Blood & Respiration By Dr. Mamdouh R El-Sawi

I-Blood First lecture

Blood Blood is a complex mixture of a reddish fluid that circulates continuously inside the cardio-vascular system. Blood is a complex mixture of a reddish fluid that circulates continuously inside the cardio-vascular system. Blood has many important functions, which are essential for life. Blood has many important functions, which are essential for life. Sudden loss of 30% of total volume of blood leads to death. Sudden loss of 30% of total volume of blood leads to death.

Functions of the blood Respiratory: Respiratory: –It transports O 2 from lungs to tissues. –It transports CO 2 from tissues to lungs. Nutritional: Nutritional: –It transports digested food from gut to tissue cells. Excretory: Excretory: –It transports wastes from tissues to kidney & other excretory organs (urea, uric acid, water).

Functions of the blood Regulatory Regulatory –The water Content of Tissues –The pH of the blood through the buffer systems –The body temperature: Water- high heat capacity, thermal conductivity, heat of vaporization Water- high heat capacity, thermal conductivity, heat of vaporization Protective Protective -blood loss from injured vessels by formation of -blood loss from injured vessels by formation of platelet plug & blood clot. platelet plug & blood clot. –Antibodies, antitoxins, white blood cells (WBC)

Composition of the blood Blood is composed of cells and cell like structures suspended in a clear yellowish fluid called plasma:-  Cells - 45% by volume.  Plasma - 55% by volume.

Plasma Red blood cells White blood cells & platelets Plasma Hematocrit

Composition of the blood A-Cells  Red cells (erythrocytes).  5x10 6 /mL blood.  White cells (leukocytes).  7x10 3 /mL blood.  Platelets (thrombocytes).  3x10 5 /mL blood.

Composition of the blood B-Blood plasma It is a clear yellowish fluid. It is a clear yellowish fluid. It is a part of the extra cellular fluid of the body. It is a part of the extra cellular fluid of the body. It is identical to the interstitial fluid except for its protein content (2-3%). It is identical to the interstitial fluid except for its protein content (2-3%).

Composition of the plasma B-Blood plasma –Water: 90%. –Proteins: 7%. –Inorganic: 1 %.  Na+, K+, Mg2+, Ca2+, PO43- … –Organic: 2%.  Metabolic end products: e.g. urea, uric acid, creatine & creatinine  Nutritive substances: e.g. fats, cholesterol, glucose...  Regulatory substances: e.g. enzymes, hormones, vitamins.

Plasma proteins 1-Albumin: (4%)  Form 60-80% of plasma proteins.  Provides the osmotic pressure needed to draw H 2 0 from interstitial fluid into capillaries.  Maintains blood pressure. MW MW Single chain, 580 amino acids, sequence is known Single chain, 580 amino acids, sequence is known Dimensions - Heart shaped molecule Dimensions - Heart shaped molecule 50%  helix. 50%  helix.

Plasma proteins 20% of plasma proteins. 20% of plasma proteins. “  ” refers to electrophoretic mobility. “  ” refers to electrophoretic mobility. Represents a group of proteins of variable structures called immunoglobulins. Represents a group of proteins of variable structures called immunoglobulins. Main functional task: is immunochemical. Main functional task: is immunochemical. –Antibodies - combine with specific antigens 2-Globulins: (2.7%)