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