Blood is composed of plasma and blood cells. Plasma is 90% water and contains proteins, minerals, nutrients, waste products and hormones. Red blood cells carry oxygen, are biconcave discs that lack nuclei, and number around 5 million per cubic millimeter. White blood cells protect against infection and come in two types - lymphocytes which produce antibodies and phagocytes which ingest pathogens. Platelets help the blood clot. Blood pressure refers to the force exerted by blood on vessel walls and is highest during systole when ventricles contract and lowest during diastole when they relax.
2. Introduction
■ Blood is basically a fluid tissue consisting of blood cells and platelets.
■ 55% of whole blood is plasma and rest 45% is the blood cells and platelets.
Blood
Blood cells
Red blood
cells
White
blood cells
Platelets
Plasma
3. Plasma
■ Plasma is a pale yellowish liquid. In plasma, 90% is
water in which substances are dissolved as such:
– Soluble proteins such as serum albumin, serum
globulin, fibrinogen and prothrombin
– Dissolved minerals such as chlorides,
bicarbonate, sulphates and phosphates of
sodium and potassium and calcium salts.
– Food substances like glucose, fats and amino
acids
– Urea, uric acid and creatinine
– Hormones
4. Red blood cells
■ Red blood cells are also known as erythrocytes.
■ Red blood cell is a circular, flattened, biconcave disc
making the center of the cell thinner than its edge.
■ It does not have a nucleus.
■ As it is elastic, it can squeeze through the capillaries
smaller than itself in diameter.
■ There are about 5 000 000 red blood cells in each
cubic millimeter of blood.
■ Red blood cells are produced by bone marrow.
■ They have a lifetime of 3 to 4 months.
■ Red blood cells contain a pigment known as
hemoglobin, which contains iron that enables it to
transport oxygen from lungs to all the cells in the
body. RBCs act as a carrier to transport oxygen to the
parts of the body.
5. White Blood
Cells
White blood cells are colorless
and do not contain hemoglobin.
They are larger than red blood
cells and fewer in number. Each
white blood cell is regular in
shape and contains a nucleus. It
can move. It can change its shape
and squeeze through the walls of
the fine blood capillaries into the
spaces among the tissue cells.
Their main role is to protect the
body against disease causing
microorganisms such as bacteria
and viruses.
6. Kinds ofWBCs
( Lymphocytes)
Lymphocytes are produced by the lymph glands. Each
lymphocytes has a large, rounded nucleus and small
amount of non-granular cytoplasm. They make up about
25% of white blood cells. They tend to be nearly round
in shape and only show limited movements. When a
lymphocyte detects foreign antigens on a bacterium or
virus, it makes chemicals called antibodies, which it
secretes into plasma. The antibodies stick to the surface
antigens on the pathogen, and destroy it. They do this by
causing bacterium to burst open or to make bacteria
stick together in clumps so that phagocytes can deal
with them easily or by neutralizing toxins or acting as a
label on a pathogen. Lymphocytes remains in bodies for
many years.
7. Kinds ofWBCs
( Phagocytes)
■ Phagocytes are produced by bone marrow. They
are so called because they can ingest foreign
particles like bacteria. The majority of white cells
in blood ( about 60-70% ) are phagocytes. They
have an unusual irregular lobe-shaped nucleus.
These cells can move around like amoeba and
change their shape, producing extensions of the
cytoplasm called pseudopodia. There are two
kinds of phagocytes, namely, monocytes and
polymorphs. A monocyte has a bean-shaped
nucleus. A polymorph has a nucleus with many
lobes and granular cytoplasm.
8. PLATELETS
■ Platelets are the fragments of cytoplasm from bone marrow.
■ It plays a important part in clotting of blood.
■ Clotting is a necessary process that can prevent you from
losing too much blood
■ Platelets and damaged tissues produce a enzyme called
thrombokinase.
■ Prothrombin is converted into thrombin (active) with the
help of thrombokinase and calcium ion.
■ Thrombin converts the soluble fibrinogen into insoluble
threads of fibrin.
■ Vitamin K is important for the blood clot.
■ Heparin prevents the clotting of blood in undamaged blood
vessels.
9. Blood pressure
Q: what is blood pressure?
■ Blood pressure is the force of blood exerted on
the walls of blood vessels.
Q: what is systole?
■ When the ventricles contract blood flows from
ventricles to blood vessel and to prevent the
backward flow of blood bicuspid and tricuspid
valves close which produce a “lub sound”. Blood
pressure is highest during systole.
10. Blood pressure
Q: what is diastole?
■ When ventricles relax they
receives the blood from the the
atrium and to prevent the
backward flow of blood in the
blood vessels ( pulmonary
artery and aorta) the semilunar
valves closes and this closer
produce a “dub” sound. Blood
pressure decrease during
diastole.
11. Blood pressure
■ Blood pressure is high in arteries. It is highest near aorta.
■ Blood pressure is low in veins. Blood pressure is lowest inVena
Cava
■ Range of systolic pressure: 120-140 mm of mercury
■ Range of diastolic pressure: 75-90 mm of mercury
■ Sphygmomanometer is used to measure blood pressure.
■ One heart beat is made up of systole and diastole.
