Cardio Exam 4 Flashcards
What do these parts do in the cardiovascular system: heart, blood vessels, blood, oxygenated and deoxygenated blood
heart: pump blood
blood vessels: plumbing
blood: carrier vehicle
oxygenated blood -> transport O2 and nutrients
deoxygenated blood -> remove CO2 and other waste products
Location of the heart
Between two hard surfaces which is good for CPR
Size of your fist
What are the four chambers of the heart
Right upper chamber -> right atrium
Left upper chamber -> left atrium
Right lower chamber -> right ventricle
Left lower chamber -> left ventricle
What is the main function of the upper and lower chambers
Upper chambers receive blood and pass it to lower chambers
Lower chambers eject blood from heart
Normally no blood flow between two atria or two ventricles
How does the right atrium receive and pass blood
Receives deoxygenated blood from superior vena cava, inferior vena cava, and coronary circulation
Passes venous blood to right ventricle
How does the right ventricle send blood
Sends deoxygenated blood to the lungs for oxygenation
Blood leaves the right ventricle for the lungs
Blood leaves via arteries
These are the only arteries that carry deoxygenated blood (only exception)
Blood leaves the heart using the __________ system
arterial
Deoxygenated blood LEAVES right side if heart through what,
superior vena cava: upper
inferior vena cava: lower
coronary circulation: blood from heart as organ
right pulmonary arteries: pulmonary arteries and capillaries of lung
Oxygenated blood LEAVES left side of heart
Ascending: head and upper limbs
Descending: trunk and lower limbs
Oxygenated blood enters left atrium and then left ventricle: left atrium receive and pass blood
Blood from lungs enter atrium via left & right pulmonary veins
Veins carry oxygenated blood (only exception to veins)
Oxygenated blood leaves the left ventricle for organs
Leaves via aorta (large artery)
Thicker wall than left side of heart (transport farther so needs to be thicker)
Oxygenated blood flow THROUGH left side of heart
Ascending aorta, descending aorta, left pulmonary arteries
Chambers fill with blood during diastole
Chambers are relaxed
Chambers pump blood during systole
Chambers contract
Eject blood
-right ventricle blood goes to pulmonary artery
-left ventricle blood goes to aorta
Where are the outflow (semilunar) valve and atrioventricular valve located
outflow (semilunar): entrance leading to pulmonary or systemic circulation
atrioventricular: entrance to ventricles
Atrioventricular valves: tricuspid and mitral (bicuspid)
How does the valve open and close
Right: tricuspid valve -> between right atrium and right ventricle
Left: mitral (bicuspid) valve -> between left atrium and left ventricle
Prevents backflow of blood
Atrium contracts and ventricle relaxes -> valve opens
Increased pressure in ventricle closes the valve
How does the atrioventricular valve open and close
Atrium contracts and ventricle relaxes -> valve opens
Increased pressure in ventricle closes the valve
Outflow (semilunar) valve: pulmonary and aortic
Pulmonary (right):
-between ventricles and pulmonary artery
-opens pulmonary trunk
-prevents backflow of blood into right ventricle
Aortic (left)
-between left ventricle and aorta
-opens into aortic arch
-prevents backflow of blood into left ventricle
How does the outflow (semilunar) valve open and close
left ventricle contracts -> mitral valve closes -> arotic valve opens -> blood flow into aorta
Ventricle relaxes -> blood flow back from artery -> valve closes
What is stenosis
Narrowing of the heart valve opening -> restriction of blood flow
cause: genetic, rheumatic fever
treatment: valve repair or valve replacement
What is mitral valve prolapse
Backflow of blood from the left ventricle into the left atrium
Cause: genetic, rheumatic fever, infection, age
Treatment: valve repair or replacement
What are the three circulatory processes in the body
Pulmonary, Coronary, Systemic Circuit
The right-sided pulmonary circulation
Deoxygenated blood is pumped to the lung to be oxygenated -> oxygenated blood returns to the heart
The left-sided systemic circulation
Oxygenated blood is pumped from the left side of the heart to tissues and cells in the body
What are the steps of the pulmonary and systemic circulation starting at right atrium
Right atrium
Right ventricle
Pulmonary trunk and arteries
Pulmonary capillaries lose CO2 gain O2
Pulmonary veins
Left atrium
Left ventricle
Aorta
Systemic capillaries lose O2 gain CO2
Superior vena cave
Inferior vena cava
Coronary sinus
Coronary Arteries
-Deliver oxygenated blood and nutrients to the heart muscle (myocardium)
-Blood flows from aorta to the right and left coronary arteries -> into arterioles and capillaries
—-During ventricular diastole (relaxation)
Coronary Veins
-Drain the deoxygenated blood away from the myocardium
-Collect deoxygenated blood into the coronary sinus
Myocardial Ischemia
-Heart muscle is not getting enough oxygenated blood
Cause: Narrowed coronary arteries
Risks: age, smoking, high cholesterol levels, hypertension
Which structure in the atria and ventricles does the blood pumping action
Muscle
What are the three layers of the heart
Epicardium:
Protective layer
Myocardium:
Cardiac Muscle, pumping action, 95% of heart wall
Endocardium:
smooth lining for heart chambers, minimizes the surface friction when blood passes through the heart
Muscle in atria and ventricles
Muscle cells known cardiomyocytes (need to be activated before contraction)
Conduction cells aka Pacemaker cells activate cardiomyocytes
What are the two systems working together for the heart to function
Conduction system -> pacemaker cells
Contraction system -> cardiomyocytes
What are the four different stages in cardiac conduction and contraction
1: Cell #1 from conduction system spread a stimulus across the atrium
2: atrium contracts and cells #2 from the conduction system picks up stimulus, cells #2 send stimulus down to Cell #3 from conduction system
3: Cells #3 from conduction system move the signal down to Cells #4 from conduction system
4: Cells #4 from the conduction system spread stimulus across ventricle, ventricles contract
What cells set the heartbeat, initiate/distribute electrical impulses, activate muscle cells, and do not contract
Cells in the conduction system (Sinoatrial node, atrioventricular node, atrioventricular bundle or Bundle of His, Purkinje fibers)
Sinoatrial node (SA)
Spontaneously depolarize most frequently
Known as natural pacemaker cells
Do not have stable resting membrane potential
Artioventrucular node (AV)
Specialized cells at the junction between atria and ventricles
Signal has a short delay in AV node
Artioventricular bundle (AV) or bundle of His
Conducts impulses from the atria to the ventricles
Conducts impulses through the interventricular septum
Right and left branches
Purkinje fibers
Distribute impulse through the ventricles
Pacemaker cells generate action potentials at different rates. What is the fastest cell
SA node (70-80)
*Like a train fastest needs to be first
What are the three phases of the action potential of pacemaker cells in the conduction system
Phase 4 - spontaneous depolarization
Phase 0 - Depolarization
Phase 3 - Reploarization
*they have unstable resting membrane potentials
Phase 4 spontaneous depolarization what are the three channels that open
Slow Na+ channels open (-60mv) -> Na+ in -> If (funny) -> activated by hyperpolarization (K+ efflux)
T-Type (transient) Ca2+ channels open (-55 to -50) further depolarization
L-type (long lasting) Ca2+ channels open (-40 mv) further depolarization
Phase 0 depolarization in pacemaker cells
Depolarization -> action potential
Ca2+ in
L-type Ca2+ channels open
phase is activated at threshold
Phase 3 repolarization in pacemaker cells
Open K+ channels
Inactivate L-type Ca2+ channels
Membrane potential becomes negative
*ion concentrations need to go back to initial concentrations
Altered normal automaticity
Occur in SA node, AV node, His-Purkinje system
Altered by ANS
-parasympathetic stimulation -> lower heart rate
-sympathetic stimulation -> increases heart rate
Regulation of Cardiac Conduction: ANS
Phase 4 slope dictates the rate of depolarization and the heart rate
Acetylcholine -> decreases heart rate
NE and E -> increases heart rate
Parasympathetic effects in cardiac conduction
-Decrease rate of spontaneous depolarization from SA node
-Activate K+ channels by beta-gamma subunits
-Increase in repolarizing K+ current (hyperpolarization, longer to reach threshold)
-Decreases heart rate
Sympathetic Stimulation effects in cardiac conduction
-Increases phase 4 slope (less time to reach threshold)
-Pacemaker rate increases, K+ current decreases
-Phosphorylation of L-type Ca2+ & slow Na+ channels
-Increase activity of both channels
-Pacemaker cells depolarize faster
Steps in how the node initiates action potential in cardiac conduction and contraction
- SA node activity and atrial activation begin
- Stimulus spreads across the atrium and reaches the AV node
- Impulse travels through AV bundle to Purkinje fibers & heart apex
- Purkinje fibers distribute impulse to ventricular myocardium
Atrial contraction is completed and ventricular begins - blood pumped out.
Action potential in contractile muscle fibers
-Action potential initiated by SA node travels along conduction system and excite the atrial and ventricular contractile muscle cells or cardiomyocytes
-Muscle cells get activated producing an action potential -> muscle contraction
What are the 5 stages in cardiomyocytes action potential
Phase 0: Depolarzation
Phase 1: Transient Repolarization
Phase 2: Plateau
Phase 3: Repolarization
Phase 4: Resting membrane potential
*cardiomyocytes have stable resting membrane potential
What do Phase 0, 1, and 2 do for action potential in cardiomyocytes
Phase 0: Na+ into cell, producing FAST channels
Phase 1: K+ out by opening some transient K+ channels
Phase 2: Plateau: Ca2+ enters, at same rate K+ leaves
What do Phase 3 and 4 do for action potential in cardiomyocytes
Phase 3: K+ out (Ca2+ and K+ transient channels close)
Phase 4: Resting membrane channel reestablished
Contraction and Refractory period in cardiomyocytes
Contraction: Electrical activity (action potential) leads to the mechanical response (contraction) - needs Ca2+ to contract
Refractory Period: second contraction can not occur (lasts longer than contraction itself, only contracts when relaxed)
Where are contractile cells found and how are they activated
Found in atria and ventricles
Activated by action potential generated by pacemaker cells
Coordinating Contractions: Atrial Contraction
Atrial muscle contracts as a single unit to force blood down into the ventricles
Action Potential is required to initiate contraction
Contract as a unit
Coordinating Contractions: Ventricular Ejection
Ventricular muscle starts contracting at the apex, squeezing blood upward to exit the outflow tracts
Cardiac Muscle Myocardium: Intercalated disc and function
Intercalated Disc: connects ends of cardiac fibers to neighbor fibrin
Function: Electrical connection between cells, contains desmosomes and gap junctions
How is cardiac muscle like and unlike skeletal muscle
Like: is striated
Unlike: fibers are shorter and the fibers branch
Desmosomes in cardiac muscle
Hold muscle fibers together
Molecular complexes -> cell-to-cell adhesion, allow the force created in one cell to be transmitted to adjacent cells
Gap Junctions in cardiac muscle
-Intercellular channels
-Allow direct movement of ions from cell to cell
-Muscle action potential is conducted from one muscle fiber to other
-Allow for atrial or ventricular myocardium to contract as a single unit
What is an electrocardiogram
A recording of electrical events in the heart, obtained by electrodes in body locations (looks at action potentials)
ECG Waves and Traces
Pattern has three distinct waves in each heartbeat
First half is related to the atria and the second half is ventricles
What is the P wave, QRS complex, and T wave
P wave: atrial depolarization (small wave because mass is smaller than ventricle)
QRS: Ventricular depolarization
T wave: ventricular repolarization
No waves for SA (small) depolarization and atrial repolarization (masked by QRS)
What is the PR interval, PR segment, ST segment, and QT interval
PR interval: Time between onset of atrial depolarization and ventricular depolarization
PR segment: AV nodal delay to allow filling of ventricles
ST segment: Ventricles are depolarized (ventricle contract)
QT Interval: Time from the beginning of ventricular depolarization to the end of ventricular repolarization
PR and QT intervals shorten with increased heart rate
What are the steps of correlation of ECG with Cardiac Cycle
1: Depolarization of atrial contractile fibers produces P wave
2: Atrial systole (contraction)
3: Depolarization of ventricular contractile fibers produces QRS complex
4: Ventricular Systole (contraction)
5: Repolarization of ventricular contractile fibers produces T wave
6: Ventricular diastole (relaxation)
What is EDV and ESV
End-diastolic Volume: amount of blood in a ventricle at the end of ventricular diastole
End-systolic Volume: amount of blood that remains in the ventricle at the end of systole
What is SV
Stroke volume: Volume ejected from left and right ventricle every beat
Mostly associated with left side of heart
Blood ejected by the left ventricle in one contraction
Cardiac Output (CO)
Volume ejected from left ventricle into the aorta or from the right ventricle into the pulmonary trunk each minute
CO = Stroke Volume * Heart Rate
What are the two factors that can change the cardiac output
Stroke Volume: preload, afterload, contractility
Heart Rate: ANS, hormones from adrenal medulla
Preload
Degree of ventricular stretching during ventricular diastole
Proportional to ventricular filling before contraction -> EDV
What are the two factors in EDV
Filling Time: duration of ventricular diastole
Venous Return: flow of blood returned to the heart from systemic circulation
Frank-Starling Law
Describes the relationship between EDV and stroke volume -> heart can change its force of contraction and stroke volume in response to changes in EDV
Contractility
Myocardial contractility (inotropy) is the strength of contraction at any given preload
Increased Contractility -> increased ejection fraction -> increased stroke volume (more blood pumped out)
Decrease ESV or volume left in the ventricle after contraction
What are the factors regulating contractility
Circulating hormones: E, NE, thyroid
Increasing heart rate
Sympathetic Activation: NE
Parasympathetic Inhibition: inhibit Ach
Pharmacy Drugs: Positive ionotropic drugs, stimulate B receptors
Increasing contractility is important during exercise
Afterload: Left and Right ventricles
Pressure that must be overcome before a semilunar valve can open
Right Ventricle: pulmonary arterial pressure must be overcome
Left Ventricle: Aortic Arterial Pressure must be overcome (greater afterload than right)
What happens if you increase afterload
Increased afterload -> increased work by the heart
Causes hypertension
Stroke volume decreases (more blood remains in the ventricles)
Vasculature
Vessels taking blood from the heart (arterial system) and vessels taking blood back to the heart (venous system)
capillaries in the middle of two systems
Tunica Interna (blood vessels)
Direct contact with blood, diffusion of materials
Tunica Media (blood vessels)
Regulates lumen diameter by sympathetic innervation (regulate blood pressure and flow)
Elastic fibers that causes stretching
Smooth muscle
Tunica Externa (blood vessels)
Anchor vessels to tissues, supply wall with nerves and tiny blood vessels
Types of Arteries: Elastic Artery
AKA: conducting arteries
Large vessels
Tunica media elastic fibers, few muscle cells
propel blood while ventricles relax
Types of Arteries: Muscular Artery
AKA distribution arteries
Medium sized vessels
Tunica Media Muscle cells, thick walls
Vasoconstriction and vasodilation
Types of Arteries: Arteriole
Smallest
Little/no tunica externa
deliver blood to capillaries
regulate blood flow to capillaries
sympathetic nerves
Arterioles: sympathetic control, endocrine control, pharmacological control
Sympathetic control: innervated by sympathetic nervous system only -> vasoconstriction
Endocrine control: E secreted by adrenal medulla causes vasoconstriction
Pharmacological control: Drugs target muscular contraction causing relaxation
*Can change size to regulate blood flow
Capillaries
Smallest and most numerous of blood vessels
Connect vessels that carry and return blood
*Exchange nutrients and waste between blood and tissue cells
NOT innervated by ANS
Venous System
Return blood to heart
Veins and venules have thinner and less rigid walls
Less smooth muscle and connective tissue
*Larger than arteries
*Operate at lower blood pressure
Have valves
Function of valves in venous system
Folds of tunica intima forming flap cusps
Valves keep blood flowing only one direction
Prevent blood from flowing backward
BP in Arteries and Veins
Pressure higher in arteries than veins
Larger arteries and veins have more BP
What does the blood pressure numbers mean
Higher pressure during left ventricular contraction when aortic valve is open (120) - systolic
Lower pressure during left ventricular relaxation when aortic valve is closed (80) - diastolic
Hypertension
An elevated systolic blood pressure, an elevated diastolic blood pressure, or both
Hypotension leading to hypo-perfusion
Low blood pressure
Hypo-perfusion results in shock
Factors affecting blood pressure (increasing)
Increase blood volume
Increase cardiac output
Increase blood viscosity
Increase Peripheral Resistance (friction between blood and wall of vessels, length and diameter)
Regulation of blood pressure: short term and long term
Short Term: Reflex control, ANS, Endocrine system
Long Term: Endocrine system
Long-Term Regulation of Blood Pressure
Endocrine System:
Renin-angiotenisin-aldosterone
Vasopressin (ADH) - antidiuretic hormone
Atrial natriuretic peptides
Erythropoietin (EPO)
Effects blood volume which affects pressure
Renin-Angiotension-Aldosterone System and Vasopressin Mechanism
Aldosterone: Angiotension II -> Adrenal Cortex -> Increase aldosterone -> Increased Na+ and water reabosrbtion -> BP Increase
Vasopressin: ADH released from posterior pituitary -> kidney water uptake, sweat gland decrease, arterioles constrict -> Increase BP
Natriuretic Peptide Mechanism
ANP (atrial natriuretic) in atria and BNP (brain type) in ventricles -> opposite system of Aldosterone system
Increase rate of kidney and decrease renin release -> decrease BP
Erythropoietin affecting BP
Produced by kidney -> form RBC -> increase blood viscosity
Vasoconstriction -> increase BP
Blood Pressure short term regulation: reflex control and endocrine system
Reflex Control:
Baroreceptor Reflexes - respond to stretch of blood vessels
Chemoreceptor - respond to decreased O2, high CO2, or low pH
Endocrine system:
Sympathetic Stimulation - release of E and NE from adrenal medulla
Baroreceptor Reflexes: Results of BP change and the CV center
Changes in BP result in changes in vasoconstriction, heart rate, and stroke volume
CV center: decreased parasympathetic stimulation, increased sympathetic stimulation
Reflexes regulated through a negative feedback loop
Chemoreceptor Reflex Control of BP
1) aortic bodies monitor O2, CO2, and pH
2) medulla oblongata monitor CO2 and pH
3) decreased blood O2 and pH, increased CO2, decrease parasympathetic system: increases heart rate, force of
contraction, and vasoconstriction
