chapter 7 & 14

Chapter 7 & 14Chapter 7 & 14

BloodBlood

ObjectivesObjectives

To differentiate RBC from WBC as To differentiate RBC from WBC as regards functions.regards functions.

To explain how blood clotsTo explain how blood clotsTo distinguish vein from arteries and To distinguish vein from arteries and

capillariescapillariesTo illustrate how the circulatory To illustrate how the circulatory

system works.system works.To investigate why fatty foods should To investigate why fatty foods should

be avoided in our dietbe avoided in our diet

BloodBlood Blood is a liquid tissue. Suspended in the watery Blood is a liquid tissue. Suspended in the watery

plasmaplasma are seven types of cells and cell are seven types of cells and cell fragments. fragments.

Red blood cellsRed blood cells ((RBCRBCs) or s) or erythrocyteserythrocytes PlateletsPlatelets or or thrombocytesthrombocytes five kinds of five kinds of white blood cellswhite blood cells ( (WBCWBCs) or s) or

leukocytesleukocytes Three kinds of Three kinds of granulocytesgranulocytes

NeutrophilsNeutrophilsEosinophilsEosinophilsBasophilsBasophils

Two kinds of leukocytes without granules in their Two kinds of leukocytes without granules in their cytoplasm cytoplasm

LymphocytesLymphocytesMonocytesMonocytes

BloodBlood The average adult has The average adult has

about about five litersfive liters of of blood living inside of blood living inside of their body, coursing their body, coursing through their vessels, through their vessels, delivering essential delivering essential elements, and elements, and removing harmful removing harmful wastes. Without blood, wastes. Without blood, the human body the human body would stop working. would stop working.

Approximately 55 Approximately 55 percent of blood is percent of blood is plasmaplasma, a straw-, a straw-colored clear liquid. colored clear liquid. The liquid plasma The liquid plasma carries the solid cells carries the solid cells and the and the plateletsplatelets which help blood which help blood clot. Without blood clot. Without blood platelets, you would platelets, you would bleed to death. bleed to death.

Functions of the bloodFunctions of the blood Blood performs two major Blood performs two major

functions: functions: Transport through the body Transport through the body

of of oxygen and carbon oxygen and carbon

dioxide dioxide food molecules (glucose, food molecules (glucose,

lipids, amino acids) lipids, amino acids) ions (e.g., Na+, Ca2+, ions (e.g., Na+, Ca2+,

HCO3-) HCO3-) wastes (e.g., urea) wastes (e.g., urea) hormones hormones heatheat

Defense of the Defense of the body against body against infections and infections and other foreign other foreign materials. All the materials. All the WBCs participate in WBCs participate in these defenses.these defenses.

If one takes a sample of If one takes a sample of blood, treats it with an agent blood, treats it with an agent to prevent clotting, and to prevent clotting, and spins it in a centrifuge, spins it in a centrifuge,

The red cells settle to the The red cells settle to the bottom bottom

The white cells settle on top The white cells settle on top of them forming the "buffy of them forming the "buffy coat".coat".

The fraction occupied by the The fraction occupied by the red cells is called the red cells is called the hematocrithematocrit. Normally it is . Normally it is approximately 45%. Values approximately 45%. Values much lower than this are a much lower than this are a sign of sign of anemiaanemia. .

Formed ElementsFormed Elements

ErythrocytesErythrocytesRed blood cells are Red blood cells are anucleate and filled anucleate and filled with the oxygen with the oxygen carrying protein carrying protein hemoglobin. hemoglobin.

There are normally There are normally 3.9-5.5 million per 3.9-5.5 million per microliter in women microliter in women and 4.1-6 million per and 4.1-6 million per microliter in men.microliter in men.

Human erythrocytes Human erythrocytes are biconcave discs are biconcave discs 7.5 microns in 7.5 microns in diameter. diameter.

The biconcave shape The biconcave shape provides a large provides a large surface-to-volume surface-to-volume ratio for oxygen ratio for oxygen delivery and better delivery and better flexibility in narrow flexibility in narrow capillaries.capillaries.

Red Blood CellRed Blood Cell

The most The most numerous type in numerous type in the blood. the blood.

Red blood cells are Red blood cells are responsible for the responsible for the transtransoxygenoxygen and and carbon carbon dioxidedioxideport ofport of

Red blood cells are Red blood cells are red only because red only because they contain a they contain a protein chemical protein chemical called called hemoglobinhemoglobin which is bright red in which is bright red in color. color.

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


They live about They live about 120 days and then 120 days and then are ingested by are ingested by phagocytic cells in phagocytic cells in the liver and the liver and spleen. spleen.

Some 3 million Some 3 million RBCs die and are RBCs die and are scavenged by the scavenged by the liver each second. liver each second.


The nucleus directs The nucleus directs the cell to produce a the cell to produce a special protein called special protein called hemoglobin. hemoglobin.

After the red cell is full After the red cell is full of hemoglobin, the job of hemoglobin, the job of the nucleus is done of the nucleus is done and it gets kicked out. and it gets kicked out. Then, the mature red Then, the mature red cell has a little dip in cell has a little dip in its middle on both its middle on both sides.sides.


White Blood Cells White Blood Cells (leukocytes)(leukocytes)

Leukocytes or white blood cells Leukocytes or white blood cells (WBC) are (WBC) are cellscells in the blood that are in the blood that are involved in involved in defending the body defending the body against infective organisms and against infective organisms and foreign substancesforeign substances.. Like all blood Like all blood cells, they are produced in the bone cells, they are produced in the bone marrow. marrow.

There are 5 main types of white There are 5 main types of white blood cell, subdivided between 2 blood cell, subdivided between 2

main groups:main groups: Polymorphonuclear Polymorphonuclear

LeukocytesLeukocytes (granulocytes): (granulocytes):

NeutrophilNeutrophil EosinophilEosinophil BasophilsBasophils

Mononuclear Mononuclear Leukocytes:Leukocytes: (agranulocytes)(agranulocytes)

MonocytesMonocytes LymphocytesLymphocytes

White Blood cellsWhite Blood cells White blood cellsWhite blood cells are the are the

principal components of the principal components of the immune systemimmune system and and function by destroying function by destroying "foreign" substances such as "foreign" substances such as bacteria and viruses. bacteria and viruses.

When an infection is When an infection is present, the production of present, the production of WBCs increases. WBCs increases.

If the number of leukocytes If the number of leukocytes is abnormally low (a is abnormally low (a condition known as condition known as leukopenia), infection is leukopenia), infection is more likely to occur and it is more likely to occur and it is more difficult for the body to more difficult for the body to get rid of the infection. get rid of the infection.

Normal values range Normal values range from 4100/ml to from 4100/ml to 10900/ml10900/ml but can be but can be altered greatly by altered greatly by factors such as factors such as exercise, stress and exercise, stress and disease. disease.

A low WBC may A low WBC may indicate viral infection indicate viral infection or toxic reactions. A or toxic reactions. A high WBC count may high WBC count may indicate infection, indicate infection, leukemia, or tissue leukemia, or tissue damage. damage.

White Blood cellsWhite Blood cells

White cells are an White cells are an extremely extremely important part of important part of the body's immune the body's immune system because system because they guard the they guard the body against body against infections and infections and diseasesdiseases

White Blood cellsWhite Blood cells

NeutrophilNeutrophil

The most abundant of The most abundant of the WBCs. the WBCs.

Neutrophils form a Neutrophils form a primary defense against primary defense against bacterial infectionbacterial infection. .

Neutrophils squeeze Neutrophils squeeze through the capillary through the capillary walls and into infected walls and into infected tissue where they kill the tissue where they kill the invaders (e.g., bacteria) invaders (e.g., bacteria) and then engulf the and then engulf the remnants by remnants by phagocytosis. phagocytosis.

EosinophilEosinophil

The number of The number of eosinophils in the blood eosinophils in the blood is normally quite low (0 - is normally quite low (0 - 450/µl). However, their 450/µl). However, their numbers increase numbers increase sharply in certain sharply in certain diseases, especially diseases, especially infections by parasitic infections by parasitic worms.worms.

The Eosinophil is The Eosinophil is distinguished by its red distinguished by its red granules and bilobed granules and bilobed nucleus. nucleus.

BasophilsBasophils

The number of The number of basophils also increases basophils also increases during infection. during infection.

Basophils leave the Basophils leave the blood and accumulate blood and accumulate at the site at the site of infection of infection or other inflammationor other inflammation..

A basophil is A basophil is characterized by a characterized by a lobed nucleus and it is lobed nucleus and it is filled by large blue-filled by large blue-black granules that black granules that sometimes cover the sometimes cover the nucleus. nucleus.

LymphocytesLymphocytes

Lymphocytes Lymphocytes Slightly larger than Slightly larger than

red blood cells and red blood cells and they have a they have a relatively large relatively large nucleus nucleus

These are These are responsible for responsible for making antibodies. making antibodies.

Kill virus-infected Kill virus-infected cells and tumor cells cells and tumor cells

MonocytesMonocytes

MonocytesMonocytes They have a They have a

horseshoe shaped horseshoe shaped nucleus or, in nucleus or, in immature monocytes, immature monocytes, they may have an they may have an indented nucleus. indented nucleus.

Macrophages are Macrophages are large, phagocytic cells large, phagocytic cells that engulf that engulf

foreign material foreign material (antigens) that enter (antigens) that enter the body the body

dead and dying cells of dead and dying cells of the body.the body.

PlateletsPlatelets

Platelets are cell Platelets are cell fragments produced fragments produced from from megakaryocytesmegakaryocytes..

Blood normally contains Blood normally contains 150,000 to 450,000 per 150,000 to 450,000 per microliter (µl). microliter (µl).

If this value should drop If this value should drop much below 50,000/µl, much below 50,000/µl, there is a danger of there is a danger of uncontrolled bleeding. uncontrolled bleeding.

This is because of the This is because of the essential role that essential role that platelets have in blood platelets have in blood clotting.clotting.

Platelets are small pieces of Platelets are small pieces of cell material, or cytoplasm, cell material, or cytoplasm, whose job it is to plug holes in whose job it is to plug holes in vessel walls. They look like two vessel walls. They look like two plates stuck together, but plates stuck together, but when they are helping to form when they are helping to form a clot, they change shape. In a clot, they change shape. In the event of a tear inside a the event of a tear inside a blood vessel wall millions of blood vessel wall millions of platelets respond to the injury, platelets respond to the injury, throwing themselves over the throwing themselves over the cut. They stick to the wound's cut. They stick to the wound's edges and to each other to edges and to each other to form a plug that slows the loss form a plug that slows the loss of blood within three to five of blood within three to five minutes.minutes.

Platelets are Platelets are extremely important extremely important in helping blood clot in helping blood clot when a cut is made. when a cut is made. The stem cell turns The stem cell turns into a factory cell into a factory cell called a called a megakaryocyte. This megakaryocyte. This is a very large cell is a very large cell with several nuclei. with several nuclei.

The megakaryocyte never The megakaryocyte never leaves the bone marrow, leaves the bone marrow, but does produce many, but does produce many, many fragments. These many fragments. These fragments are actually fragments are actually the platelets: small pieces the platelets: small pieces of cell material or of cell material or cytoplasm. And they do cytoplasm. And they do leave the bone marrow leave the bone marrow and circulate freely in the and circulate freely in the bloodstream. bloodstream.

Platelets are Platelets are another important another important part or component part or component of your blood. of your blood. Platelets are sticky Platelets are sticky little pieces that little pieces that help prevent help prevent bleeding and make bleeding and make a blood clot when a a blood clot when a cut is made in the cut is made in the vessel wall.vessel wall.

Blood ClottingBlood Clotting A clot begins to form when A clot begins to form when

the blood is exposed to air. the blood is exposed to air. The platelets sense the The platelets sense the presence of air and begin to presence of air and begin to break apart. break apart.

They react with the fibrinogen They react with the fibrinogen to begin forming fibrin, which to begin forming fibrin, which resembles tiny threads. resembles tiny threads.

The fibrin threads then begin The fibrin threads then begin to form a web-like mesh that to form a web-like mesh that traps the blood cells within it. traps the blood cells within it.

This mesh of blood cells This mesh of blood cells hardens as it dries, forming a hardens as it dries, forming a clot, or "scab." clot, or "scab."

When blood vessels are When blood vessels are cut or damaged, the loss of cut or damaged, the loss of blood from the system blood from the system must be stopped before must be stopped before shock and possible death shock and possible death occur. This is accomplished occur. This is accomplished by solidification of the by solidification of the blood, a process called blood, a process called coagulationcoagulation or clotting. or clotting.

A blood clot consists of A blood clot consists of a a plug of plateletsplug of platelets

enmeshed in a enmeshed in a network of insoluble network of insoluble

fibrinfibrin molecules. molecules.

Normally, platelets look round and smooth, but when they begin to work to plug up they become spiky and ragged around the edges. When an injury occurs to a blood vessel wall, the platelets respond by attaching themselves over the cut to form a temporary plug within minutes slowing the loss of blood.

In addition to carrying blood cells throughout your body, plasma also carries hormones, nutrients and chemicals, such as iron. Plasma has the important function of maintaining the pH of the blood at approximately 7.4.

PlasmaPlasma

Plasma is the straw-colored liquid in which the blood cells are suspended. It is mostly is mostly made up of made up of water, but also water, but also contains contains proteins, sugars proteins, sugars and salt.and salt.

The main plasma proteins are albumin, The main plasma proteins are albumin, globulins, and fibrinogen. globulins, and fibrinogen. Albumin Albumin is necessary in maintaining is necessary in maintaining

osmotic pressure and acts as a transport osmotic pressure and acts as a transport protein for various substances. protein for various substances.

The The globulinsglobulins are, for the most part, are, for the most part, antibodies antibodies

And And fibrinogenfibrinogen is involved in the clotting is involved in the clotting process.process.

PlasmaPlasma

Serum ProteinsSerum Proteins Proteins make up 6-8% of Proteins make up 6-8% of

the blood.the blood. After blood is withdrawn After blood is withdrawn

from a vein and allowed from a vein and allowed to clot, the clot slowly to clot, the clot slowly shrinks. As it does so, a shrinks. As it does so, a clear fluid called serum is clear fluid called serum is squeezed out. squeezed out.

SerumSerum is blood plasma is blood plasma without fibrinogen without fibrinogen and and other clotting factors.other clotting factors.

Human red Human red blood cells take blood cells take on average 20 on average 20 seconds to seconds to complete one complete one cycle of cycle of circulation.circulation.

lungs

head & arms

liver

digestive system

kidneys

legs

pulmonary artery

aorta

pulmonary vein

main vein

Left Right

How does this system work?

Circulatory System

Vena cava

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.

Parts of The HeartParts of The Heart

The AtriaThe Atria

-Receiving -Receiving ChambersChambers

The VentriclesThe Ventricles

-Pumping -Pumping ChambersChambers

The ValvesThe Valves

-Controls Flow-Controls Flow The SeptumThe Septum

-Divides the Heart-Divides the Heart

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

Coronary arteries, the hearts own blood supply

2 atria

2 ventricles

Left Ventricle

Left Atrium

valve

Artery to Lungs

valve

Types of Blood VesselsTypes of Blood Vessels

ArteriesArteries -Carry blood away from the -Carry blood away from the

HeartHeart -The -The AortaAorta is the largest artery is the largest artery VeinsVeins -Carry blood away from the -Carry blood away from the

HeartHeart -Veins contain valves-Veins contain valves -The -The Vena CavaVena Cava is the largest is the largest

veinvein CapillariesCapillaries --Known as the “Distribution Known as the “Distribution

Pipes”Pipes”

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.

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.

Veins carry blood towards from the heart.

Capillaries 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.

artery vein

capillaries

body cell

A collection of capillaries is known as a capillary bedcapillary bed.

chapter 7 & 14

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