Cardio - Blood Flashcards
Functions of the Blood
Transportation, Defense, Distribution of Heat, Maintenance of Homeostasis
What is involved in transportation?
delivery of oxygen and nutrients to and removal of wastes from the body
What is involved in defense?
Blood contains WBC which protects the body from external threats and platelets and other clotting factors that prevent blood loss.
What is involved in the distribution of heat?
diversion of blood to deep or superficial blood vessels to maintain core body temperature
pH of blood
venous blood: 7.4-7.35
arterial blood: 7.45
The function of Plasma proteins
synthesized in the liver; maintain normal blood circulation
Types of Plasma Proteins
Albumins (maintain osmotic balance of blood)
Globulins (antibodies; essential to immune mechanism)
Fibrogen (key role in blood clotting)
Composition of Blood Plasma
92% water; 10% other solutes
Components of Plasma
Water, proteins, regulatory substances, Ions, Nutrients, waste products, gases
Composition of Formed Elements
Cells, cellular elements, hematocrit, buffy coat
In utero hematopoesis
takes place in yolk sac of embryo, liver, speen, lymphatic tissue, red bone marrow
after birth hematopoesis
red marrow within spong bone
hematopoesis in children
can occur in medullary cavity of long bones
hematopoesis in adults
can occur in cranial and pelvic bones, vertebrae, sternum, epiphyses of femur and humerus
Hematopoietic growth factors
erythropoietin (RBC)
Thrombopoietin (platelets)
Cytokines
Erythropoietin
a hormone produced by kidneys to stimulate RBC production, often in response to low O2 levels
Thrombopoietin
a hormone produced by liver and kidneys to stimulate development of megakaryocytes into platelets
Cytokines
autocrine and paracine factors secreted by a wide variety of cells and act on a cell to have an effect
Primary functions of erythrocytes(RBC)
- transport inhaled oxygen from the lungs to the body’s tissues
- transport CO2 waste from tissues to the lungs for exhalation
Polycythemia
When blood has a higher % of RBC which leads to increase work for the heart to circulate blood
Anemia
when blood has lower % of RBC which leads to reduced O2 transportation from lungs to tissue
Reticulocyte
immature RBCs released with remnants of organelles which are quickly shed as mature
Mature RBCs
- no nucleus, ribosomes, ER, mitochondria, or other organelles
- contains 200-300 million hemoglobin
- biconcave disks(donuts)
The purpose for Biconcave shape of RBCs
allows folding to enable passage through capillaries.
Oxyhemoglobin
bright red, forms when O2 binds to iron and O2 in lung capillaries
Deoxyhemoglobin
is darker red, forms when O2 dissociates from iron in Hb in tissue capillaries
Carbaminohemoglobin
has no effect on the colour, forms when CO2 binds to amino acids in HB in tissue capillaries
Rate of RBC production
2 million per second
Location of RBC production
redbone marrow
What stimulates RBC production
Erythropoietin(EPO) hormone
Granular leukocytes
contain abundant granular within the cytoplasm; produced in red bone marrow
Neutrophils
contain lysozyme and other enzymes for rapid phagocytosis of bacteria; rapid responders to site of infection
Eosinophils
contain antihistamine; effective phagocytes in presence of antigen-antibody complexes
Basophils
contain histamines and heparin; intensifies inflammatory response
Why do WBCs leave blood vessels
move to perform their defensive functions in the body’s tissues
WBCs defensive functions
respond to chemical attractants released by pathogens and chemical signals from nearby injured cells
Functions of thrombocytes (platelets)
critical to hemostasis; secrete a variety of growth factors essential for growth and repair of tissue, particularly connective tissue
Lifespan of Platelets
10 days
WBC stimulated by…
thrombopoietin from the kidneys and liver
Hemostasis is caused by
- blood vessel wall is severed, punctured, or damaged
- vascular spasm
- formation of the platelet plug
- coagulation
Vascular spasm
smooth muscles in blood vessel wall contract: circular layers constrict blood flow while longitudinal layers retract into surrounding tissue
Formation of a platelet plug
platelets near damaged vessel clump together, become spiked and sticky, bind to exposed collagen endothelium
Coagulation
cascade of events produce a fibrin clot to trap platelets and blood cells
Coagulation extrinsic pathway
quicker and more direct; external trauma to blood vessel causes damaged extravascular cells to release factor III upon contact with blood plasma
Coagulation intrinsic pathway
less direct and slower; internal damage to blood vessel wall: foreign materials activate XII upon contact
Coagulation common pathway
leads to the activation of factor X; leads to the production of fibrin mesh to seal the blood vessel
What dissolves clots?
Fibrinolysis
Plasminogen
Inactive plasma protein produced by the liver; activated by chemicals released from damaged cells
Plasmin
active form of plasminogen; enzyme that catalyzes the hydrolysis of fibrin strands, dissolving the clot slowly
