Exam 2 - Blood

components of blood

erythrocytes

buffy coat

plasma

erythrocytes (RBC)

make up the bottom layer (44-45% of blood)

buffy coat

thin middle layer made up of leukocytes and platelets (less than 1% of blood)

plasma

makes up the light-colored top layer (55% of blood)

erythrocytes and buffy coat

formed elements of blood

plasma

extracellular fluid/liquid component of blood

accounts of 55% of the blood

plasma proteins

exert osmotic pressure and prevent loss of fluid from the blood (through the capillaries)

this pressure is responsible for drawing fluids into the blood and preventing excess fluid loss

osmotic pressure from plasma proteins

this pressure is responsible for drawing fluids into the blood and preventing excess fluid loss

hematocrit

the percentage of the formed elements in the blood

42-56%

percentage of hematocrit in males

38-46%

percentage of hematocrit in females

hemopoiesis

production of blood cells (formed elements)

red bone marrow

where hemopoiesis occurs

erythrocytes

make up over 99% of the formed elements

biconcave structure

function to transport oxygen and carbon dioxide between the tissues and the lungs

lack a nucleus and organelles

biconcave structure in RBC

makes them flexible and allows them to stack up and pass through the smallest capillaries

RBC

consists of a plasma membrane and hemoglobin molecules

hemoglobin

a protein that transports oxygen and carbon dioxide

heme

oxygen binds to the iron in this group of hemoglobin and is transported in the blood

globin

carbon dioxide binds to this protein molecule in hemoglobin as it moves through the systemic capillaries

erythropoiesis

myeloid stem cell transforms into reticulocyte that circulates in blood, all organelles degenerate —> becomes a mature erythrocyte

triggering of erythropoiesis

if oxygen levels in the blood decrease, kidneys release the hormone erythropoietin (EPO) into the blood —> EPO stimulates myeloid cells in red bone marrow to produce more erythrocytes —> more erythrocytes enter circulation —> more oxygen can be delivered to the tissues —> blood oxygen levels increase

erythropoietin

hormone released when oxygen levels in the blood decrease

testosterone

stimulates the kidneys to produce more EPO —> affects erythrocyte production

living in higher altitude

lower oxygen levels stimulates increased EPO —> affects erythrocyte production

blood doping

dangers:

increased blood viscosity

heart required to work harder

erythrocyte destruction

erythrocytes circulate in the blood for about 120 days —> the worn-out erythrocytes are phagocytized by macrophages in the spleen and liver

macrophages

liver

spleen

worn-out erythrocytes are phagocytized by ______ in _____ and _____ during erythrocyte destruction

globin

part of RBC that is broken down into amino acids and reused during erythrocyte destruction

iron

part of RBC that is released as waste or stored in liver for reuse during erythrocyte destruction

heme

part of RBC broken down into bilirubin during erythrocyte destruction

anemia

a condition where there is a lower percentage of red blood cells or hemoglobin present (decreased oxygen-carrying capacity)

decreased oxygen delivery to tissues

most common blood disorder

leukocytes

make up less than 0.01% of formed elements

defend the body against pathogens

agranulocytes

granulocytes

2 classes of leukocytes

granulocytes

have granules in the cytoplasm

agranulocytes

granules are not clearly visible

neutrophils, eosinophils, and basophils

types of granulocytes

lymphocytes and monocytes

types of agranulocytes

leukopoiesis

granulocytes —> starts with myeloid stem cells

monocytes —> myeloid stem cell

lymphocytes —> lymphoid stem cell

granulocytes and monocytes

both start with myeloid stem cells in leukopoiesis

lymphocytes

starts with lymphoid stem cell in leukopoiesis

neutrophils

help fight bacterial infections —> increase during bacterial infection

most numerous leukocyte

multi-lobed nucleus

eosinophils

help fight parasitic infections —> increase with allergies and parasitic infections

basophils

involved in allergic reactions and the inflammatory response

lymphocytes

produce antibodies

involved in immune response

make up 20-40% of total number of leukocytes

monocytes

exit the blood and enter the tissues where they become macrophages —> phagocytize bacteria, viruses, cellular debris

neutropenia

disease with low WBC counts, usually due to decreased number of neutrophils

increased risk of infection

thrombocytes

cell fragments with no nucleus

30% stored in the spleen

function in hemostasis: blood clotting

thrombopoiesis

production of platelets

starts with myeloid stem cell

hemostasis

process where blood clots and stops the flow (of blood) through an injured vessel

1. vascular spasm

2. platelet plug formation

3. coagulation phase

3 phases of hemostasis

vascular spasm

immediately following vessel injury, the vessel constricts, decreasing blood flow

platelet plug formation

platelet plug is formed —> closes off injury site

they release chemicals and following events occur:

• prolonged vascular spasm

• attraction of other platelets

• stimulation of coagulation

• repair of the blood vessel

prolonged vascular spasm

attraction of other platelets

stimulation of coagulation

repair of the blood vessel

events following the release of chemicals in platelet plug formation

coagulation phase

a blood clot —> protein network composed of fibrin (an insoluble protein)

fibrin traps other elements in this network:

• erythrocytes, leukocytes, platelets, and plasma proteins

blood clot

protein network composed of fibrin (insoluble protein)

erythrocytes

leukocytes

platelets

plasma proteins

elements that fibrin traps in coagulation phase

coagulation cascade

1. intrinsic pathway

2. extrinsic pathway

intrinsic pathway

initiated by trauma in the vessel wall (blood trauma) in coagulation cascade

extrinsic pathway

initiated by tissue trauma (tissue damage) outside the vessel in coagulation cascade

hemophilia

decreased ability for blood to clot

increased tendency to bleed

thrombophilia

excessive clotting of blood

increased tendency to clot

blood types

based on specific antigens (agglutinogens) found on the plasma membrane of RBC

A

RBCs have this antigen for Type A

B

RBCs have this antigen for Type B

A + B

RBCs have this antigens for Type AB

none

RBCs have this antigen for Type O

antibodies

recognize and immobilize antigens it perceives as foreign to the body

anti-B

antibodies in plasma of Type A

anti-A

antibodies in plasma of Type B

none

antibodies in plasma of Type AB

anti-A and anti-B

antibodies in plasma of Type O

Rh factor (surface antigen D)

another antigen that may be present on surface of erythrocyte

Rh+

if Rh factor (surface antigen) is present

Rh-

if Rh factor is not present

type O

type of blood that is classified as universal donor

neither antigen on membrane

type AB

type of blood that is classified as universal recipient

no antibodies in plasma