OBJECTIVE The role of the circulatory system and its key organs. Blood is a moving tissue containing blood, cells,

oxygen, carbon dioxide, nutrients, hormones and waste products.

The role of red blood cells and how hemoglobin aids in oxygen transportation.

The anatomy and function of the heart as a four chamber pump.

The role of arteries, veins and capillaries. The heart cycle during systole and diastole. What lifestyle factors contribute to the development of

heart disease. The the sickle cell anemia affects oxygen transport to

cells. How maintaining fitness can lead to a health body. The role of blood cells.

PHYSIOLOGY The function of all of the bodies organs and

systems.

All the bodies organs are required to function within certain parameters. What this achieves is homeostasis.

What is homeostasis?Homeostasis is the state of relative constancy in

the internal environment of the body. Food and water is converted into energy and is used to fuel the body.

Among the most important ways that humans maintain homeostasis is by regulating their own body temperature and PH automatically.

CIRCULATORY SYSTEM

Its role is to transport useful substances like oxygen, amino acids and glucose around the body while removing waste substances like carbon dioxide and urea. This done by the heart circulating blood through the entire body to help maintain helping to maintainhomeostasis.

Both gas exchange and nutrient for waste exchange occur across the walls of the smallest blood vessels- capillaries.

Completely contained within a network of vesselsknown as a closed circulatory system.

What is the Circulatory System? Like any

other organ system the circulatory system is a collection of specialized cells, tissues and organs. Consists of the heart, blood and blood vessels.

This system pumps blood faster and this is why it is suitable for animals with a high metabolic rate. These animals are active and their digestion is fast, so is the process of elimination of waste from the body.

Exchanges of gases, nutrients, and wastes takes place across capillary walls.

SOME INVERTEBRATES DO NOT HAVE A CIRCULATORY SYSTEM Cnidarians, such as hydras, and flatworms, such as planarians, do not have a

circulatory system In a hydra

The cells are either part of an external layer, or they line the gastrovascular cavity

In either case, each cell is exposed to water and can independently exchange gases and get rid of wastes

In a planarian Trilobed gastrovascular cavity branches throughout the small, flattened

body No cell is very far from one of the three digestive branches, so nutrient

molecules can diffuse from cell to cell

INVERTEBRATES WITH A GASTROVASCULAR CAVITY

OTHER INVERTEBRATES HAVE AN OPEN OR A CLOSED CIRCULATORY SYSTEM

There are two types of circulatory fluid: Blood - always contained within blood vessels Hemolymph - a mixture of blood and tissue fluid that flows into a

body cavity Open circulatory system - found in arthropods and molluscs

Heart pumps hemolymph via vessels into tissue spaces and eventually hemolymph drains back to the heart

Slow delivery of oxygen and nutrients is sufficient for a sluggish animal (clam)

A grasshopper has colorless blood and doesn’t depend on its open circulatory system to deliver oxygen to its muscles

Tracheae open to outside and take oxygen directly to flight muscles Closed circulatory system - found in annelids (earthworms)

Heart pumps blood, which usually consists of cells and plasma, into a system of blood vessels and valves prevent the backward flow of blood

Blood moves into capillaries, for exchanges with tissue fluid Blood then moves from small veins into the dorsal blood vessel (a

vein) This dorsal blood vessel returns blood to the heart for repumping

OPEN CIRCULATORY SYSTEM IN A GRASSHOPPER

CLOSED CIRCULATORY SYSTEM IN AN EARTHWORM

ALL VERTEBRATES HAVE A CLOSED CIRCULATORY SYSTEM Two different circulatory pathways in vertebrates

Single-loop: heart only pumps blood to gills Two-circuit: systemic circuit - heart pumps blood to all parts

of the body except for the lungs; the pulmonary circuit - heart pumps blood to the lungs

Fishes - heart has a single atrium and a single ventricle Blood is fully enriched with oxygen when it leaves gills, the

respiratory organ for aquatic organisms Amphibians and Reptiles - single ventricle pumps blood

in the pulmonary circuit to the lungs Also pumps blood in the systemic circuit to the rest of the body Although both O2 -rich and O2 -poor blood enter the single

ventricle, it is kept separate O2 -poor blood is pumped out of the ventricle to the lungs before O2-

rich blood enters and is pumped to the systemic circuit Birds and Mammals

Two atria and two ventricles in the heart and the complete separation of the pulmonary and systemic circuits

Right ventricle pumps blood under pressure to the lungs, and the larger left ventricle pumps blood under pressure to the rest of the body

SINGLE-LOOP CIRCULATORY PATHWAY IN FISHES

TWO-CIRCUIT PATHWAY IN AMPHIBIANS AND MOST REPTILES

THE MAMMALIAN CARDIOVASCULAR SYSTEM CONSISTS OF THE HEART AND BLOOD VESSELS

Complete separation of pulmonary and systemic circuits in birds, mammals, and some reptiles

THE HEART An organ that supplies blood carrying oxygen to all

parts of the body.

The heart is located in the chest cavity just behind the breastbone and between the lungs.

The outer wall of the human heart is composed of three layers.

The outer layer is called pericardium .

The middle layer is called the myocardium and is composed of muscle which contracts.

The inner layer is called the endocardium and is in contact with the blood that the heart pumps.

• Cardiac muscle needs a reliable supply of oxygen. The coronary arteries supply blood to the heart itself.

ANATOMY OF THE HEART.* 4 CHAMBERS: LEFT AND RIGHT ATRIUMS.* LEFT AND RIGHT VENTRICLES.* AORTA* PULMONARY ARTERY* PULMONARY VEINS* VENA CAVA.

Aorta

Pulmonary artery

Pulmonary veins

Left atrium

Left ventricle

Right ve n t r i c l e

Right atrium

Vena cava

PHYSIOLOGY OF THE HEART.The right side of the heart pumps deoxygenated

blood to the lungs.

Venous blood from the body enters the right atrium via the vena cava.

The blood flows from the right atrium into the right ventricle. Valves prevent blood from flowing back.

The right ventricle squeezes and pumps the venous blood to the lungs via the pulmonary arteries.

In the lungs, the blood picks up oxygen, and carbon dioxide is removed.

The left side of the heart pumps oxygenated blood from the lungs to the rest of the body.

Oxygen-rich blood from the lungs enters the left atrium of the heart.

Blood is pumped from the left atrium into the left ventricle.

The left ventricle contracts and pumps the oxygen-rich (arterial) blood to the body via the aorta.

http://The circulatory system

Blood passes through the heart twice during a complete circuit-normally 45 seconds.

HEART VALVES

Atrioventricular valves - between the atria and ventricles

Semilunar valves - between the ventricles and their attached vessels

After the blood passes through the right atrioventricular valve, the right ventricle pumps it through the pulmonary semilunar valve into the pulmonary trunk and pulmonary arteries that take it to the lungs Pulmonary veins bring O2-rich blood back to the

left atrium After the blood passes through the left

atrioventricular valve, the left ventricle pumps it through the aortic semilunar valve into the aorta, which takes it to the tissues Heart murmur is often due to leaky atrioventricular

valves, which allow blood to pass back into the atria after they have closed

THE HEARTBEAT IS RHYTHMIC The average human heart contracts, or beats, about

70 times a minute, or 2.5 billion times in a lifetime Each heartbeat, called the cardiac cycle, can be

divided into three phases The atria contract (while the ventricles relax) The ventricles contract (while the atria relax) All chambers rest

Systole refers to contraction of the heart chambers, and the word diastole refers to relaxation of these chambers

When the heart beats, the familiar “lub-dub ” sound is heard as the valves of the heart close Pulse - wave effect that passes down walls of arterial

blood vessels following ventricular systole Rhythmic contraction of heart is due to cardiac

conduction system The SA (sinoatrial) node initiates the heartbeat every

0.85 seconds and is called the cardiac pacemaker An electrocardiogram (ECG) is a recording of the

electrical changes that occur in the heart during a cardiac cycle

THE PHASES OF A HEARTBEAT

CONDUCTION SYSTEM OF THE HEART

ARTERIES The main artery of the heart divides and branches out into

many smaller arteries so that each region of your body has its own system of arteries supplying it with fresh, oxygen-rich blood.

Arteries are tough on the outside and smooth on the inside to allow blood to flow.

When the heart beats, the artery expands as it fills with blood. When the heart relaxes, the artery contracts, exerting a force that is strong enough to push the blood along.

This rhythm between the heart and the artery results in an efficient circulation system.

VEINS Transport blood at a lower pressure,

and are not as strong as arteries.

Layers are thinner, containing less tissue.

It is important that keeps blood moving in the proper direction and not be allowed to flow backward. The valves are like gates that only allow traffic to move in one direction.

Veins receive blood from the capillaries after the exchange of oxygen and carbon dioxide has taken place.

CAPILLARIES

Capillaries are very thin and fragile.

The exchange of oxygen and carbon dioxide takes place through the thin capillary wall.

The red blood cells inside the capillary release their oxygen which passes through the wall and into the surrounding tissue.

The tissue releases its waste products, like carbon dioxide, which passes through the wall and into the red blood cells. This process is called diffusion.

heart circulation

The heart pumps blood in two phases.

In the systolic phase, the ventricles contract, pumping blood into the arteries.

In the diastolic phase, the ventricles relax and blood flows into them from the atria.

What is Blood Pressure?

Blood pressure is the force of blood against the walls of blood vessels specifically the arteries, and is responsible for the movement of blood through the arteries.

BLOOD PRESSURE IS ESSENTIAL TO THE FLOW OF BLOOD IN EACH CIRCUIT Blood pressure accounts for the flow of blood

from the heart to the capillaries As blood flows from the aorta into the various

arteries and arterioles, blood pressure falls Blood pressure in the veins is low and cannot move

blood back to the heart, especially from the limbs Venous return depends upon three factors:

Skeletal muscle contraction, presence of valves in veins, and respiratory movements

VELOCITY AND BLOOD PRESSURE ARE RELATED TO THE CROSS-SECTIONAL AREA OF THE BLOOD VESSELS

HOW A VALVE AFFECTS THE MOVEMENT OF BLOOD IN A VEIN

HEART RATE AND EXERCISEIF YOU START RUNNING, YOUR BODY DEMANDS EVEN MORE OXYGEN AND THE ELIMINATION OF MORE CARBON DIOXIDE

If you start running, your body demands even more oxygen and the elimination of more carbon dioxide

As the heart beats, it presses the blood against the elastic walls of the arteries.

Each artery expands as blood is forced from the ventricles of the heart.

The artery wall then contracts to “push” the blood onward, further through the body- pulse..

How would the circulatory system respond?- raising the heart rate (how often the pump contracts) - stroke volume (how much blood the heart pumps with each

contraction).- Which increases the cardiac output (the amount of blood pumped from

the left ventricle per minute).

While you are running, blood flow is diverted toward tissues that need it most.

BLOOD VESSEL DETERIORATION RESULTS IN CARDIOVASCULAR DISEASE

In U.S., about 20% of population suffers from hypertension, high blood pressure

Heredity and lifestyle contribute to hypertensionHypertension is often seen in individuals who have atherosclerosis, which occurs when plaque protrudes into the lumen of a vessel and interferes with the flow of bloodPlaque can cause a clot to form on the irregular arterial wall

As long as the clot remains stationary, it is called a thrombus, but when and if it dislodges and moves along with the blood, it is called an embolus A stroke often occurs when a small cranial arteriole bursts or is blocked by an embolusHeart attack - when a coronary artery is completely blocked, a portion of the heart muscle dies due to lack of oxygen

CARDIOVASCULAR DISEASE CAN OFTEN BE PREVENTED

The Don’tsSmoking - When a person smokes, nicotine enters the bloodstream and causes the arterioles to constrict and the blood pressure to riseDrug Abuse - Stimulants, such as cocaine and amphetamines, can cause an irregular heartbeat and lead to heart attacks and strokesWeight Gain - in persons who are more than 20% above the recommended weight more tissues require servicing, and the heart sends the extra blood out under greater pressureThe DosHealthy Diet - Physicians advise people to replace harmful saturated fats and trans fats with healthier ones, such as monounsaturated fats (olive and canola oils) and polyunsaturated fats (corn, safflower, and soybean oils)Cholesterol Profile - Starting at age 20, all adults are advised to have their cholesterol levels tested at least every five yearsExercise - People who exercise are less apt to have cardiovascular disease

PLAQUE BUILDUP IN A CORONARY ARTERY

BLOODBlood travels through vessels, delivering essential

elements and removing harmful wastes.

* transporting oxygen

* carbon dioxide

* hormones

* vitamins/minerals

* ability to clot

* fight disease

COMPOSITION OF BLOOD

Red blood cells contain a protein chemical called hemoglobin which is bright red in color.

Hemoglobin contains the element Iron, making it an excellent vehicle for transporting oxygen and carbon dioxide.

Whenever a germ or infection enters the body, the white blood cells have a variety of ways by which they can attack.

Some will produce protective antibodies that will overpower the germ. Others will surround and devour the bacteria.

White Blood cells.

* Have a sticky surface allowing them to form clots in order to stop bleeding.

* A clot begins to form when the blood is exposed to air. The platelets then form a mesh-scab.

Platelets

* Plasma is a clear liquid that is 90 percent water, and it is an essential ingredient for human survival.

* Besides water, plasma also contains dissolved salts and minerals like calcium, sodium, magnesium, and potassium.

* Microbe-fighting antibodies travel to the battlefields of disease by hitching a ride in the plasma. Without plasma, the life-giving blood cells would be left floundering without transportation.

ADULT STEM CELLS INCLUDE BLOOD STEM CELLS

A stem cell is a cell that is capable of becoming different types of cells While embryonic stem cells possess the ability to

become virtually any cell type, adult stem cells are not quite as versatile because they can become only certain other types of cell

Adult stem cells have been identified in many tissues, including the liver, skin, muscle, and even within the brain, but the richest source is in the red bone marrow Adult stem cells from bone marrow are used to treat

many white blood cell and immune system disorders, including leukemia, certain blood cancers, and anemia

Like any organ transplant, a bone marrow transplant poses the risk of rejection

HEMATOPOIETIC CELLS (ADULT STEM CELLS IN RED BONE MARROW) PRODUCE CELLS THAT BECOME THE VARIOUS TYPES OF BLOOD CELLS.

CAPILLARY EXCHANGE IS VITAL TO CELLS Capillary exchange occurs between a systemic capillary

and tissue fluid, the fluid between the body’s cells Two forces control movement of fluid through capillary wall

Blood pressure, which tends to cause water to move out of a capillary into the tissue fluid

Osmotic pressure, which tends to cause water to move from the tissue fluid into a capillary

Red blood cells and almost all plasma proteins remain in the capillaries Fluid and other substances that leave a capillary contribute

to the tissue fluid At the venous end of a capillary, blood pressure has

fallen so osmotic pressure is greater than blood pressure, and water tends to move into the capillary Some excess tissue fluid is always collected by the lymphatic

capillaries Tissue fluid contained within lymphatic vessels is called

lymph Lymph is returned to the systemic venous blood when the major

lymphatic vessels enter the subclavian veins in the shoulder region

CAPILLARY EXCHANGE

A LYMPHATIC CAPILLARY BED LIES NEAR A BLOOD CAPILLARY BED

BLOOD TYPES MUST BE MATCHED FOR TRANSFUSIONS

Presence or absence of type A and type B antigens on red blood cells determines a person’s blood typeIn the ABO system, there are four types of blood: A, B, AB, and O Type O blood has no antigens on the red blood cells

and is sometimes called the universal donor

RH SYSTEM AND ERYTHROBLASTOSIS FETALIS Rh System

Another important antigen in matching blood types is the Rh factor

85% of the U.S. population have this particular antigen on red blood cells and are called Rh-positive

Erythroblastosis Fetalis During pregnancy, if the mother is Rh-negative and

the father is Rh-positive, the child may be Rh-positive

Rh-positive red blood cells may begin leaking across the placenta into the mother’s cardiovascular system, since placental tissues normally break down before and at birth

The mother produces anti-Rh antibodies, which may cross the placenta and destroy the child’s red blood cells during a subsequent pregnancy

No agglutination occurs when the donor and recipient have the same type blood

Agglutination occurs because blood type B has anti-A antibodies in the plasma

CONNECTING THE CONCEPTS

It is possible to relate the type of cardiovascular system to the lifestyle of an animal Some small, aquatic animals have no cardiovascular

system—external water passing in and out of a gastrovascular cavity is sufficient to meet the needs of their cells

Grasshoppers have an open circulatory system, but they utilize tracheae to deliver oxygen directly to their muscles

We traced the evolution of the two-circuit circulatory pathway in vertebrates and saw that a two-circuit pathway allows blood to pass to the lungs and to the tissues under pressure This is particularly useful in birds and mammals, which

maintain a warm body and an active way of life Body fluids make ideal culture media for the growth of

infectious parasites, and these fluids often have ways to ward off an invasion. You already know that white blood cells are involved in these endeavors