BLOOD

•Blood transports many substances through your body.

•blood carries oxygen to and carbon dioxide from your lungs.

•Blood also picks up nutrients in the small intestine and carries them to all body cells.

•It transport hormones that are produced by the endocrine system.

•Blood carries waste products to the excretory system.

•Most of the substances are dissolved in the liquid part of blood.

Functions of Blood: Transportation

•Some blood cells fight infection.

•They help protect you from harmful organisms, such as bacteria, viruses, fungi, and parasites.

•Blood also contains materials that help repair torn blood vessels and heal wounds.

•When you get a cut or a scrape, materials in your blood help protect your body from losing too much blood.

Functions of Blood: Protection

•Blood helps your body stay at a temperature of about 37C.

•Blood vessels near the surface of the skin dilate or constrict to release or retain body heat.

Functions of Blood: Temp. Regulation

•Blood is always red - bright red when it is oxygenated and a darker red when it's lacking oxygen.

•Deoxygenated blood just “looks” blue because you're seeing it through your skin.

•Oxygen poor blood is most definitely NOT blue. It is a sort of purplish/maroon colour at best.

•To see the vein at all, light has to go THROUGH the skin and hit the blood in the vein. The blood absorbs certain colours of light, and reflects others back through the skin. For some reason, the combination of these effects gives a blue color.

Colour of Blood: Red? Blue?

•Blood is always red - bright red when it is oxygenated and a darker red when it's lacking oxygen.

•Deoxygenated blood just “looks” blue because you're seeing it through your skin.

•Oxygen poor blood is most definitely NOT blue. It is a sort of purplish/maroon colour at best.

•To see the vein at all, light has to go THROUGH the skin and hit the blood in the vein. The blood absorbs certain colours of light, and reflects others back through the skin. For some reason, the combination of these effects gives a blue color.

Colour of Blood: Red? Blue?

•On average, about 8% of your body weight is blood.

•Therefore….60kg *0.08 = 4.8kg

•You have about 6.67 L of blood.

How much blood do you have?

•Plasma•Platelets

•Red blood cells

•White blood cells

What is in your blood?

What is in your blood?

What’s in your blood

•Plasma• Platelets

• Red blood cells

•White blood cells

•Liquid part of blood

•Mostly water

•Makes up more than half the volume of blood (55%)

•Nutrients, minerals, oxygen and wastes are dissolved in plasma

• Plasma

•Platelets• Red blood cells

•White blood cells

•Irregularly shaped cell fragments

•Help clot blood

▫They plug holes in small vessels.

▫They release chemicals that help form filaments of fibrin.

•A cubic millimeter of blood has…..

•400,000 platelets

•Life span: 5-9 days

What’s in your blood

Blood Clotting•What stops the bleeding? •Platelets stick to the wound and release chemicals. •Then clotting factors carry out a series of chemical reactions.

•The reactions cause threadlike fibers called fibrin to form a sticky net.•The net traps escaping blood cells and plasma and forms a clot.

Blood Clotting

•The reactions cause threadlike fibers called fibrin to form a sticky net.•The net traps escaping blood cells and plasma and forms a clot.

Blood Clotting

•Once the clot becomes hard, skin cells begin to reform under the scab.

•Eventually the scab is lifted off, revealing fresh, new skin!

Blood Clotting

•What if you can’t clot?? •You have a genetic disorder called hemophilia.•You lack one of the clotting factors that begin the clotting process.

Blood Clotting

• Plasma

• Platelets

•Red blood cells•White blood cells

▫Red Blood Cells are disk-shaped blood cells that have no nuclei and contain hemoglobin.

▫Hemoglobin carries oxygen and some carbon dioxide (the rest of the CO2 is carried in the cytoplasm of the red blood cell)

▫Hemoglobin is made of an iron compound that gives blood its red colour.

What’s in your blood

• Plasma

• Platelets

•Red blood cells•White blood cells

•The life span of a red blood cell is 120 days (4 months)

•They are made at a rate of 2-3 million per second. WOW!!!

•Where are they made? Bone Marrow

•RBC are also destroyed at about the same rate, 2-3 million per second

•1 cubic millimeter of blood has 5 million red blood cells!!! WOW!!

What’s in your blood

• Plasma

• Platelets

•Red blood cells•White blood cells

•We have approximately 25-30 trillion RBC in our bodies at any given time.

•Each RBC has 250 million hemoglobin molecules.

•Every hemoglobin can hold 4 O2

molecules.

•How many O2 molecules can one RBC carry?

•One Billion!!!

What’s in your blood

• Plasma

• Platelets

• Red blood cells

•White blood cells

•1 cubic millimeter of blood has only 5,000 to 10,000 white blood cells.

•Function: fight bacteria, viruses and other invaders.

•Your body produces more white blood cells when invaders enter your body.

What’s in your blood

• Plasma

• Platelets

• Red blood cells

•White blood cells

•WBC Leave blood through the capillary walls and go into the tissues that have been invaded.

•Here they fight the intruder.•Life span: few days to many

months.

•There are several types, sizes, and

shapes of white blood cells.

What’s in your blood

Blood Types•There are 4 different blood types: •a, b, ab and o

•Types a, b and ab have chemical identification tags called antigens on their red blood cells. Type O red blood cells have no antigens.

Blood Types•Each blood type has specific antibodies in its plasma.

They are proteins in your plasma that destroy or neutralize substances that do not belong to your body.

•Because of this, certain blood types cannot mix. If type A is mixed with type B blood, the type A antibodies determine that the type B does not belong there. The antibodies will cause the type B red blood cells to clump.

Blood Types

•What would happen if type AB had antibodies?

Blood Types

Rh Factor•Another chemical id tag in blood is the Rh factor.

•If the Rh factor is on red blood cells, the person has Rh-positive (Rh +) blood.

•If the Rh factor is not on the red blood cells, the person has Rh-negative (Rh - ) blood.

•If an Rh- person receives a blood transfusion from an Rh+ person, he or she will produce antibodies against the Rh+ factor. Clots will then form in the blood vessels and the person will die.

Rh Factor•If an Rh- mother is pregnant with an Rh+ baby, the

mother might make antibodies to the child’s Rh factor. Close to the time of birth, Rh antibodies from the mother can pass from her blood into the baby’s blood.

•These antibodies can destroy the baby’s red blood cells.

•If this occurs, the baby will have to receive a blood transfusion before or after the birth.

Rh Factor•But at 28 weeks, the mother can receive an injection that

blocks the production of antibodies to the Rh+ factor.

•These injections prevent the life-threatening situation.

Diseases of Blood•Leukemia

▫a disease in which one or more types of white blood cells are made in excessive numbers.

▫These cells are immature and do not fight infections well.

▫they fill the bone marrow and crowd out the normal cells.

▫Then not enough red & white blood cells and platelets can be made.

Diseases of Blood•Leukemia

▫Types of leukemia affect children or adults.

▫medicines, blood transfusions, and bone marrow transplants are used to treat this disease.

Diseases of Blood•Anemia

▫Anemia is a disease of the Red Blood CElls, in which body cells can’t get enough oxygen and are unable to carry on their usual activities.

▫Causes:

๏Loss of blood

๏diet lacking iron or certain vitamins

๏side effect of the treatment of another disease

Diseases of Blood•Anemia

▫One type of anemia results from the disease Sickle Cell Anemia, a recessive genetic disorder.

▫In sickle cell anemia the red blood cells are abnormally shaped and cannot carry oxygen properly.