Blood Flashcards
the cardiovascular system includes
the heart, blood vessels, and blood
the cardiovascular system is a major transportation system for
-substances we need for the external environment
-substance we need to eliminate through wastes
-substances we synthesize that need delivery to other organs
the functions of bloods is
-transports dissolved gasses, nutrients, hormones, and metabolic wastes
-regulates pH and ion makeup of interstitial fluids
-restricts fluid loss at injury sites
-defends against toxins and pathogens
-stabilizes body temperature
composition of blood
a liquid connective tissue made of plasma and formed elements
human blood temperature is ___, a little _____ body temperature
38 C, above
blood is five times more viscous than water
this is caused by plasma proteins, formed elements
viscosity refers to
thickness and stickiness
pH is slightly alkaline in a range of
7.35 - 7.45
plasma and interstitial fluid makes up most of
ECF
plasma contains
plasma proteins, hormones, nutrients, gases, and water
three major types of plasma proteins are
albumins, globulins, and fibrinogen
albumins
-most abundant
-maintains osmotic pressure of plasma
globulins
acts as transport proteins and antibodies
fibrinogen
functions in blood clotting, converting to fibrin
plasma minus the clotting proteins like fibrinogen is called
serum
90 percent of plasma proteins are synthesized by
liver
blood contains
plasma and formed elements
plasma(55%, 46%-63%) contains
plasma proteins, water, and other solutes
formed elements(45%, 37%-54%) contains
platelets, white blood cells, and red blood cells
red blood cells are also called
erythrocytes
RBSs
-make up 99.9 percent of formed elements
-measured in red blood cell count /micrometer
-measured as a percentage of whole blood
-contains pigment molecule such as hemoglobin or hemocyanin
men has
5.4 million /microliter of RBCs
women have
4.8 million /microliter of RBCs
hematocrit in men is
46 percent
hematocrit in women is
42 percent
RBCs function
transports oxygen and carbon dioxide
structure of mammal RBCs
-unique biconcave shape provides advantages
-increased surface area increases rate of diffusion
-increases flexibility to squeeze through narrow capillaries
-during RBC formation organelles are lost
-cannot go through cell division
-can only rely on glucose from plasma for energy
structure of reptile and bird RBCs
-Different selective pressures resulted in different characteristics
-Cells are nucleated and not biconcave
-Cells are elliptical rather than round
-Oxygen carrying capacity is generally higher than mammals in birds, lower than mammals in nonavian reptiles
hemoglobin abbreviation is
Hb
hemoglobin is 95% of all
RBC intracellur proteins
hemoglobin transports
oxygen and carbon dioxide
hemoglobin composed of two pairs of _________, called ________
globular proteins, called subunits
subunits contains
heme, with an iron atom
oxygen binds to ______, carbon dioxide binds to the ______
heme, globular subunits
O2- heme bond is
fairly weak
high plasma O2
-causes hemoglobin to O2 until saturated
-occurs as blood circulated through lung capillaries
low plasma O2 and high CO2
-causes hemoglobin to release O2
-occurs as blood circulating through systemic capillaries
anemia is
a reduction in oxygen-carrying capacity
-iron deficiency, pernicious, other types
anemia is cause by
low hematocrit
low hemoglobin content in RBCs
anemia symptoms include
muscle fatigue and weakness
lack of energy in general
if RBCs hemolyze in bloodstream
Hb breaks down in blood
kidneys filter out Hb
if a lot of RBCs rupture at once it causes hemoglobinuria, indicated by reddish-brown urine
most RBCs are phagocytized in liver, spleen, and bone marrow
Hb components are recycled
three steps of hemoglobin recycling
- Globular proteins are broken into amino acids
- Heme is stripped of iron, converted to biliverdin
-Biliverdin is converted to bilirubin, orange-yellow
-Liver absorbs bilirubin, it becomes part of bile
-If not put into bile, tissues become yellow, jaundiced
3.Iron can be stored or released into blood to bind with transferrin
stages of erythropoiesis also called
RBC formation
embryonic cells differentiate into multipotent stem cells called
hemocytoblasts
erythropoiesis occurs in
red bone marrow, or myeloid tissue
hemocytoblasts produce
myeloid stem cells
erythroblasts are
immature and are synthesizing Hb
regulation of erythropoiesis
requires amino acids, iron, and B vitamins
stimulated by low tissue oxygen, called hypoxia
kidney hypoxia triggers release of erythropoietin
-when blood flow to kidney decreases
-when anemia occurs
-when oxygen content of air declines
-when damage to respiratory membrane occurs
erythropoietin(EPO) are
target tissue is myeloid stem cell tissue
EPO
-stimulated increase in cell division
-speeds up rate of maturation of RBCs
-essential for patients recovering from blood loss
-EPO infusions can help cancer patients recover from RBC loss of chemotherapy
ABO blood types and Rh system
based on antigen-antibody responses
your surface antigens are considered normal, not foreign, and will not trigger an immune response
antigens or agglutinogens
are substances that can trigger an immune response
presence or absence of antigens on membrane on RBC determines
blood type
three major human antigens are
A,B, Rh
type A blood has only antigen
A
type B blood has only antigen
B
type AB blood has both antigen
A and B
type O blood has neither antigen
A nor B
Rh positive notation indicated
the presence of the Rh antigen, Rh negative, the absence of it
antibodies also called agglutinins
found in plasma, will not attack your own antigens on your RBCs
will attack foreign antigens of different blood type
type A blood contains
anti-B antibodies
type B blood contains
anti-A antibodies
type AB contains
neither antibodies
type O blood contains
both antibodies
cross-reactions in transfusions
-occurs when antibodies in recipient react with their specific antigen on donor’s RBCs
-cause agglutination or clumping of RBCs
-referred to as cross-reactions or transfusion reactions
-checking blood types before transfusions ensures compatibility
anti-A or anti-B antibodies
spontaneously develop during first six months of life
no exposure to foreign antigens needed
anti-Rh antibodies in Rh negative person
do not develop unless individual is exposed to Rh positive blood
exposure can occur accidentally, during a transfusion or during childbirth
WBCs
larger than RBCs, involved in immune responses
contains nucleus and other organelles and lack hemoglobin
granulocytes
neutrophils(mammals), heterophils, azurophils (reptiles)
agranulocytes
lymphocytes and monocytes
four characteristics of WBCs
- all are capable of amoeboid movement
- all can migrate outside of bloodstream through diapedsis
- all are attached to specific chemical stimuli, referred to as positive chemotaxis, guiding them to pathogens
- neutrophils, heterophils, eosinophils, and monocytes are phagocytes
types of WBCs
granulocytes, monocytes, and lymphocytes
granulocytes and monocytes
respond to any threat
are part of the nonspecific immune response
lymphocytes
respond to specific, individual pathogens
are responsible for specific immune response
neutrophils
-makes up 50-70 percent of circulating WBCs in mammals
-usually first WBC to arrive at injury
-phagocytic, attacking and digesting bacteria
-numbers increase during acute bacterial infections
eosinophils
-make up 2-4 percent of circulating WBCs in mammals
-similar in size to neutrophils
-are phagocytic, but also attack through exocytosis of toxic compounds
-numbers increase during parasitic infection or allergic reactions
basophils
-somewhat smaller than neutrophils and eosinophils
-rare, less than 1 percent of circulating WBCs
-granules
granules contain
heparin and histamine
anticoagulant
heparin
inflammatory compound
histamine
heterophils
-large, common phagocytes
-may be most common WBC type in some reptiles
azurophils
-bluish, comparable in size to heterophils
-around 5% of WBCs in reptiles
-increase in number during bacterial infection and necrosis
-function not definitively known
monocytes
-about twice the size of RBC with a large, kidney bean-shaped nucleus
-usually 2-8 percent of circulating WBCs
-migrate into tissues and become macropahages
-aggressive phagosytes
lymphocytes
-slightly larger than typically RBC with nucleus taking up most of cell
-about 20-40 percent of circulating WBCs
-large numbers are migrating in and out of tissues and lymphatics
-some attack foreign cells, others secrete antibodies into circulation
the differential WBC count
counting the numbers of the five unique WBCs of a stained blood smear, called a differential count
change in numbers or percentage is diagnostic, three types
leukopenia, leukocytosis, and leukemia
leukopenia
is a reduction in total WBCs
leukocytosis
is excessive numbers of WBCs
leukemia
is an extremely high WBC count and is a cancer of blood-forming tissues
WBC formation
derived from hemocytoblasts
regulated by colony-stimulating factors, thymosins
produce lymphoid stem cells
differentiate into lymphocytes, called lymphopoiesis
migrate from bone marrow to lymphatic tissues
produce myeloid stem cells
differentiate into all other formed elements
platelets also known as thrombocytes
cell fragments involved in prevention of blood loss
contains granules of chemicals
normal count is 150,000-500,000 /microliter
hemocytoblasts differentiate into
megakaryocytes
platelets granules of chemicals which
initiate clotting process and aid in closing tears in blood vessels
low count of platelets is called
thrombocytopenia
three phases of hemostasis are
vascular, platelet, and coagulation phase
hemostasis function
halts bleeding and prevents blood loss
the vascular phase
-blood vessels contain smooth muscle lined with endothelium
-damage causes decrease in vessel diameter
-endothelial cells become sticky
-a vascular spasm of smooth muscle occurs
the platelet phase
-platelets attach to sticky endothelium and exposed collagen
-more platelets arrive and stick to each other forming a platelet plug
-may be enough to close a small break
the coagulation phase also called blood clotting
-a chemical cascade of reactions that leads to fibrinogen being converted to fibrin
-fibrin mesh grows, trapping cells and more platelets forming a blood clot
the common pathway of blood clotting
begins when enzymes from either extrinsic or intrinsic pathways activate Factor X
Factor X
forms enzyme prothrombinase
which converts prothrombin into thrombin
which converts fibrinogen into fibrin
and stimulates tissue factor and platelet factors
positive feedback loop rapidly prevents blood loss
clot retraction and removal
-fibrin network traps platelets and RBCs
-platelets contract, pulling tissue close together in clot retraction
during repair of tissue, clot dissolves through fibrinolysis
plasminogen is activated by
thrombin and tissue plasminogen activator (t-PA)
