Biology 20Circulatory System

General Outcome 2 – Students will explain the role of the circulatory and defence systems in maintaining an internal equilibrium.

A. Functions of the Circulatory System

Circulatory systems can be either open or closed. Open systems do not have the blood contained to vessels – insects. Closed systems have all of the blood moving through the body via vessels – humans. Closed systems are more efficient at transporting material than open systems.

On average, your body has about 5 liters of blood continually traveling through it by way of the circulatory system.

The heart, lungs, and blood vessels work together to form the circle part of the circulatory system. The pumping of the heart forces the blood on its journey.

Our circulatory system has several functions: 1. Carries nutrients to cells2. Carries wastes away from cells3. Transports chemical messengers to all parts of the body (hormones)4. Distributes heat5. Houses immune system cells

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The body’s circulatory system has three distinct parts:

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1. Pulmonary circulation – blood to the lungs 2. Coronary circulation – blood to the heart

3. Systemic circulation – blood to the rest of the body Systemic circulatory system supplies nourishment to all the tissues located throughout the body, with the exception of the heart and lungs because they have their own systems. The systemic circulatory system is an intensive network of blood vessels.

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B. Blood Vessels

The human body has three types of blood vessels. Arteries Capillaries Veins

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a) Arteries

High pressure blood vessels that carry blood away from the heart. Composed of three distinct layers.

The outer and inner layers are rigid connective tissue, whereas the middle layer is made up of muscle fibers.

Real-life Applications Aneurysm – fluid-filled bulge in a weakened wall. Atherosclerosis – buildup of fat deposits in inner wall of the artery.

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b) Arterioles

Fine branches from the arteries. The middle layer is composed of elastic fibers and smooth muscle. The diameter of the arterioles is regulated by the nerves from the autonomic nervous system (unconscious control = involuntary).

Vasoconstriction – contraction of smooth muscle in the arterioles, reducing the diameter of the blood vessel. This reduces blood flow to an area.

Vasodilation – relaxation of smooth muscle in the arterioles, increasing the diameter of the blood vessel. This increase blood flow to that area, thereby, increasing the delivery of nutrients to tissues, and increasing the capacity of the cells in that localized area to perform energy-consuming tasks.

Real-life Applications Blushing Paleness due to being frightened or sick

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c) Capillaries

Single layer of cells – site of fluid and gas exchange between the blood and the body cells. The single layer is ideal for diffusion; however the capillary beds are easily destroyed. High blood pressure or any impact can rupture the thin layered capillary.

Real-life Application Bruising – rupture the capillary beds, which allows for blood to flow into the

interstitial spaces

d) Venules

Small veins that lead away from the tissues (capillaries) to begin the journey back to the heart.

e) Veins

Carry blood back to the heart. Large vessels with thin walls – there is no muscle fibers located here.

Contains one-way valves to help pull the blood back towards the heart against the force of gravity. Contraction of skeletal muscles surrounding the veins will also help to pump the blood back towards the heart. The one-way valves will open when pressure increases inside the vein.

Veins act as blood reservoir – as much as 50% of your total blood volume can be found in the veins at any one time.

Real-life Application Varicose (Spider) Veins – large

volumes of blood can distend the veins. When this pooling of blood occurs over a long period of time the one-way valves are damaged.

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Worksheet – Blood Vessels

1. Label the following diagram

2. Use blue and red to indicate whether the vessel carries oxygenated blood (red), deoxygenated blood (blue) or both.

3. Compare the structure and function of the three types of blood vessels.

Blood Vessel Type Structure Description FunctionArtery

Vein

Capillary

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Heart → Arteries → Arterioles → Capillaries → Venules → Veins → Heart → Lungs

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C. Heart Structure/Function

Define the following terms:Aorta

Septum

Right atrium

Left atrium

Right ventricle

Left ventricle

Superior vena cava

Inferior vena Cava

Chordae tendonae

Left pulmonary artery

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Left pulmonary vein

Right pulmonary artery

Right pulmonary vein

Semilunar valves

Atrioventricular valves

Tricuspid valve

Bicuspid valve

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D. Blood Flow and the HeartPulmonary Circulation – blood vessels that carry blood to and from the lungs.Systemic Circulation – blood vessels that carry blood to and from the body.Blood Flow:

1. Deoxygenated blood reaches the heart through the inferior and superior vena cava and empties into the right atrium.

2. Blood moves through the AV valve into the right ventricle.3. Blood is pumped through the semilunar valve into the right and left pulmonary

arteries (**these are the only arteries that carry deoxygenated blood**)4. Oxygen diffuses into the blood in the lungs.5. Oxygenated blood now enters the pulmonary veins which take the blood back to

the heart (**these are the only veins that carry oxygenated blood**)6. Blood enters the left atrium and moves through the AV valve into the left

ventricle. 7. Oxygenated blood is pumped out through the semilunar valve into the aorta where

it will travel to the body tissues.8. Tissues use the oxygen/nutrients/fluids in the blood, then the deoxygenated blood

moves through the venous system back towards the inferior and superior vena cava.

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Worksheet - Flow of Blood Through the Heart

1. Using blue and red pencils or pens, diagram the pathway of blood through the heart using arrows. Use blue to represent deoxygenated blood and red for oxygenated blood.

2. Using the above diagram as a reference, fill in the missing terms in the sentences below.

a) Blood enters the right atrium through the _______________________.

b) Blood flows from the right atrium into the right ventricle through the

_________________.

c) Blood is pumped from the right ventricle into the pulmonary trunk that splits into

the right and left _____________________.

d) Blood returns from the lungs by way of the right and left

____________________.

e) Blood enters the ____________________ when it returns from the lungs.

f) Blood flows past the ________________________ as it enters the left ventricle.

g) The left ventricle pumps out past the ______________________ into the aorta.

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E. Nervous Control of the HeartReceptors in the body monitor the concentration of chemicals in the blood and the blood pressure.

1. Baroreceptors – monitor pressure in the aorta and carotid artery2. Chemoreceptors – monitor amount of CO2 in the blood.

These receptors send signals to a specialized area in the brain called the medulla oblongata. The medulla responds by stimulating one of two nerves:1. Parasympathetic nerve – tells the heart to beat at a normal rate.2. Sympathetic nerve – tells the heart to increase the heart rate.

These nerve control the heart by stimulating a specialized area in the right atrium called the sinoatrial node (SA node).The SA node is the pacemaker…. It causes the heart to beat approximately 70 times each minute. The following sequence of events outlines the nervous control of the heart:1. The beat (contraction)

is generated in the SA node.

2. Electrical impulses pass on to both atria, causing them to simultaneously contract.

3. The impulses then move on to a second node called the atrioventricular node (AV node).

4. The message to contract is then relayed quickly down special nerves in the septum called the Bundle of His.

5. The message is sent into extensions of nerves in the ventricle walls called the Perkinje Fibres.

6. Both ventricles are now stimulated to contract at the same time.

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F. Electrical Conductivity of the HeartThe electrical activity of the heart can be monitored by using an electrocardiogram (ECG).Changes in the electrical current reveal normal or abnormal events in the cardiac cycle.

Pwave – atrial contractionQRS – ventricular contractionT – ventricles relaxed

G. Heart Sounds The sounds of the heart are referred to as lub and dub.Lub is the closing of the AV valves (ventricles pumping).Dub is the closing of the semilunar valves (atria pumping).

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The Cycle1. AV valves open.2. Ventricular contraction – systole3. AV valves close 4. Lub sound heart5. Semilunar valves close6. Dub sound heard7. Ventricular relaxation (filling with blood again) – diastole

Heart rate – the number of beats per minute (around 72 bpm)Stroke volume is the amount of blood passing through the heart with each beat (about 80mL)Cardiac output is the amount of blood pumped each minute.Cardiac output = heart rate x stroke volume = 72bpm x 80mL/beat

= 5760 mL/beat

Thought Lab - How Much Blood Does Your Heart Pump?Investigate the relationship between cardiac output and heart rate

Cardiac output is the volume of blood pumped by each ventricle per minute. Because humans have a closed circulatory system, the cardiac output is the same as the volume of blood that traverses the systemic or pulmonary circulations per minute. It is calculated by multiplying the heart rate by the stroke volume. Stroke volume is the volume of blood ejected by each ventricle per beat.

A healthy heart with a normal cardiac output pumps about 5 to 6 litres of blood every minute when a person is at rest. The heart pumps about 75 mL each time it beats, and it beats an average of 70 times each minute.

Cardiac output = stroke volume × heart rate

Cardiac output = 75 mL × 70 beats per minute

Cardiac output = 5.3 litres per minute

Cardiac output increases during exercise because of an increase in heart rate and stroke volume. When exercise begins, the heart rate increases up to about 100 beats per minute. As exercise becomes more intense, skeletal muscles squeeze on veins more vigorously, returning blood to the heart more rapidly. In addition, the ventricles contract more strongly, so they empty more completely with each beat.

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During exercise, the cardiac output increases to a maximum of about 25 litres per minute in an average young adult. Although the cardiac output has increased by five times, not all organs receive five times the blood flow; some receive more, others less. This is because the arterioles in some organs, such as those in the digestive system, constrict, while arterioles in the muscles that are working and in the heart (another muscle) dilate. Vasodilation greatly increases blood flow; vasoconstriction greatly decreases blood flow.

What to do

1. Determine your heart rate by taking your pulse.

2. Multiply your pulse rate by the stoke volume (75 mL). Assume for the purposes of this activity that the stroke volume remains constant.

3. Do this for different levels of activity (sitting at rest, lying on the floor, running on the spot), and compare your results.

Answer the questions below

Type of ActivityPulse rate per

minuteStroke volume

(mL)Cardiac Output

(L)

Sitting, at rest

Lying on the floorAfter 2 minutes of running on the spot

1. Define the terms “cardiac output” and “stroke volume.”

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2. Did your cardiac output increase or decrease during the 2 minutes of exercise? Explain why.

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3. Explain why some of your arterioles dilate while others constrict when you exercise.

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4. Your body contains approximately 5 litres of blood. How long does it take for the entire volume of blood to pump through your heart when you are sitting?

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H. Blood Pressure

Blood pressure is the pressure exerted on the walls of the blood vessels. Constant blood pressure is needed to maintain the proper functioning of all other systems. Blood pressure is measured in the arteries.

Diastolic (relaxation) pressure is about 35% lower than systolic (contraction) pressure. Normal blood pressure for an adult at rest is 120/80 mmHg (systolic/diastolic)Blood pressure is measured using a sphygmomanometer. Blood pressure readings can vary depending where in the body it is being measured.

1. Highest in left ventricle – needs to pump blood to the entire body.2. High in systemic circulation – body3. Lower in pulmonary circulation – lungs4. Lowest in the right side of the heart – only has to pump blood to the lungs.

Regulation of Blood Pressure Blood pressure is regulated by special receptors called baroreceptors, the medulla oblongata, and nerves called the sympathetic and parasympathetic.

High Blood Pressure

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Baroreceptors in the aorta and carotid artery signal the medulla. This in turn is going to increase parasympathetic nerve function and decrease sympathetic nerve function in order to decrease blood pressure.Arterioles dilate which makes the stroke volume decrease and therefore, the blood pressure will also decrease.

Low Blood PressureBaroreceptors in the aorta and carotid artery signal the medulla. The medulla increases sympathetic nervous system function and decreases parasympathetic nervous system function. Arterioles constrict which makes the stroke volume increase and therefore, increasing the blood pressure.

Stress and ExerciseSympathetic nerve stimulates the adrenal gland which then secretes adrenalin (epinephrine). Adrenalin has three functions:

1. Releases red blood cells from the spleen to increase O2 delivery.2. Vasodilation of arterioles in heart, brain, muscles.3. Vasoconstriction of arterioles in kidneys, stomach, intestines.

Most active tissues get the priority – fight or flight response.

Lab – Factors Affecting Heart Rate and Blood Pressure

HypothesisMake and record a hypothesis about the effects of at least two different factors on heart rate and blood pressure.

Safety PrecautionsDo not over-inflate the blood pressure cuff. Students with circulatory or blood pressure problems should not be test subjects.

Materials blood pressure cuff watch with a second hand or a digital display of seconds

Experimental Plan1. Working in a group, prepare a list of ideas for testing your hypothesis, using the

materials available in your classroom.

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2. Decide on one idea you can use to design an experiment that can be conducted in your classroom.

3. What will be your manipulated variable? What will be your responding variable(s)? What will be your control variable(s)? How many trials will you run? Remember that you should test one variable at a time. Plan to collect quantitative data.

4. Outline, step-by-step, a procedure for your experiment. Assemble the materials you will require.

5. Design a table for collecting your data.

6. Obtain your teacher’s approval before starting your experiment.

Data and Observations7. Conduct your experiment, and record your results. Prepare a graph or chart to help

you communicate your findings to other groups in the class.

Analysis1. What was the resting blood pressure and heart rate for each test subject?

2. How did the blood pressure change as a result of the factor you were testing? How did the heart rate change as a result of the variable you were testing?

3. How long did each change last after termination of the testing factor?

Conclusions4. Compare your results with the results of other groups in the class. Explain any

differences.

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5. What is the adaptive advantage of a temporary increase in blood pressure? What is the adaptive advantage of a temporary increase in heart rate?

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Extension6. High blood pressure is a common problem in North America. Fortunately, many

different treatments are available. Some examples include treatments used in Western medicine, traditional Aboriginal medicine, traditional Chinese medicine, Ayurvedic medicine, naturopathy, homeopathy, massage therapy, and yoga. Research three different treatments for high blood pressure, and prepare a brief report to compare the main features of these treatments. If someone wanted to receive treatment for high blood pressure, which would you recommend? Justify your choice.

7. If possible, obtain two types of blood pressure cuffs. Newer cuffs give digital readings, while older cuffs require the use of a stethoscope to listen to the sounds of blood moving through the vessels. Use both types of blood pressure cuff to measure a partner’s blood pressure. Compare the readings you got, and describe the differences in your experiences with the two cuffs.

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I. Capillary Fluid Exchange

Every cell in the body is within 0.1mm of a capillary. Capillaries serve very important functions:

1. Provides cells with nutrients and gases (glucose and O2).2. Takes away cell wastes (CO2).3. Maintains a constant fluid level.4. Exchanges fluid between blood and extracellular fluid (ECF).

A. Filtration

Occurs in the arteriole end of the capillary. Water and small ions move out f the capillary into the ECF. This movement is the result of a pressure gradient. The water and ions move from an area of high pressure to an area of low pressure.

B. Absorption

Occurs in the venule end of the capillary. Water moves from ECF into the capillary – large proteins in the capillary makes the concentration of H2O greater in the ECF. This movement is the result of an osmotic gradient – going from an area of high water concentration to an area of low water concentration.

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Cause Effect

Hemorrhage

Edema

Allergic Reaction

J. Lymphatic System

• a noncircular system of vessels that takes fluids from tissues to the bloodstream • vessels are similar to veins…they use one-way valves and muscular contractions

to move the fluids • lymph is any fluids and proteins that collect in the ECF (mostly water)

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• large lymphatic ducts collect the lymph…the main duct is called the thoracic duct • lymph nodes are located along the vessels (mainly in neck, groin and armpits) • these nodes manufacture and house immune system cells that filter bacteria and

debris from the lymph • blocking of lymphatic ducts can cause severe edema

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Worksheet – The Lymphatic System

1. Label the human lymphatic system diagram below. Use green to indicate the lymphatic vessels.

2.

a) Where does lymph come from?

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b) How is lymph returned to the cardiovascular system?

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c) What feature do lymphatic vessels share with veins to ensure one-way flow?

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d) What is the key difference in the circulation systems of blood and lymph?

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3. Label the diagram below.

4. Another function of the lymphatic system is to help fight infection.

a) How does the lymphatic system fight infection?

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b) Why do your lymph nodes swell when you are ill?

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K. Blood Functions

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• our blood has five main functions 1. transportation – nutrients, wastes, hormones, etc. 2. water balance 3. pH balance 4. maintain body temperature 5. house immune system cells

L. Blood Composition

• blood is made up of a variety of blood cells • all blood cells come from stem cells in bone marrow…the stem cells differentiate

to become the different blood cells • 1 L of blood contains 200 mL of O2 which is carried by hemoglobin

***blood carries 70X more O2 with hemoglobin (you can live ~ 5 minutes without O2 but without hemoglobin you would live 4.5 seconds!)

Component (%)

Structure Function Other

Plasma (~55 %) • 90 % water • maintains blood • proteins –

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• 10 % glucose, proteins, vitamins/minerals, wastes, gases

volume • proteins for homeostasis • carries O2 and CO2

globulin, albumin, fibrinogen

RBC’s (~45 %) • contains

hemoglobin…280 million on one RBC (heme is pigment, globin is protein) • no nucleus • biconcave disks • live ~ 120 days • produced in bone marrow

• carry oxygen • hemoglobin + O2

forms oxyhemoglobin • also carries CO2

• hemoglobin + CO2

forms carbaminohemoglobin

• anemia is a ↓ in RBC’s • injury ↓ RBC’s • high altitude – need more RBC’s because less O2

WBC’s (<1 %) • have a nucleus

• larger than RBC’s • several types • produced in bone marrow

• destroy foreign invaders • produce antibodies • produce pus • perform phagocytosis

• AIDS • leukemia • ↑ WBC’s during infection

Platelets (<<1%) • no nucleus

• irregular shape, fragile • produced in bone marrow

• initiate blood clotting reactions when ruptured

• hemophilia

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Worksheet – Blood Cells

Blood is often described as the “river of life” because it transports substances needed by the body. It has a fluid portion called plasma and a formed portion made up of the red blood cells, white blood cells, and platelets. Doctors use blood as a diagnostic tool that can help them identify what may be happening with a patient.

STUDY THE INFORMATION IN THE CHART BELOW AND MATCH THE PATIENT WITH THE CORRECT CONDITION.

Patient Red Blood Cells (× 109/mL blood)

White Blood Cells (× 106/mL blood)

Platelets (× 108/mL blood)

1 (normal) 5 7 3

2 3.5 12 2

3 3.7 7 3

4 7 7 3

5 5 8 1

1. Which two patients may be having difficulty with blood clotting? How do you know?

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2. Which two patients might appear tired and lack energy? How do you know?

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3. Which patient is likely fighting off an infection? How do you know?

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Worksheet – When Red Blood Cells Go Wrong!

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Red blood cells (erythrocytes) carry oxygen to the cells of the body. A condition called hypoxia (low oxygen) can result if the number of red blood cells is diminished or if there is a problem with the hemoglobin within the red blood cells.

Study the chart below, and match the condition with the correct patient. Please note that the information in the chart refers only to the patient’s systemic circulation.

Patient Condition Hemoglobin(grams Hb/100 mL blood)

Oxygenated blood (mL O2/100 mL blood)

Deoxygenated blood (mL O2/100 mL blood)

Cardiac Output (L/min)

1 Normal 15 19 15 5.02 Hypoxic 15 15 12 6.63 Hypoxic 9 9.5 6.5 7.04 Hypoxic 16 21 13 3.05 Hypoxic 15 19 18 No

information given.

1. Which patient might be suffering from a dietary iron deficiency? How do you know?

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2. Which patient may be experiencing heart failure and thus poor blood circulation? How do you know?

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3. Which patient may recently have experienced high altitude (hiked up a mountain) where air is lower in atmospheric oxygen? How do you know?

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4. Which patient may have been exposed to a poison that prevents the cells from using oxygen? How do you know?

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5. Patient 2 is experiencing increased breathing. Describe the mechanism responsible.

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6. Answer the following questions in relation to Patient 1:

a) How much blood is flowing through the lungs each minute?

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b) How much oxygen (in mL) is transported to the lungs each minute? Explain.

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c) How much oxygen (in mL) is carried away from the lungs each minute? Explain.

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d) Use the answers from b) and c) to calculate the oxygen consumed each minute. Show and explain all of your work.

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M. Blood Types

A blood transfusion is the transfer of blood from one person into the blood of another. Many early blood transfusions resulted in illness, and sometimes the death, of some recipients. Eventually, scientists discovered that only certain types of blood are compatible because red blood cell membranes carry specific substances that are antigens to blood recipients. Several groups of red blood cell antigens exist. The most significant of these is the group of antigens in the ABO system.

The ABO System

In the ABO system, the presence or absence of type A and type B antigens on red blood cells determines a person’s blood type. The presence or absence of these antigens is an inherited characteristic.

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A person who has type A antigen on the surface of the red blood cells has type A blood. A person with type B blood has type B antigen on the surface of the red blood cells. A person with type AB blood has both antigens, and a person with type O blood has neither antigen on the surface of the red blood cells.

A person who has type A blood has anti-B antibodies in the plasma. A person with type B blood has anti-A antibodies, and a person with type O has both antibodies in the plasma. These antibodies appear within several months after birth. The presence of these antibodies can cause agglutination. Agglutination is a clumping of red blood cells that occurs when incompatible blood types are mixed. Agglutinated red blood cells can clog blood vessels, blocking circulation and causing severe damage to organs.

Universal Donor – type O blood can go into any other blood type and therefore, is called the universal donor.

Universal Recipient – type AB blood can receive any blood type as it will not recognize any antigen as foreign, and therefore it has been termed the universal recipient.

The Rh System

Another group of antigens found in most red blood cells is the Rh factor. People with the Rh factor on their red blood cells are termed Rh positive (Rh+). People without it are Rh negative (Rh-). Individuals who are Rh- usually do not have antibodies to the Rh factor, but they may make them when they are exposed to the Rh factor during a blood transfusion or pregnancy.

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If a mother is Rh- and the father is Rh+, a child may be Rh+. The Rh+ red blood cells of the child may leak across the placenta into the mother’s bloodstream. The presence of these Rh+ antigens causes the mother’s immune system to produce anti-Rh antibodies. Usually, in a subsequent pregnancy with another Rh+ baby, the anti-Rh antibodies may cross the placenta and destroy the4 child’s red blood cells. This is called hemolytic disease of the newborn (HDN). This condition can lead to brain damage, deafness, and death.

In HDN, as the red blood cells break down, the liver produces a substance called bilirubin in such excess that bilirubin ends up in their blood an other tissues and fluids of the baby’s blood. Bilirubin is a pigment that causes the baby’s blood and tissue to turn yellow. This condition is called jaundice. The presence of jaundice is a sign for diagnosing HDN. Treatment at this stage may involve a blood transfusion for the child or inducing early labor to prevent the situation from becoming worse.

The Rh problem is prevented by injecting Rh- women with an antibody preparing against he Rh factor within 72 hours after the birth of an Rh+ child. The anti-Rh antibodies in the injection attack any of the baby’s red blood cells can stimulate her immune system to produce her own antibodies. This procedure will not help if the woman has already begun to produce antibodies. Thus, the timing of the injection is crucial.

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Worksheet – Blood Types

What to Do

1. COMPLETE THE FOLLOWING CHART ABOUT BLOOD TYPES AND THEIR RELATED ANTIGENS AND ANTIBODIES.

Blood Type Antigen on surface of red blood cells

Antibodies found in plasma

ABABO

2. COMPLETE THE FOLLOWING CHART ABOUT BLOOD TRANSFUSIONS.

Blood Type Possible Donors Possible RecipientsABABO

3. Use the information in the charts above to answer the following questions.

a) What blood type is considered to be the universal donor? Explain.

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b) What blood type is considered to be the universal recipient? Explain.

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N. Blood Clotting

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• when a blood vessel is injured, a series of reactions are triggered with the end result being a blood clot

• keep in mind that this is an incredibly simplified version of blood clotting!!!

platelets in bloodstream ↓

rupture↓

release of thromboplastin ↓

Ca2+ in blood

prothrombin activated ↓

conversion of prothrombin to thrombin ↓

fibrinogen in plasma ↓

converted to fibrin threads↓

CLOT

O. The Immune System • when a “foreign invader” enters our bodies, our immune system kicks into action • cells in the immune system are white blood cells and include:

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1. macrophages 2. B-cells – plasma (make antibodies), memory 3. T-cells – helper, killer, suppressor, memory

• antigens are protein markers that are found on the cell membranes of most cells

antibodies are Y-shaped proteins that bind to specific antigen markers on other cells

• antibodies tie up the invaders so they can’t damage our cells • when our immune system recognizes a foreign invader, our antibodies for that

invader attach to the antigen markers making an antigen-antibody complex • the antigen-antibody complex is really large making it easy to be found by

macrophages which engulf and destroy the complex • the immune system has memory cells which don’t die off after the foreign

invader is destroyed…they are to recognize the invader if it returns • immunizations expose you to weakened viruses and cause your immune system

to produce antibodies against that disease

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Worksheet – Immune Response Non-Specific

The body’s immune system has three lines of defence. The first line of defence is barriers, the second line of defence is non-specific immune responses, and the third line of defence is classified as specific immune responses. All three defences work together to provide the body with an immune system.

1. Define the term “non-specific immune response.”

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2. Barriers are the first line of defence, designed to prevent pathogens from entering the body.

a) Fill in the chart below to summarize the physical and chemical aspects of the skin that prevent pathogens from entering the body.

Skin Structures involved Function

Chemical

Physical

b) List four other barriers of the body, identify them as either physical or chemical, and explain HOW THEY WORK TO PROTECT THE BODY.

Barrier Chemical or Physical

How it works

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3. Once a pathogen has entered the body there is a second non-specific line of defence that involves white blood cells.

a) What white blood cell types are involved in the second line of defence?

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b) By what process do these white blood cells destroy pathogens? Describe this process.

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Worksheet – Immune Response Specific

The specific defence system is primarily a function of the B and T lymphocytes (white blood cells in the circulatory system). These cells produce antibodies—proteins that can recognize foreign substances in the body and neutralize or destroy them. B lymphocytes (B cells) are made in the bone marrow, while T lymphocytes (T cells) are made in the thymus gland.

1. Define the term “antigen” in terms of pathogens.

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Use the graph below to answer the next three QUESTIONS.

2. Explain what is happening in the graph.

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3. Compare how long the body took to produce antibodies after the first exposure to how long it took after the second exposure.

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4. Compare the quantity of antibodies from the first exposure to the second exposure.

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5. Create a flow chart that illustrates the B cell response to pathogens.

6. Fill in the chart below, describing the function of each of the T cells in cellular-mediated immunity.

T Cell Type Function

Helper T Cell

Killer (Cytotoxic) T Cell

Suppressor T Cell

Memory T Cell

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P. Circulatory System DisordersUse this chart to create a summary of circulatory system disorders.

Circulatory System Disorder

Circulatory structure(s) involved

Description of disorder

Treatment(s)

Arteriosclerosis, atherosclerosis

Heart murmur

Anemia

Hemophilia

Leukemia

Autoimmune Disorders (Arthritis)

Allergic Responses

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