Lecture Quiz 9 Flashcards
What color does blood have under what circumstances?
scarlet/bright red - oxygen rich
dark red - oxygen poor
What is the pH of blood?
7.35-7.45
slightly alkaline
kidneys and lungs maintain
What is the temperature of blood?
38 degrees celsius
slightly higher than normal body temp
What is the average volume of blood in men and women?
men - 5-6 L
women - 4-5 L
What are the three functions of blood?
transport and distribution
regulation
protection
Describe how blood transports and distributes
oxygens from the lungs
nutrients from the digestive tract
metabolic wastes from cells to lungs, liver, and kidneys for elimination
hormones from endocrine glands to target organs
How does the liver excrete wastes?
converts hydrophilic substances into hydrophobic substances
excretes these molecules with bile
Describe how blood regulates the body
maintains appropriate body temperature by absorbing and distributing heat
uses buffer system to maintain normal pH in body tissues
regulates fluid volume in the circulatory system
Describe how blood protects the body?
prevents fluid/blood loss by activating plasma proteins and platelets and initiating clot formation when a vessel is broken
prevents infection by synthesizing and utilizing antibodies and activating complement proteins and WBCs to defend the body against foreign invaders - both intracellular and extracellular
What does bloody vaguely consist of?
erythrocytes, leukocytes, platelets
plasma
What is a hematocrit?
the percentage of volume of RBCs in the total blood volume
~45% typically
What is plasma?
a fluid extracellular matrix that consists of water (91%), plasma proteins (7%), organic solutes (1%), and inorganic solutes (1%)
Describe plasma proteins
large molecules synthesized in the liver
What are plasma proteins responsible for?
too large to leak out of the vessels and are therefore responsible for osmotic pressure
What are the different types of plasma proteins?
albumin
clotting proteins
gamma globulins
alpha and beta globulins
What are the organic solutes found in plasma?
nutrients (glucose, amino acids, lipids)
waste products (urea, uric acid)
hormones
What inorganic solutes are found in plasma?
mostly ions chloride sodium potassium calcium iron phosphate bicarbonate other minerals
What gasses are found in blood?
oxygen
carbon dioxide
nitrogen
How many of each type of blood cell are there?
RBC - 4-6 million/microliter, live 3-4 months
WBC - 5-10 thousand/microliter, live for years
thrombocytes - 150-400 thousand/microliter 7-10 days
Describe hematopoiesis
the formation of blood cells
occurs in the red bone marrox of the axial skeleton and girdles, and the epiphyses of the humerus and femur
Describe hemocytoblasts
give rise to all formed elements in blood
may remain uncommitted, pluripotential stem cells and continue to proliferate, or differentiate into precursors for WBC, RBC, or platelets
What is a complete blood count?
quick and easy test that includes hematocrit, hemoglobin, and formed element count
What is a chemistry profile?
may be subdivided into a few tests
measures electrolytes, glucose, lipids, heart and liver enzymes, creatinine, bilirubin, urea, etc
What does prothrombin time evaluate?
hemostasis
platelet count
pt’s blood clotting properties are examined
if PT is too fast, anti coagulant may be prescribed
Describe leukocytes (WBCs)
the only blood components that are complete cells
make up on 1% total blood volume
normal count is 5000-10000/mm^3
What is leukocytosis?
an increase of a WBC count over 11000/mm^3
this is a normal response to inflammation
all cells are mature
What is leukemia?
also an increase of WBC in the blood stream
blasts appear in the peripheral blood
all immature cells that are incapable of normal function
What is diapedesis?
WBCs leave capillaries and move through interstitial spaces?
What are the two divisions of WBCs?
agranulocytes
granulocytes, which contain granules in cytoplasm and their nucleus is usually segmented into loves
What are neutrophils?
granulocytes with both pink and purple granules
highly lobulated nucleus - polymorphonuclear leukocytes
compose 50-70% WBC count
What is the major function of neutrophils?
phagocytosis
especially in response to bacterial infections
What are eosinophils?
granulocytes with pink acidophilic granules and lobulated nucleus
compose 1-4% of WBC count
What is the major function of eosinophils?
secretion of toxic materials to kill parasites
phagocytosis of parasites, which can be unicellular or multicellular
What are basophils?
granulocytes with purple granules and a lobulated nucleus
0.5-1% WBC count
What is the major function of basophils? Provide examples
secretion of chemicals that promote inflammation
ex: histamine causes vasodilation and attracts WBCS
heparin slows clotting
What are monocytes?
agranulocytes with horseshoe-shaped nucleus
nucleus may contain bubbles
2-8% WBC count
What is the major function of monocytes?
phagocytosis
migrate into tissue (diapedesis) and become macrophages
What are lymphocytes?
agranulocytes with a large round nucleus
20-40% WBC count
What is the major function of lymphocytes?
immune response
some secrete toxic chemicals, others are more directly involved in an immune response
What is leukopoiesis?
formation of leukocytes
all leukocytes originate from hemocytoblasts
What is the route of hemocytoblast development into WBCs?
hemocytoblast -> myeloid stem cells or lymphoid stem cell
Myeloid cell -> myeloblasts or monoblasts
lymphoid stem cell -> lymphoblast
Myeloblast -> eosinophil, neutrophil, basophil
lymphoblast -> lymphocyte
Describe erythrocytes
biconcave discs
no nucleus
essentially without organelles
filled with hemoglobin, which is a protein dedicated to respiratory gas transport
What does sickle cell anemia cause?
sickle shaped RBCs
inefficient O2 transport
sickle shape plugs capillaries
Describe what hemoglobin does
binds reversible with O2
can transport 4 O2 at a time
Describe the anatomy of hemoglobin
composed of the protein globin, which is comprise of two alpha and two beta chains
each chain binds to a heme group
each heme group bears an atom of iron, which can bind to one oxygen
What are the three states hemoglobin can be found in?
deoxyhemoglobin (reduced Hb)
oxyhemoglobin (bound to O2)
carbaminohemoglobin (bound to CO2)
What binds to hemoglobin irreversibly?
carbon monoxide
What are normal concentrations of RBCs in men? women?
Men - 13-18 g/dL
female - 12-16 g/dL
Describe what happens to oxygen in the lungs
greater pressure of oxygen gas from the air forces oxygen into the blood
O2 binds to reduced hemoglobin and forms oxyhemoglobin
Hb +4O2 -> Hb-O2
What happens to carbon dioxide in the lungs?
carbon dioxide pressure in the air is less than in the blood
carbon dioxide breaks off from carbaminohemoglobin and diffuses into the air in the lungs
Hb-CO2 -> Hb + 2CO2
What happens to oxygen in the tissues?
oxygen pressure is less than in the blood
oxygen
oxygen breaks off from oxyhemoglobin and diffuses into the tissues
Hb-O2 -? Hb + 4O2
What happens to carbon dioxide in the tissues?
it is released into the blood and partially binds to a reduced hemoglobin
Hb + 2CO2 -> Hb-CO2
Where else can carbon dioxide travel in the body and what does this cause?
can form bicarbonate ions in plasma
CO2 + H2O -> H2CO -> H+ + CO3-
makes blood more acidic
What is the hierarchy of erythropoiesis?
hemocytoblast -> myeloid stem cell
myeloid stem cell -> proerythroblast (committed at this point)
proerythroblasts -> early erythroblasts
synthesize a lot of Hb, become normoblast
normoblast loses nucleus -> reticulocyte
reticulocyte -> erythrocyte
How is erythropoiesis regulated?
the hormone erythropoietin
stimulates RBC production
What produces erythropoietin and what conditions cause stimulation of its production?
produced by the kidneys
triggered by hypoxia due to decreased RBCs, decreased O2 availability, or increased tissue demand for O2
What is a typical life span of an erythrocyte?
100-120 days
What happens to dying erythrocytes?
engulfed by macrophages
Hb is destroyed and dissasembled into heme and globin
What happens to the heme of a destroyed RBC
stripped of its iron
degraded into a yellow pigment called bilirubin
conjugated and excreted by the liver
iron is stored and reused in synthesis of new Hb
What happens to the iron of degraded RBCs?
stored in the liver and spleen
transported in blood by transferrin
*read this in the book
What happens to the globin of broken down RBCs?
metabolized into amino acids
released into the circulation
recycled in synthesis of protein
What happens to bilirubin in the liver?
it is bound with glocuronic acid formin conjugated (direct) bilirubin
excreted with bile into the GI tract
metabolized into urobilinogen (excreted with urine) and sterocobilin (excreted with feces)
What causes jaundice?
results when bilirubin is not removed from the blood
What occurs during pre hepatic jaundic?
too much RBC destruction genetic disorder (i think? notes unclear pls google)
What occurs during hepatocellular jaundice?
liver fails to perform its function
What happens during sub hepatic jaundice?
bilirubin is not being secreted well
Describe platelets/thrombocytes
formed in the bone marrow from cells called megakaryocytes
remain functional for about 7-10 days
no nucleus
can secrete variety of substances and can contract
What is the normal concentration of thrombocytes?
150-400 thousand/mm^3
What is the hierarchy of the formation of platelets?
hemocytoblasts -> megakaryoblasts
- > promegakaryocytes
- > megakaryocytea
- > thrombocytes
What is hemostasis ultimately for?
to stop bleeding
What are the four stages of hemostasis?
vascular spasm
platelet plug formation
coagulation
clot retraction
What happens during vascular spasm?
immediate vasoconstriction in response to injury
smooth muscle in the wall of the vessel contracts
What does a vascular spasm accomplish?
may reduce blood flow and blood loss
will not stop blood loss
What happens during platelet plug formation?
platelets stick to exposed collagen fibers and form a platelet plug
release serotonin and ADP, which attracts more platelets
What happens during coagulation (vague)?
a set of reactions in which blood is transformed from a liquid to a gel
What happens during the final three steps of coagulation?
formation of prothrombin activator, which converts prothrombin to thrombin
thrombin catalyzes fibrinogen to form a fibrin mesh
What initiates the final three steps in coagulation?
a cascade of reactions
either intrinsic or extrinsic
generally both mechanisms work simultaneously
What is significant about fibrin?
all proteins are dissolvable in plasma except fibrin
Which route is faster - extrinsic or intrinsic?
extrinsic
fewer steps
What happens during clot retraction?
tightening of the clot
platelets trapped within the clot contract
fibrin mesh shrinks
damaged vessel edges are pulled closer
What is fibrinolysis?
dissolution of a clot
How is fibrinolysis achieved?
plasminogen is activated by many factors
becomes plasmin
plasmin breaks down fibrin mesh
phagocytic WBCs remove the products
What does platelet derived growth factor do?
stimulates smooth muscles and fibroblasts to repair damage
How is clotting limited?
swift removal of clotting factors by rapid blood flow
inhibition of clotting factors by antithrombin III
What is antithrombin III?
deactivated thrombin that is not attached to fibrin
