Cardiovascular System Pt.1 Flashcards
Cardiovascular system is made up of…
Heart, blood vessels, & Blood
[heart pumps blood into blood vessels throughout the body]
Heart
(Shape and location)
🔸️cone-shaped organ
🔸️located slightly to the left side in the thoracic cavity
(in mediastinum)
🔸️rests on the diaphragm
🔸️Apex
Apex of the heart is…
🔸️Inferior aspect
🔸️The point of the heart
🔸️Left ventricle
What is mediastinum?
a central compartment in the thoracic cavity that houses various organs and structures.
Chambers of the heart are?
RA (right atrium) superior
LA (left atrium) superior
RV (right ventricle) inferior
LV (left ventricle) inferior
Atrioventricular sulcus
- external indentation between the atria and ventricles
Interventricular sulcus
- external depression between RV and LV
Veins
- carry blood to heart
Arteries
carry blood away from the heart
Great vessels
(Definition)
main veins and arteries that bring blood to and from heart
What are the 5 greater vessels?
🔸️SVC -Superior Vena Cava
🔸️IVC -Inferior vena Cava
🔸️pulmonary V (veins)
🔸️pulmonary A (artery)
🔸️aorta
SVC -Superior Vena Cava
Carries deoxygenated blood from the upper body to the right atrium
Inferior vena cava:
Carries deoxygenated blood from the lower body to the right atrium
Pulmonary artery:
Carries deoxygenated blood from the right ventricle to the lungs
Pulmonary veins:
Carry oxygenated blood from the lungs to the left atrium
Aorta:
The largest artery in the body, carrying oxygenated blood from the left ventricle to the rest of the body
Pulmonary circuit:
Right side of heart (pulmonary pump) pumps blood to lungs
Pulmonary arteries
deliver oxygen-poor (deoxygenated) blood to lungs
Gas exchange
between alveoli and pulmonary capillaries
Alveoli
tiny, balloon-shaped air sacs located at the end of the bronchioles in the lungs
pulmonary capillaries
tiny blood vessels located in the lungs that facilitate gas exchange between the bloodstream and the alveoli (air sacs).
Pulmonary veins
deliver oxygen-rich (oxygenated) blood to the left side of the heart from the lungs
Systemic Circuit: What are the 4 things.
Systemic pump
Systemic arteries
Gas exchange
Systemic veins
Systemic pump
(left side of heart)
-receives oxygenated blood from pulmonary veins and pumps it to rest of body
Systemic arteries
pump oxygen-rich (oxygenated) blood to the body (not lungs)
Gas exchange in the systemic circuit happens?
at systemic capillaries
Systemic veins return
Oxygen-poor (deoxygenated) blood to RA
Pulmonary circuit is low or high pressure circuit? And pumps blood where?
-low-pressure circuit
pumps blood only to lungs
Systemic circuit is low or high pressure circuit? And pumps blood where?
high-pressure circuit
pumps blood to rest of body
FUNCTIONS OF THE HEART
🔸️maintain BP (blood pressure)
🔸️Atria produce hormone: atrial natriuretic peptide (ANP)
Rate & force (heart function)
contraction influence BP and blood flow to organs
Atria produce hormone?
And what does it do?
🔸️atrial natriuretic peptide (ANP)
🔸️ ANP lowers BP by decreasing Na+(sodium) retention in kidneys →decr. osmotic H2O reabsorption
Pericardium
membrane surrounding heart
The 4 types of pericardium that surround the heart are…
Fibrous pericardium
Serous pericardium
Parietal pericardium
Visceral pericardium
Fibrous pericardium
outermost layer
Serous pericardium produces?
produces serous fluid
Parietal pericardium
Lines the pericardial cavity
Visceral pericardium
aka epicardium
Surface of heart
Pericardial cavity has what kind of fluid and what does this fluid do?
🔸️contains serous fluid (pericardial fluid)
🔸️acts as a lubricant, decreasing friction.
HEART WALL is made up of…
- Epicardium
- Myocardium
- Endocardium
Epicardium
🔸️outmost layer (surface of the heart)🔸️Also known as visceral pericardium
Myocardium
(most of the tissue in the heart)
🔸️middle muscle layer
[What type of muscle??]
Cardiac muscle (most of heart)
🔸️fibrous skeleton (dense irregular collagenous CT)
Endocardium
innermost endothelial layer
Myocardium has what type of muscle?
Cardiac muscle (most of heart)
Cardiac muscle is made up of?
fibrous skeleton (dense irregular collagenous CT)
CORONARY CIRCULATION
Coronary vessels (supply heart wall):
Branch off ascending aorta:
1. Right Coronary artery
2. left coronary artery
Right Coronary artery
→ post. interventricular (post. descending a.)
→ marginal branch
left coronary artery
🔸️circumflex branch
🔸️ant. interventricular
🔸️LAD (left ant. descending)
What are the 3 coronary veins?
Great cardiac vein
Small cardiac vein
Middle cardiac vein
Heart consists of four chambers:
RA (right atrium) superior
LA (left atrium) superior
RV (right ventricle) inferior
LV (left ventricle) inferior
RA (right atrium) superior & LA (left atrium) superior
What do the do?
- 2 Atria
-receive blood from veins - pump through atrioventricular (AV) valves into ventricles
RV (right ventricle) inferior & LV (left ventricle) inferior do what?
- 2 Ventricles
-ejects blood into arteries - carry blood through systemic or pulmonary circuit
(CAD)
What is it?
🔸️Coronary artery disease
🔸️buildup of plagues (fatty material) in coronary arteries
🔸️decreases blood flow to myocardium →myocardial ischemia
🔸️leading cause of death worldwide
Coronary artery disease (CAD)
Symptoms:
-Symptoms: angina pectoris (chest pains)
myocardial ischemia
What is it?
A condition caused by decreased blood flow to myocardium
(MI) or heart attack
🔸️Myocardial infarction
🔸️The most dangerous potential consequence of CAD
🔸️Occurs when plaques in coronary arteries rupture
🔸️Clot forms → myocardial tissue infarct (dead tissue)
Myocardial infarction (MI) or heart attack
Symptoms:
🔸️Symptoms include
chest pain radiating to left arm shortness of breath,
sweating,
anxiety,
and nausea and/or vomiting
🔸️Women may present with back, Jaw, or arm pain instead
Myocardial infarction (MI) or heart attack
Risks and after effects
Risk factors include
smoking,
incr. BP,
poorly controlled diabetes,
high levels of certain lipids,
obesity
Angiography
diagnostic test for CAD
Myocardial infarction (MI) or heart attack
Treatments
🔸️modify Lifestyle
🔸️medications
🔸️then invasive treatments
Coronary angioplasty
balloon is inflated in blocked artery, and Stent is inserted
Coronary artery bypass grafting (CABG)
- other vessels are grafted onto diseased coronary artery to bypass blockage
Pectinate muscles -
muscular ridges inside RA
Interatrial septum -
wall between RA & LA
Fossa ovalis -
indentation in interatrial septum; remnant of opening from fetal circulation
Trabeculae carneae -
ridged surface in ventricles “beams of flesh”
ELECTROPHYSIOLOGY
🔸️Cardiac muscle exhibits autorhythmicity
🔸️Cardiac muscle cells contract in response to electrical excitation in the form of APs
🔸️Cardiac muscle cells do not require stimulation from the nervous system to generate APS
*They get the AP from themselves
Pacemaker Cells
- specialized cardiac muscle cells (=1% of cardiac muscle cells)
- coordinate cardiac electrical activity
- rhythmically and spontaneously generate APS to other types of cardiac muscle cells (contractile cells = 99% of cardiac muscle)
Cardiac muscle cells
Are made of?
🔸️Striated (Bands of light & dark)
🔸️branched
🔸️uninucleated
🔸️intercalated discs
🔸️generate tension through sliding-filament mech.
Ex. of Structure-Function Core Principle
Cardiac conduction system
- Pacemaker cells undergo rhythmic, spontaneous depolarizations → APs
Functional syncytium
- Permits heart to contract as a unit and produce a coordinated heart beat
Plateau phase
lengthens cardiac AP slow’s HR providing time required for heart to fill with blood;
also increases the strength of the heart’s contraction
Refractory period
🔸️in cardiac muscle cells is so long that cells can not maintain a sustained contraction
🔸️allows heart to relax & ventricles to refill before cardiac muscle cells are stimulated to contract again
Sinoatrial node (SA node)
🔸️Main pacemaker
🔸️ located in upper RA
🔸️60 to 100 bpm influenced by SNS & PSN
Atrioventricular node (AV node)
🔸️ located near tricuspid valve
🔸️40 bpm
🔸️AV node delay
Purkinje fiber system
🔸️Atrioventricular bundle (Av bundle
🔸️Right and left bundle branch
🔸️Purkinje fibers
- located in ventricular walls
AV node delay
🔸️allows atria to depolarize (and contract) before ventricles, giving ventricles time to fill with blood
🔸️also helps to prevent current from flowing backward from Av bundle into AV node and atria
Sinus rhythms =
electrical rhythms generated & maintained by SA node
Electrocardiogram (ECG)- EKG (rest of world)
🔸️graph of electrical activity in cardiac muscle cells over time
-🔸️electrodes placed on patient’s skin (6 on chest, 2 on each leg)
🔸️detects disturbance in electrical rhythm = dysrhythmia or arrhythmia (= no rhythm)
arrhythmia
(= no rhythm)
ECG represents
- depolarization or repolarization of parts of heart
P wave represents
depolarization of atria
QRS complex represents
🔸️ventricular depolarization
T wave represents
ventricular repolarization
Atrial fibrillation
🔸️generally not life threatening
🔸️atrial contraction isn’t necessary for ventricular filling
🔸️ECG tracing “irregularly irregular” rhythm (one that has no discernible pattern) that lacks P waves
Ventricular fibrillation (v-fib)
🔸️immediately life-threatening
🔸️ECG exhibits chaotic activity
defibrillation
🔸️ (an electric shock to heart) depolarizes all ventricular muscle cells simultaneously
🔸️SA node will resume pacing heart after shock is delivered (ideally)
“Flat-lining” is also known as…
Asystole
defibrillation is not used for asystole because…
heart is not fibrillating and there is no electrical activity to reset
asystole is treated
with CPR and pharmacological agents that stimulate heart such as atropine and Epi
Mechanical physiology
- actual processes by which blood fills and is pumped out of chambers
Heartbeat
Cardiac muscle cells contract as a unit to produce coordinated contractions
Cardiac cycle
- sequence of events that take place from one heartbeat to next (systole followed diastole for each chamber)
Gradients Core Principle
as ventricles contract and relax, pressure in chambers changes, causing blood to push on valves and open or close them:
Ventricular systole
Ventricular diastole
Ventricular systole
(contraction phase)
- Both of AV valves are forced shut by blood pushing against them
- Both of semilunar valves are forced open by outgoing blood
Ventricular diastole
(relaxation phase) -
Press. In ventricles falls below those in atria and in pulmonary trunk and aorta
→ forces AV valves open, allowing blood to drain from atria into relaxed ventricles
Stethoscope
- used to listen to (auscultate) rhythmic heart sounds:
🔸️S1 (“lub”) = AV valves close
🔸️S2 (“dub”)= Semilunar valves close
S1 (“lub”)
= AV valves close
S2 (“dub”)=
Semilunar valves close
Heart rate (HR) is how many bpm?
60-80 cardiac cycles or bpm
Stroke volume
70 ml/beat (amt. of blood ejected from each ventricle in a beat)
What does (CO) stand for?
Cardiac output
vol. of blood pumped into pulmonary & systemic circuits in 1 min. (ml/min.)
DETERMINATION OF CARDIAC OUTPUT (formula)
🔸️heart rate x stroke volume= C.O.
🔸️72 beats/min x 70 ml/beat = 5040 ml/min = 5 liters/min (C.O.)
Resting C.O. is how many liters/ min? And how many goes through the circuits?
- averages about 5 liters/min;
🔸️RV pumps 5 liters into pulmonary circuit
🔸️LV pumps same amt. to systemic circuit
In myocardial infarction, dead cells are replaced with
🔸️ scar tissue
Death of part of myocardium increases the
workload for remaining heart muscles
Atrial repolarization is masked by…
QRS complex
The two AV valves are?
the tricuspid valve and the mitral valve.
The two Semilunar valves are?
Pulmonary valve and aortic valve
FACTORS THAT INFLUENCE STROKE VOLUME
Frank-Starling law
🔸️Increased ventricular muscle cells stretch, leads to forceful contraction
🔸️Ensures that vol. of blood discharged from heart is equal to vol. that enters it
🔸️Important during exercise, when C.O. must increase to meet the body’s needs
FACTORS THAT INFLUENCE HEART RATE
HR due to rate at which SA node generates APS
chronotropic agents
Factors that influence rate at which SA node depolarizes
Positive chronotropic agents
SNS, some hormones, increased body temp.
Negative chronotropic agents
PSN, decreased body temperature
REGULATION OF CARDIAC OUTPUT
Heart is autorhythmic but still requires regulation to ensure C.O. meets body’s needs at all times
Regulated by nervous (ANS) and endocrine systems
SNS (NEpi) ↑HR then it
↑ force of contraction
PSN (ACH) ⬇️ HR then
⬇️ force of contraction
Hormonal regulation
Adrenal medulla
Adrenal medulla
affected by SNS → Epi and NEpi
-thyroid hormone and glucagon
Blood volume
- Aldosterone and antidiuretic
Aldosterone and antidiuretic
hormone increase blood vol. incr. C.O. - ANP decreases blood vol. reduces C.O.
Other factors that influence cardiac output:
-[Electrolyte] in ECF
-Body temperature
- Age
- Exercise
Body temperature
SA node fires more rapidly at higher body temp. and more slowly at lower body temp.
Heart failure
Heart failure (formerly CHF) = any condition that reduces heart’s ability to pump effectively
myocardial ischemia and/or M.I
valvular heart diseases, any disease of heart muscle (cardiomyopathy), and electrolyte imbalances
Heart failure →
decreased SV → reduced C.O.
Signs and symptoms of heart failure depend on type of heart failure and side of heart that is affected
LV failure
blood often backs up within pulmonary circuit; known as pulmonary congestion → pulmonary edema
Both RV and LV failure
peripheral edema, in which blood backs up in systemic capillaries (systemic congestion)
Symptoms of heart failure
Swelling in legs and feet
- Peripheral edema exacerbated by kidneys retain excess fluid
Treatment f or heart failure
- increase cardiac output
- Lifestyle modifications -weight loss and mild exercise, dietary sodium and fluid restrictions
- Drug therapy
- Heart transplant and/or pacemaker
