Blood: The River of Life

transcript

►List the components of the cardiovascular system and explain the major functions of this system.

►Describe the important components and major functions of the blood

►List the characteristics and functions of red blood cells.

►Describe the structure of hemoglobin and indicate its functions.

►Discuss red blood cell production and maturation.

►Explain the importance of blood typing and the basis for ABO and Rh incompatibilities.

►Categorize the various white blood cells on the basis of structure and function.

►Describe the structure, function and production of platelets.

►Describe the reaction sequences responsible for blood clotting.

►Provides a mechanism for rapid transport of nutrients, waste products, respiratory gases and cells

The cardiovascular system

►Fluid connective tissue►Functions

Transporting dissolved gases, nutrients, hormones, and metabolic wastes

Regulating pH and ion composition of interstitial fluids

Restricting fluid loss at injury sites Defending the body against toxins and

pathogens Regulating body temperature by

absorbing and redistributing heat

The composition of blood►Plasma and formed elements comprise

whole blood Red blood cells (RBC) White blood cells (WBC) Platelets

►Can fractionate whole blood for analytical or clinical purposes

The Composition of Whole Blood

Review:

List, by %, the components of blood.

In 1 L of Blood: How much plasma? How much RBC? WBC? Platelets

►Accounts for 46-63% of blood volume 92% of plasma is water Higher concentration of dissolved oxygen

and dissolved proteins than interstitial fluid

Plasma

►more than 90% are synthesized in the liver

►Albumins 60% of plasma proteins Responsible for viscosity and osmotic

pressure of blood

Plasma proteins

►Globulins ~35% of plasma proteins Include immunoglobins which

attack foreign proteins and pathogens

Include transport globulins which bind ions, hormones and other compounds

►Fibrinogen Converted to fibrin during

clotting Removal of fibrinogen leaves

Gamma Globulin Shots: temporarily boost for immunity against disease

Why Usually given to patients exposed to Hepatitis A?

Hep A vaccine now developed

Red Blood Cells

Artery Vein

The Anatomy of Red Blood Cells

►Erythrocytes account for slightly less than half the blood volume, and 99.9% of the formed elements

►Hematocrit measures the percentage of whole blood occupied by formed elements Commonly referred to as the volume of

packed red cells

Abundance of RBCs

►Biconcave disc, providing a large surface to volume ration

►Shape allows RBCs to stack, bend and flex

►RBCs lack organelles►Typically degenerate in about 120

Structure of RBCs

“Sickling” in Red Blood Cells

In certain parts of Africa today, the frequency of the mutant gene for sickle-cell (HbS) is very high (5-20%) as shown in the distribution map below:

malaria, caused by the protozoan

Plasmodium falciparum

►3 million new blood cells entering the circulation per second.

►Components of hemoglobin individually recycled Heme stripped of iron and converted to

biliverdin, then bilirubin►Iron is recycled by being stored in

phagocytes, or transported throughout the blood stream bound to transferrin

RBC life span and circulation

The Structure of Hemoglobin

White Blood Cells

►Have nuclei and other organelles►Defend the body against pathogens ►Remove toxins, wastes, and abnormal

or damaged cells►Are capable of amoeboid movement

(margination) and positive chemotaxis►Some are capable of phagocytosis

Leukocytes-WBC

►Granular leukocytes Neutrophils – 50 to 70 % total WBC

population- phagocytize bacteria Eosinophils – phagocytes attracted to

foreign compounds that have reacted with antibodies- worms/allergy/asthma

Basophils – migrate to damaged tissue and release histamine and heparin- inflamation response

Types of WBC

►Agranular leukocytes Monocytes - become macrophage Lymphocytes – includes T cells, B cells,

and NK cells- immune response

Types of WBC

Exercise 29A Activity 2

Activity 7

Review Sheet 29A Composition of Blood Hematologic Tests

Stages of RBC Maturation

►Erythropoeisis = the formation of new red blood cells

►Occurs in red bone marrow►Process speeds up with in the presence

of EPO (Erythropoeisis stimulating hormone) RBCs pass through reticulocyte and

erythroblast stages

RBC Production

Red Blood Cell Turnover

►Determined by the presence or absence of surface antigens (agglutinogens) Antigens A, B and Rh (D)

►Antibodies in the plasma (agglutinins)►Cross-reactions occur when antigens

meet antibodies

Blood types

Blood Typing & Cross-Reactions

Rh Factors and Pregnancy

►Indicates a number of disorders Leukemia = inordinate number of

leukocytes

Differential counts-Blood Tests

Platelets

►Flattened discs►Circulate for 9-12 days before being

removed by phagocytes

Platelets

►Transporting chemicals important to clotting

►Forming temporary patch in walls of damaged blood vessels

►Contracting after a clot has formed

Platelet functions

►Megakaryocytes release platelets into circulating blood

►Rate of platelet formation is stimulated by thrombopoietin, thrombocyte-stimulating factor, interleukin-6, and Multi-CSF

Platelet production (thrombocytopoiesis)

HemostasisStoppage of Blood

Hemostasis

►Prevents the loss of blood through vessel walls

►Three phases – Vascular phase Platelet phase Coagulation phase

Hemostasis►Vascular phase

Local blood vessel constriction (vascular spasm)

►Platelet phase Platelets are activated, aggregate at the

site, adhere to the damaged surfaces

The Vascular and Platelet Phases of Hemostasis

http://heart-disease.emedtv.com/blood-clots-video/how-does-blood-clot-video.html

Coagulation phase►Factors released by platelets and

endothelial cells interact with clotting factors to form a clot Extrinsic pathway Intrinsic pathway Common pathway

►Suspended fibrinogen is converted to large insoluble fibrin fibers

The Coagulation Phase of Hemostasis

Clot retraction

►Final phase of healing►Platelets contract and pull the edges of

the vessel together

Blood: The River of Life

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