Blood

Lectures on Hematology for 2nd medical students2014-2015

Dr.Baybeen Selevany Assist. Professor PhD( Hematology) , M.Sc( Heart) Dept. Of Medical Physiology College of Medicine University of Mosul


REFERENCES1. Text Book of Medical Physiology. Guyton and Hall. 11ed.2.Review of Medical Physiology.Willam F.Ganong.3.Essentials of Phsiology.Nicholas sperelakis ,Robert O.Banks.4.Human Physiology .Vander ,Sherman,Luciano.5.internet

BLOOD PHYSIOLOGY

LEC.1 29-11-2015


Objectives 1.definitions 2.compostion of blood 3.functions of blood 4.plasma 5.serum 6.lymph

Hematology: scientific study of the structure and functions of blood in health & disease. i.e. study the normal and abnormal morphology and physiology of blood.

Blood has been defined as a highly specialized tissue, which along with the circulatory system (heart, blood vessels and blood).


Composition of Blood total blood volume(TBV) is 8% of the body weight of a 70kg man (i.e.5.6 Liters( 5600ml). Blood is a type of connective tissue, consisting of: Plasma: the fluid portion of blood. Blood cells: the solid portion of blood. a: erythrocytes b.Leukocytes. C: Cell fragments (platelets or thrombocytes)


General Functions of blood 1.Transportation:. O2 from lungs --- cells cells , CO2 by cells ---- lungs 2.nutrients, electrolytes & water from gastrointestinal tract to cells ingested , waste products are transported from cells ---- kidneys for elimination in urine

2) Maintenance: homeostasis. a: Many of the hormones and enzymes --------buffers ------blood’s PH within its normal limits of 7.35 – 7.45. b:The osmotic composition----- ----normal fluid & electrolyte balance. c: temperature regulation3) Protection: 1.immune system, 2.Blood clotting also provides

PLASMA

The normal plasma volume is about 55% of total blood volume(TBV or roughly 3080 ml in a 70-k gm man


Composition of Plasma Is a pale yellow fluid that consist of: 91% water 2% other solutes 3.7% plasma proteins: Plasma is a colloidal solution Origin of plasma proteins:

plasma proteins are synthesized in the liver except circulating antibodies or immunoglobulin's (Ig's) which are manufactured in the plasma cells (from B-lymphocytes Separation of proteins performed by a technique called electrophoresis.

Functions of plasma proteins

1.Coagulation: fibrinogen is responsible for blood clots. fibrinolytic factors such as plasminogen, which prevent formation of spontaneous clots in the blood vessels. 2.Transport :Albumin & globulins acts as carrier proteins

. Inflammation: Plasma also contains a. number of proteins that play a major role in the production of inflammatory responses e.g. β- globulins.4. Immunglobulins (Ig's) or antibodies: Formed by β – lymphocytes & play a major role in the body’s defense against invading pathogens. Ig's are found mainly in the γ - globulin fraction of plasma. Ig's are: IgG, IgA, IgM, IgD, and IgE


5-Transvascular exchange of water
osmotic (oncotic) pressure of albumins-----25mmHg at arterial and venous ends-- tends to cause osmosis of fluid inward through the capillary (reabsorption) capillary hydrostatic pressure-- 40 mmHg at arterial end and 12 mmHg at venous end-----tends to cause osmosis of fluid outward through the capillary (filtration) Arterial end -----filtration Venous end ---reabsorption

Odema (Dropsy) : Is the failure of reabsorption of tissue fluids ( i.e. the filtration rate is exceed the reabsorption rate). Causes of edema: Hypoproteinemia----nephrotic syndrome high venous pressure: e.g. congestive heart failure. a venous thrombosis---pregnant women Increased capillary permeability: e.g. insect bit

Serum

no clotting factors: fibrinogen (factor I), prothrombin (factor II), labile factor (factor V), and antihemophilic factor VIII it has a higher serotonin

Lymph is tissue fluid that enters the venous blood through lymphatic circulation.

Composition: clotting factors s proteins that traverse capillary walls and return to blood via the lymph.

Table : protein content of lymph in humans.

Protein content (g / dL)
Source of lymph
6.2
Liver
4.4
Heart
4.1
Gastrointestinal Tract
4
Lung
2
Skeletal muscle
2
Skin
0
Ciliary body
0
Choroid plexus