Human Biology: Circulatory System

Lesson 2: Blood and the Lymphatic System

(Inquiry into Life pg. 226-230, 240-251)

Today’s Objectives Describe the components of blood,

including: Describe the shape, function, and origin of red

blood cells, white blood cells, and platelets List the major components of plasma Explain the roles of antigens and antibodies

Describe the inter-relationships of the structures of the lymphatic system, including: Describe the functions of the lymphatic system Identify and give functions of lymph capillaries,

veins, and nodes

Components of Blood A) Plasma: 55% of blood B) Formed Elements: 45% of blood

Erythrocytes (Red Blood Cells) Leukocytes (White Blood Cells) Thrombocytes (Platelets)

FEATURE RED BLOOD CELLS WHITE BLOOD CELLS PLATELETS

SHAPE Biconcave disc Variable, Amoeboid Tiny, Cell fragments

FUNCTION Transport O2 and CO2 Combat infection Blood clotting

ORIGIN Bone marrow Bone marrowLymphoid Tissue

Bone Marrow

ALSO CALLED Erythrocytes Leukocytes Thrombocytes

Constituents of Plasma NAME FUNCTION

A. Water (90%) Blood Volume Transport of cells and materials   B. Plasma Proteins Helps maintain Osmotic pressure in blood. a) Albumen -Transports b) Fibrinogen -Blood Clotting c) Globulins -Infection fighting C. Gases a) Oxygen -For respiration b) Carbon Dioxide -Waste   D. Nutrients Energy source - Raw materials for the a) A.A. Glucose, body Fatty acids, Glycerol   E. Salts Osmotic Pressure Helps in Metabolism   F. Wastes Waste production of Cellular Reactions.

Shape, Function, and Origin of RBC Red Blood Cells

(Erythrocytes) Video Live about 120 days Produced in Red Bone

Marrow (in skull, ribs, vertebrae, and long bones)

Myeloid stem cells form RBC These stem cells are called

Erythroblasts, which will differentiate into Erythrocytes

Produce about 5 million/second RBC contain a protein called

hemoglobin Old RBC destroyed in the

liver and spleen

Hemoglobin Hemoglobin contains iron (gives its red color) Picks up oxygen in the lungs then releases is it in the

tissues Approximately 200,000,000 hemoglobin molecules in

one RBC If hemoglobin was not packaged in RBC, oxygen would

leak out of the circulatory system

Shape, Function, and Origin of WBC White Blood Cells (Leukocytes)Video

Larger than RBC Have a nucleus (RBC do not) Less numerous than RBC (700:1) Do not have a definite shape

Function: Fights against infection in two ways:

Phagocytosis Produce Antibodies

Types of White Blood Cells Granular Leukocytes (Granulocytes)

Have grains, or granules in their cytoplasm which are filled with enzymes and proteins to fight against microbes

Formed in the bone marrow 60-70% of Leukocytes Example: Neutrophil – phagocytize and digest bacteria

Agranular Leukocytes (Agranulocytes) No granules in cytoplasm Produced by lymphatic tissue 25-30% of Leukocytes Example: Monocytes (phagocytize pathogens and

cellular debris) and Lymphocytes (responsible for specific immunity)

Agranulocytes Monocytes:

Largest WBC Take up residence in tissues Differentiate into larger ``macrophages`` which

phagocytize microbes and stimulate other WBC Lymphocytes:

B-Lymphocytes – produced in bone and lymphoid tissue

T-Lymphocytes – produced in the thymus and give rise to plasma cells

Platelets (Thrombocytes) 2 billion produced/day Broken fragments of larger cells Very important in blood clotting

Blood Clotting: Need three things in blood:

- Platelets - Prothrombin - Fibrinogen

1) Platelets clump at the site of the “leak” and partially close it

2) Platelets and the injured tissue together release an enzyme called Thromboplastin

Blood Clotting 3) Thromboplastin converts a blood protein

(Prothrombin) into a new substance called Thrombin

4) Thrombin acts as an enzyme that breaks the ends off another blood protein called Fibrinogen

5) Fibrinogen is then converted into Fibrin 6) Fibrin has sticky ends and forms a lattice or

network over the leak where blood cells get trapped, forming a clot

7) Fibrin clot is only temporary – as soon as the blood vessel repair is initiated, and enzyme called Plasmin destroys the network

RBC trapped in the FIBRIN network

Lymphatic System (see video) Functions:

1) Takes excess tissue fluid and sends it to the circulatory system (lymphatic system joins the circulatory system at the subclavian veins)

2) Products of fat digestion are absorbed into Lacteals which lead to the Lymph vessels and Nodes

3) Lymph nodes produce Lymphocytes (a type of WBC) and help the body defend against disease

4) Lymph nodes act as filters and trap bacteria and other debris (helps to purify the body fluids)

Lymphatic Structures Spleen: Largest Lymphatic Tissue Produces lymphocytes and stores excess blood

If your blood pressure is high, stores blood so blood pressure lowers

If your blood pressure is low, it contracts and squeezes out blood, sending it back to the system so that blood pressure rises

Thymus Gland: Bi-lobed structure which is important In the maturing of lymphocytes Gets smaller as you age

Lymphatic Structures Tonsils and Appendix:

Contain lymphoid tissue Thought to help remove invading

organisms and viruses Lymphatic Tissue:

Produce lymphocytes and stores excess blood

Lymph Vessels: Similar to veins, but fluid only travels in

one direction (lymph veins and capillaries, but no lymph arteries)

Lymph Nodes: Small oval or round tissues which filter

fluids and produce lymphocytes Lacteals:

Sacs in villi of digestive system which absorb products of fat digestion

Infection Fighting – Inflammatory Response Foreign Substances (bacteria or viruses)

attack Monocytes and Neutrophils engulf the

bacteria or viruses in amoeboid fashion (phagocytosis)

These WBC are able to travel to the site of the infection through capillary network

Dead tissue, cells, bacteria, dead and living neutrophils all together make up Pus

Lymphocytes Produce antibodies One antibody fights a specific antigen (foreign

protein) Antigen + Antibody inactive complex Antigens:

A protein found in the outer membrane of RBCs Stimulate an immune response (production of antibodies) The type of protein determines the blood type Can also be a foreign protein introduced to the body

Antibodies: A protein found in the plasma Attack unwanted proteins (bacteria or viruses) End result is agglutination

ABO Blood System (see video)

Blood Group Proteins on Red Blood

Cells(Antigen)

Clumping Chemicals in

Plasma(Antibody)

Can Accept Transfusions

from Group(s)

A A Anti B A, O

B B Anti A B, O

AB A and B None A, B, AB, O(universal

recipient)

O None Anti A Anti B(universal donor)

O

Rhesus Factor Red blood cells may have another antigen

called antigen D, known as the Rhesus Factor.

This distinguishes blood as being RH+ or RH-.

Therefore there are 8 possible blood types.