The Circulatory SystemThe Circulatory System

Functions of the Functions of the Circulatory SystemCirculatory System

Brings blood containing oxygen, nutrients, and hormones to cells

Transports CO2 and other wastes away from cells

Fights infectionRegulates body

temperatureHelps stabilize pH and

ionic concentration of body fluids.

Functions Continued

Circulatory System

ComponentsHeartBloodVessels

ArteriesVeinsCapillaries

The Heart A muscular pump Moves blood through the body Is suspended in the pericardial sac

Composed of four chambers

Divided into right and left halves

Made up of cardiac muscle cells

Aorta

Left pulmonary artery

Left atrium

Left pulmonary veins

Left ventricle

Superior vena cava

Right pulmonaryveins

Right atrium

Right ventricle

Inferior vena cava

Pericardium Protective sac of

connective tissue Surrounds the heart

Filled with fluid

Myocardium The muscle of the heart Strong and thick Composed of

spontaneously contracting cardiac muscle fibers

Can conduct electricity like nerves

It’s blood supply comes from the coronary arteries

Myocardium (heart muscle) shown in red

Epicardium(Outer surface

of myocardium)

Endocardium(Inner surface of myocardium)

Structures of the Heart Chambers

Atria- (2) upper chambers

Thin walled Receive blood from veins Send blood to ventricles

Ventricles- (2) lower chambers

Thick walled Receive blood from atria Pump blood out through

arteries Septum

Wall that divides heart into right and left halves

Septum

Pulmonary valve

Right atrium

Tricuspid valve

Right ventricle

Left atrium

Aortic valve

Mitral valve

Left ventricle

Structures of the Heart Valves

Prevent backflow of blood Keep blood moving in one

direction

Between the chambers

At junctions of artery and chamber

Tricuspid valve

Pulmonary veins

Mitral valve

Left atrium

Pulmonary valve

Aortic valve

Right atrium

Valves seen from above

Chordea tendinea

Pulmonary valve

Structures of the HeartChordae tendinease

“Heart strings” Cord-like tendons Connect papillary

muscles to tricuspid and mitral valves

Prevent inversionof valve

Papillary musclesSmall muscles that

anchor the cords Papillary muscle

aortic valve

left common carotid artery

left subclavian artery

brachiocephalic artery

right pulmonary artery

septum

left pulmonary artery

aorta

pulmonary trunk

left pulmonary veins

left atrium (auricle)

mitral valve

pulmonary valve

papillary muscle

left ventricle

right pulmonary veins

superior vena cava

right atrium

tricuspid valve

right ventricle

inferior vena cava

© 2006 Merriam-Webster, Inc.

Structures of the Heart

6

11

10

14

1

9

8

7

5

3

4

2

17

1216

13

15

Cardiac Cycle

Refers to all of the events from the beginning of one heart beat to the beginning of the next heart beat

When cardiac muscle contracts it does so as a single unit, creating a heart beat

One heartbeat - a cardiac cycle - consists of two parts called systole and diastole

Cardiac Cycle Diastole is the

period of time when the heart relaxes after contraction

Oxygenated blood from the lungs fills the left atrium

Deoxygenated blood from other parts of the body fills the right atrium.

At the end of the diastole, the atria contract, starting the Systole

Cardiac Cycle

Atrial systole is the contraction of the heart muscle of the left and right atria. Both atria contract at the same time, sending blood into the corresponding ventricle

Ventricular systole is the contraction of the muscles of the left and right ventricles, which contract at the same time.

The term systole is synonymous with contraction of a muscle.

Cardiac Cycle During systole

the ventricles contract, forcing the blood into the pulmonary artery to be re-oxygenated in the lungs, and into the aorta for systemic distribution of oxygenated blood

Cardiac Cycle

Two normal heart sounds with each heart beat described as a…..

Heart Sounds “Lub”- sound- due

to closure of the atrioventricular valves (mitral and tricuspid)

“Dub”- sound- due to closure of the aortic valve and pulmonary valve

Cardiac Cycle Heart Rate - count of each heart beat

On average, a heart beats 72 times a minute when at rest

Usually it is calculated as number of contractions of heart (heart beats)in one minute and expressed as "beats per minute" (bpm).

The pulse is the most straightforward way of measuring the heart rate

Heart rate is controlled by nervous system

Hearse on an emergency

Cardiac Cycle

Resting heart rate can be significantly lower in athletes

Sympathetic division increases heart rate

Parasympathetic division decreases heart rate

Heart rate increases when more food and oxygen are needed by the cells, or when under stress

Cardiac Cycle

An electrocardiogram abbreviated as EKG or ECG is a test that measures the electrical activity of the heartbeat or one cardiac cycle.

Cardiac Conduction System Why don’t the

atria and ventricles contract at the same time?

Inefficient….Blood would not be moved in one direction,some would flow backwards

Cardiac Conduction System Includes:

SA node AV node Bundle of His Purkinje fibers

Purkinje fibers

Cardiac Conduction System Sinoatrial Node (SA node) Located high on the right

atrium. Pacemaker of the heart. Causes the wave of

contractions in the atria.

Sending bloodinto the ventricles

Cardiac Conduction System Atrioventricular Node (AV node) Located in the interatrial septum close to

the tricuspid valve Carries the electrical impulse

from the SA node to fiber bundles in the ventricles.

This causes the ventricles to contract

The location of nerve fiber bundles cause the ventricles to contract from the apex (bottom) upsqueezing blood up and out

Pathway of Circulation Oxygen-poor blood

draining from the body through veins into the superior and inferior vena cava flows to the right atrium, through the tricuspid valve, and into the right ventricle.

As the right ventricle contracts, oxygen-poor blood passes through the pulmonary valve into the pulmonary arteries and on to the lungs to receive oxygen.

Pathway of Circulation Oxygen-rich blood from

the lungs enters the heart through the pulmonary veins, passing into the left atrium.

Then through the mitral valve to the left ventricle. Contraction of the left ventricle forces blood through the aortic valve into the aorta.

Various arteries branch off from the aorta to supply blood to all parts of the body.

Pathway of Circulation Arteries branch into

smaller and smaller vessels (arterioles)

They eventually become capillaries, which supply blood to all body parts

Capillaries merge into (venuoles) which join into veins and carry blood back to the heart.

Nutrients pass into tissuesWaste products filter back

Blood pumped out ofheart into arteries,which branch into smaller and smallervessels until blood flowsinto capillaries

Blood returns to theheart through the veins

Heart

Capillary

Capillarynetwork

Pathway of Circulation

Pathway of Circulation14

9

11

10

8

6

13

12

6

5

4

32

1

1

16

15

14

7

And so on…It takes about 1 min. for blood to make 1 complete cycle

Pulmonary Circuit

Systemic Circuit

Lung

Pulmonaryvein

Aorta

Left atrium

Leftventricle

Pulmonaryartery

Rightatrium

Rightventricle

Venacava

oxygen-poor blood

oxygen-rich blood

CardiovascularCircuits

Pulmonary CirculationTakes place on the right side of the heart.Pumps

blood low in oxygento the lungs to pick up oxygen and return to heart

Systemic Circulation Takes place on left side of heart Oxygenated blood is pumped to

the body cells thruthe aortaand otherarteries

Blood lowin oxygenreturns to the heart

Coronary Circulation

Although blood fills the chambersof the heart, the muscle tissue of the heart is so thick that it requires coronary blood vessels to deliver blood deepinto the myocardium.

The coronary circulation consists of the blood vessels that supply blood to, and remove blood from the heart muscle itself.

Coronary Circulation

The vessels that supply blood high in oxygen to the myocardium are known as coronary arteries.

Blood Vessels Form a closed circuit

of tubes that carry blood throughout the body

Laid end to end, the blood vessels in an average human body will stretch approximately 62,000 miles……2.5 times around the earth

Blood Vessels Have characteristic

features Are distinguished by

size, tissue layers and direction of blood flow

Blood Vessels Arteries

Receive blood from ventricles

Take blood away from the heart

Usually carry oxygenated blood

Thickest vessel walls Withstand greater blood pressure Are very elastic Connect to capillaries Aorta is the largest artery

Blood Vessels Veins

Transport blood away from capillaries Carry blood

toward heart Take blood to atria Have valves Thinner vessel

walls with lesssmooth muscles

than arteries Can stretch a great deal Have larger diameters Usually carry de-oxygenated blood Vena cava is the largest vein

Blood Vessels The contraction of muscles compressing

veins helps push blood up through the leg veins back to the heart. The valves allow the blood to flow towards the heart only.

Calf musclerelaxed

Calf musclecontracts

Musclesqueezes veins

Veins constrict;blood moves;valves open

Veins dialated;blood still;valves closed

Valves OPEN

Valves CLOSED

Blood VesselsCapillaries

Smallest of blood vesselsOnly one cell thick (epithelial cell)Connect arteries to veinsBring oxygen

and nutrients to cells

Removes CO2, urea, and other wastes from cells

Where blood is under low pressure and moving slowly

Blood Vessels A network of capillaries runs

close to the cells in every part of the body. The capillaries have very thin walls which allows nutrients to diffuse through into the tissues and waste products to filter back into the capillaries.

Arteriole Venule

Tissue cells VeinArtery capillaries

Capillaries

C B O L M O PO A D R I V SE O S N S

E O L FS

Blood PressureBlood pressure refers to the force

exerted by circulating blood on the walls of blood vessels

The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, venules, and veins

Blood PressureBlood pressure is most commonly

measured via a sphygmomanometer(blood pressure cuff)

It uses the height of a column of mercury to reflect the circulating pressure

Average blood pressure for an adult is 120/80

Blood PressureSystolic pressure is defined as the

maximum pressure in the arteries exerted during ventricular contraction (which occurs near the beginning of the cardiac cycle)

Diastolic pressure is the minimum pressure exerted when ventricles relax and fill (at the resting phase or end of the cardiac cycle)

Blood pressure readings = S/D

Blood Pressure Pressure waves move through

the blood vessels A person's pulse is the throbbing

of their arteries as an effect of the pressure waves (heart beat)

Pulse is used to denote the frequency of the heart beat

It can be felt at neck, wrist, and other places

Pulse is usually measured in beats per minute.

In most people, the pulse is an accurate measure of heart rate..

Blood Pressure

Vasoconstriction is narrowing of a blood vessel. When a blood vessel constricts, the flow of

blood is restricted or slowed. Blood pressure will increase Vasodilatation is where blood vessels in the

body become wider following relaxation of smooth muscle in vessel wall. This will reduce blood pressure - since there is more room for the blood.

and

BloodThe life stream of the body, affecting every

cell and system we have.

The blood is an accumulation of many different elements, each working in a specific way to keep us alive.

Blood

A circulating connective tissue consisting of several types of cells suspended in a fluid medium known as plasma.

Blood Functions of blood:

Supply oxygen to tissues Supply nutrients such as glucose, amino acids and

fatty acids to tissues

Removal of wastes such as CO2 ,

urea and lactic acid from tissues

Immunological functions, including circulation of white cells, and detection of foreign material by antibodies

BloodFunctions of blood continued:

Messenger functions, including transport of hormones and signaling of tissue

Coagulation, part of body's self-repair mechanism

Regulation ofcore body temperature

Regulation of body pH and ion concentrations

Blood What percent of your body is blood? How much blood do we contain?

On average 4-6 liters We contain about a pint of

blood for every 15 pounds of body weight

Composition of Blood: What percent of your blood is

cellular? What percent of your blood is

plasma?

8%

45%

55%

BloodWhat is plasma?

A clear, straw colored fluid

What percent of plasma is water?

What’s in plasma? Dissolved gasses Vitamins Minerals Salts Nutrients

Enzymes Hormones Waste products Plasma proteins

90%Buffy coat leukocytesand platelets(<1% of whole blood)

Erythrocytes(45% of whole blood)

Plasma(55% of whole blood)

Formedelements

Layering of blood components in a centrifuged blood sample

BloodThe cellular components are:

red blood cells (erythrocytes)

white blood cells (leukocytes)

platelets (thrombocytes)

Blood cells are formed in bonemarrow

BloodBBLLOOOOD D

CCEELLLL

FFOORRMMA A TT IIOONN

Blood Red Blood Cell CharacteristicsRed Blood Cell Characteristics

(RBC)- Erythrocyte(RBC)- Erythrocyte Biconcave disksBiconcave disks No nucleusNo nucleus Contain the iron based pigment hemoglobinContain the iron based pigment hemoglobin

which binds with oxygen to transport itwhich binds with oxygen to transport it Life span about 120 daysLife span about 120 days 5 billion/1mL of blood = most numerous 5 billion/1mL of blood = most numerous Are very smallAre very small

Blood

To the right is an artist's drawing showing the biconcave shape of the red blood cell.

To the right is a Wright's stained peripheral blood smear under 1000 X magnification.

The average size of a red blood cell is 7.2 micrometers in diameter.

Blood How RBC’s transport

oxygen....Hemoglobin .…the iron containing pigment

Hemoglobin makes red blood cells red

BloodWhite Blood Cell Characteristics

(WBC)- LeukocyteNo definite shapeHave nucleusProtect body against infectionLife span varies (3 days-a few months)

7,000/1mL of bloodNumbers increase if

infection is presentLarger than RBC’s

BloodTypes of white

blood cells:Monocytes are the

largestNeutrophils are the

most numerousLymphocytes are

produced by the lymph tissue

Basophils releasehistamines

BloodTypes of white blood cells:

When a cell undergoes apoptosis, programmed cell death, white blood cells called macrophages consume cell debris.

The role of a macrophage is to phagocytize (engulf and then digest) cellular debris and pathogens.

BloodPlatelet Characteristics:

ThrombocyteRBC fragmentsIrregularly shapedNo nucleus150,000-400,000/1mLLife span about 7-11 daysHave a sticky surfaceResponsible for blood

clotting (injury healing)

Blood This is an actual picture of White Blood Cells,

in with some red blood cells. The platelets are stained purple, a T-Lymphocyte white cell is stained green, and a Monocyte white cell is stained gold as seen through a scanning electronmicroscope.

Blood Red blood cells and

platelets are the most numerous.

Of the leukocytes, neutrophils are the most numerous

Lymphocytes are the predominant cell type responsible for immune responses.

Blood ClottingSteps in Blood Clotting:platelets clumpplatelets release thromboblastinthromboblastin

produces thrombinthrombin converts

fibrinogen into fibrinfibrin causes a clot

Fibrin

Let’s simplify this shall we?

Blood Clotting Blood vessel is injured.

Platelets clump at the site and produce a substance that produces strands of fibrin.

Fibrin strands help to clog the opening or hole in the vessel.

Blood Clotting

Needed to stop

bleeding(hemorrhage)

Blood Types ABO Blood Groups: Red blood cell membranes may

contain antigens – a substancethat triggers an immune response in blood that does not contain the same antigen.

Blood plasma may contain antibodies, specialized proteins that bind to non-self antigens to destroy them.

It is important to prevent the mixing of red cells that contain an antigen with plasma that contains the corresponding antibody.

Blood Types

Antigens

Blood Types

Type ReceiveFrom

DonateTo

Anti-BodyAntigen

A

O

AB

B

A

B

A + B

None

A or O

Anti - A

Neither

Both

AB

O,A,B,AB

Anti - B

O

A or AB

B or AB B or O

AB,A,B,O

UniversalDonor

UniversalReceiver

Blood Types

Blood Types

Blood Transfusion The process of

transferring blood or blood-based products from one person into the circulatory system of another

For blood loss due to trauma, surgery, or severe anemia

Can be life-saving

Blood Types

What Happens When Mixing Wrong Blood Type? Antibodies in blood will attack the foreign blood.

They will cause the blood cells to clump…. agglutination.

Will stop the blood from moving.

Circulatorysystem shuts down

Blood Types: Rh Factor An additional antigen found on the surface of red

blood cells.

Rh + Means that the person carries the antigen.

Rh - Means that the person DOES NOT carry the antigen.

Blood Types: Rh FactorPercentage of the Population With Each Blood Type

Rh+ Rh-

O 38.5% 6.5%

A 34.3% 5.7%

B 8.6% 1.4%

AB 4.3% 0.7%

The Rh, or rhesus, factor wasdiscovered in1940 when testing bloodwith a rhesus monkey. The Rh system was named after rhesus monkeys, since they were initially used in the research to make the antiserum for typing blood samples. 

Blood Types: Rh Factor

Rh-negativeWoman and

Rh-positive manconceive a child

Rh-negativeWoman withRh-positive

fetus

Cells fromRh-positivefetus enterwoman’s

bloodstream

In the nextRh-positivepregnancy,

maternalantibodiesattack fetalred blood

cells

Womanbecomes

sensitized-antibodies( ) from

to fightRh-positiveblood cells

+

Circulatory System DisordersHeart Disease

Risk factors Older age Male gender Cigarette smoking High cholesterol Diabetes Stress Obesity Heredity Physical inactivity  High blood pressure  

Quitting smoking, a healthy diet and exercise mayreduce your risk of heart disease

Plaque incoronaryartery

Circulatory System DisordersAtherosclerosis

Starts with damage or injury to the inner layer of an artery

Fatty deposits called plaquebuild up in the arteries

This causes: Blockage

in artery Less

flexible vessels

High BloodPressure

Circulatory System DisordersHypertension

High Blood PressureMakes the heart

and blood vessels work

harder

Increases the chance of heart disease, heart

attack or stroke

Circulatory System DisordersHeart Attack

acute myocardial infarction Interruption of oxygen

supply to the heartCauses death of

the heart muscleLeading cause of

death in both men and women

Coronary Blockage

Circulatory System Disorders

Symptoms Chest pain Squeezing or heavy pressure

on chest Pain that radiates down left

shoulder and arm Shortness of breath Nausea or vomiting Anxiety or Fainting Lightheadedness - dizziness Palpitations (feeling like your

heart is beating too fast) Sweating, which may be

extreme

Heart Attack

Circulatory System DisordersStroke

Interruption of oxygen supply to the brainCaused by:

A clot in an artery in the brain

Breakage of an artery in the brain

Causes brain cells to be deprivedof oxygen and die

Thrombotic strokeblood clot in

cerebral artery

Hemorrhagic strokeblood vessel ruptures

Circulatory System Disorders

Embolism occurs when an object (usually a blood clot) migrates from one part of the body (through circulation) and causes a blockage (occlusion) of a blood vessel in another part of the body

Thrombosis is the formation of a clot (thrombus) inside a blood vessel, obstructing the flow of blood

Thrombosis/Embolism

Circulatory System Disorders

Hemorrhage is the medical term for bleeding - the loss of blood from the body

Hemorrhage generally becomesdangerous, or even fatal, when it causes hypovolemia (low blood volume) or hypotension (low blood pressure).

Hematoma- a collection of blood due to internal bleeding (burse)

Hemorrhage

Gingival Hemorrhage

Circulatory System DisordersHem philia

A rare inherited bleeding disorder in which the blood does not clot normally

The person is missing or has low levels of certain proteins in the blood called clotting factors

Usually occurs only in males They suffer prolonged bleeding

even with minor injuries Bleeding can occur internally,

in joints and muscles, which causes swelling and pain

Swelling in left knee joint due to spontaneous bleeding

Circulatory System DisordersAnemia

A condition where there is an abnormally low number of red blood cells circulating in the body or when the blood does not have enough hemoglobin

The body's tissues are being starved of oxygen Most common disorder of the red blood cells,

affecting (~) 3.5 millionAmericans

There are different kinds of anemia Iron Deficiency Vitamin Deficiency Hemolytic Anemias Sickle Cell Anemia

Circulatory System DisordersAnemia

A person with anemia will feel tired, weak, breathless, and dizzy

They may have a pale complexion, increased heart rate, low blood pressure, and difficulty concentrating

The severity of the symptoms is related to the severity of anemia

Iron Deficiency Anemia

Circulatory System Disorders

Sickle cell trait- The person is carrying the defective gene, but also has some normal hemoglobin

Sickle cell anemia-The person has most or all of the normal hemoglobin replaced with the sickle hemoglobin

Sickle Cell Disease

Circulatory System Disorders

Valvular Regurgitation Valvular stenosis A condition in which

there is a narrowing, stiffening, thickening, fusion or blockage of one or more

valves of the heart.

Valve Disorders

Circulatory System DisordersHeart Murmur

A whooshing sound between the heart beats The whoosh is an extra noise that blood makes as it

flows through any of the heart's chambers or valves or even through a hole within the heart

More than half of all children have a heart murmur at some time in their lives and most of these don't mean anything is wrong

Normal Heart Valve

ClosedOpened

Problems Closing

Problems Opening

Circulatory System DisordersHeart Murmur

Innocent heart murmurs can occur when blood flows more rapidly through the heart - such as during physical activity or exercise, pregnancy, fever, anemia, from aging or even heart surgery

Over time, innocent heart murmurs may disappear

Abnormal heart murmurs are caused by structural defects in the heart…. congenital heart defects, valve abnormalities, or holes in the heart

Some abnormal defects can be treated with medicines while others require surgical repair

Circulatory System DisordersAneurysm

Localized, blood-filled dilation (bulge) of a blood vessel caused by disease or weakening of the vessel wall

Most commonly occur in arteries at the base ofthe brain and in the aorta

Can burst andlead to deathat any time

Blood Vessel Microscope Slide