Unit 6: Jeopardy (cardio)
These arteries and arterioles do not vasoconstrict during exercise
- arterioles in active skeletal muscles - coronary arteries - cerebral arterioles
These are the compensatory mechanisms activated to maintain CO and organ perfusion during compensated circulatory shock
- baroreceptor response to low BP - activation of sympathetic ns - activation of RAAS
These factors are important in maintaining blood pressure
- contraction of left ventricle - resistance of arterioles and capillaries - elasticity of arterial walls - viscosity and volume of blood
Causes of neurogenic Shock
- deep general anesthesia -spinal anesthesia and traumatic - brain injury involving medulla
Common causes of secondary HTN
- renal artery stenosis - ischemic kidney disease - primary aldosteronism - coarctation of aorta
These are the steps in the development of coronary ischemia
1. LDL deposits below endothelium 2. fibrous tissue and calcium intertwine with cholesterol 3. atherosclerotic plaque forms 4. decreased blood flow thru coronary arteries
Aortic valve heart sounds are heard best here
2nd ICS @ RSB
A patient with a heart rate of 80 beats per minute and a stroke volume of 40 ml per beat has a cardiac output of:
3.2 L/min
About _____% of the atrial blood flows into the ventricles before the atria contract
70-75%
A 22 year old male enters the emergency room after severing a major artery in a motorcycle accident. It is estimated that he lost approximately 700 milliliters of blood. His blood pressure is 90/55 mmHg. Which of the following sets of changes would be expected in response to hemorrhage in this man?
decreased parasympathetic activity, increased total peripheral resistance, decreased renal blood flow
These chemicals and hormones cause vasodilation of arterioles
histamine nitric oxide prostacyclin AcH bradykinin ANP
A healthy 25 year old male physician assistant student has an exercise stress test at the local health club. Which of the following sets of physiologic changes is most likely to occur in this man's skeletal muscles?
increased arteriolar diameter, increased vascular return
These are common causes of hypovolemic shock due to plasma loss
intestinal obstruction, severe burns and dehydration
During this phase of circulatory shock, lysosomal enzymes are released , energy stores are depleted , and there is decreased perfusion to coronary arteries
irreversible circulatory shock
During these phases of the cardiac cycle, all heart valves are closed
isovolumetric ventricular relaxation & isovolumetric ventricular contraction
Which of the following is the reason the mitral valve opens at the beginning of diastolic filling?
left atrial pressure is higher than left ventricular pressure
All the heart valves are open during which stage of cardiac cycle?
none of the above
The events that happen during Phase 0 of the cardiac action potential
opening of Na ion channels and influx of Na ions
Three types of distributive shock
septic shock endocrine shock neurogenic shock
What is the cause of the plateau phase of the cardiac myocyte action potential?
slow Ca+ influx (Ca+ moving into cell)
The _____ layer of an artery contains the greatest amount of smooth muscle
tunica media
When a person moves from a supine position to a standing position, which of the following compensatory changes occur?
⬆️ contractility
The following factors increase cardiac output except
Afterload
This substance decreases BP by inhibiting the vasomotor center and inhibits the release of ADH
Alcohol
Acute regulation of high blood pressure involves the response of the:
All of the Above
Which factor assists venous return to the heart?
All of these
At the instant following the second heart sound, which heart valves are open?
All valves are closed
These chemicals and hormones cause vasoconstriction
Angiotensin II Endothelin ADH
This valvular disorder is typically associated with a systolic murmur in the right second intercostal space
Aortic Stenosis
Hormone produced by left ventricular cells in response to excessive stretching during diastole
BNP
Which is true of the pulmonary circuit?
Blood oxygen content is higher in the pulmonary vein than in the pulmonary artery
In terms of being open or closed, what is the state of the mitral and tricuspid valves (left and right atrioventricular valves), respectively at the end of the first heart sound?
Both are closed
Blood pressure changes based on these two parameters
CO & Peripheral Resistance
This is the equation for cardiac output
CO (mL / min) = heart rate (beats / min) x stroke volume (mL / beat)
Myocardial contractility is best correlated with the intracellular concentration of which ion?
Ca++
This type of vessel is well adapted for diffusion of gases, nutrients and waste products between cells and blood
Capillaries
These string like structures prevent the AV valves from swinging back into the atrium
Chordae Tendinae
In this type of shock, fluid and blood volume are normal, but there is a problem with distribution of fluid and blood
Distributive Shock
These are the 3 layers of the heart
Endocardium Myocardium Epicardium
Which of the following is most likely to cause the heart to go into spastic contraction?
Excess extracellular fluid calcium ions
These are ion channels between cell cardiac myocytes that transmit impulses freely
Gap junctions
These electrolyte disturbances can cause cardiac irritability and increased contractility
Hypercalcemia Hypokalemia
A flaccid heart can be a result of these electrolyte disturbances
Hypocalcemia Hyperkalemia
These leads are associated with the inferior wall
II, III, aVF
During this phase of the cardiac cycle, the pressure within the ventricles rises quickly since the ventricle is contracting with all valves closed
Isovolumetric Contraction
Artery occluded in patients with AWMI
LAD
This coronary artery supplies the interventricular septum and left atrium
LAD
The lowest blood pressure is found in this part of the circulatory system
Large Veins & Vena Cava
Occlusion of circumflex artery can cause an MI affecting this portion of the heart
Left Lateral Wall
The cardiac reflex control centers are located within the _____.
Medulla oblongata
Major controller of myocardial blood flow
Myocardial Oxygen Consumption
In this type of shock, there is a sudden loss of vasomotor tone throughout the body; can be caused by stimulation of parasympathetic ns or inhibition of sympathetic ns
Neurogenic Shock
This chemical in cigarettes increases BP by stimulating the SNS
Nicotine
Vasodilating substance that is secreted by endothelial cells, originates from arginine
Nitric Oxide
The initial depolarization during cardiac action potential results from:
Opening of fast Na+ channels
Pathophysiology of aortic aneurysm
Plaque formation that weakens the aortic wall
Amount of ventricular stretch at end of diastole (LVEDP)
Preload
The closing of AV valves is a direct result of this
Pressure differences between atria and ventricles ( pressure in ventricles is greater then atrial pressures)
90-95% of patients with HTN have this type of HTN
Primary or essential HTN
During exercise, vasodilation results from these
Reduction of oxygen in skeletal muscle, lactic acid and CO2
This heart sound is a result of the closing of the AV valves
S1 "Lub"
This abnormal heart sound in adults > 40 years of age is heard frequently in patients with heart failure
S3 or S3 gallop
Formula used to calculate stroke volume
SV = EDV - ESV
Intracellular tubules with cardiac muscle that store large quantities of calcium ions
Sarcoplasmic Reticulum
At the end of ventricular systole, ventricular pressures drop rapidly; blood in the aorta and pulmonary trunk start to flow back to the ventricles which causes these valves to close
Semilunar Valves
These valves prevent the backflow of blood from the pulmonary trunk and aorta into the ventricles
Semilunar Valves
Which heart valves are NOT actively closed by the contraction of muscular structures?
Semilunar valves
Fever, vasodilation, leaky capillaries and coagulopathy are typical findings in this type of shock
Septic Shock
The greatest resistance to blood flow occurs in these vessels
Small arteries & Arterioles
In this type of myocardial injury, ST depression is noted on EKG
Subendocardial Injury
STEMI are associated with this type of injury to the myocardium
Transmural (Epicardial) Injury
Calcium binds to this protein complex which then causes a conformational change of tropomyosin
Troponin C
This layer of blood vessels is composed of connective tissue
Tunica Adventitia
This layer of blood vessels is continuous with the endothelium of the heart
Tunica Intima or Endothelium
This layer of blood vessels is composed of elastic tissue and smooth muscle
Tunica Media
A systolic heart murmur coincides with this part of the carotid pulsation
Upstroke of carotid pulse
How can the circulatory system promote heat retention/conservation, such as on a cold day?
Vasoconstriction
Common causes of cardiogenic shock
arrhythmias, MI and HF
Most common risk factor for aortic aneurysm
atherosclerosis
Baroreceptors are key pressure receptors that are located in
carotid and aortic bodies
Baroreceptors are located here
carotid sinus and aortic arch