B LOOD & C IRCULATORY S YSTEMS A & P. B LOOD 3-4 times thicker than H 2 O (hence the saying) Heavier...
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Transcript of B LOOD & C IRCULATORY S YSTEMS A & P. B LOOD 3-4 times thicker than H 2 O (hence the saying) Heavier...
BLOOD & CIRCULATORY SYSTEMSA & P
BLOOD3-4 times thicker than H2O (hence the saying)
Heavier than waterpH 7.35-7.455-6 L M/4-5 L F
FUNCTIONSTransportRegulation
pHbody tempH2O
ProtectionBlood lossForeign microbes
COMPONENTS
Formed elements Plasma
Formed elementscells & cell like structures(rbcs, wbcs, platelets)
45% of volume
RBC % is HematocritFormed elements are:
erythrocytes- RBCsleucocytes- WBCsthrombocytes- platelets
ErythrocytesBiconcave, no nuclei
???red due to hemoglobin
33% of cell weight1 globin + 4 hemeEach Hgb carries 4 O2 & each RBC has 280,000,000
Heme molecules contain iron that can exist in 2 states (ferrous & ferric)Ferrous combines w/O2 forms Oxyhemoglobin
When in periphery changes to ferric & O2 released
O2 released combines w/CO2 forms carbaminohemoglobin
HEMOGLOBIN
23% CO2 transported RBCs live 120 days M 5.4 /F 4.8 Million per Cubic millimeter of bloodAnemia- insufficiencyPolycethemia- abundance
ErythropoiesisHomeostasisRenal erythropoietic factorconverts plasma protein to erythropoietin
Leucocytes (WBCs)Have nuclei, no hemoglobin5-10,000 per cubic millimeterLeucocytosis- high WBC
infection Leucopenia- low WBC
Cancers & viruses
Thrombocytes (platelets)no nucleus250-400 thousand repair/initiates clottingproduced in Red marrow
Plasmastraw colored55% of whole blood
H2O= 91.5%proteins= 7.5%,electrolytes= 1%
Plasmatransport medium
cellular wastefoodenzymesrespiratory gases
Human Red Blood Cells, Platelets and T-lymphocyte (erythocytes = red; platelets = yellow; T-lymphocyte = light green)
HEMOSTASISstoppage of bleeding (in order that it occurs)vascular spasmplatelet plug formationcoagulation
Vascular Spasmcontraction of tunica media
reduces blood losscaused by pain receptor reflex
Platelet Plugplatelets adhere to rough edges of injurythis forms a plug
this stops the bleeding
Coagulation- clotprothrombin activators
thrombinfibrinogen
fibrin (spider’s web)clot
Clot replaced by healthy tissueThrombus- abnormal vessel clot
Embolus- floating clot
HEMOSTASIS REVIEW
BLOOD TYPING
Agglutination- transfusion reaction
Agglutinogens (antigens)- glycoproteins stuck to cell wall
Agglutinins- antibodies in plasma
ABO blood groupingspresence or absence of
Agglutinogen A and/or BAntibodies found in the plasmaAnti-A or B agglutinin
Blood transfusionmust be done correctly (dah)
Universal recipient- AB Blood
Universal donor- type O
Rh blood Groupif Rh factor (Antigen D) is presentRh positive
if Rh factor is not presentRh negative
VESSEL TYPES
ArteryCapillaryVeins
STRUCTURETunica Intima-
SmoothTunica Media
Smooth Muscle & connective tissue (elastic)
Tunica Externa-–Thin layer of connective tissue
–Elastic and Collagenous fibers running parallel to long axis of vessel
ARTERIESWall composition differs according to size
Transports blood under high pressure
Walls are generally thicker than that of veins
TYPES–Elastic (Large)–Muscular (Medium)–Arterioles
ELASTICVery thick T-mediaElastic fibersVery little Smooth MuscleTunica Externa thin but strong to limit stretching
Suited as shock absorber
Maintaining constant flow of blood
Examples–Aorta–Pulmonary TrunkPulmonary Trunk
MUSCULAR
More Smooth MuscleVery Few Elastic FibersInfluences:
Blood flowPressureDistribution
ARTERIOLES
Under 0.5mm in diameter
Thick Tunica Media Major role in regulating blood into capillaries
END ARTERIES
Have no or inadequate anastomosis
Found within organsOcclusion causes death of supplied areabed sores
CAPILLARIESMicro CirculationPenetrate almost every tissue in body1.5 acresend-to-end 60,000 miles
Single layer endothelial cells
Allows relatively free exchange of H20 electrolytes, O2 and CO2
Surface area and slow rate of flow allows for efficient exchange
CAPILLARY BEDSThoroughfare ChannelsTrue CapillariesPre-capillary sphincter
Channels- –scattered smooth muscle cells
–between arteries & venules
True Capillaries–branch from and join with channels
Pre Cap. Sphincter–Usually surrounds true capillary where it arises from thoroughfare channel
–Contraction helps regulate blood flow
VEINSSame 3 layers as ArteriesMuch thinner Greater in diameter and #Types
Small (Venules)Large
Small- closest to capillariesLarge- Tunica Media is quite
thinTunica Externa composes greatest part of wall
BLOOD PROPULSION
Slight positive pressureActivity of MusclesValves found in larger veins usually of lower extremities
CIRCULATORY SYSTEM
Composed of 2 distinct circuitsPulmonarySystemic
Coronary Circulation- takes blood to heart (nutritional)
Portal Circulation- blood from digestive tract
PULMONARY CIRCUIT
Pulmonary TrunkPulmonary Arteries- 2 (deoxygenated)
Pulmonary Veins- 4 (oxygenated)
SYSTEMIC CIRCUIT
VEINS
VASCULARIZATION
Small Vessels - blood withinLarger Vessels-
Diffusion not enoughSmall adjacent Arts. (Vasa Vasorum)
Arteries penetrate through Tunica Externa
Veins penetrate to Tunica Intima
PHYSIOLOGY OF CIRCULATION
Blood FlowBlood Pressure
Systolic DiastolicPulse
Blood Pressure- force exerted on inner walls
Systolic Pressure (SP)- maximum pressure
Diastolic Pressure (DP)- Minimum or lowest pressure
Pulse- Rhythmic expansion and recoil of arterial wall
Pulse Pressure Pulse Pressure (PP)(PP) - - difference between difference between Systolic and Diastolic Systolic and Diastolic pressure usually 40mm pressure usually 40mm HgHg
PP= SP - DPPP= SP - DP
Mean Arterial Pressure (MAP)
Pressure in system for driving blood to tissues
MAP = DP + 1/3 PP
INFLUENCES ON BP
Cardiac Output Peripheral Resistance
Cardiac Output (CO)Heart Rate (HR)Stroke Volume (SV)
– CO= HR x SV
PERIPHERAL
RESISTANCE (TPR)Resistance through vessels
DiameterViscosityLength of VesselBlood Volume
BP = CO x TPR
BP CONTROLVasomotor Center
In MedullaControls DiameterSymp. incr. Vasoconstriction
Symp dec. Vasodialation
Pressoreceptors–in carotid Sinus and Aorta–Impulses go to Cardiac Center resulting in inc. or dec. cardiac output
–Also sends impulses to Vasomotor Ctr.
Chemoreceptors–In Carotid and Aortic bodies
–Sensitive to Art. content of O2, CO2 and H+ ions
–When stim. send impulses to vasomotor Center
CONTROL BY HIGHER BRAIN FUNCTION
Strong emotions (anger, stress)Increases Sympathetic Impulses to VM Centers–vasoconstriction
Decrease in Sympathetic Impulses to VM Centersvasodilation
CHEMICALS
Epinephrine & Norepinephrine produced by adrenal medullaCauses vasoconstriction of abd and cutaneous arterioles
Dilation of cardiac & skeletal arterioles
Antidiuretic Hormone (ADH) produced by hypothalamus–Vasoconstriction in the case of severe blood loss
AUTOREGULATION (LOCAL CONTROL)
Automatic adjustments are made to regulate blood flow
In most cases O2 is the principal stimulus
QUESTIONS????