Blood

ATS Unit 7

Learning Targets

• Identify the functions of the blood.

• Discuss the components of the blood.

• Describe the process of blood formation and recycling.

• Discuss the blood clotting process (hemostasis)

Fun Facts

• Each adult has 8 to 10 pints of blood.

• A newborn has just over 6 ounces of blood.

• A single RBC can make a full circuit of the circulatory system in 30 seconds.

• There are 150 billion RBCs in one ounce of blood.

Functions of Blood

• If the circulatory system in the body’s highway system, the blood is like the commuters and travelers.

– It Transports: electrolytes, nutrients, waste.

– It Regulates: balances pH, hormones, body temperature, and concentration of water/electrolytes in the tissues.

– It Protects: mobilizes immune cells, clotting ability to heal injury.

Blood Components

• Blood has 4 major components:

– Plasma

– Erythrocytes

– Leukocytes

– Thrombocytes

Blood Plasma (55% of volume)

• This is the slightly yellow solution that carries the following important elements: – Water (92%)

– Plasma Proteins

– Nutrients (from the digestive system)

– Electrolytes (important to pH balance and exchange)

– Hormones, vitamins, enzymes

– Waste products

Plasma Proteins – Top 3

• Fibrinogen:

– This protein is needed for blood to clot.

– Produced in the liver.

• Albumin:

– This is the most abundant.

– Made in the liver.

– Creates osmotic pressure to prevent all of the water from seeping into the tissues.

• Globulin:

– Formed in the liver and lymphatic system.

– Some of this becomes Immunoglobulin.

– Some is made into Prothrombin in the liver to allow blood to clot.

Erythrocytes

• The Red Blood Cells– These have the

function of carrying oxygen via hemoglobin molecules located in the cells.

– They have no nucleus.

– These are developed in a complex process called erythropoiesis.

Erythropoiesis

• The process of making red blood cells occurs in the red bone marrow.

– All blood cells (except special lymphocytes) are born in red bone marrow.

– Stems cells called hemocytoblasts are stimulated by the hormone erythropoietin (released by the kidneys when RBC level drops)

– Requires B12, copper, folic acid, cobalt and iron to complete process.

The RBC Lifecycle

• RBC are usable in the body for about 120 days.

– After this time, they become worn out.

– RBCs are recycled in the spleen and liver.

– The cell parts are waste, but most of the iron is saved for reuse.

– Some iron that is not saved is eliminated in bilirubin via the digestive tract.

Hemoglobin

• As discusses, is the special molecule that carrier oxygen in RBCs.

– It is a protein.

– 1 RBC has several million hemoglobins.

• Hemoglobin functions by binding oxygen to iron (forming iron oxide which is red).

Leukocytes

• White Blood Cells have two major types:

– Granulocytes – made in red bone marrow

– Agranulocyte – made in lymphatic tissue

• These cells are part of the immune system.

Agranulocyte

• This applies to about 35% of all WBCs. These cells have solid (nongrainy) middles when examined under a microscope. – There are two types:

Lymphocytes and Macrophages (monocyte)

– The function as part of the specific immune response.

– These are made in the lymphatic tissue.

Granulocytes

• These are cells formed in red bone marrow from cells called myelocytes. They have a grainy appearance.

• There are 3 types: – Neutrophils (phagocytes)

– Eosinophils (respond to allergic or parasitic issues)

– Basophils (phagocytes that also release histamines)

Thrombocytes

• These are blood platelets.

– They are fragments of cells called megakaryocytes formed in the red bone marrow.

– They are necessary to allow the process of blood clotting to occur.

Hemostasis

• This is term for the process that stops bleeding. – When a break is detected in a blood vessel, several

actions occur. • Serotonin is released to constrict the vessels. -->

• Thromboplastin (from platelets and tissues) uses calcium to act as an enzyme, deactivates anticoagulants in blood

• Prothrombin (reacts with calcium, clotting factors and thromboplastin to covert to…)

• Thrombin (acts asn an enzyme to convert Fibrinogen in plasma to Fibrin)

• Fibrin forms a net that catches together blood cells, platelets anf forms the clot.

DISCUSS: WHY IS THE CLOTTING PROCESS SO COMPLICATED?

Because…

• A clot is only a good thing to have if there is a bleed.

• Clots can cause impairment of circulation, strokes, heart attacks.

• For those reasons, we do not want clots to form spontaneously.

• The complicated process is a safeguard to prevent accidental clot formation.

Blood Types

• Blood type is an inherited trait. – It is named based on the presence of proteins on

RBC called agglutinogen. • They have labeled A and B ( O types have none)

• People with a type of agglutinogen have antibodies against there opposite. – Ex: A has anti B, O has both anti A and B, AB has none.

• Human Blood also may contain the Rh factor. – This is the + or – part of the blood type.

– People with the Rh factor can receive Rh negative blood, but not the other way around.

What Happens When We Receive the Wrong Blood Type?

• Bad things. – The Antibodies and protein in the blood that do

not match react with each other.

– This leads to clumping of cells and hemolysis (destruction of RBCs) by immune system which is responding to the foreign proteins.

– Signs of an acute reaction include fever, increased blood pressure, pain, and shortness of breath.

– These reactions can be deadly, lead to kidney failure, etc.