10 or 11 depending on whether muscles and skeleton are considered one system. Also: Lymphatic system is anatomical system, physiologically it belongs to circulatory, digestive and immune systems. Regulation of plasma concentration: The endocrine system acts on bones, kidneys, and intestine to ensure that plasma calcium concentrations remain within a certain range.
introduction BLOOD Dr Alamzeb MBBS M.Phil Assistant Professor
Body systems work together (Integration of function)
Internal vs. external failure of homeostasis
Communication and movement across cell membranes
Vital to integration & homeostasis
Cells communicate with other cells, tissues & organs
Energy Flow and Law of Mass Balance All living processes require constant input of energy Where from? - How is it stored? How is it used to do work? Total amount of substance in body = intake + production - output What substances are maintained through law of mass balance? Major routes for output? Major routes for input?
If we take some blood, prevented from clotting, in a centrifuge, after centrifugation we have this result.
Let us understand the composition of the sedimented blood:
Composition of Blood Blood consist of 1 Red cell 2 White cell 3 Platelets 4 Plasma – in which the above elements are suspended Plasma is the liquid component. which contain soluble fibrinogen Serum is what remains after the formation fibrin clot Dr Alamzeb MBBS M.Phil
Your circulatory system contains about 5 liters of the most remarkable fluid on earth,
traveling through 65,000 miles(104650)Kms of blood vessels to carry oxygen and nutrients to every one of your 100 trillion cells,
and remove waste products from them.
45% of the volume is red blood cells (RBCs) which make round trips to your big toe about every 20 seconds,
flowing through capillaries just 1/10th the diameter of a human hair where the transfer takes place...so small that only one RBC at a time can wriggle through.
Dr Alamzeb MBBS M.Phil
BLOOD. Blood is also vital to maintain a stable body temperature by varying the amount of blood to different areas of the body. To do all this, the heart pumps about 2,000 gallons (9100 liters) of blood per day; its valves operate some 5000 times per hour , and it never stops for maintenance...not even once! The Bible said a long time ago that " the life of the flesh is in the blood ." Dr Alamzeb MBBS M.Phil
Thickness continue A sheet of paper is approximately 75 micron thick Therefore 10 Erythrocytes could be aligned side by side across the edge of a sheet paper Dr Alamzeb MBBS M.Phil
Shape of RBCs Under Microscope Red blood cells (erythrocytes) shown above in a stained slide. Note how they stain darker at the edges than in the middle reflecting their biconcave shape. Dr Alamzeb MBBS M Phil
Appearance under microscope Red blood cells (erythrocytes) shown in a stained slide. Note how they stain darker at the edges than in the middle reflecting their biconcave shape.
Red blood cells have the ability to concentrate hemoglobin in the cell fluid up to about 34 grams in each 100 milliliters of cells.
The concentration does not rise above this value, because this is the metabolic limit of the cell's hemoglobin-forming mechanism.
Furthermore, in normal people, the percentage of hemoglobin is almost always near the maximum in each cell.
However, when hemoglobin formation is deficient, the percentage of hemoglobin in the cells may fall considerably below this value, and the volume of the red cell may also decrease because of diminished hemoglobin to fill the cell.
When the hematocrit (the percentage of blood that is cells-normally, 40 to 45 per cent) and the quantity of hemoglobin in each respective cell are normal, the whole blood of men contains an average of 15 grams of hemoglobin per 100 milliliters of cells;
for women, it contains an average of 14 grams per 100 milliliters.
Formation of the growth inducers and differentiation inducers is itself controlled by factors outside the bone marrow.
For instance, in the case of erythrocytes (red blood cells), exposure of the blood to low oxygen for a long time results in growth induction, differentiation, and production of greatly increased numbers of erythrocytes
In the case of some of the white blood cells, infectious diseases cause growth, differentiation, and eventual formation of specific types of white blood cells that are needed to combat each infection.
Once the proerythroblast has been formed, it divides multiple times, eventually forming many mature red blood cells. The first-generation cells are called basophil erythroblasts
because they stain with basic dyes; the cell at this time has accumulated very little hemoglobin.
In the succeeding generations, the cells become filled with hemoglobin to a concentration of about 34 per cent, the nucleus condenses to a small size, and its final remnant is absorbed or extruded from the cell.
At the same time, the endoplasmic reticulum is also reabsorbed. The cell at this stage is called a reticulocyte because it still contains a small amount of basophilic material, consisting of remnants of the Golgi apparatus, mitochondria, and a few other cytoplasmic organelles.
During this reticulocyte stage, the cells pass from the bone marrow into the blood capillaries by diapedesis (squeezing through the pores of the capillary membrane).
The proliferation & differentiation of stem cells are under the control of growth factors produced by several cells including stromal cells & lymphocytes.
These growth factors binds to specific receptors on the cell surface , promote proliferation,differention ,survival & functions of mature cells
Dr Alamzeb MBBS M.Phil
Regulation of Red Blood Cell Production-Role of Erythropoietin
The total mass of red blood cells in the circulatory system is regulated within narrow limits, so that
(1) an adequate number of red cells is always available to provide sufficient transport of oxygen from the lungs to the tissues, yet
(2) the cells do not become so numerous that they impede blood flow.
Tissue Oxygenation Is the Most Essential Regulator of Red Blood Cell Production.
Any condition that causes the quantity of oxygen transported to the tissues to decrease ordinarily increases the rate of red blood cell production.
Thus, when a person becomes extremely anemic as a result of hemorrhage or any other condition, the bone marrow immediately begins to produce large quantities of red blood cells.
Also, destruction of major portions of the bone marrow by any means, especially by x-ray therapy, causes hyperplasia of the remaining bone marrow, thereby attempting to supply the demand for red blood cells in the body.
Various diseases of the circulation that cause decreased blood flow through the peripheral vessels, and particularly those that cause failure of oxygen absorption by the blood as it passes through the lungs, can also increase the rate of red cell production.
This is especially apparent in prolonged cardiac failure and in many lung diseases, because the tissue hypoxia resulting from these conditions increases red cell production, with a resultant increase in hematocrit and usually total blood volume as well.
Seventy percent of the CO 2 is removed in this way.
Seven percent of the CO 2 is dissolved in the plasma.
The remaining 23 percent of the CO 2 combines directly with hemoglobin and then is released into the lungs.
Alamzeb MBBS M.Phil
OTHER FUNCTIONS BESIDES TRANSPORT OF HEMOGLOBIN.
The red blood cells contain a large quantity of carbonic anhydrase, an enzyme that catalyzes the reversible reaction between carbon dioxide (CO 2 ) and water to form carbonic acid (H 2 CO 3 ), increasing the rate of this reaction several thousand fold.H2o+Co2 H2Co3
The rapidity of this reaction makes it possible for the water of the blood to transport enormous quantities of CO 2 in the form of bicarbonate ion (HCO 3 - ) from the tissues to the lungs,
where it is reconverted to CO 2 and expelled into the atmosphere as a body waste product.
The hemoglobin in the cells is an excellent acid-base buffer (as is true of most proteins), so that the red blood cells are responsible for most of the acid-base buffering power of whole blood.