Blood Flashcards
cardiovascular system
anatomical division
a circulating transport system: heart, blood vessels, blood
circulatory system
clinical division
cardiovascular system, lymphatic system
functions of the cardiovascular system
to transport materials to and from cells:
oxygen and carbon dioxide
nutrients and waste products
hormones
immune system components
blood
fluid connective tissue
functions: distribution, regulation, protection
distribution
deliver oxygen and nutrients to cells
remove metabolic waste
transport hormones to targets
regulation
maintain body temp-> distribute heat
maintain pH & fluid volume
protection
restrict loss at injury (clotting)
prevent infection (leukocytes)
characteristics of blood
pH 7.4
temperature in average- 37C/98.6F
total volume: 4-6 Liters
fractionation
process of separating whole blood into plasma and formed elements
blood matrix
plasma
~55 of blood (water and soluble proteins)
blood cells
formed elements
erythrocytes: ~45%, transport oxygen
leukocytes: <1%, defense
platelets: <1%, cell fragments and for clotting
plasma
92% water + dissolved solutes
nutrients, gasses, hormones, wastes, ions
plasma proteins
(~8% of total plasma)
7/6g/100mL of plasma
5x more proteins than interstitial fluid
proteins remain in plasma- maintain the osmotic balance
three classes of plasma proteins
albumins (60%)
globulins (35%)
fibrinogen (4%)
other (1%)
albumins
produced by the liver
functions:
act as pH buffer for blood
contribute to osmotic pressure of blood- keep water in blood
transport fatty acids
transport thyroid hormones
transport steroid hormones
globulins
gamma globulins/antibodies/immunoglobulins
alpha and beta globulins/transport globulins
gamma globulins/antibodies/immunoglobulins
produced by plasma cells in the lymphatic system
function to attack foreign substances
alpha and beta globulins/transport globulins
produced by the liver
function to transport small or insoluble compounds to prevent filtration loss by the kidney
clotting factors
produced by the liver
11 total, fibrinogen most abundant
all function to promote or form a clot
fibrinogen produce long, insoluble strands of fibrin
other plasma proteins
from liver: metabolic enzymes and antibacterial proteins
from endocrine organs: hormones
liver disease
leads to blood disorders b/c plasma proteins are produced by the liver
hemopoiesis
process of producing formed elements
blood cell production
all formed elements arise from the same progenitor cell- the hemocytoblast, located in the red bone marrow
total blood volume (liters)
7% of body weight (kilograms)
about 1/2 the volume of whole blood is
cells and cell products
plasma resembles interstitial fluid, but
contains a unique mixture of proteins not found in other extracellular fluids
erythrocytesa
99.9% of blood’s formed elements
1/3 of total body cells- average human = ~75 trillion cells
average RBC count= 4.2-6.3 million/ml
red blood cell count
reports the number of RBCs in 1 microliter of whole blood
hematocrit
packed cell volume, PCV
% of whole blood occupied by formed elements
mostly erythrocytes: 99.9%
males have a greater percentage of RBC then females
anemia
not enough RBCs
polycythemia
too many RBCs (over 50%) but normal blood volume- dehydration, tissue hypoxia, high altitude, blood doping in athletes
also can be due to bone marrow cancer
high hematocrit = high viscosity-> heart strain and stroke
RBC
normal blood counts
male: 4.5-6.3 million/ml
female: 4-5.5 million/ml
structure of erythrocytes
small and highly specialized biconcave disc
thin in middle and thicker at edge
importance of RBC shape and size
large surface area for gas exchange: quickly absorbs and releases oxygen
folds and forms stacks: passes through narrow blood vessels
discs bend and flex entering small capillaries: 7.8 mm diameter (AVG) passes through capillary (5 to 10mm)
erythrocytes
mature erythrocytes lack all organelles
lack nuclei, mitochondria, and ribosomes
no division, no repair
life span < 120 days
cell in 97% hemoglobin protein (red color)
hemoglobin transports oxygen and some carbon dioxide
hemoglobin structure
complex quaternary structure
2 alpha chains and 2 beta chains
each chain has one heme group with iron in center: iron binds oxygen
oxyhemoglobin
oxygen bound, RED
deoxyhemoglobin
no oxygen, BURGUNDY
fetal Hb
binds oxygen stronger than adults
insures transfer of oxygen from mom
most oxygen
is carried in blood bound to Hb, some in plasma
only 20% carbon dioxide carried by Hb
carbaminohemoglobin- carbon dioxide bound to amino acids on alpha/beta chains, not on heme
hemoglobin
280 million Hb/RBC, 4 hemes/Hb, each heme binds 1 oxygen = >1 billion oxygen/RBC
25 trillion RBC per person
normal hemoglobin (adult male): 14-18 g/dl whole blood
hemoglobin function
when plasma oxygen is low, Hb releases oxygen and binds carbon dioxide
at lungs carbon dioxide exchanged for oxygen by diffusion
anemia
hemoglobin levels are below normal
oxygen starvation due to: insufficent number of RBCs, low Hb, abnormal Hb- thalassemia, sickle-cell anemia
thalassemia
inability to produce alpha or beta chains
slow RBC production
cells fragile and short lived
sickle-cell anemia
single amino acid mutation in beta chain high oxygen
cells normal low oxygen
Hb misfolds
RBCs deform into crescent shape- RBCs block capillaries
recycling RBCs
macrophages (phagocytes) of liver, spleen, and bone marrow: monitor RBCs and engulf old/damaged RBCs
replaced by new- 1% of circulating RBCs replaced per day: about 2-3 million RBCs per second
phagocytes break cells down
protein and heme
phagocytes break down protein
globulin amino acids, released for use
phagocytes break down heme
hemoglobin into components
1. iron is removed- it is bound to transferrin in blood for recycling back to bone marrow (new RBCs)
2. pigment-> heme-> biliverdin (green)-> bilirubin (yellow-green)-> bilirubin is released into blood, filtered by liver, excreted in bile
3. in gut, bilirubin-> urobilins (yellow) and stercobilins (brown)-> urobilins is excreted in urine, stercobilins remain in feces
jaundice
failure of bilirubin to be excreted in bile, collects in peripheral tissues
causes yellow skin and eyes
hemoglobinuria
cause-> hemolysis, RBC rupture in blood
red/brown urine due to kidney filtering intact alpha and beta chains of hemoglobin
erythropoiesis
red blood cell formation
occurs in reticular CT in red bone marrow, in spongy bone
stem cells mature to become RBCs
2-3 million/sec (1 oz new blood per day)
hemocytoblasts stem cells in bone marrow divide to produce
myeloid stem cells- become RBCs, some WBCs
lymphoid stem cells- become lymphocytes
erythropoiesis process
- hemocytoblast differentiates into myeloid stem cells
- followed by many stages of differentiation, all involve an increase in protein synthesis
- cell fills with Hb- loses organelles including the nucleus
- 3-5 days reticulocytes are formed (Hb + some ribosomes), released into blood- 1-2% of total blood RBCs
- 2 days in circulation lose ribosomes = mature erythrocytes- no more protein synthesis
building red blood cells requires
amino acids
iron
vitamins B12, B6, and folic acid
lack B12= pernicious anemia
low RBC production
erythropoietin (EPO)
also called- erythropoiesis-stimulating hormone
secreted by the kidney
secreted when oxygen in tissues is low (hypoxia= low oxygen level)
due to disease or high altitude
no EPO= kidney failure b/c low RBCs
EPO stimulate RBC production
increase cell division rates (up to 30 million/sec)
increase Hb synthesis = decrease maturation time
blood doping
injection EPO or RBC to enhance athletic performance
pros- increase oxygen to tissue
cons- increase hematocrit/viscosity= clots, stroke and heart strain
blood types
all cells membranes have surface antigens
antigens indicate “self”
normal cells are ignored, and foreign cells attacked
are genetically determined
classified by the presence or absence of RBC surface antigens: A, B, or D (Rh)
RBCs have 3 important antigens for transfusion, agglutinogens A, B, D (Rh)
antigen
substance that triggers immune response
agglutinogens
antigens on surface of RBCs
screened by immune system
plasma antibodies attack (agglutinate) foreign antigens
4 basic blood types
A (surface antigen A)
B (surface antigen B)
AB (surface antigens A and B)
O (neither A nor B)
blood plasma antibodies
type A: type B antibodies
type B: type A antibodies
type O: both A and B antibodies
type AB: neither A nor B
the Rh factor
also called D antigen
either Rh positive (Rh+) or Rh negative (Rh-)
only sensitized Rh- blood has anti-Rh antibodies
blood type test
determines blood type and compatibility
cross-reaction
also called and is a type of transfusion reaction
if donor and recipient blood types not compatible
plasma antibody meets its specific surface
antibodies will cause blood agglutination (clumping) of antigen (agglutinogen) and hemolyze
cross-match test
performed on donor and recipient blood for compatibility
without cross-match, type O- blood is universal donor
it lacks all agglutinogens (A,B and D)
no risk of agglutination by antibodies in anyone
universal donor
AB
universal recipient
O
erythroblastosis fetalis
AKA hemolytic disease of the newborn
antibodies against D antigen only form upon exposure and can cross the placenta
Rh- mom pregnant with Rh+ baby- gets exposed to D antigen during birth, makes anti-D antibodies, pregnant with second Rh+ baby, antibodies cross placenta, causes agglutination and lysis of fetal RBCs-> anemia and death of the fetus
prevention= treat mom with RhoGAM during first birth to prevent antibody formation
leukocytes (WBCs)
<1% of total blood volume
6000-9000 leukocytes/ml blood
use blood to travel to tissues
not permanent residents of blood
most in connective tissue proper and lymphatic system organs
all have nuclei & organelles, no hemoglobin
function of leukocytes
defend against pathogens
remove toxins and wastes
attack abnormal/damaged cells
circulating WBCs
- migrate out of bloodstream (diapedesis)
- have amoeboid movement in bloodstream
- attracted to chemical stimuli (positive chemotaxis)
- some are phagocytic: engulf pathogens and debris
neutrophils, eosinophils and monocytes
margination
adhere to vessel
emigration
pass between endothelial cells in vessel walls
5 types of leukocytes
- neutrophils
- eosinophils
- basophils (in tissues very similar to basophils are the mast cells)
- monocytes (progenitors of macrophages and dendritic cells in tissues)
- lymphocytes
neutrophils
also called polymorphonuclear leukocytes (PMNs)
non-specific defense
phagocytic
50-70% of circulating WBCs
3-5 lobed nucleus
pale cytoplasm granules with: lysosomal enzymes and defensins, bactericides- hydrogen peroxide and superoxide
very mobile: first at injury
life span less than 10 hours
neutrophil function
- respiratory burst- H2O2 and O2-, kills and phagocytize
- release leukotrienes- attract phagocytes
- release prostaglandins- induce inflammation to stop the spread of injury
- degranulation- release defensins (against some bacteria, fungi, and viruses), lyse bacteria
eosinophils
also called acidophils
phagocytic
2-4% of circulating WBCs
bilobed nucleus
granules contain toxins
life span 9 days
attack large parasites
eosinophil functions
- phagocytosis of antibody covered objects
- defense against parasites: exocytose toxins on large pathogens
- reduce inflammations- anti-inflammatory chemicals/enzymes that counteract inflammatory effects of neutrophils and mast cells
basophils
non-specific defense
not phagocytic usually
are less than 1% of circulating WBCs
granules contain: histamine- dilate blood vessels, heparin: prevents clotting
accumulate in damaged tissue
life span 9 days
basophil functions
- inflammation (histamine)
- allergic response, also via histamine
monocytes
in tissues = macrophages
non-specific defense
phagocytic
2-8% of circulating WBCs
are large and spherical, kidney shaped nucleus
circulate 24 hours, exit to tissues = macrophage
life span several months
macrophage functions
- phagocytosis: virus and bacteria
- attract phagocytes
- attract fibroblasts for scar formation
- activate lymphocytes: mount immune response
lymphocytes
immune response
20-30% of circulating WBCs
large round nucleus
migrate between blood and tissues
mostly in connective tissues and lymphatic organs
life span days to lifetime
3 classes of lymphocytes
- B cells
- T cells (Helper T cells)
- Natural killer (NK) cells (Cytotoxic T cells)
B cells
humoral immunity
differentiate into plasma cells
synthesize and secrete antibodies- memory cells
T cells (Helper T cells)
cell-mediated immunity
attack foreign cells
Natural killer (NK) cells (Cytotoxic T cells)
immune surveillance
destroy abnormal tissues
the activated cytotoxic T cell
secretes proteins that destroy the infected target cell
most to least abundant WBCs
neutrophils, lymphocytes, monocytes, eosinophils, basophils
platelets (thrombocytes)
cell fragments involved in clotting
flattened discs, no nucleus
constantly replace- 5-6 days in circulation, phagocytosed by cells in spleen
in average 350,000/ml blood
1/3 of total platelets held in reserve in spleen, mobilized for crisis
platelet counts
150,000 to 500,000 per microliter
thrombocytopenia
thrombocytosis
thrombocytopenia
<80,000/ml
abnormally low platelet count
results in bleeding
thrombocytosis
> 1 million/ml
abnormally high platelet count
due to cancer or infection
results in a clotting risk
3 functions of platelets
- transport clotting chemicals, and release important clotting chemicals when activated
- temporarily form patch (platelet plug) over damaged vessel walls
- actively contract wound after clot formation- contain actin and myosin
the cessation of bleeding
vascular phase
platelet phase
coagulation phase
vascular phase
endothelial cells contract and release chemical factors to stimulate smooth muscle contraction and cell division and their membranes become “sticky”
platelet phase
platelet adhesion (attachment) to sticky endothelial surfaces and exposed collagen fibers
platelet aggregation (stick together) and forms platelet plug
two reaction pathways to coagulation
(both pathways require calcium)
extrinsic mechanism
intrinsic mechanism
extrinsic mechanism
clotting factors from sources outside of the blood: released by damaged vessel and perivascular tissues
intrinsic mechanism
uses only clotting factors found in the blood itself
blood clotting (coagulation)
enzymes activate factor X
forms enzyme prothrombinase
converts prothrombin to thrombin
thrombin converts fibrinogen to fibrin
