THECIRCULATORY

SYSTEM

THECardiovascular

SYSTEM

GROUP 6

PASCUA, Jane QUIDLAT, Adrien

QUILAPIO, RawnsleyRAMIREZ, Reina

RANTE, TaraSACDALAN, Ramon

UST-CRS1PTA S.Y. 2009-2010

What is the CIRCULATORY

SYSTEM?

The cardiovascular (cardio = heart; vascular = blood vessels) consists of three interrelated components: the heart, blood, and blood vessels to transport oxygen and nutrients to organs and tissues throughout the body and carry away waste products.

What are the some of the

vital functions of

the CIRCULATORY

SYSTEM?

The circulatory system increases the flow of blood to meet increased energy demands during exercise and regulates body temperature.

Also, when foreign substances or organisms invade the body, the circulatory system swiftly conveys disease-fighting elements of the immune system, such as white blood cells and antibodies, to regions under attack. In addition, in the case of injury or bleeding, the circulatory system sends clotting cells and proteins to the affected site, which quickly stop bleeding and promote healing.

What is CIRCULATION

?

CIRCULATION• Movement of an object or substance through a

CIRCULAR course that it RETURNS to its STARTING POINT.

• Extent to which the blood flows unobstructed at an appropriate pressure through large vessels of the systematic and pulmonary circuits.

INTERNAL FLUIDS

INTRACELLULAR COMPARTMENT Collective

fluid inside the body cell.

EXTRACELLULAR COMPARTMENT

Fluid outside and surrounding the cell.

EXTRACELLULAR

BLOOD PLASMA* In BLOOD VESSELS

* Pathway of exchange between the cells of the

body & the outside environment.

*Have more proteins

INTERSTITIAL FLUID

* In SPACES surrounding the cells in the body

* Formed from plasma by movement of fluid

Body Fluids

• ANIMALS- 70% - 90% water• Humans- 70% water by weight

» 50%= cell water» 15%= interstitial- fluid water » 5% = blood plasma

Plasma interstitia

l

intracellular

WATER

Composition of the Body Fluids

Organic

Intracellular electrolytes

PotassiumMagnesium

Phosphate ions proteins

Inorganic

Extracellular electrolytes

SodiumChloride

Bicarbonate ions

>(water)

BLOOD

PLASMA

WATER

DISSOLVED PROTEINS

DISSOLVED GASES

PROTEIN GROUPS

ALBUMINS

GLOBULINS

FIBRINOGEN

FORMED ELEMEN

TS

Composition of Blood• PLASMA – 55%• WATER – 90% • DISSOLVED PROTEINS

o Plasma proteinso Organic and Inorganic materials

• DISSOLVED GASESo OXYGENo CARBON DIOXIDEoNITROGEN

Composition of Blood

• PROTEIN GROUPS• ALBUMINS- keeps osmotic

equilibrium of plasma w/ other cells• GLOBULINS- metal bonding proteins• FIBRINOGEN- functions in blood

coagulation

Composition of Blood• FORMED ELEMENTS – 45% of blood

1.  BLOOD CELLS (ERYTHROCYTES), contains HEMOGLOBIN for

transport of O2 and CO2. -54 million/milliliter of

blood for MEN-48 million/milliliter of

blood for WOMEN      HEMOGLOBIN- pigment that gives

color to the RED BLOOD CELLS

Composition of Blood

2. WHITE BLOOD CELLS (LEUKOCYTES)      -Produces antibodies      -Protects body against infection      -50 000- 100 00 million/milliliter of blood      - 1WBC - 1000 RBC3. CELL FRAGMENTS (PLATELETS IN

MAMMALS) or cells (THROMBOCYTES in other vertebrates) function of blood coagulation.

Hemostasis

- Prevention of blood loss, BLOOD COAGULATION, process of clotting

- There are special elements & proteins in forming clots

- There’s a continuous sequence of catalytic action (involving series of plasma proteins).

Hemostasis

• Major Elements1. Fibrinogen – plasma protein that

forms Fibrin2. Prothrombin – inactive form of the

enzyme Thrombin3. Thromboplastin – one of the major

clotting factors (from platelets)

Trivia

• Hemophilia– Also known as the “royal disease”– Blood clots fail to form, resulting in

severe bleeding– Due to the lack of X chromosome

VertebrateCirculation System:

THE HEART

Remember!

All Vertebrates have CLOSED circulation systems. These systems are classified by the number of chambers in the heart, which determines the basic configuration of blood flow.

FISH

In the simplest vertebrate circulatory systems, seen in fish, blood flows in a single loop, traveling from the heart to the gills,

and then on around the body.

Fishes have two-chambered hearts with one atrium and one

ventricle.

The sinus venosus is an enlarged chamber preceding the atrium which collects the blood from the venous system to guarantee a smooth delivery of blood to the heart.

Blood pumped from the ventricle travels through arteries to the gills, where it diverges into capillaries and exchanges gases. Leaving the gills, the capillaries reconvene into blood vessels that carry the oxygenated blood to the rest of the body, where the vessels again diverge into capillaries before reconvening into veins that return to the heart.

FROG

In other vertebrates, a more complex pattern has gradually evolved. Instead

of flowing in a single circuit, blood flows in a double loop, first through the

lungs, and then back to the heart before moving on through the rest

of the body.

Frogs and other amphibians have three-chambered hearts with two

atria and one ventricle.

Blood pumped from the ventricle enters a forked artery.

One fork, the pulmonary circulation, leads to the lung.

The other fork, the systemic circulation,

leads to the rest of the body.

Blood returning from the pulmonary circulation enters the left atrium, while blood from the systemic circulation enters the right atrium. Although there is some mixing of oxygenated and deoxygenated blood in the ventricle, a ridge within the ventricle assures that most of the oxygenated blood is diverted to the systemic circulation and most of the deoxygenated blood goes to the pulmonary circulation.

The three–chambered heart of amphibians createsan opportunity for blood to mix inthe ventricle which pumpsboth oxygenated and deoxygenatedblood with each beat.

While in birds and mammals this would bedeadly, scientists now understand that a

three-chambered heart is actuallyadvantageous for amphibians and reptiles.

These animals do not breathe constantly—for example, amphibians absorb oxygen through their skin when they are underwater—and the three-chambered heart enables them to adjust the proportions of blood flowing to the body and the lungs depending on whether the animal is breathing or not. The three-chambered heart actually results in more efficient oxygen delivery for amphibians and reptiles.

What is the difference between

Pulmonary Circulationand

Systemic Circulation?

The circuit that takesblood to and from the lungs is known as thePulmonary Circulation.

The circuit that takes theblood around the rest

of the body is calledSystemic Circulation.

As vertebrates moved from life in the sea to life on land,

they evolved lungs as new respiratory organs for breathing.

At the same time, they became more active and

developed greater energy requirements.

Animals use oxygen to release energy from food molecules in a

process called cellular respiration, so land-dwelling vertebrates

also developed a greater requirement for oxygen. These changes, in turn,

led to changes in the structure of the heart and circulatory system.

Their hearts have four chambers—two atria and two ventricles—resulting in a complete separation of oxygenated and deoxygenated blood and highly efficient delivery of oxygen to the tissues.

Birds and mammals have high energy requirements even by vertebrate standards,

and a corresponding high demand for oxygen.

Small mammals have more rapid heart rates than large mammals because they have the highest energy needs. The resting heart rate of a mouse is 500 to 600 beats per minute, while that of an elephant is 30 beats per minute. Blood pressure also varies among different mammal species. Blood pressure in a giraffe’s aorta is about 220 mm of mercury when the animal is standing. This pressure would be dangerously high in a human, but is necessary in a giraffe to lift blood up the animal’s long neck to its brain.

Although other groups of vertebrates have hearts with a different structure than those of humans, they are still sufficiently similar that scientists can learn about the human heart from other animals. Scientists use a transparent fish, the zebra fish, to learn how the heart and the blood vessels that connect to it form before birth. Fish embryos are exposed to chemicals known to cause congenital heart defects, and scientists look for resulting genetic changes. Researchers hope that these studies will help us understand why congenital heart malformations occur, and perhaps one day prevent these birth defects.

TheHUMANHEART

Anterior view of the Heart

Posterior view of the Heart

Location AND SIZE

of theHeart

The relative size and weight of the heart give few hints of its incredible strength. Approximately the size of a person’s fist, the hollow, cone-shaped heart weighs less than a pound. The heart is located within the bony thorax and is flanked on each side by the lungs. Its more pointed apex is directed toward the left hip and rests on the diaphragm. The broad base, from which the great vessels of the body emerge, points toward the right shoulder and lies beneath the second rib.

It lies in the mediastinum, a mass of tissue that extends from the sternum to the vertebral column between the lungs. About two-thirds of the mass of the heart lies to the left of the body’s midline. You can visualize the heart as a cone lying on its side.

STRUCTUREof theHeart:

The Four Chambers

The human heart has four chambers. The upper two chambers, the right and left atria, are receiving chambers for blood. The atria are sometimes known as auricles. They collect blood that pours in from veins, blood vessels that return blood to the heart. The heart’s lower two chambers, the right and left ventricles, are the powerful pumping chambers. The ventricles propel blood into arteries, blood vessels that carry blood away from the heart.

A wall of tissue (septum) separates the right and left sides of the heart. Each side pumps blood through a different circuit of blood vessels: The right side of the heart pumps oxygen-poor blood to the lungs, while the left side of the heart pumps oxygen-rich blood to the body. Blood returning from a trip around the body has given up most of its oxygen and picked up carbon dioxide in the body’s tissues. This oxygen-poor blood feeds into two large veins, the superior vena cava and inferior vena cava, which empty into the right atrium of the heart.

STRUCTUREof theHeart:

The Heart Valves

The Heart Valves

Atrioventricular Valves

Tricuspid Valve

Mitral Valve

Semilunar Valves

Pulmonary Valve

Aortic Valve

Four valves within the heart prevent blood from flowing backward in the heart. The valves open easily in the direction of blood flow, but when blood pushes against the valves in the opposite direction, the valves close. Two valves, known as atrioventricular valves, are located between the atria and ventricles.

ATRIOVENTRICULAR VALVES: relating to the heart structure

The right atrioventricular valve is formed from three flaps of tissue and is called the TRICUSPID VALVE. The left atrioventricular valve has two flaps and is called the bicuspid or MITRAL VALVE.

Tiny white cords, the chordae tendineae – literally, “heart strings” – anchor the cusps to the walls of the ventricles. When the heart is relaxed and blood is passively filling its chambers, the AV valve flaps hang limply into the ventricles.

As the ventricles contract, they press on the blood in their chambers, and the intraventricular pressure (pressure inside the ventricles) begins to rise. This causes the AV valve flaps to be forced upward, closing the valves.

At this point the chordae tendineae are working to anchor flaps in a closed position. If the flaps were unanchored, they would blow upward into the atria like an umbrella being turned inside out by a gusty wind.

In this manner, the AV valves prevent backflow into the atria when the ventricles are contracting.

The other two heart valves are located between the ventricles and arteries. They are called semilunar valves because they each consist of three half-moon-shaped flaps of tissue.

The other two heart valves are located between the ventricles and arteries.

They are called semilunar valves because they each consist of three half-

moon-shaped flaps of tissue. The right semilunar valve, between the right

ventricle and pulmonary artery, is also called the PULMONARY VALVE. The left

semilunar valve, between the left ventricle and aorta, is also called the

AORTIC VALVE.

STRUCTUREof theHeart:

Myocardium

Muscle tissue, known as myocardium or cardiac muscle, wraps around a scaffolding of tough connective tissue to form the walls of the heart’s chambers. The atria, the receiving chambers of the heart, have relatively thin walls compared to the ventricles, the pumping chambers. The left ventricle has the thickest walls—nearly 1 cm (0.5 in) thick in an adult—because it must work the hardest to propel blood to the farthest reaches of the body.

Microscopic view of the Cardiac Muscle

STRUCTUREof theHeart:

Pericardium

A tough, double-layered sac known as the pericardium surrounds the heart. The inner layer of the pericardium, known as the epicardium, rests directly on top of the heart muscle. The outer layer of the pericardium attaches to the breastbone and other structures in the chest cavity and helps hold the heart in place. Between the two layers of the pericardium is a thin space filled with a watery fluid that helps prevent these layers from rubbing against each other when the heart beats.

STRUCTUREof theHeart:

Endocardium

The inner surfaces of the heart’s chambers are lined with a thin sheet of shiny, white tissue known as the endocardium. The same type of tissue, more broadly referred to as endothelium, also lines the body’s blood vessels, forming one continuous lining throughout the circulatory system. This lining helps blood flow smoothly and prevents blood clots from forming inside the circulatory system.

STRUCTUREof theHeart:

The Coronary Arteries

The heart is nourished not by the blood passing through its chambers but by a specialized network of blood vessels. Known as the coronary arteries, these blood vessels encircle the heart like a crown. About 5 percent of the blood pumped to the body enters the coronary arteries, which branch from the aorta just above where it emerges from the left ventricle.

Veins running through the heart muscle converge to form a large channel called the coronary sinus, which returns blood to the right atrium.

Three main coronary arteries—the right, the left circumflex, and the left anterior descending—nourish different regions of the heart muscle.From these three arteries arise smaller branches that enter the muscular walls of the heart to provide a constant supply of oxygen and nutrients.

FUNCTIONS OF THE HEART

The heart’s duties are much broader than simply pumping blood continuously throughout life. The heart must also respond to changes in the body’s demand for oxygen. The heart works very differently during sleep, for example, than in the middle of a 5-km (3-mi) run. Moreover, the heart and the rest of the circulatory system can respond almost instantaneously to shifting situations—when a person stands up or lies down, for example, or when a person is faced with a potentially dangerous situation.

FUNCTIONS OF THE HEART

Cardiac Cycle

What is theCardiac Cycle?

The cardiac cycle refers to the events of one complete heartbeat, during which both atria and ventricles contract and then relax.

DIASTOLE

SYSTOLE contraction

relaxation

FUNCTIONS OF THE HEART

Generation of the Heartbeat

LUB

DUP

The first sound (lub) is caused by the closing of the AV valves. The second heart sound (dup) occurs when the semilunar valves close. The first sound is longer and louder than the second heart sound, which tends to be short and snap.

FUNCTIONS OF THE HEART

Regulation of Heart Rate

The normal resting heart rate of an average adult is 70 bpm. However the heart can beat as much as 3x faster – at more than 200 bpm – when the person is exercising vigorously. Younger people have faster heart rates than adults do. In infants the normal heart rate is about 120, while 100 in young children.Many athletes, by contrast, often have relatively slow resting heart rates because physical training makes the heart stronger and enables it to pump the same amount of blood with fewer beats. An athlete’s resting heart rate may be only 40 to 60 beats per minute.

FUNCTIONS OF THE HEART

Cardiac Output

What is the Cardiac Output?The cardiac output (CO) is the amount of blood pumped out by each side of the heart (actually, each ventricle) in 1 minute. It is the product of the heart rate (HR) and the stroke volume (SV). *Stroke volume is the volume of blood pumped out be a ventricle with each heartbeat.

If we use the normal resting values for heart rate (75 bpm) and stroke volume (70 ml/beat), the average adult cardiac output can easily be figured:

CO = HR * SVCO = 75 beat/min * 70 ml/beatCO = 5250 ml/min

VertebrateCirculation System:

BLOOD VESSELS

Blood Vessels

Veins

Arteries

Capillaries

Arteries carry oxygen-rich blood from the heart, branching to smaller and smaller units ending at the capillaries, which transfer oxygen and other blood components to and from the tissues. Oxygen-poor blood continues through the capillaries to veins, which converge to carry blood back to the heart, lungs, and liver.

BLOOD VESSELS:

Veins

The vein conducts the deoxygenated blood from the capillaries back to the heart.

And the umbilical veins convey blood from the fetus to the mother's placenta.

However, three exceptions to this description exist:

The pulmonary veins return blood from the lungs, where it has been oxygenated, to the heart;

The portal veins receive blood from the pyloric, gastric, cystic, superior mesenteric, and splenic veins and, entering the liver, break up into small branches that pass through all parts of that organ;

Veins enlarge as they proceed, gathering blood from their tributaries. They finally pour the blood through the superior and inferior venae cavae into the right atrium of the heart. Their coats are similar to those of the arteries, but thinner, and often transparent.

This false-color electron micrograph shows red blood cells packed into a capillary, the smallest type of blood vessel. Blood flows from the capillaries into veins after oxygen has been exchanged.

BLOOD VESSELS:

Arteries

Tubular vessels that conveys blood from the heart to the tissues of the body.Two arteries have direct connection with the heart: (1) the aorta, which, with its branches, conveys oxygenated blood from the left ventricle to every part of the body; and (2) the pulmonary artery, which conveys blood from the right ventricle to the lungs, whence it is returned bearing oxygen to the left side of the heart.

BLOOD VESSELS:

capillaries

•Connects arteries and the veins. •Diameter: 0.0127 to about 0.2032 mm (0.0005 to about 0.008 in)•Present in great numbers throughout the entire body.•Walls are exceedingly thin and readily permeable. They are surrounded by lymph, and there is a constant interchange between the substances in the blood within the capillaries and the waste products in the body tissues and lymph outside.•This interchange facilitates the processes of nutrition and elimination and enables the exchange of oxygen and carbon dioxide to take place. Lymph capillaries assist the blood capillaries in this process.

invertebrateCirculation System:

The Heart

IN

The simplest kinds of hearts, present in some invertebrates such as some types of worms, consist of a muscular tube which squeezes rhythmically and moves blood-like liquid by peristaltic contraction (in sea squirts such heart can actually pump blood several minutes in one direction and then reverse the flow into the opposite direction).

IN

Such diversity in the structure and number of invertebrate hearts can be explained by the relatively small size and low metabolic activity of these animals as well by the fact that the role of invertebrate circulatory system is not necessarily respiratory exchange, but rather nutrient transport (which does not require as rigid and systematic circulation as does respiratory exchange).

IN

On the other hand, some mollusk hearts have quite a complex structure, which may include four atria and one ventricle (Nautilus), or be composed from multiple (seven and more) individual hearts as in annelid worms.

IN

Invertebrateswith

Hearts

IN

WORMS

IN

Some species of earthworm have four pairs of hearts (as in Pheretima posthuma) and some other have five pairs (Lumbricus) of hearts. The hearts of earthworm have valves and help push blood in one direction – forward or backward.

IN

OCTOPUS

IN

An octopus is a fast moving mollusk that has closed circulatory system and has three hearts, one systemic heart and two branchial hearts.

IN

COCKROACH

IN

IN

A cockroach has a chain of hearts, in all totaling to 13. Some regard it as a single heart with 13 chambers. These are funnel shaped chambers with a pair of tiny holes called ostia.

The ostia allow blood into the cockroach hearts. The hearts push the blood forward, in the

direction of the head.

SCORPIONScorpions have a heart with 7 chambers which is green in color.

IN

PRAWNSA prawn like, Indian fresh water prawn, Palemon malcomsonii has one heart with five pairs of ostia.

IN

End

References:• Hickman. (2006). Integrated Principles of ZOOLOGY. New York:

McGraw Hill.• Marieb, E.N. (2004). Essentials of Human Anatomy and Physiology.

Pearson Education Inc.:Philippines.• Mosby. (2006). Mosby’s Dictionary of Medicine, Nursing and Health

Professions 7th Edition. Missouri: Mosby Elvier Inc. • Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation.

All rights reserved.

GROUP 6

PASCUA, Jane QUIDLAT, Adrien

QUILAPIO, RawnsleyRAMIREZ, Reina

RANTE, TaraSACDALAN, Ramon

UST-CRS1PTA S.Y. 2009-2010