Komposisi Darah Komposisi Darah dan Fungsinyadan Fungsinya

Drg. Erna SulistyaniDrg. Erna Sulistyani

DarahDarah BloodBlood is a specialized is a specialized bodily fluidbodily fluid that that

delivers necessary substances to the body's delivers necessary substances to the body's cellscells—such as nutrients and oxygen—and —such as nutrients and oxygen—and transports transports wastewaste products away from those products away from those same cells. same cells.

Terdiri dari Terdiri dari blood cellsblood cells 45% dari volume darah tu adlh 45% dari volume darah tu adlh red blood cellsred blood cells

(also called RBCs or erythrocytes) and (also called RBCs or erythrocytes) and white blood cellswhite blood cells, including leukocytes and , including leukocytes and plateletsplatelets (also called thrombocytes). (also called thrombocytes).

blood plasmablood plasma. 55%, 90 5 Air dan . 55%, 90 5 Air dan bahan terlarut didalamnya meliputi bahan terlarut didalamnya meliputi proteins, proteins, glucoseglucose, mineral ions, , mineral ions, hormoneshormones, , carbon dioxidecarbon dioxide (plasma (plasma being the main medium for being the main medium for excretory product transportation), excretory product transportation), plateletsplatelets and blood cells themselves and blood cells themselves

Berat darah 7% of the human body weight, dengan berat jenis rata2 antara 1060 kg/m³, sgt dekat dgn air (1000 kg/m3.)

Rata2 volume pada dewasa 5 litres,  

Komposisi Komposisi Komposisi darah setelah diempar atau dibiarkan 24 jam.

Blood performs many important Blood performs many important functions within the body including:functions within the body including:

Supply of Supply of oxygenoxygen to tissues (bound to tissues (bound to to hemoglobinhemoglobin which is carried in which is carried in red cells) red cells)

Supply of nutrients such as Supply of nutrients such as glucoseglucose, , amino acidsamino acids and and fatty acidsfatty acids (dissolved in the blood or bound to (dissolved in the blood or bound to plasma proteins (eg plasma proteins (eg blood lipidsblood lipids) )

Removal of waste such as Removal of waste such as carbon dioxidecarbon dioxide, , ureaurea and and lactic acidlactic acid

Immunological functions, including Immunological functions, including circulation of white cells, and detection circulation of white cells, and detection of foreign material by of foreign material by antibodiesantibodies

CoagulationCoagulation, which is one part of the , which is one part of the body's self-repair mechanism body's self-repair mechanism

Messenger functions, including the Messenger functions, including the transport of transport of hormoneshormones and the signaling and the signaling of of tissuetissue damage damage

Regulation of body Regulation of body pHpH (the normal pH (the normal pH of blood is in the range of 7.35 - 7.45) of blood is in the range of 7.35 - 7.45)

Regulation of core Regulation of core body temperaturebody temperature HydraulicHydraulic functions functions

One microliter of blood containsOne microliter of blood contains:: 4.7 to 6.1 million (male), 4.2 to 5.4 million 4.7 to 6.1 million (male), 4.2 to 5.4 million

(female) (female) erythrocyteserythrocytes::[4[4 4,000-11,000 4,000-11,000 leukocytesleukocytes 200,000-500,000 thrombocytes200,000-500,000 thrombocytes

Sel darah

Sel darah merah Sel darah merah Komponen sel darah yang Komponen sel darah yang

terbanyak ,mengandung terbanyak ,mengandung hemoglobinhemoglobin, an , an ironiron--containing protein, which facilitates containing protein, which facilitates transportation of transportation of oxygenoxygen by reversibly binding by reversibly binding to this to this respiratoryrespiratory gas and greatly increasing gas and greatly increasing its solubility in blood. In contrast, carbon its solubility in blood. In contrast, carbon dioxide is almost entirely transported dioxide is almost entirely transported extracellularly dissolved in plasma as extracellularly dissolved in plasma as bicarbonatebicarbonate ion. ion.

Vertebrate blood is bright red when its Vertebrate blood is bright red when its hemoglobin is oxygenated. hemoglobin is oxygenated.

red blood cells (together with red blood cells (together with endothelialendothelial vessel cells and other cells) are also vessel cells and other cells) are also marked by marked by glycoproteinsglycoproteins that define the that define the different different blood typesblood types. The proportion of . The proportion of blood occupied by red blood cells is blood occupied by red blood cells is referred to as the referred to as the hematocrithematocrit, and is , and is normally about 45%. The combined normally about 45%. The combined surface area of all the red cells in the surface area of all the red cells in the human body would be roughly 2,000 times human body would be roughly 2,000 times as great as the body's exterior surface.as great as the body's exterior surface.[5][5]

Sel darah putih Sel darah putih White blood cells are part of the White blood cells are part of the

immune systemimmune system; they destroy and ; they destroy and remove old or aberrant cells and remove old or aberrant cells and cellular debris, as well as attack cellular debris, as well as attack infectious agents (infectious agents (pathogenspathogens) and ) and foreign substances. The cancer of foreign substances. The cancer of leukocytes is called leukemia. leukocytes is called leukemia.

Sel limfosit yang menghasilkan antibodi Sel limfosit yang menghasilkan antibodi bertindak melalui beberapa cara : -     bertindak melalui beberapa cara : -      - menyelaput bakteria dan memudahkan - menyelaput bakteria dan memudahkan

fagosit menelannya. fagosit menelannya. - melarutkan lapisan luar bakteria. -      - melarutkan lapisan luar bakteria. -      - meneutralkan toksin yang dihasilkan oleh - meneutralkan toksin yang dihasilkan oleh bakteria. bakteria. - membalut bakteria dan menjadikannya - membalut bakteria dan menjadikannya tidak aktif.     tidak aktif.    

Platlet dan fibrinogen yang mengatur Platlet dan fibrinogen yang mengatur pembekuan darah. pembekuan darah.

TrombositTrombosit 200,000-500,000 thrombocytes:200,000-500,000 thrombocytes:[6][6]

thrombocytesthrombocytes, also called , also called plateletsplatelets, are , are responsible for blood clotting (responsible for blood clotting (coagulationcoagulation). They change ). They change fibrinogenfibrinogen into into fibrinfibrin. This fibrin creates a mesh . This fibrin creates a mesh onto which red blood cells collect and onto which red blood cells collect and clot, which then stops more blood from clot, which then stops more blood from leaving the body and also helps to leaving the body and also helps to prevent bacteria from entering the body. prevent bacteria from entering the body.

PlasmaPlasmaPlasma meliputi sekitar 55% dari darahPlasma meliputi sekitar 55% dari darahwarna straw-yellow warna straw-yellow volume totals of 2.7-3.0 litres in an average human.volume totals of 2.7-3.0 litres in an average human.Containing 92% water, 8% blood plasma Containing 92% water, 8% blood plasma proteinsproteins, , and trace amounts of other materials. and trace amounts of other materials. Plasma circulates dissolved nutrients, such as, Plasma circulates dissolved nutrients, such as, glucoseglucose, , amino acidsamino acids and and fatty acidsfatty acids (dissolved in (dissolved in the blood or bound to plasma proteins), and the blood or bound to plasma proteins), and removes waste products, such as, removes waste products, such as, carbon dioxidecarbon dioxide, , ureaurea and and lactic acidlactic acid..Plasma also circulates Plasma also circulates hormoneshormones transmitting their transmitting their messages to various tissues. The list of normal messages to various tissues. The list of normal reference rangesreference ranges for various blood electrolytes is for various blood electrolytes is extensive.extensive.

Other important Other important componentscomponents include: include: Serum albuminSerum albumin Blood clotting factors (to facilitate Blood clotting factors (to facilitate

coagulationcoagulation) ) ImmunoglobulinsImmunoglobulins (antibodies) (antibodies) lipoproteinlipoprotein particles particles Various other Various other proteinsproteins Various Various electrolyteselectrolytes (mainly (mainly sodiumsodium and and

chloridechlorideSerumSerum ad. plasma tanpa faktor ad. plasma tanpa faktor koagulan Most of the proteins koagulan Most of the proteins remaining are albumin and remaining are albumin and immunoglobulins. .

pHpH nomal darah arteri sekitar 7.40 ( 7.36- nomal darah arteri sekitar 7.40 ( 7.36-7.44), a weak alkaline solution. 7.44), a weak alkaline solution.

Blood that has a pH below 7.35 is too Blood that has a pH below 7.35 is too acidicacidic, while blood pH above 7.45 is too , while blood pH above 7.45 is too alkalinealkaline. .

Blood pH, Blood pH, partial pressurepartial pressure of oxygen of oxygen (PaO2), partial pressure of carbon (PaO2), partial pressure of carbon dioxide(PaCO2) and dioxide(PaCO2) and HCO3HCO3 are carefully are carefully regulated by a number of regulated by a number of homeostatic mechanismshomeostatic mechanisms, which principally , which principally exert their influence through influence the exert their influence through influence the respiratory systemrespiratory system and the and the urinary systemurinary system in the control the in the control the acid-base balanceacid-base balance and and respiration. respiration.

HemoglobinHemoglobin Yang menentukan warna darah. Yang menentukan warna darah.

Tiap meolekul tdd 4 grup heme dan Tiap meolekul tdd 4 grup heme dan interaksi dgn molekul lain interaksi dgn molekul lain menyebabkan perubahan dari warna menyebabkan perubahan dari warna aslinya. In aslinya. In vertebratesvertebrates and other and other hemoglobin-using creatures, arterial hemoglobin-using creatures, arterial blood and capillary blood are bright blood and capillary blood are bright red as oxygen imparts a strong red red as oxygen imparts a strong red color to the heme group. color to the heme group.

Deoxygenated blood is a darker shade Deoxygenated blood is a darker shade of red; this is present in veins, and of red; this is present in veins, and can be seen during blood donation can be seen during blood donation and when venous blood samples are and when venous blood samples are taken. taken.

Blood in Blood in carbon monoxide poisoningcarbon monoxide poisoning is is bright red, because bright red, because carbon monoxidecarbon monoxide causes the formation of causes the formation of carboxyhemoglobin. In cyanide carboxyhemoglobin. In cyanide poisoning, the body cannot utilize poisoning, the body cannot utilize oxygen, so the venous blood remains oxygen, so the venous blood remains oxygenated, increasing the redness. oxygenated, increasing the redness. While hemoglobin containing blood is While hemoglobin containing blood is never blue, there are several conditions never blue, there are several conditions and diseases where the color of the and diseases where the color of the heme groups make the skin appear heme groups make the skin appear blue. blue.

If the heme is oxidized, methemoglobin, which If the heme is oxidized, methemoglobin, which is more brownish and cannot transport is more brownish and cannot transport oxygen, is formed. In the rare condition oxygen, is formed. In the rare condition sulfhemoglobinemia, arterial hemoglobin is sulfhemoglobinemia, arterial hemoglobin is partially oxygenated, and appears dark-red partially oxygenated, and appears dark-red with a bluish hue (cyanosis).with a bluish hue (cyanosis).

Veins in the skin appear blue for a variety of Veins in the skin appear blue for a variety of reasons only weakly dependent on the color of reasons only weakly dependent on the color of the blood. Light scattering in the skin, and the the blood. Light scattering in the skin, and the visual processing of color play roles as well.visual processing of color play roles as well.[17][17]