A&P 1
Blood Part 1
COMPOSITION OF BLOOD
1) fluid
plasma
2) whole cells
RBC, WBC
3) cell fragments
platelets
FUNCTIONS OF BLOOD
1) to transport
2) to regulate
3) to protect
TRANSPORT
food
oxygen
wastes
hormones
enzymes
REGULATE
pH buffers
body temperature
water content of cells
PROTECT
clotting mechanisms
immune system factors
FORMED ELEMENTS OF BLOOD
45% of blood
cells, platelets
1) red blood cells (erythrocytes) “RBC”
2) white blood cells (leukocytes) “WBC”
3) platelets (thrombocytes)
PLASMA
55% of blood
fluid portion of blood
90% water, 10% solutes
solutes are mostly proteins
includes wastes, vitamins and nutrients
BLOOD VOLUME
154 lbs= 1.5 gal of blood
8% of the total body weight
blood volume varies
age
body type
sex
HEMATOCRIT
describes the volume % of RBC in whole blood
(PCV)- packed cell volume
avg 45% hematocrit
45 ml/100 ml RBC
55 ml/100 ml plasma
decreased RBC numbers= anemia
elevated RBC numbers= polycythemia
individuals living in high altitude
blood viscosity rises elevating BP and contributing to thrombosis and hemorrhage
FORMED ELEMENTS
WBC, platelets account for less than 1% of the total blood volume
RBC account for over 95% of the formed elements in blood
RED BLOOD CELLS
erythrocytes
lack a nucleus, ribosomes, and mitochondria
RBC perform anaerobic respiration
biconcave disks
shape gives a large surface area relative to its volume
cumulative surface area of all RBC in the body is larger than a football field for exchange of
respiratory gases
able to change shape without injury
primary component is a red pigment
hemoglobin (1/3 of cell volume)
RBC counts
Male -- 5.5 million / mm3
Female -- 4.8 million / mm3
SICKLE CELL ANEMIA
hereditary condition caused by formation of abnormal hemoglobin
distorts the shape of RBC when blood oxygen levels are low
FUNCTION OF RBC
1) transport oxygen
2) transport carbon dioxide
both dependent on hemoglobin
HEMOGLOBIN
protein
red pigment
contains iron compound
able to combine with oxygen to form oxyhemoglobin
combines with carbon dioxide to form carbaminohemoglobin
HEMOGLOBIN LEVELS
100 ml blood ===> 12-16 g hemoglobin
less than 10 g/ 100 ml of hemoglobin is diagnosed as anemia
CO2 TRANSPORT
enzyme in RBC (carbonic anhydrase) catalyzes a reaction that joins CO2 and water
CO2 + H2O ===> HCO3 (carbonic acid)
carbonic acid dissolved in water forms bicarbonate ions ( HCO3-)
bicarbonate ion diffuses out of the RBC and serves to transport CO 2 in the blood plasma
bicarbonate ions are also important in maintaining normal blood pH levels
FORMATION OF RBC
erythropoiesis (hemopoieses)
form in red bone marrow from hemocytoblasts
nucleated stem cells
maturation process requires about 4 days
every minute 100 million RBC are formed
if blood oxygen levels reaching the tissues is decreased the rate of RBC production increases
tissue oxygen levels influence the rate of RBC production
ERYTHROPOIETIN
hormone which stimulates bone marrow to accelerate RBC production
produced by the liver
athletes have been known to use erythropoietin to improve performance
RBC CLUMPING
Note the clumping of red blood cells, typical of stress, health problems or fatigue
Magnetic treatments????
RETICULOCYTE COUNT
used to measure rate of erythropoiesis
0.5 % -1.5% of RBC are reticulocytes (newly formed RBC)
counts less than 0.5% or higher than 1.5% indicate slowdown or acceleration of RBC
production
DESTRUCTION OF RBC
life span of RBC averages 105-120 days
macrophage cells in the liver and spleen phagocytose aged, abnormal or fragmented RBC
breakdown causes release of amino acids, iron and pigments (bilirubin) into the
bloodstream
bilirubin is removed from the bloodstream by the liver
liver excretes bilirubin into the intestine as bile
amino acids are recycled in protein synthesis
WHITE BLOOD CELLS
leukocytes
lack hemoglobin
contain nucleus and all other cell organelles
classified according to presence of granules and staining of cytoplasm
Granulocytes
Agranulocytes
GRANULOCYTES
1) neutrophils
2) eosinophils
3) basophils
AGRANULOCYTES
1) lymphocytes
2) monocytes
NEUTROPHILS
granules stain a light purple
cytoplasm appears course
nuclei has 2-6 lobes “polys”
65% of total WBC count
highly mobile, active phagocytes
able to migrate out of blood vessels into tissues (diapedesis)
contain powerful lysosomes which destroy bacteria
damaged cells release chemicals which attract neutrophils (positive chemotaxis)
ex: interleukin(macrophage), histamine(basophil), CRP(liver), C3a, C5a(complement)
EOSINOPHILS
large, numerous cytoplasmic granules
nuclei has 2 lobes
2%-5% of total WBC count
very numerous in lining of respiratory and digestive tract
weak phagocytes
capable of ingesting inflammatory chemicals and proteins associated with antigen-antibody
reactions
help to protect against parasitic worms and allergic reactions
BASOPHILS
large, sparse cytoplasmic granules
least numerous of WBC
0.5%-1% of total leukocyte count
motile, capable of diapedesis, non- phagocytic
play a major role in allergic responses
contain histamine (inflammatory)
contain heparin (anticoagulant)
LYMPHOCYTES
smallest of WBC
large spherical nuclei
25% of WBC count
T- cells
attack directly
mature and reside in the Thymus gland
B- cells
produce antibodies
are released directly to the blood from the Bone marrow
MONOCYTES
largest WBC
dark, kidney bean shaped nuclei
mobile, highly phagocytic
engulf large bacterial organisms and viral infected cells
WHITE BLOOD CELL NUMBERS
1 cubic mm= 5000-9000 leukocytes
clinical significance is given to a numbers or percentage change in WBC numbers
acute appendicitis
neutrophil numbers increase
DIFFERENTIAL COUNT
% count of WBC
leukopenia== decreased WBC numbers
leukocytosis== increased WBC numbers
NEUTROPHIL (66%)
HIGH
infection
burn
stress
inflammation
LOW
radiation
vitamin B12 deficiency
system lupus
EOSINOPHIL(3%)
HIGH
allergic reaction
parasitic infection
autoimmune disease
LOW
stress
Cushing’s disease
BASOPHIL (1%)
HIGH
leukemia
cancer
LOW
pregnancy
ovulation
stress
LYMPHOCYTE (24%)
HIGH
viral infection
immune disease
LOW
prolonged illness
high steroid levels
MONOCYTE (6%)
HIGH
viral, fungal infections
TB
LOW
rarely occurs
FORMATION OF WHITE BLOOD CELLS
most WBC originate in red bone marrow
many lymphocytes and monocytes are derived from lymphatic tissue
WBC LIFESPAN
most live only a few hours or days
some lymphocytes may live for many years (10 years or more)
WBC PHYSIOLOGY
combat pathogens
1) phagocytosis
2) immune responses
neutrophils and macrophages are active in phagocytosis
ingest bacteria
most leukocytes possess the ability to squeeze through the minute spaces of the capillary
walls (diapedisis)
PHAGOCYTES
several chemicals attract phagocytes
inflamed tissues
toxins produced by microbes
kinins from damaged tissue
colony stimulating factors (CSF)
NEUTROPHIL PHYSIOLOGY
neutrophils respond to tissue destruction by bacteria quickest
release destructive chemicals after phagocytosis
RELEASED LEUKOCYTE CHEMICALS
1) lysozyme
2) defensins
proteins which poke holes in microbe membranes
3) oxidants
O2H2O2 ( hydrogen peroxide )
OCl- ( bleach )
MONOCYTE PHYSIOLOGY
monocytes take longer to reach infection site
arrive in larger numbers & destroy more microbes
upon arrival they enlarge and differentiate into wandering macrophages
clean up cell debris and microbes
EOSINOPHIL PHYSIOLOGY
eosinophils arrive and release histaminase which counteracts effects of histamine in allergic
reactions
phagocytize antigen-antibody complexes
high counts indicate a parasitic worm infection or an allergic condition
BASOPHIL PHYSIOLOGY
arrive and develop into mast cells
release heparin, histamine, serotonin
intensify inflammatory reaction
LYMPHOCYTE PHYSIOLOGY
major combatants in immune responses
B-cells and T-cells
substances which initiate an immune response are called antigens
B-CELLS
B-cells develop into plasma cells in response to antigen presence
plasma cells produce antibodies
specific atibodies will bind to specific antigens creating antigen-antibody complexes
antibodies “cover” the antigen inactivating them
T-CELLS
Killer T-cells (cytotoxic T-cells)
destroy foreign invaders directly
virus, fungi. cancer, transplanted cells, some bacteria
Helper T-cells
assist B-cells and killer T-cells
LEUKEMIA
malignant disease of blood forming tissue
uncontrolled production and accumulation of immature leukocytes
anemia and bleeding problems occur due to crowding out of normal bone marrow cells
preventing normal production of RBC and platelets
cause of death can be from internal hemorrhaging or from uncontrolled infection due to lack of
mature leukocytes
abnormal accumulations can be reduced by radiation or chemotherapy which destroys the
abnormal bone marrow
BONE MARROW TRANSPLANT
bone marrow containing WBC are aspirated from the red bone marrow of the hip
injected into the vein of the recipient
injected cells “reseed” the unhealthy bone marrow
MONONUCLEOSIS
contagious disease affecting lymphoid tissue throughout the body
caused by “Epstein-Barr virus” (EBV) and occurs mainly in young adults and children (mostly
females)
most commonly enters the body through intimate oral contact
infects and multiplies in B-lymphocytes
B-cells enlarge and become abnormal in appearance (look like monocytes)
elevated WBC count with high number of lymphocytes
PLATELETS
also called thrombocytes
small, colorless, irregular shaped
fragments of larger cells
about 20%-25% of the size of WBC and RBC
250,000 per mm3
FORMATION AND LIFE SPAN OF PLATELETS
formed in red bone marrow, lungs and spleen
fragments of larger cells called megakaryocytes
life span of about 9 days
FUNCTIONS OF PLATELETS
promote blood clotting
important factors in agglutination, adhesiveness, aggregation
aged platelets are removed by liver macrophages
END BLOOD PART 1