Chapter 6 Biology

What are the functions of the blood?

• Transportation - oxygen, nutrients, waste, carbon dioxide, and hormones - chemicals are excreted by endrocrine glands

• Defense - Against invasion of pathogens -White Blood cells

• Regulatory Factors - Body temperature, water-salt balance and body ph

• Blood has two components - plasma and formed elements

• Humans have 5L of blood in the veins,

What is the composition of blood?

• Remember: blood is a fluid connective tissue.

• Formed elements are produced in red bone marrow

• Red Blood Cells - erthrocytes (RBC)

• White Blood Cells - leukocytes (WBC)

• Platelets - thrombocytes

Plasma

• Consists of 91% water and 9% salts (ions, and organic molecules

• Plasma Proteins are the most abundant in organic molecules

• Albumin

• Fibrinogen

• Immunoglobulins - anti bodies

3 Major Types

Albumin - Most abundant and important for plasmas osmotic pressure as well as transport

Globulins - Also important in transport

Fibrinogen - Important for the formation of blood clots

Red Blood Cell Functions

• Contain hemogloblin and prevents fluctutation in ph

• Transports oxygen O2 from your lungs to your bodys tissues and carry carbon dioxide CO2 from body tissues back to the lungs so it can leave the body

White Blood Cells Functions

• protect your body from infections, illnesses, and foreign invaders, like bacteria, viruses, and fungi

Platelets Functions

• Help in blood clotting

Structure of Red Blood Cells

• They lack a nucleus and have few organelles

• 99% of our cells are red blood cells

• Their biconcave shape increases surface area

• Each RBC contains about 280 million hemogloblin molecules that bind 4 molecules of O2 each

Hemogloblin Structure

• Quatnary Structure

• Four polypeptide chains

• They carry oxygen and carbon dioxide

How is carbon dioxide transported

• 68% as a bicarbonate ion in the plasma (This conversion takes place in RBCs)

• 25% bound to hemogloblin in red blood cells

• 7% as carbon dioxide in the plasma - dissolves in plasma

• CO2 is constantly generated by cells in the body, cannot contain it too much or it will cause acidosis, transported from the cells to the lungs, and then eliminate to the from the body

production of red blood cells

• All generate in the red bone marrow

• Lifespan of about 90 to 120 days

• Erythropoiten EPO -a hormone- is secreted by the kidney cells and moves to red bone marrow whe oxygen levels are low

White blood cells

• Come from red bone marrow

• Large blood cells that have a nucleus

• production is regulated by colony-stimulating factor -CSF

• Can be found in the tissuesas well as the blood

• Fight infection and are an important part of the immune system

• Some live for days while others live months or for years

Types of White Blood Cells

Granulocytes

• Neutrophils - phagocytize pathogens and celluar debris, make up 70% of WBC, have a multilobal nucelus

• Eosinphils - Use granule contents to digest large pathogens, such as worms, or parasites, and reduces inflammation, 2-3% of WBC, have bilo bed nucleus

• Basophils - promote blood flow to injured tissues and inflammatory response, least abundant, have a U shaped or lobed nucelus

Agranulocytes

• Lymphocytes - Responsible for specific immunity— B-cells produce antibodies and T-cells destroy cancer and virus-infected cells, 25-27% of WBC, large nucelus that takes up most of the cytoplasm

• Monocytes - Become macrophages that phagocytize pathogens and celluar debris, Largest with a horse shoe shaped nucleus

Granulocyte and Agranular leukocytes

• Granular - Contain noticeable granules, lobed nuclei Neutrophils, Eosinphils, and Basophils

• Agranular - No granules, nonlobed nuclei, Lymphocytes, Monocyte

How do blood cells leave circulation

• Diapedesis - The process where leukocytes squeeze through intact blood vessel walls to to reach sites of tissue damage, and inflammation

platelets

• They result from the fragmentation of large cells, called megakaryocytes, in the red bone marrow

• About 200 billion platelets are made per day

• They function in blood clotting

• Blood proteins called thrombin and fibrinogen create clots by forming fribrin threads that catch RBCs

How do platelets clot blood

1. Blood vessel is punctured

2. platelets congregrate and form a plug

3. platelets and damaged tissues cells released prothrombin activator, which initiates a cascade of enzymatic reactions

4. Fibrin threads form and trap red blood cells

What terminology can help you understand ABO blood typing

Antigen - A foreign substance, often a polysaccharide or a protein, that stimulates an immune response

Antibody - a protein made in response to an antigen in the body which binds specifically to that antigen

Blood Transfusion - The transfer of blood from one individual into another individual

What determines the A, B, AB, or O blood type

• presence or/absence of of 2 blood anitgens, A and B

• Types of antibodies present

• Antibodies are only present for those antigens lacking on the cells because these proteins recognize and bind the protein they are named after

Type A blood. Red blood cells have —— surface antigens. plasma has —— antibodies

Type A blood. Red blood cells have type a surface antigens. plasma has anti B antibodies

For type A blood

• Red blood cells have type A surface antigens

• plasma has anti-b anitbodies

For type B blood

• Red blood cells have type b surface antigens

• plasma has anti-a antibodies

Type AB blood

• Red blood cells have type A and type B surface antigens

• plasma has neither anti A nor anti B antibodies

Type O blood

• Red blood cells have neither type A or type B surface antigens

• plasma has type a and type b antibodies

How can you determine is blood types are compatible

• First consider the antigens found on the blood transfusion donors RBC

• Second, consider the antibodies found in the recipients blood

• If the antibodies in recipients blood can recognize the antigens on the donors RBCs, then the blood will agglutinate-clump-and cause rejection