Exam 1: Cardiac Physiology Flashcards
Number 1 cause of death
Cardiovascular disease
Major underlying cause of cardiovascular disease
Ischemia
Ischemia can be due to
Atherosclerosis
Artery spasm
White thrombus
Platelet plug
Red thrombus
Blood coagulation
Inflammatory mechanisms couple dyslipidemia to
Atheroma formation
2 things that characterize early atherogeneis
Leukocyte recruitment
Proinflammatory cytokines
Inflammatory pathways promote
Thrombosis
___ responsible for MI and most strokes
Thrombosis
___ can modulate inflammation
NS
Hemostasis
Prevention of blood loss
Mechanisms of hemostasis
Vascular spasm
Platelet plug
Blood coagulation
Fibrous tissue
Vascular constriction can be due to
Neural reflexes
Local myogenic spasms
Local humoral factors
Local humoral factors include
Thromboxane A2 (from platelets) Serotonin
___ important in small vessels
Local humoral factors
Responsible for most constriction
Local myogenic spasms
Platelets cannot
Divide
Platelet cell membrane contains
Phospholipids with platelet factor 3
Mechanisms of platelet activation
- Swell
- Irregular form (spikey)
- Contractile proteins cause granule release
- Secrete ADP, thromboxane A2, and serotonin
Constrictors
Thromboxane A2
Serotonin
___ potentials release of granule contents but is not essential
Thromboxane A2
Platelets are important in
Minute ruptures
Platelets are eliminated primarily by
Macrophage action
Endothelium prevents
Platelet aggregation
Endothelium produces
PGI2
PGI2 acts as a _____ and stimulates platelet adenyl cyclase, which ____
Vasodilator
Suppresses release of granules
Endothelium produces ___ important in clotting
Factor VIII
COX2 pathway produces prostacyclin, which is
Cardioprotective
Aspirin and ibuprofen both block ____ and ____
Thromboxane A2 and prostacyclin
COX inhibitors are a type of
NSAID
Inhibition of COX1 effects
Low thromboxane A2
Inhibition of COX2 effects
Endothelium (low PGI2)
Anticoagulants
Prevents clots form forming
Lysis of clots
Dissolves clots
Anticoagulants
Chelators
Tie up calcium
Anticoagulants
Heparin
Complexes with antithrobin 3
Anticoagulants
Dicumarol
Inhibition of Vit k dependent factors
___ is needed for lysis of clots
Plasmin
There are both ___ and ____ activators or plasminogen
Endogenous activators
Exogenous activators
Endogenous activators of plasminogen
Tissues
Plasma
Urine
Exogenous activators of plasminogen in
Streptokinase
TPA
Administration of tPA has a ____ for MI and stoke
3 hr window
Reperfusion injury
ROS flood damaged area when pressure on tissues relieved and blood returns
Collateralization
Ability to open up alternative routes of blood flow to compensate for blocked vessel
3 methods of collateralization
- Angiogenesis
- Vasodilation
- SNS
The SNS may ___ or ____ collateralization
Impede
Augment
SNS may impede collateralization by
Vasoconstriction
SNS may augment collateralization by
NPY
Extrinsic thrombosis
Initiated by chemical factors released by damaged tissues
Intrinsic thrombosis
Components in blood and trauma to blood or exposure to collagen
Coumarin depresses liver formation of clotting factors by blocking
Vit K
Hemophilia is
Sex linked
85% of hemophilia defect in
Factor VIII
15% hemophilia defect in
Factor IX
Without ____, blood won’t clot
Calcium
Intrinsic and extrinsic pathways of coagulation meet at formation of
Factor X
Factor V
Key step in clotting
Conversion of fibrinogen to fibrin
Clots are dissolved by ___ which is activated by ___
Plasmin
TPA
Conversion of fibrinogen to fibrin requires
Thrombin
Antiphospholipid antibody syndrome
Autoimmune
Body makes Ab against phospholipids
Causes abnormal clots
Homocysteine
AA that may irritate blood vessels, promoting atherosclerosis
Homocysteine can make blood more likely to
Clot
Homocysteine levels can be reduced by
Increasing folic acid
B6
B12
A and B antigens on RBCs are known as
Agglutinogens
O is
Functionless
Agglutinins are formed
Spontaneously
Ab titers peak at
Age 10
Hemolysis occurs to ____ in mismatched transfusion
Donors RBCs
Primary Ab in lysis of RBCs
IgM
____ most lethal effect on transfusion reaction
Kidney failure
__ from lysed RBCs precipitates and blocks renal tubules
Hemoglobin
In Rh blood types, spontaneous agglutinins _____
Never arise
Rh blood: ___ antigen MC and means you are
D antigen
Rh+
Lacking D antigen means you are
Rh-
Erythroblastosis Fetalis aka
Hemolytic Disease of newborn
Released hemoglobin is converted by ____ into ____ which can cause jaundice
Macrophages
Bilirubin
Most cases of erythroblastosis Fetalis, mother is ___, father is ___, and fetus is ___
Rh-
Rh+
Rh+
Erythroblastosis Fetalis only occurs after the ____
Initial exposure
Kernicterus
Bilirubin precipitating in neurons causing mental impairment
Prevention of erythroblastosis Fetalis
Rh immunoglobulin globulin (RhoGAM)
Anti-D antibody
Heart muscle is ___ and has 1-2 centrally located __
Striated
Nuclei
Heart muscle contains specialized ____ and ____ muscle fibers
Excitatory
Conductive
Syncytium
Many acting as one
Cardiac muscle follows “all or none” law due to presence of
Intercalated discs
Gap junctions allow flux of
Na+
Duration of action potential
.2-.3 Sec
Channels in cardiac muscle
Fast Na
Slow Ca/Na
K channels
Permeability changes in heart muscle
Na sharp increase as onset of depolarization
Ca increases during plateau
K increased during resting polarized state
Time for entire heart to depolarize
.22 sec
AV node delay
.12 seconds
Purpose of AV node delay
Allows atria to contract before ventricles
___ blocks fast Na channels
Tetradotoxin
Specialized excitatory cells only have _____
Slow Ca/Na channels
Nernst equilibrium potential
Concentration gradient favoring ion movement in one direction offset by electrical gradient
During Er, ____ are closed, ___ is open
Fast Na and slow Ca/Na
K
During Er, ___ are free to move
K ions
___ binds and inhibited Na/K ATPase pump
Digitalis
Digitalis is used to
Increase strength of contraction (make heart stronger)
If Na/K pump inhibited, more ____ allowed to accumulate and ____ increased
Ca
Contractile strength
Absolute refractory period
Unable to re-stimulate
Occurs during plateau
Relative refractory period
Requires Supra-normal stimulus
Occurs during repolarization
In slow response cardiac muscle cell, relative refractory period is ___ and refractory period is
Prolonged
25% longer
Prolonged refractory period serves to
Protect ventricles from Supra-ventricular arrhythmias
Normal pacemaker of heart
SA node
SA node is ___ due to ___
Self excitatory
Leaky membrane to Na/Ca
In SA node, only ___ are operational
Slow Ca/Na channels
SA node spontaneously ___ at fastest rate
Depolarizes
___ lacks stable resting Er
SA node
Overdrive suppression
Drive self-excitatory cell at rate faster than inherent rate, you will suppress cell’s automaticity
Cells of AV node and purkinje system are under overdrive suppression of
SA node
Function of AV node
Delays wave of depolarization from entering ventricle
In absence of SA node, ___ may act as pacemaker, but at a lower rate
AV node
As HR increases, CL
Decreases
At resting HR, systole ____ diastole
<
As HR increases, both S and D shorten, but ___ shortens to greater extent
D
During S, perfusion of myocardium is restricted by
Contracting cardiac muscle
Systole associated with
Isovolumic contraction
Isovolumic contraction means
BP increasing
Diastole associated with
Isovolumic relaxation
Isovolumic relaxation means
BP decreasing
Ventricles are sealed ___ during cardiac cycle
2X
Valves open under
Forward pressure
Valves close under
Backward pressure
End diastolic volume
Volume in ventricles at end of filling
End systolic volume
Volume in ventricles end of ejection
Stroke volume
Volume ejected by ventricles
A wave associated with
Atrial contraction
C wave associated with
Ventricular contraction
V wave associated with
Atrial filling
AV valves
Mitral and tricuspid
Semilunar valves
Aortic and pulmonary
Semilunar valves are
Stronger construction
AV valves are thin so need
Chorda Tendineae
Papillary muscles
Valvular dysfunction creates
Vibrational noise (murmurs)
Valve not opening fully
Stenotic
Heart murmur during both S and D
Patent ductus arteriosis
Combined valvular defect