Circulation

Chapter 28

Students will understand that

• The parts of a system are interdependent.• The proper functioning of the circulatory

system is essential to our good health.• Our choices can impact the health of the

circulatory system.

Essential Questions

• Why do we need a circulatory system?• What is the worst type of damage that could

happen to my circulatory system?• How do you thin your lifestyle affects the

health of your circulatory system?• In what ways are the respiratory system and

circulatory system interdependent?

Students will know …

• That the circulatory system is responsible for transporting oxygen, nutrients and waste products through our body.

• That the proper functioning of each part is necessary for the circulatory system to function properly.

• The names and functions of blood vessels, parts of blood, and chambers of the heart.

• Examples of diseases or activities that may damage the system.

• The relationship between circulatory, respiratory and digestive systems.

Skills –Students will be able to

• Demonstrate an understanding of the relationship of the form to the system's function through written communication.

• Compare and contrast a model of the process of diffusion to what happens in the circulatory system.

• Use the internet to research a circulatory health topic.

• Communicate about personal actions that can promote the health of the system using power point.

Asssessment • Performance – Based Assessment: • “Health of the circulatory system.” This task has several components. • Students are grouped to find out about one specific disease or health risks to the circulatory system. The

list should include, but need not be limited to, heart attack, strokes, diet, smoking and sedentary lifestyle. Each member of the group will get a specific research assignment pertinent to their topic. These topics could include cause, treatment, affects, data and recommendations from current research. This individual assignment provides an opportunity to differentiate based on student ability.

• The student groups compile their information to prepare a presentation that includes a power point as the visual aid for their portion of the health forum.

• Students present their presentations, which can be viewed by other students in the student portal.• Class as a whole will view completed presentations and give their understanding of the health of the

circulatory system and the care they need to take and write an article that includes the 5 pieces of information they felt to be most important.

• Other Assessment Evidence: (Tests, quizzes, self-assessment, peer-assessment, etc.)• • Learning activities• Effect of exercise on heart rate• Dissecting a goat’s heart

Case Study –Sudden Death

• Case study of Darryl Kile• Read Page number 549• Do you know him? • Need to know more about him?

Movie of Darryl Kile

The circulatory system carries blood and dissolved substances to and from different places in the body.

The Heart has the job of pumping these things around the body.

The Heart pumps blood and substances around the body in tubes called blood vessels.

The Heart and blood vessels together make up the

Circulatory System.

What is the circulatory system?

Three major parts of the circulatory system

• A fluid, blood, that serves as a medium of transport.

• A system of channels, or blood vessels, that conduct the blood throughout the body.

• A pump, the heart, that keep the blood circulating.

Functions of Blood

• Transports oxygen and nutrients to cells• Carries carbon dioxide and wastes away from

cells• Helps stabilize internal pH• Carries infection-fighting cells• Helps equalize temperature

Two types of Circulatory System

• Open circulatory systems• - blood is pumped from a heart (or heart-like

organ) into large cavity where organs are "bathed" in hemolymph - blood and tissue fluid not distinguishable - Arthropods, most mollusks have open systems

Closed circulatory system

• - blood is pumped from the heart and throughout the body via a network of vessels: from arteries to capillaries to veins (Note: flow in capillaries much slower than in large-diameter vessels; allows time for diffusion into and out of tissue fluid.)- All vertebrates, some mollusks and annelid worms (ex: earthworms) have closed systems

The Heart

These are arteries. They carry blood away from the heart.

This is a vein. It brings blood from the body, except the lungs.

Coronary arteries, the hearts own blood supply

The heart has four chambers

2 atria

2 ventricles

now lets look inside the heart

The Heart

Left Ventricle

Left AtriumRight Atrium

Right Ventricle

valve

Vein from Lungs

Artery to Head and BodyArtery to Lungs

Vein from Head and Body

valve

How does the Heart work?

blood from the body

blood from the lungs

The heart beat begins when the

heart muscles relax and blood

flows into the atria.

STEP ONE

The atria then contract and

the valves open to allow blood

into the ventricles.

How does the Heart work?

STEP TWO

How does the Heart work?

The valves close to stop blood

flowing backwards.

The ventricles contract forcing

the blood to leave the heart.

At the same time, the atria are

relaxing and once again filling with

blood.

The cycle then repeats itself.

STEP THREE

Passage of Blood Through the Heart

• Blood follows this sequence through the heart: superior and inferior vena cava → right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk and arteries to the lungs → pulmonary veins leaving the lungs → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → aorta → to the body.

Path of blood through the heart

The Vascular Pathways

• The cardiovascular system includes two circuits:

1) Pulmonary circuit which circulates blood through the lungs, and

2) Systemic circuit which circulates blood to the rest of the body.

3) Both circuits are vital to homeostasis.

Lungs

Body cells

Our circulatory system is a double circulatory system.

This means it has two parts parts.

the right side of the

system

deals with

deoxygenated blood.

the left side of the

system

deals with

oxygenated blood.

Pulmonary Circuit

This loop oxygenates blood

right pulmonary artery left pulmonary artery

capillarybed ofrightlung

pulmonarytrunk

capillary bedof left lung

(to systemic circuit)

pulmonary veins

lungs

(fromsystemiccircuit)

heart

Systemic Circuit

Longer loop carries blood to and from body tissues

capillary beds of headand upper extremities

(to pulmonarycircuit)

aorta

(frompulmonarycircuit)

heart

capillary beds of otherorgans in thoracic cavity

capillary bed of liver

capillary beds of intestines

capillary beds of other abdominalorgans and lower extremities

The Heartbeat• Each heartbeat is called a cardiac cycle.• When the heart beats, the two atria contract

together, then the two ventricles contract; then the whole heart relaxes.

• Systole is the contraction of heart chambers; diastole is their relaxation.

• The heart sounds, lub-dup, are due to the closing of the atrioventricular valves, followed by the closing of the semilunar valves.

Factors affecting heart beat

• Exercise• Stress• Hormone adrenaline

Conduction system of the heart

The SA node sends out a stimulus, which cause the atria to contract. When this stimulus reaches the AV node, it signals the ventricles to contract. Impulses pass down the two branches of the atrioventricular bundle to the Purkinje fibers, and thereafter the ventricles contract.

Conduction and Contraction

• SA node in right atrium is pacemaker

• Electrical signals cause contraction of atria

• Signal flows to AV node and down septum to ventricles

SA node

Blood Vessels

There are 3 types of blood vessels

a. ARTERY

b. VEIN

c. CAPILLARY

The ARTERY

thick muscle and elastic fibres

Arteries carry blood away from the heart.

the elastic fibres allow the artery to stretch under pressure

the thick muscle can contract to push the blood along.

The VEINVeins carry blood towards from the heart.

thin muscle and elastic fibres

veins have valves which act to stop the blood from going in the wrong direction.

body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

The CAPILLARYCapillaries link Arteries with Veins

the wall of a capillaryis only one cell thick

they exchange materials between the blood and other body cells.

The exchange of materials between the blood and the body can only occur through capillaries.

what’s in

red blood cells white blood cells

platelets

plasma

carbon dioxide

digested food

waste (urea)

hormones

oxygen

The Blood

plasma

red blood cell white blood cell

platelets

Red Blood Cells

contain haemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it.

can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries.

a biconcave disc that is round and flat without a nucleus

White Blood Cells

there are many different types and all contain a big nucleus.

the two main ones are the lymphocytes and the macrophages.

some lymphocytes fight disease by making antibodies to destroy invaders by dissolving them.

other lymphocytes make antitoxins to break down poisons.

macrophages ‘eat’ and digest micro-organisms .

Platelets

Platelets are bits of cell broken off larger cells.

Platelets produce tiny fibrinogen fibres to form a net. This net traps other blood cells to form a blood clot.

Plasma

A straw-coloured liquid that carries the cells and the platelets which help blood clot.

• carbon dioxide

• glucose

• amino acids

• proteins

• minerals

• vitamins

• hormones

• waste materials like urea.

It also contains useful things like;

Diffusion Zone

• Capillary beds are the site of exchange between blood and interstitial fluid

• Capillary is a single sheet ofepithelial cells

• Flow is slow; allows gasses to diffuse across membranes of blood cells and across endothelium

Negative Feedback Regulates rd Blood Cell Numbers

Some endurance athletes cheat by “blood –doping” injecting large doses of erythropoietin. How do you think this provide a competitive advantage?

Cardiovascular Disorders

• Cardiovascular disease (CVD) is the leading cause of death in Western countries.

• Modern research efforts have improved diagnosis, treatment, and prevention.

• Major cardiovascular disorders include atherosclerosis, stroke, heart attack, aneurysm, and hypertension.

Atherosclerosis

• Atherosclerosis is due to a build-up of fatty material (plaque), mainly cholesterol, under the inner lining of arteries.

• The plaque can cause a thrombus (blood clot) to form.

• The thrombus can dislodge as an embolus and lead to thromboembolism.

Atherosclerosis

• Arteries thicken, lose elasticity, and fill up with cholesterol and lipids

• High LDL increases risk

Stroke, Heart Attack, and Aneurysm

• A cerebrovascular accident, or stroke, results when an embolus lodges in a cerebral blood vessel or a cerebral blood vessel bursts; a portion of the brain dies due to lack of oxygen.

• A myocardial infarction, or heart attack, occurs when a portion of heart muscle dies due to lack of oxygen.

Coronary bypass operation

During this operation, the surgeon grafts segments of another vessel, usually a small vein from the leg, between the aorta and the coronary vessels, bypassing areas of blockage. Patients who require surgery often receive two to five bypasses in a single operation.

Angioplasty

On the left, a plastic tube is inserted into the coronary artery until it reaches the clogged area. In the middle diagram, a metal tip with a balloon attached is pushed out the end of the plastic tube into the clogged area. On the right, when the balloon is inflated, the vessel opens. Sometimes metal coils or slotted tubes, called stents, are inserted to keep the vessel open.

Read Matters of the Heart in Page number 562

• Share your understanding with your partner.• Write down the cause, effect, and prevention

of these disorders that you have read.• Research any (Two) other cardiovascular

disorders and present your findings.• How do you think you can prevent these

disosrders?

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