U8 - Blood Cells and Types

homeostasis

relatively constant internal physical and chemical conditions that organisms maintain

blood maintains this by...

- transporting vital substances

- maintaining the stability of interstitial fluid (fluid outside cells)

- distributing heat

blood

type of connective tissue that has two basic components

- 45% cells such as RBCs, WBCs (leukocytes), platelets

- 55% plasma -> includes water, proteins, amino acids (matrix - ground substance and fibers)

hematopoiesis

formation of blood cells that occurs from the stem cells in red bone marrow

erythrocytes

aka red blood cells

- biconcave discs that lack a nuclei & mitochondria

- short-lived (~120 days)

- destroyed in liver & spleen by phagocytosis

Function: transport oxygen to tissues and carbon dioxide from tissues back to lungs

-> uses HEMOGLOBIN: protein molecule that combines with oxygen, makes up 1/3 of RBC volume and 95% of dry weight

hypoxia

the state of low blood oxygen, which stimulates erythropoiesis (formation of red blood cells)

erythropoietin (EPO)

the hormone secreted by the kidneys and liver in response to decreased blood oxygen (hypoxia); it stimulates RBC production

oxyhemoglobin

hemoglobin bound to oxygen; bright red

- found in arteries

deoxyhemoglobin

hemoglobin without oxygen; dark red

- found in veins

anemia

too few RBCs/hemoglobin

leukocytes

aka white blood cells

Function: defend against infection and foreign invaders

Types: neutrophils, basophils, eosinophils, monocytes, lymphocytes

neutrophils

most common type of WBC; 60-70% of WBC

- active phagocytes

- found in the pus of wounds

basophils

1% of WBC

produce heparin (blood thinner, less coagulation) and histamines (loosen capillaries); important in inflammatory response

eosinophils

2-4% of WBC

mainly attack parasites, produce antihistamines

monocytes

2-8% of WBC

largest of all blood cells, leave blood to become macrophages in tissue

lymphocytes

WBC; two types that are both a part of the immune response

T (thymus) cells: directly attack invaders

B cells: yield antibodies

platelets

come from thrombocytes; form blood clots and aid in vessel repair

plasma

liquid portion of blood; made up of 92% water and also other nutrients (amino acids, sugars, nucleotides, lipids), gases (O2, CO2), vitamins, electrolytes (ions), nonprotein nitrogenous substances (urea, uric acid, creatine) and plasma proteins

plasma proteins

albumin: blood pressure and transport

globulins (alpha, beta, gamma): transport lipids and antibodies for immunity

fibrinogen: important for blood clotting, converted to fibrin

blood type

refers to the presence or absence of certain markers on the surface of RBCs

antigens

a chemical/molecule that stimulates cells to produce antibodies (on a cell); identifying markers

antibodies

a protein that reacts against a specific antigen

agglutination

clumping of RBCs in response to a reaction between antibody/antigen

Type A Blood

blood that has the A antigen and anti-B antibodies

Type B Blood

blood that has the B antigen and anti-A antibodies

Type AB Blood

blood that has both the A and B antigens and no antibodies; considered universal recipient

Type O Blood

blood that has no antigens and both anti-A and anti-B antibodies; considered universal donors

Rh positive blood

the presence of antigen D and/or other Rh antigens on the RBC membrane; have no Rh antibodies

Rh negative blood

the lack of Rh antigens; has Rh antibodies

erythroblastosis fetalis

a disorder that results from the incompatibility of a fetus with Rh-positive blood and a mother with Rh-negative blood, causing red blood cell destruction in the fetus; a blood transfusion is necessary to save the fetus, occurs after the mom first gives birth to an Rh+ baby (problem with subsequent pregnancies)