BloodBlood

Marie ČernáMarie Černá

BloodBlood

The blood consists of

a suspension of special cells - formed elements

in a liquid called plasma

In an adult man:

the blood is about 1/12th of the body weight

and this corresponds to 5-6 liters

HematocritHematocrit – relation (volume %) – relation (volume %) of plasma (55 %) to cells (45 %) of plasma (55 %) to cells (45 %)

Blood functionsBlood functions• maintenance of homeostasis

osmotic pressure stability (0.15 mM NaCl)pH = 7.4 (buffer system - HCO3

-)

• carries respiratory gases: oxygen O2 to tissues (by the hemoglobin in red cell) carbon dioxide CO2 from tissues (by the plasma

in the form of soluble carbonates HCO3-)

• conveys nutrients (amino acids, sugars, fatty acids) • gathers waste products of metabolism which will be

excreted through the renal filter• carries hormones, enzymes, vitamins, mineral salts• performs the defense of the organism • performs thermoregulation of the organism

PlasmaPlasmais a slightly alkaline fluid, with a typical yellowish color can be obtained by centrifugation cells free serum - clotted

plasma - unclotted due to adding anticoagulants It consists of 90 % water and 10% dry matter:

9/10 is made up by organic substances1/10 is made up by minerals

These organic substances are composed of glucides (glucose)lipids (cholesterol, triglycerides, phospholipids, lecithin, fats)proteins (globulins, albumins, fibrinogen)glycoproteins, amino acids hormones, vitamins, minerals

The mineral substances are dissolved in ionic formthat is dissociated into positive and negative ions

Plasma / SerumPlasma / Serum

Hematic cellsHematic cells

Special cells • erythrocytes• leukocytes

• thrombocytes

are not considered real cells

Erythrocytes (red cells)Erythrocytes (red cells) providing oxygen in hemoglobin to tissuesproviding oxygen in hemoglobin to tissues

4.5 .106 / mm3 = 4.5 .1012 / l in female

5 . 106 / mm3 = 5 .1012 / l in male

7 . 106 / mm3 = 7 .1012 / l in newborn

8 . 106 / mm3 = 8 .1012 / l in sportsmen

size 7,2 µm in diameter

In man and in all mammals: they are devoid of a nucleus

In the other vertebrates: they have a nucleus

the lack of nucleus allows more room for hemoglobin =>

the shape of a biconcave lens raises the surface and cytoplasm volume ratio.

=> more efficient the diffusion of oxygen

The mean life is about 120 days

Leucocytes (white cells)Leucocytes (white cells) the defense of the organismthe defense of the organism

4-10 .103 / mm3 = 4-10 .109 / l size ≥10 µm in diameter

granulocytes (presence of granules in the cytoplasm) 70% granules have a different affinity towards neutral, acid or basic stains and give the cytoplasm different colors.

neutrophils eosinophils (or acidophils)basophils

agranulocytes (lymphoid cells) 30% lymphocytes (upper slide)monocytes (lower slide)

Thrombocytes (platelets)Thrombocytes (platelets)

150-300 .103 / mm3 = 150-300 .109 / lsize 3µm in diameter

They gemmate from big leukocytes called megakaryocytes.

main function: hematostasisto stop the loss of blood from wounds => they aggregate and release factors which promote the blood coagulation: serotonin - vasoconstriction fibrin - traps cells + forms clotting

Hematopoiesis regulationHematopoiesis regulationin red bone marrowin red bone marrow

ribs, vertebrae, breastbone, pelvisribs, vertebrae, breastbone, pelvis

Erythropoietin Erythropoietin is converted from a plasma protein in the kidneyis converted from a plasma protein in the kidney

a negative-feedback mechanism

- is sensitive to the amont of O2 in the blood:

↓ O2 => ↑ erythropoietin

↑ O2 => ↓ erythropoietin

Erythropoietin

stimulates production of erythrocytes in the bone marrow

Blood clottingBlood clotting

1) Platelet adhesion

2) Platelet plug

3) Fibrin clot with trapped cells

Blood clottingBlood clotting

Blood clottingBlood clotting

HemophiliaX-linked disease

missing -

coagulation factor VIII

symptoms:- spontaneous bleeding- bleeding into organs

(join, brain)

LiteratureLiterature

Biology, eighth edition,Campbell, Reece

Unit seven: Animal Form and FunctionChapter 42: Circulation and Gas ExchangeConcept 42.4Pages 911 – 915