Pathology Lesson 6 Flashcards
What are five charecteristics of cardiac muscle?
- Striated
- Generally Uninucleate
- Branched
- Intercalated Discs
- Sliding Filament Mechanism
What holds the cardiac muscle together?
Desmosomes
What is a functional syncytium in a cardiac muscle?
All cells in a functional unit which contract together
What contraction characteristic is specific to pacemaker cells?
Automaticity
Does cardiac contration have a long or short refractory period?
Long
What are the three stages of cardiac contraction?
- Depolarization
- Plateau
- Repolarization
Cardiac or skeletal:
AP: 1-5 MS
Skeletal
Cardiac or skeletal:
Contract: 200 MS
Cardiac
Cardiac or skeletal:
AP: 200 MS
Cardiac
Cardiac or skeletal:
Contract: 15-100 MS
Skeletal
True or false:
Pacemaker cells have a resting potential.
False
(They have no resting potential)
With pacemaker cells, there is a cycle between ________ and ______.
Drift
Fire
There is a drift due a changing permeability in what?
K+
What are four components of the structural support and circulation of cardiac anatomy?
- Chamber walls
- Fibrous skeleton
- Valves
- Great vessels
How does the heart get its oxygen?
Choose all that apply:
- marginal artery
- right coronary artery
- inferior vena cava
- ligamentum arteriosum
Marginal artery
Right coronary artery
(Part of the coronary circulation)
What stimulates and controls heart action?
intrinsic conduction system and nerves
What ventricle has a higher muscle mass?
Left ventricle
How are cardiac muscles packaged?
In bundles
Does cardiac muscle have:
- a lot of mitochondria
- a little mitochondria
- no mitochondria
A lot of mitochondria
Name the arteries of coronary circulation.
- Left coronary artery
- Circumflex artery
- Anterior interventricular artery
- Right coronary artery
- Marginal
What are the five steps of conduction?
- SA node (pacemaker)
- Atroventricular node
- Atrioventricular bundle (Bundle of His)
- Bundle branches
- Purkinje fibers
In the sequence of exitation of the heart, what happens when SA node generates impulse?
Artial excitation begins
In the sequence of exitation of the heart, where are impulses delayed?
AV node
In the sequence of exitation of the heart, what happens when an impulse passes to the heart apex?
Ventricular excitation begins
In the sequence of exitation of the heart, what does the impulse need to reach in order for ventricular excitation to be complete?
Purkinje fibers, BITCHES!!!
What are the only arteries, in the whole body, that carry deoxygenated blood?
Right and left pulmonary arteries
Name the flow of the blood starting from the superior and inferior vena cavae including valves.
- Inferior / Superior Vena Cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary semilunar valve
- Right / left pulmonary arteries
- Lungs
- Pulmonary veins
- Left atrium
- Mitral valve
- Left ventricle
- Aortic semilunar valve
- Systemic circulation
What are the only veins with oxygenated blood?
Pulmonary veins
What does the heart sit in?
Pericardial sac
What part of the heart can palpated in order to test for size and position?
Apex
What are the five stages of the heart cycle?
- Late diastole
- Atrial systole
- Isovolumic ventricular contraction
- Ventricular ejection
- Ventricular relaxation
What happens during late diastole?
All chambers relax, filling with blood
What happens during atrial systole?
Atria contract, add 20% more blood to ventricles
Where would afibrillation take place?
Atrial systole
(Not life threatening but can cause clots)
What happens during isovolumic ventricular contraction?
AV valves close, builds pressure
(“lub”)
What happens during ventricular ejection?
The semi lunar valves are pushed open and blood is forced out
What happens during ventricular relaxation?
- Aortic back flow slams semi lunar valves shut (“dup”)
- AV valves open, refilling starts
When the atrioventricular valve is open, the pressure in the atrium is greater than or less than the ventricle?
Greater than
When the atrioventricular valve is closed, the pressure in the atrium is greater than or less than the ventricle?
Less than
When the aortic valve is open, the pressure in the ventricle is greater than or less than the aorta?
Greater than
When the aortic valve is closed, the pressure in the ventricle is greater than or less than the aorta?
Less than
Other than the “lub dub” sounds, what other kinds of sounds can you hear pertaining to the heart?
Murmurs
What are three types of murmurs?
- Blowing
- Crescendo
- Decrescendo
What are three major questions you could ask while examining a heart murmur?
- How long is the murmur lasting?
- Is it whole systole?
- Is it whole diastole?
- Where do you hear it loudest?
- What is the intensity?
What are four factors of cardiac performance?
- Preload
- Afterload
- Contractility
- Heart Rate
In cardiac performance, what is preload?
The pressure generated at the end of diastole
In cardiac performance, what is afterload?
Resistance to ejection during systole
In cardiac performance, what is contractility?
Variable shortening in response to stimuli
What is the Frank-Starling Law?
The heart will increase contractility to pump as much blood as the ventricle is presented with, up to a limit.
What does the amount of tension generated in the wall of the ventricle to produce certain pressue depend on? What is the name of this law?
- Radius and wall thicknes
- LaPlace’s Law
What is the normal range of the heart heart?
about 50 - near 200
What is the typical resting heart rate?
near 70
What slows the heart rate? What increases it?
- Parasympathetic slows
- Sympathetic increases
Where are the three places blood is contained? And what are the percentages?
- Heart, arterioles, and arteries (25%)
- Capillaries and Pulmonaries (15%)
- Venous system (60%)
What is the definition for cardiac output?
What is the formula for it?
The amount of blood that is pumped out in a minute.
HR (heart rate) x SV (stroke volume)
What is the normal value for cardiac output?
Around 5L
(72 beats/m x 70 ml/beat = 5040 ml)
What is the definition of heart rate?
Beats per minute
What is residual volume? What is the normal percentage?
- The amount of blood that remains in the heart after a contraction.
- about 50%
What are three factors that influence the stroke volume?
- Starling’s Law - how much stress the heart can have
- Force of contraction
- Venous return
- Skeletal pumping
- Respiratory pumping
True or false:
You will not have pulsations in veins.
True
What are Korotkoff sounds?
Created by pulsatile blood flow (turbulence) through the compressed artery.
(Systolic)
What is laminar flow?
The absence of sound. (Diastolic)
What are baroreceptor mechanisms and where are the two places they are located?
- Respond to changes in smooth muscle fiber length
- Aorta and Carotic sinus
What are arterial chemoreceptors and where are they located?
- Transmit impulses to medullary cardovascular control center / dectect O2 concentration, pH, CO2
- Aorta, carotid arteries
What are four things that determine mean arterial blood pressure?
- Blood volume
- Effectiveness of the heart as a pump (CO)
- Resistance of system to blood flow
- Relative distribution of blood between arteries and veins
What is the flow rate of the blood?
Change in pressure divided by resistance
What creates resistance?
- Blood viscosity
- Total blood vessel length
- Vessel diameter
- Turbulent flow
What are five characteristics of venous flow?
- Distensible
- Low pressure, low resistance
- One-way valves
- Skeletal contraction “pump”
- Affected by respiration
What are three characteristics of capillaries?
- Site of exchange of nutrients, oxygen, and wastes
- Slow intermittent flows
- Autoregulation by capillary sphincters
What are five kinds of heart murmurs?
- Aortic stenosis
- Mitral stenosis
- Aortic regurgitation
- Mitral regurgitation
- Mitral valve prolaps
What is colloid osmotic pressure?
Pulls fluid back into the capillary
Shlomo, name 11 tests for cardiac function.
- Physical examination
- EKG
- Echocardiogram
- Doppler Studies
- Stress Test
- CXR
- MRI
- CT
- Nuclear Imaging
- Cardiac Catheterization
- Cardiac Angiogram
What is an aneurysm?
Localized blood-filled dilation (bulge) of a blood vessel.
What is an aneurysm caused by?
Disease or weakening or vessel wall (Hypertension / Atherosclerosis)
What are the common sites for an aneurysm?
- Aorta
- Circle of Willis (arteries at base of brain)
What are the four kinds of aneurysms?
- Fusiform, cirumferential
- Fusiform, sacular
- False
- Dissecting, secular
Why is a false aneurysm considered false?
Because a clot formed to plug a gap in the vessel creating a bulge that looks like an aneurysm.
What is a dissecting anuerysm?
Tear of inner wall with extravascular hematoma
Why are there complications with an aneurysm in the adominal aorta?
- No surrounding muscles
- Clinically may find pulsating mass (>4cm)
- Risk of rupture increases with increasing size
What is an echocardiogram?
Assess both heart structure and function
What does an electrocardiogram measure?
- Ventricular dimensions
- Valve and wall movements
- Blood movement and ejection fraction
What does an electrocardiogram record and where does it record from?
- Sum of action potentials
- From the skin surface
What does the P wave represent on an electrocardiogram?
Atrial depolarization
On an electrocardiogram, what does the QRS complex represent?
Ventricular depolarization
On an electrocardiogram, what does the T wave represent?
Ventricular depolarization
Why cannot you not see atrial depolarization on an EKG?
It is buried within the QRS complex
Each EKG lead has a different _______ of the heart.
view
On an EKG, what does depolarization towards a positive lead mean?
Upward deflection
What is the vector in an EKG?
When the chest leads gradually change from negative to positive.
(The net movement / the main point)
What do intervals and segments on an EKG demonstrate?
The heart’s efficiency at conduction impulses down the pathway
What does the P-R interval measure and what does it reflect?
- Measured from beginning of P to beginning of QRS
- Reflects the normal delay of conduction at the AV node
What does the Q-T interval measure and what does it reflect?
- Measured from beginning of QRS to end of T wave
- Reflects the critical timing of repolarization of the ventricles
What does the S-T segment represent?
Flat line between QRS complex and T wave
What might a S-T depression indicate?
Ischemia
What might a S-T elevation indicate?
Infarction
During an electrocardiogram, where are electrodes placed?
Different locations on the chest
What does the cardiac cycle include?
All cardiac events occurring during one single heartbeat
What are the two parts of the cardiac cycle?
- Systole
- Diastole
The EKG records ________ and _______ ______ it takes for each part of the cardiac cycle to occur.
- Intensity
- Cardiac cycle
How many leads are there in an EKG?
12
What are the six frontal plane leads?
- Lead I
- Lead II
- Lead III
- AVR
- AVL
- AVF
What are the six precordial (chest) leads?
V-1 through V-6
On an EKG, what kind of line is recorded when no electrical impulse is sensed?
Isoelectric (Flat line)
On an EKG, what happens when an electrical impulse is sensed?
There is an upward or downward reflection
In an EKG, what determines the size of the deflection?
Strength of electrical impulse
How large are the very small squares on the EKG paper?
1 mm long and 1 mm high
On EKG paper, how many small squares are there between the heavy black lines?
Five
On EKG paper, how many small squares are there in one big sqaure?
Five
On EKG paper, how much time is represented by the distance between heavy black lines?
0.2 seconds
On EKG paper, how much time is represented by each small square?
0.04 seconds
On EKG paper, how much time is represented by three small squares?
0.12 seconds
How long seconds is the normal P-R interval?
What should it be less than?
between 0.12 and 0.20 seconds
< 0.2 seconds
How long (in seconds) is the normal QRS complex or how many squares should it take up?
< 0.12 seconds
3 small squares
What is normal sinus rhythm (NSR)?
Regular heart rate that falls between 60 to 80 beats / min
Shlomo, what are eleven abnormalities caused by cardiac pathology?
- Sinus tachycardia
- Sinus bradycardia
- Ventricular tachycardia
- Vantricular fibrillation
- Premature atrial contractions (PACs)
- Premature ventricular contractions (PVCs)
- Paroxysmal atrial tachycardia (PAT)
- Atrial flutter
- Atrial fibrillation
- AV heart block
- Myocardial Infarction (MI)
Cardiac arrhythmias may be due to what four things?
- Damage to myocardium
- Injuries to pacemaker or conduction pathways
- Exposure to drugs
- Variations in electrolyte concentrations
What are two types of atrial arrhythmias?
- Premature atrial contraction (PAC)
- Atrial flutter
What are two types of ventricular arrhythmias?
- Premature ventricular contraction (PVC)
- Ventricular fibrilliation
What are five characteristics of satisfactory tracings on an EKG?
- Accurate
- Readable
- Clear
- Travels down the center of the page
- A consistently horizontal baseline
What is an artifact?
Electrical activity from a source other than the heart that the sensors detect.
↓↓
Can impari accurate interpretation of the tracings
What are four causes of artifact?
- Somatic tremors
- Patient moving or talking
- Wandering baseline and baseline shifts
- AC interference
What drives perfusion?
Aortic pressure
What is autoregulation?
Metabolic need met through release of vasoactive mediators by endothelium
What two things are controlled through autonomic regulation?
- Heart rate
- Cardiac contractility
List the steps that lead to myocardial infarction.
Coronary artery disease (CAD)
↓
Myocardial Ischemia
↓
Myocardial infarction (MI)
What disease is linked to atherosclerosis?
Dyslipidemia
What percentage of the arteries need to be narrowed to be considered coronary artery disease?
> 50%
(deacreased cellular metabolism)
What are eleven cardiovascular risk factors?
- Dyslipidemia
- Hypertension
- Sedentary Lifestyly (most in the US now)
- Obesity
- Genetic predisposition
- Smoking
- Diabetes
- Hyperhomocysteinemia
- Aging
- Male
- Psychological factors
What are two psychological cardiovascular risk factors?
- Hostility
- Social isolation
What is arteriosclerosis?
Abnormal thickening and hardening of vessel walls
What is atherosclerosis?
Form of arteriosclerosis where there are deposits of fat and fibrin
What is the leading contributor to CAD and Cerebrovascular disease?
Atherosclerosis
What are four different types of atherosclerosis?
- Damaged endothelium
- Fatty streak
- Fibrous plaque
- Complicated lesion
What are the five most common locations for atherosclerosis?
- Abdominal aorta
- Coronary arteries
- Thoracic aorta, femoral, and popliteal arteries
- Internal carotid arteries
- Vertebral, basilar, middle cerebral arteries
What are four lipoproteins?
- Lipids
- Phospolipids
- Cholesterol
- Triglycerides
The liver packages cholesterol with triglycerides (fat) and sends them into the bloodstream as what?
Very Low-Density Lipoproteins (VLDLs)
As VLDLs travel through the bloodstream, they are broken down into triglycerides (fat) and cholesterol-rich what?
Low-density Lipoproteins
What organ regulates the body’s production of cholesterol?
Liver
What do high LDL levels cause?
An excess of cholesterol to be delivered to cells
What happens to cholesterol not used by the cells?
They spill out and collect on artery walls
What do high-density lipoproteins (HDLs) do?
Seek out excess cholesterol, reducing the amount available for builup on artery walls.
They then bring the cholesterol back to the liver where it is converted into bile acids for elimination or recycling.
High levels of what can help reverse heart disease?
HDL
What are five functions of HDL?
- Bring excess cholesterol back to liver
- Inhibit smooth muscle proliferation
- Stimulate endothelial repai
- Stimulate vasodilator prostaglandins
- Facilitate fibrinolysis
What is a thrombus?
Blood clot attached to vessel wall
What is an embolism?
Obstruction of vessel by embolus (circulation bolus of matter)
What is a thromboembolism?
Vascular obstruction by dislodged thrombus
What are the three stages of hypertension?
- Mild
- Moderate
- Severe
What are four causes of secondary hypertension?
- Renal artery stenosis
- Hyperthyroidism
- Coarctation of the aorta
- Pheochromocytoma
In 2007, how many cases of heart failure were there in the US?
about 5 million
What is systolic failure of the heart?
Decrease in myocardial contractility, impaired ability to ject blood from ventricle
=
low ejection fraction (EF)
(percentage different than amount)
What is diastolic failure?
Abnormality in ventricular relaxation and filling
=
normal EF (ejection fraction)
(decrease stroke volume and cardiac output)
What can left heart failure cause?
Pulmonary edema / orthopnea
What can right heart failure cause?
- Congestion of peripheral tissues
- Edema / Ascites / Liver congestion
In circulatory shock, where is the ultimate effect?
At the cellular level
What compensatory mechanisms, due to circulatory shock, can have a detrimental effect over a long term?
- Vasoconstriciton
- Decreased Oxygen
A long term of vasoconstriction can equal what?
Decreased tissue perfusion
A long term of decreased oxygen can lead to what?
Cellular metabolism impaired
↓
Excessive lactic acid and free radical formation
↓
Increased acidity
↓
Cell dysfunction or death
What does cardiogenic shock lead to?
Myocardial infarction (MI)
Fill in the blank:
Chemoreceptors are activated by decrease in blood pH
↓
Activation of respiratory centers
↓
______________________
↓
CO2 blown off: blood pH rises
Increase in the rate and depth of breathing
Fill in the blank:
Sympathetic nervous system activated
↓
Increase in heart rate
↓
_______________________
Tachycardia, weak, thready pulse
Fill in the blank:
Sympathetic nervous system activated
↓
Intense vasoconstriction (only heart and brain spared)
↓
______________________
Skin becomes cold, clammy, and cyanotic
Fill in the blank:
Hypothalamus activated (by decrease in pH and decrease in blood volume)
↓
_________
Thirst
Fill in the blank:
Neurons depress by decrease in pH
↓
___________________
↓
Central nervous system depressed
__________________
Restlessness (early sign)
Come (late sign)
Fill in the blank:
Hypothalamus activated (by decrease in pH and decrease in blood volume)
↓
ADH released which targets kidneys
↓
Water retention
↓
______________
decrease in urine output
What two hormones lead to a decrease in urine output?
Aldesterone (from Adrenal Cortex) –> Kidneys retain salt and water
ADH (targets kidney) –> Water retention
What three things lead to blood pessure being maintained?
- Systemic nervous system being activated
- Intense vasoconstriction (only heart and brain spared)
- Increased blood volume
