Cardiovascular Flashcards
Where is the heart located?
In the media stinum between the lungs
What is the heart enclosed in?
A double walled pericardial sac
How many layers is the heart composed of; names of the layers
3 layers:
Endocardium - inner layer
Myocardium - specialized cardiac muscles
Epicardium = visceral pericardium
Epicardium
Visceral pericardium
Serous membrane with small amounts of lubricating fluid within the pericardial cavity between the membranes to facilitate heart movements
What are the AV valves; names
Valves that separate the atria from the ventricles
- Tricuspid - right
- Bicuspid - left
What are the semilunar valves; names
Prevent backflow from the arteries
- Aortic valve
- Pulmonary valve
What do arteries generally do?
Arteries and arterioles transport oxygenated blood away from the heart to the body
Which artery is the exception to normal arterial function? What does it do?
Pulmonary artery transports deoxygenated blood from the heart to the lungs to become oxygenated
What do veins generally do ?
Veins transport deoxygenated blood back to the heart to receive oxygen
Which vein is the exception to normal vein function? What does it do?
Pulmonary vein transports oxygenated blood from the lungs to the heart
Briefly describe pulmonary circulation
Exchange of gas in the lungs
Briefly describe systemic circulation
Exchange of gases, nutrients, and wastes in the tissues
Pathway of cardiopulmonary circulation
deoxygenated blood from the tissue –> returns to the heart through the inferior and superior vena cava –> right atrium –> tricuspid –> right ventricle –> pulmonary artery –> lungs –> pulmonary vein –> left atrium–> bicuspid –> left ventricle –> aorta
Systole
Contraction of myocardium
Diastole
Relaxation of myocardium
Why does the heart need constant supply of oxygen?
Because it has very little storage space
When is the blood flow to the myocardium greatest?
During diastole
How does rapid contraction impact oxygen flow?
Rapid contractions reduce oxygen flow to the heart since blood flow is greatest during diastole - if the heart is beating rapidly, diastole is reduced, thus lowering oxygen/blood flow to the heart.
The right coronary artery supplies…
- The right side of the heart
- inferior posterior left ventricle
- posterior intraventricular septum
The left anterior descending artery supplies..
- anterior wall of the ventricles
- anterior septum
- bundle branches
- circumflex artery
The circumflex artery supplies…
- left atrium
- lateral and posterior ventricles
Baroreceptors
- location
- function
Location: aortic arch and carotid sinus
Function: sensitive to stretch or pressure within the arterial system and stimulate the basal motor center to initiate a CNS response (sympathetic or parasympathetic)
Chemoreceptors
- location
- function
Location: aortic body and carotid body
Function: Recognize increased CO2 levels and stimulate the basal motor sensor to increase cardiac activity in response to the hypercapnia
What is the parasympathetic nervous system mediated by?
What is the function of the Parasympathetic Nervous System?
- Mediated by the vagus nerve
- Decreases HR rate (by slowing SA rate and AV conduction rate)
What is the Sympathetic Nervous System regulated by?
What is the function of the Sympathetic Nervous System?
- Regulated by the cardiac accelerator nerve
- Increases HR rate and force of ventricular contraction
What is the S1 sound?
“Lubb”
Closure of the AV valves
What is the S2 sound?
“Dubb”
Closure of the semilunar valves
What are murmurs caused by
Murmurs are caused by incompetent valves
What does a pulse indicate?
Pulse indicates heart rate
What is a pulse deficit?
Pulse deficit is the difference between the apical and radial pulse
Cardiac conduction - Automaticity
Automaticity = ability to discharge an electronic impulse spontaneously
Cardiac conduction - Rhythmicity
Rhythmicity = ability to generate an electrical impulse in regular intervals (pattern)
Cardiac conduction - Conductivity
Conductivity = ability to send an electrical impulse
What is the normal/basic pulse rate?
60-100 bpm
Why is there a delay in conduction at the AV node?
To allow for complete ventricular filling
Pathway of impulses
SA node (pacemaker) –> atrial conduction pathway –> AV node –> bundle of His –> bundle branches –> Purkinje fibers
What does depolarization indicate?
Contraction
What does repolarization indiate?
Relaxation
What is the P Wave initiated by?
What does the P Wave represent?
Initiated by: SA node
P Wave = atrial depolarization
What is the QRS Complex initiated by?
What does the QRS Complex represent?
Initiated by: AV node
QRS Wave = ventricular repolarization
What does the ST Segment represent?
Ventricular depolarization
aka “recovery phase”
What is the equation for Cardiac Output?
CO = HR x SV
What is cardiac output?
The amount of blood pumped by a ventricle per minute
What is heart rate?
The number of ventricular contractions per minute
What is the stroke volume?
The amount of blood ejected from a ventricle with each contraction
Would a slower heart rate increase or decrease diastolic filling time?
Slower heart rate would increase diastolic filling time.
What are some factors that increase HR?
Elevated temp (internal and environmental), exercise, stress, smoking, pregnancy, pain
Preload
The amount of work imposed on the heart before contraction (systole) begins
-It is the volume coming into the ventricles at end of diastolic
Would hypervolemia increase or decrease preload?
Hypervolemia would increase preload
Afterload
The force that blood ejected from the ventricle must overcome to circulate
-Determined by peripheral resistance to the semilunar valves
Contractility
Force of contraction
Cardiac Reserve
ability of the heart to increase output in response to increased demand
What is BP dependent on?
- Peripheral resistance
- Blood volume
- Blood viscosity
- Contraction of left ventricle
What is the equation for BP?
BP = CO x PR
Does sympathetic stimulation increase or decrease BP?
Sympathetic stimulation increases BP
-Vasoconstriction increases BP
Does local vasoconstriction or vasodilation affect BP?
No, only systemic changes affect BP
What are the receptors in the heart that are stimulated by SNS?
What do they do?
Beta-1 adrenergic receptors in the heart increase HR and force of contraction–> elevate BP
What are the receptors in the skin and viscera that are stimulated by the SNS?
What do they do?
Alpha-1 Receptors
- In the arterials in the skin an viscera
- reduce capacity of the system and increase venous return –> elevate BP
What is perfusion?
Process of the body delivering blood and oxygen through the vessel into tissue
Example of ventilation-perfusion mismatch
Pulmonary emoblism
Example of Impaired circulation
Hemorrhage, third spacing, clot (thrombus)
Example of Inadequate cardiac output
Structural defects of the heart
Example of Excessive perfusion demands
Prolonged exertion, hypermetabolic states
What is the VQ ratio?
Ventilation : Perfusion ratio
V = air that reaches alveoli Q = blood that reaches alveoli
Example of High VQ ratio
pulmonary embolism
-adequate ventilation but poor perfusion
Example of Low VQ ratio
choking
-poor ventilation but perfusion still happens
What are the components of Virchow’s Triad?
Hypercoagulability, endothelial injury, circulatory stasis
What are the general manifestations of altered perfusion? (10)
- Cyanosis - bluish discoloration from hypoxia
- Pain
- Pallor
- Coolness
- Edema
- SOB
- Tachychardia
- Tachypnea
- Fatigue
- Heart murmur
What is an ECG or EKG?
Records electrical activity of the heart
What does auscultation help detect?
Auscultation helps detect abnormalities of blood flow that cause murmurs, and checks blood pressure
What is an echocardiography?
Sonogram of the heart
-Records heart valve movement, blood flow, cardiac ouput
Exercise Stress Test
Measures heart’s response to external stress
How do chest x-rays help?
Provides imaging of the chest to help diagnose conditions
What is cardiac catherization?
Insertion of a catheter into the heart to measure pressure and assess heart function
What is an angiography?
Imaging of the blood vessels, arteries, veins, and heart chambers
-Radio-opque contrast agents are inserted to blood vessels for imaging of blood flow in the coronary arteries
Doppler Studies
Probes on the skin enable you to see peripheral vessels
What is Percutaenous Transluminal Coronary Angioplastic?
Procedure during cardiac catheterization that compresses fatty deposits in the coronary arteries and alleviates occlusion
What procedure enables bypassing of the obstructed artery?
Coronary byspass grafting
What procedure vaporizes fatty deposits with a hot-tip laser device?
Laser Angioplasty
What kind of medication is a vasodilator?
Nitroglycerin
What kind of medication is a beta-blocker (slows HR)
Metroprolol
What kind of medication is a diuretic?
Lasix
What medications help with anti-coagulation?
ASA (aspirin), heparin, coumadin
In older adults, ____ increases and _____ decreases, causing heart valves and vessels to become thick and stiff
Collagen increases and elastin decreases
In older adults, cardiac output and stroke volume ____
Cardiac output and stroke volume decrease
In older adults, the # of pacemaker cells increases or decreases?
of pacemaker cells decrease
How does the number and function of beta-adrenergic cells change in older adults?
of beta-adrenergic cells decrease, leading to decrease response to emotional stress
Arteries of older adults become more sensitive to what hormone?
How does this gerontologic change affect BP?
Arteries become more sensitive to ADH
- Leads to progressive increase in systolic blood pressure
- But none/decrease in diastolic
What is shock?
A syndrome of decreased or impaired tissue perfusion
What is low flow shock?
What are 2 types of low flow shock?
Low flow shock = decreased CO
Hypovolemic, cardiogeneic
What is distributive shock?
What are 3 types of distributive shock?
Distributive shock = normal/increased CO
Anaphylactic, septic, neurogenic
What are the main, common manifestations of shock? (3)
- Vital organs are not being perfused –> lethargy and weakness
- Ischemia of vital organs
- Not enough O2 for aerobic respiration –> anaerobic respiration –> lactic acid buildup –> metabolic acidosis
What are the early manifestations of shock?
SNS stimulation –> anxiety and restlessness
- tachycardia
- cool, pale, diaphoretic skin
- oliguria
- thirst
- tachypnea
What are progressive manifestations of shock?
Metabolic acidosis –> lethargy, weakness, faintness
-Production of bicarbonate decreases glomerular filtration rate and renal excretion of acids
What are the decompensated manifestations of shock?
Stupor Confusion Arrhythmias Weak pulse Metabolic acidosis Acute respiratory distress syndrome Multiple thrombi Acute liver failure Acute renal failure Paralytic ileus GI hemorrhage
