2011 foms pl11 - blood & blood vessels - cop
TRANSCRIPT
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Blood & Blood Vessels
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Aims & Objectives
To describe different blood cell types.
To explain plasma (serum & its difference withplasma) & its composition.
To outline the structures & properties o
fthethree main types ofblood vessels, namely,
arteries, veins & capillaries.
Clinical relevance: supply ofO2, nutrients &removal ofwaste products,functioning immune
system..
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Functions ofBlood
Maintenance ofhomeostasis:
1. Transport ofgases, nutrients & waste products.
2. Transport ofprocessed molecules.
3. Transport of regulatory molecules.4. Regulation ofpH & osmosis.
5. Maintenance ofbody temperature.
6. Protection against foreign substances.
7. Clotform
ation.Transport/ distribution, regulation (body temperature,
pH, fluid volume), protection (blood loss, infection).
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Composition ofBlood
Connective tissue cells & cell fragments (formedelements) surrounded by liquid matrix (plasma) Totalblood volume (whole blood), ~ 4 to 5 L (females), 5 to 6L (males)
Plasma pale yellow fluid, ~91% water, 7% proteins, 2%
other substances: ions (ECF), nutrients, gases, wasteproducts, regulatory substances.
Plasma proteins albumin (58%)- Oncotic pressure
globulins (38%)-transport protein
fibrinogen (4%), clotting factors
Serum = plasma minus clotting factors (used up to formclots).
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Composition ofBlood
O2 enters blood in lungs, CO2 fromtissues
Formed elements :
erythrocytes/ red blood cells/ RBCs;
leukocytes/ white blood cells/ WBCs
thrombocytes /platelets
% packed RBCs (after spinning/ centrifugation) =
hematocrit,ind
icat
ion o
fanemia.
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Formed Elements ofBlood
RBC biconcave, no nucleus, contains hemoglobin (Hb) red colour,
7.5 microm diam transports O2 & CO2, pH regulation duration ofdevelopment (DD) 5-7 days, life span (LS) 100-120 days.
WBCwith nucleus, (no Hb) 5 types, each with specific functions:
Granulocytes:
(1) neutrophil nucleus 2 to 4 lobes, cytoplasmic granules light pink/reddish purple, 10-12 microm diam phagocytizesmicroorganisms & other substances
(2) basophil nucleus with 2 distinct lobes, granules blue-purple, 10-12 microm diam releases histamine & othermediators ofinflammation, & heparin which prevents clot formation/
anticoagulant(3) eosinophil nucleus o ften bilobed, granules orange-red/ bright
red, 11-14 microm diam, kills parasitic worms, destroys Ag-Abcomplexes, inactivates some inflammatory chemicals ofallergy
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Formed Elements ofBlood
Agranulocytes:(4) lymphocyte round nucleus, thin ring ofcytoplasm
(pale blue) around nucleus, 6-14 microm diam , mountimmune response by direct cell attack orviaantibodies, allergic reactions, graft rejection, tumorcontrol, regulation ofimmune system
(5) monocyte nucleus round/ kidney/ horseshoe/ U-shaped, pale blue cytoplasm, 12-20 microm diam,phagocytic cell in blood, leaves blood to become tissuemacrophage (bacteria, dead cells, cell fragments/ debris
Platelets/ thrombocytes discoid cytoplasmic fragmentswith granules, deep purple, 2-4 microm diam, seal smalltears in blood vessels/ platelet plugs, blood clottingDD 4-5 days, LS 5-10 days.
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WBC Count
Differential WBC count - % different types of leukocytes inblood sample :
N (50-70%),
E (2-4%),
B (0.5-1%),L (25-45%),
M (3-8%).
Descending order: NeverLet Monkey Eat Bananas.
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Formed Elements ofBlood & Their Origins
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Formed Elements ofBlood
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Formed Elements ofBlood
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Blood Vessels
Peripheral circulation, heart as central pump.
Functions ofcirculation to carry blood to all tissues & backto heart; exchange nutrients & gases (between blood &all tissues); transport (eg hormones, clotting factors,
enzym
es); regulate blood pressure (+ heart action BP within normal range); direct blood flow as required
by tissue need.
Systemic vessels all parts ofbody from left ventricleback to right atrium (+ coronary vessels supplying heartitself).
Pulmonary vessels to lungs from right ventricle to leftatrium.
Systemic + pulmonary = peripheral circulation, closedcircuit. Central=heart.
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Circulatory System
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Overview ofBlood Vessel
Structures &F
uncti
ons3 major types arteries (As), capillaries (Cs),veins (Vs).
From heart into large artery, then into
successively smaller arteries to smallestbranches (arterioles), then into capillaries (inorgans & tissues, close to cells), then intosmallest veins (venules), into larger & largerveins that merge into large veins emptying intoheart - ~ 100,000 km (60,000 miles).
Systemic circulation Arteries high O2, Veins lowO2, opposite in pulmonary circulation.
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Blood Vessels
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Blood Vessels
Microcirculation arterioles, capillaries, venules.
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Arterial vessels
Arteries -Thick, strong wall, 3 layers: endothelium,middle layer ofsmooth M & elastic tissue, outer layer ofconnective tissue high pressure elastic/ conductingArteries,
Arterioles thinner wall, still 3 layers, smooth M in middlelayer, control blood flow into cap by vasoconstricting/vasodilating major effect on BP has SympatheticNS innervation. Highest RESISTANCE
Endothelium smooth surface, inhibition ofplateletaggregation/ clot, regulation local Blood Flow bysecreting vasodilators/ vasoconstrictors.
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Capillaries
Thin wall nutrients, gases & wastes exchanged between blood &
tissue fluid/ ISF, close intimate contact with cells of tissues/ organs connect arterioles to venules 1 mm length, 8-10 microm diam(diam ofRBCs?).
Types
continuous C (skin, skeletal M), tight junctions between cells,intercellular clefts allow fluid & small solutes through,especially tightin bra
in (BBB);fenestrated C - endothelial cells with pores/ fenestrations (small
intestine for absorption, kidney for glomerularfiltration);
sinusoidal C/ sinusoids (liver, bone marrow, lymphoid tissues,some endocrine glands) large intercellular clefts to allow largemolecules, blood cells - liver: discontinuous endothelium withmacrophages (Kuppfer cells).
Metarterioles
--thoroughfare channels/ shunts arterioles directly to venules
true capillaries/ exchange vessels, precapillary sphincters atm
etarterioles.
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Capillary
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Capillary Endothelium
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Capillary Endothelium
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Exchanges at Capillary
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Exchanges at Capillary
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Veins
enules thinner walls, less smooth M & elastic tissuesthan arterioles, connect Cappilaries to veins.
Veins thinner walls than arteries, but similar layers,
valves (unidirectional Blood Flow), larger lumens,contain large amount ofblood (65%) capacitancevessels, blood reservoirs ( venoconstriction pushesblood to heart), low pressure.