Blood part 1

Blood functions

• distribution of nutrients

• oxygen transport

• carbon dioxide transport

• transport of waste products

• transport of hormones

• body temperature control

• maintain pH of body fluids

• blood loss prevention

• defense of body against disease

Blood consists of

cells suspended in plasma

Blood componants

plasma, serum, cellular components

Plasma componants

water, proteins, bicarbonate, electrolytes, urea, glucose

Largest component of blood plasma

water

Second largest blood plasma componant

proteins

Blood plasma proteins

albumin, globulin, fibrinogen

Blood serum is

blood plasma without fibrinogen

Cellular components of blood

erythrocytes, leukocytes, thrombocytes

Erythrocytes cellular component of blood

red blood cells

Leukocytes cellular component of blood

white blood cells

Thrombocytes cellular component of blood

platelets

Hematopoiesis

formation and development of the cells of blood in the bone marrow

Hematopietins

chemical messengers that signal for hematopoiesis

Erythrocytes structure in mammals

biconcave discs, non-nuceleated with very few organelles in mammals

Major component of erythrocytes

hemoglobin

Hemoglobin consists of

a globin proteins with 4 hemegroups, each containing a ferrous iron (fe2+)

Ferrous iron

O2 and CO2 loosely and reversibly bind to Fe2+

Erythrocytes function to

transport O2 from lungs to tissues and CO2 from tissues to lungs

When O2 binds to the Fe2+ on hemoglobin

oxyglobin is formed

When CO2 binds to the Fe2+ on hemoglobin

carbaminohemoglobin is formed

When things go bad in erythrocyte hemoglobin

Carbon monoxide binding and Fe2+ oxidized

Carbon monoxide and erythrocytes

Carbon monoxide binds tightly to Fe2+ of hemoglobin forming carboxyhemoglobin

Carbon monoxide binding to Fe2+ reduces

O2 transport throughout body

Fe2+ oxidized and erythrocytes

when Fe2+ is oxidized to Fe3+ (ferric), it cannot bind O2, forms methemoglobin

Fe2+ oxidizing to Fe3+ caused by

nitrate poisoning

Erythropoiesis

production of erythrocytes in bone marrow

Erythropoiesis stimulated by

Erythropoietin

Erythropoietin secreted by

kidneys

Erythropoietin secreted in response to

low O2 in blood

Erythrocytes are removed from circulation by

liver or spleen

Macrophages role in recycling components of erythrocytes

engulf the erythrocytes and break them down

Globin protein in recycling of components of erythrocytes

break down to amino acids which can be reused for protein synthesis

Iron heme groups in recycling of components of erythrocytes

removed and can be reused for hemoglobin synthesis

Heme groups except iron in recycling of components of erythrocytes

become biliverdin

Biliverdin in recycling of components of erythrocytes

made from heme groups other than iron, get reduced to bilirubin

Bilirubin recycling of components of erythrocytes

reduced form of biliverdin, becomes incorporated into bile

Incorporates bilirubin into bile

liver

When recycling of componants of erythrocytes goes wrong

Icterus/jaundice and hemolysis

Icterus/Jaundice

accumulation of bilirubin in the blood

Icterus/Jaundice presents as

skin and mucous membrane have yellowish pigment

Icterus/Jaundice caused by

liver damage

Hemolysis definition

breakdown of erythrocytes and release of free hemoglobin

Hemolysis caused by

snake venom, bacterial toxins

Hemolysis types

hemoglobinemia and hemoglobinuria

Hemoglobinemia

hemoglobin in blood turns plasma red

Hemoglobinuria

hemoglobin in urine turns urine red

antigens

Proteins on cell membranes that erythrocytes express

Antibodies bind to

antigens

Hemoglutination

clumping of erythrocytes

Hemoglutination used for

blood typing

Hematocrit/packed cell volume definition

the percentage by volume of whole blood that is erythrocytes

Hematocrit/packed cell volume used to

determine if an animal has anemia or polycythemia

Anemia hematocrit/packed cell volume

number of red blood cells is below normal

Polycythemia hematocrit/packed cell volume

decrease in fluid component of blood

Leukocyte types

granulocytes and agranulocytes

Granulocytes

cells that contain cytoplasmic granules

Granulocytes are

polymorphonuclear cells

Polymorphonuclear cells

have many different shapes of nuclei

Types of granulocytes

Neutrophils, eosinophils, basophils

Neutrophils

perform phagocytosis

Neutrophils in bird called

heterophils

Eosinophils

release cytoplasmic granules in response to parasitic infection

Basophils

release cytoplasmic granules in response to parasitic infection

Agranulocytes

cells do not contain cytoplasmic granules

Types of agranulocytes

monocytes and lymphocytes

Monocytes

enter tissues and become macrophages

Lymphocyte types

B lymphocytes and T lymphocytes

B lymphocytes

secrete antibodies

T lymphocytes

kill variety of infected cells

Differential white blood cell count

determines the percentage of each type of white blood cells in blood samples

Hemostasis

the stoppage of bleeding

Stages of hemostasis

1. vasoconstriction

2. platelet plug formation

3. coagulation

Vasoconstriction step of hemostasis

smooth muscle of blood vessel contracts to make the site of injury smaller

Platelet plug formation step

• platelets bind to collagen from exposed connective tissue

• platelets become activated and secrete thomboxane A2

• thromboxane A2 recruits more platelets that bind to activated platelets

• platelets aggregate and form a plug over site of injury

• activated platelets express a receptor from fibrinogin

Activated platelets secrete

Thromboxan A2

Thromboxane A2

recruits more platelets that bind to activated platelets

Once theres enough activated platelets

platelets aggregate and form a plug over site of injury

Activated platelets express a receptor from

fibrinogen

Coagulation

a series of reactions to produce fibrin

Coagulation pathways result in

the activation of fibrinogen to fibrin

activation of fibrinogen to fibrin forms

a blood clot

Fibrinolysis

breakdown of fibrin to remove a blood clot

Plasminogen is activated to

plasmin

Plasmin

breaks down fibrin

Tissue plasminogen activator

causes plasminogen to be activated to plasmin which breaks down fibrin