Lecture 26: Peripheral Blood Flashcards
What is circulating blood
Not in bone marrow or other sites of hematopoiesis
5 functions of peripheral blood
-transport
-coagulation
-thermoregulation
-acid base balance
-osmotic balance
What kind of tissue is peripheral blood
Specialized connective tissue
2 components of peripheral blood
Cells
Plasma
Formed elements
Cells in peripheral blood
Extracellular matrix in peripheral blood
Plasma
What is serum (hematocrit)
Plasma without coagulation factors
Erythrocytes function
Gas transport
Platelets function
Coagulation
Polycythemia
Too many rbcs
Anemia
Not enough rbcs
Leukocytosis
Wbcs appear like they’re exploding (leukemia)
What is the most numerous cell type
Erythrocytes
What percent of total blood volume is occupied by erythrocytes
40-45%
How are erythrocytes removed from bloodstream at the end of their lives
Macrophages in spleen, liver and bone marrow
Erythrocytes: shape
Biconcave disk
Importance of erythrocyte shape
Maximize cell surface are and maneuverability through small blood vessels
Can squeeze into vessels (due to indentation in pale center)
What color is the center of erythrocytes
Pale
What structures do erythrocytes lack (compared to other normal cells)
Nucleus
Organelles
Erythropoiesis: duration, location, stimulated by
-7 days
-in bone marrow
-stimulated by erythropoietin/hypoxia
What 3 elements are essential for hemoglobin production
Iron
Folic acid
Vitamin B12
5 Characteristics of erythropoiesis (summary of events)
-decreasing volume
-condensing/ejection of nucleus
-free ribosomes decrease
-hemoglobin increases
-shift from basophilic to acidophilic
Immature erythrocytes are called
Reticulocytes
Injury that causes blood loss: what happens to erythrocytes
Reticulocytes go into circulation prematurely
Location of leukocyte transport vs function
Transport = peripheral blood
Function = connective tissue
4 steps of leukocyte transport to injury
-release of cytokines
-wbcs migrate
-adhesion to endothelium (epithelial cells) of postcapillary venule
-diapedesis (aided by histamine and heparin)
-amoeboid movement through connective tissue
Diapedesis
Passage of wbc’s through capillary walls (walls create small opening for cells to go through)
2 general types of leukocytes
-granulocytes
-agranulocytosis
Granulocytes: 3 types, nuclei shape
-neutrophils, eosinophils, basophils
-lobulated nuclei
Agranuloctyes: 2 types, nuclei shape
- lympocytes, monocytes
-round nuclei
Granulocytes vs agranuloctyes: main difference
Agranulocytes = no specific granules
Granulocytes = specific granules
2 types of granules in granulocytes
-primary
-secondary
Primary granules
Lysosomes
Secondary granules
Enzymes with specific function
Which granulocyte is most numerous wbc
Neutrophil
Function of neutrophils
Phagocytosis and destruction of bacteria
Neutrophil appearance: histology
-granules are pale pink/lavender
-multi lobed dark nucleus (2-5 lobes)
What are azurophilic granules
Lysosomes
Specific granules vs primary granules
Specific more oblong than lysosomes
Which cell type if a major component of pus
Neutrophils
Function of cytokine release
Recruit more leukocytes
Promote inflammation and fever
Function of eosinophils
PARASITE destruction
Phagocytosis antigen-antibody complexes
Modulate inflammatory response
Eosinophils: nucleus
2 lobes
Eosinophils: specific granules
Contain major basic protein that is antiparasitic
Looks like a cat’s eye at TEM
Function of basophils
Initiate inflammatory response and hypersensitivity reactions
Basophils: nucleus
S shaped
Obscured by granules
Basophils: cytoplasm color
Purple = basophilic
Basophils: specific granules
Heparin, histamine
Dark appearance
Basophils have a similar function/structure as what cells
Mast cells
Agranuloctyes: nucleus
Round (not lobed)
Are granulocytes or agranulocytes long lived
Agranuloctyes
Lymphocytes: cytoplasm appearance
Light blue
Thin rim around nucleus
Small relative to nucleus
What is the only wbc/agranulocyte to return to blood after being in connective tissue or lymphatic organ
Lymphocytes
Lymphocytes have an abundance of what organelle
Free ribosomes
3 types of lymphocytes
T cells
B cells
Natural killer (NK) cells
B cells: function
Antibody mediated immunity
B cells differentiate into
Plasma cells
T cells function
Participate in cell mediated immunity
Act against foreign cells, virus infected
**antigen
Natural killer cells: function
Innate immune response
What kind of circulation system is peripheral blood
Closed
Why do we call rbcs formed elements
Not really cells because no organelles or nuclei
Hematocrit
-after centrifugation
55% plasma (top layer)
40-45% rbcs (bottom layer)
1% Buffy coat (wbcs and platelets) in middle layer
Peripheral blood smear: stain
Eosin and methylene blue
Erythropoiesis: process
Erythroblast (with nucleus) -> nucleus ejected —> Reticulocyte —> condensed down more into mature erythrocyte
Where does diapedesis occur
Postcapillary venules/beds
How are wbcs removed
Commit apoptosis
Cleaned up by macrophages
How are agranulocytes similar to all other leukocytes
-travel in peripheral blood
Diapedesis
Host defense
Have primary granules
Agranulocytes vs granulocytes
-no specific granules
-long lived
Round nuclei
Largest agranulocyte
Monocytes
Monocytes: functions
Become macrophages (clean up after injury)
Assist with antigen presentation
Monocytes: nucleus
Kidney bean shaped
Platelets aka
Thrombocytes
Function of platelets
Limit hemorrhage
Neutrophils are specific to
Bacteria
Platelets: nucleus
None
Platelets: staining
Dark
Platelets originate from what cells and where
Megakaryocytes
Bone marrow
Demarcation channels
Invaginations of plasma membrane that partition cytoplasmic fragments into proplatelets that break off to form platelets
Where are demarcation channels found
In platelets
3 steps of platelet function
Activation - find injury
Adhesion to injury
Aggregation - adhere to each other
