blood Flashcards
formed elements of blood
cells + platelets
ECM of blood
plasma (liquid when not clotted)
plasma
90% water
9% plasma proteins
1% dissolved ions and gases
blood constituents
55% plasma
45% RBC (hematocrit)
<1% WBCs + platelets
lower O2, higher hematocrit
lower iron, lower hematocrit
RBCs
transport hemoglobin (O2 and CO2)
- small enough to squeeze through closed capillaries
- biconcave shape: incr SA for gas exchange
- few cytoplasmic organelles, no nucleus
- carbonic anhydrase
carbonic anhydrase
converts CO2 and H2O to bicarbonate ion, buffers plasma
anemia
RBC deficiency
- metabolic: iron deficiency
- genetic: sickle cell
hemoglobin
protein + iron/heme group, binds O2 and CO2
RBC plasma membr + cytoskeleton
Plasma membr: 50% glycoprotein
Cytoskeleton: maintains shape and is flexible (capillaries)
- filamentous spectrin
- actin
RBC destruction
120 day lifespan
- loss of cytoskeleton integrity -> slow and fragile in small vessels
- destroyed by spleen
WBCs
function outside circulatory system
- exit via diapedesis
2 types: granulocytes and agranulocytes
granulocytes
innate immunity
- cytoplasmic granules, secretory vesicles
neutrophils
most abundant WBCs
- multilobed nucleus
- granules (chromophobic), contain anti-bacterial enzymes
- live hrs in circulation, days in CT
- phagocytic
- generate pus when they swell and die after ingesting bacteria
basophils
few, long lived (1-2 yrs in CT)
- amplify innate response
- granules with histamine (vasodilator), heparin (anti-coag)
- secrete chemoattractants
anaphylactic shock
release of histamine from basophils + mast cells leads to swelling, low BV, constriction of bronchial tree
- counteracted by epinephrine: constricts blood vessels, relaxes bronchiolar smooth muscle
eosinophils
cat eyed granules, 1-2 weeks
- mop up in late stages of innate + adpative resp
- phagocytoses + destroys neutralized antigens
- granules: major basic protein, histaminase
major basic protein
permeabilizes parasite membranes
- released by eosinophils
histaminase
dampens innate resp from basophils + mast cells
agranulocytes
monocytes->macrophages, lymphocytes
monocytes
largest blood cell, exits by diapedesis, diff into macrophages in CT
- kidney shaped nucleus
macrophages
phagocytes, innate immune resp
- respond to foreign material
- APCs
lymphocytes
Unactivated: round nucleus, pale cytoplasmic ring
B: Ab-mediated adaptive immunity
T: cell-mediated adaptive immunity
platelets
cell fragments
- granules/secretory vesicles
- integrins + cytoskeleton
- prod by megakaryocytes in BM
thrombospondin
released by activated platelets, increases platelet aggregation to generate platelet plug
platelet factor 3
released by activated platelets
- facilitates clotting cascade to generate fibrin fibers from fibrinogen in plasma
clotting + platelet plug
- platelets bind to sub-endothelial collagen in wounded blood vessels
- platelets activated by collagen binding + signals from wounded cells (vWF)
- platelets aggregate and release thrombospondin and platelet factor 3
megakaryocytes
in BM, form platelets
- platelet demarcation channels: membr invaginations which fuse to create platelet fragments
- very large, polyploid nucleus
