to acquire
sufficient oxygen from the air. The table shows an analysis of blood of 3 people.
Measurement Person A Person B Person C
Red blood cells (mm3) 8,000,000 4,500,000 2,000,000
White blood cells (mm3) 6,000 7,000 6,000
Platelets (mm3) 200,000 210,000 1000
13: (a) which individual lives at the highest and lowest altitude. Explain your answer.
(b) Which person is suffering from non-sickle cell anaemia.
(c) Which person will not clot properly when their blood vessels are cut.
(d) Which person can deliver most oxygen (mm3/min) to the muscle cells.
Internet:
Go to google.co.uk and find about how platelets form scabs when the skin and its capillaries are cut. Find out how a
high fat diet affects the cardiovascular system and what is a heart attack.