A&P Flashcards
Contents of the mediastinum
Heart, great vessels (aorta, pulmonary arteries, venue cava, pulmonary veins), esophagus, trachea, mainstream bronchi, thymus, lymph nodes, phrenic and vagus nerves
The heart extends vertically from what rib to what rib?
2nd to the 6th
Tough, inelastic fibrous sac covering the heart; comprised of the visceral and parietal layers
Pericardium
What two layers make up the pericardium?
Viscera and the parietal
What is the outer layer of the pericardium called?
Parietal
What is the name of the layer of the pericardium that hugs the surface of the heart?
Visceral
How many cc’s of pericardial fluid lie between the visceral and parietal layers?
15-50
What are the four main functions of the pericardium?
1) reduce friction
2) anchors the heart within the chest
3) protective barrier to infection and malignancy
4) helps minimize acute over-expansion of the heart
Property of the heart that allows it to beat as a single unit; organized contraction
Syncytium
In a fetus, what is the name of the conduit between right and left atrium to allow blood to bypass the lungs?
Foramen ovale
What is the name of the Foramen ovale once it shuts?
Fossa ovalis
Receives blood from the body via the superior and inferior vena cava
Right atrium
Receives blood from the myocardium via the coronary sinus
Right atrium
Receives blood from the lungs via the four pulmonary veins
Left atrium
What separates the ventricles?
Interventricular septum
Which chamber I. The heart receives blood from the right atrium
Right ventricle
Which chamber in the heart pumps blood to the lungs via the pulmonary arteries?
Right ventricle
Which chamber of the heart receives blood from the left atrium?
Left ventricle
Which chamber of the heart pumps blood to the body via the aorta?
Left ventricle
What structure externally separates the atria from the ventricles?
Coronary sulcus
What houses the circumflex artery and the coronary sinus?
Coronary sulcus
Where do the AV sulcus (coronary sulcus) and the IV sulcus meet?
Crux
What structure externally separates the RT and LT ventricles?
Interventricular sulcus
Where are the LT anterior descending coronary artery, posterior descending coronary artery, and great cardiac vein housed?
Interventricular sulcus
What prevents the prolapse of the atrioventricular valves?
The papillary muscles and the chordae tendinae
Which valve is located between the RT atrium and RT ventricle?
Tricuspid valve
Which valve is located between the LT atrium and LT ventricle?
Mitral valve/bicuspid valve
What causes the semilunar valves to close to prevent backflow into the ventricles?
Pressure differentials
What valve is located between the RT ventricle and the main pulmonary artery?
Pulmonic valve (PV)
What valve is located between the LT ventricle and the aorta?
Aortic valve (AOV)
What three great vessels empty into the RT atrium?
Superior vena cava, inferior vena cava, and coronary sinus
What arteries branch off the aortic arch?
Brachiocephalic artery, LT common carotid artery, LT subclavian artery
When does the major blood flow to the coronary arteries occur?
During diastole
What main coronary artery descends down the IV sulcus to the apex?
Left anterior descending (LAD)
How is blood supplied to the anterior portion of the interventricular septum?
Septal perforators
How is blood supplied to the left atrium?
Left atrial branch
Which coronary artery courses around the AV sulcus to the posterior section of the heart?
Left circumflex (LCx)
What’s the name of the first branch of the RT coronary artery?
Conus
Name the 6 branches of the RT coronary artery
1) conus
2) SA nodal
3) Acute marginals
4) AV nodal
5) posterior descending artery (PDA)
6) posterolateral branches
What is the name of the RT coronary artery branch the supplies blood to the SA node in 60% of the population?
SA nodal
What branch of the RT coronary artery supplies blood to the AV node in 90% of the population?
AV noda
What branch of the RT coronary artery supplies blood to the posterior third of the interventricular septum?
Posterior descending artery (PDA)
Drains directly in the RT atrium and RT ventricle; small amount into LT atrium
Thebesian veins
What two veins are sometimes used for catheter placement during electrophysiologic studies
Coronary sinus and great cardiac vein
Alters the force of muscle contraction
Inotropy
Does sympathetic stimulation, like sympathomimetic drugs, and exercise cause inotropy to increase or decrease?
Increase
Does myocardial ischemia or infarction, cardiomyopathy, hypoxemia, and acidosis cause inotropy to increase or decrease?
Decrease
Chronotropy
Heart rate
Do exercise, fever, infection, pain, anxiety, hypovolemia, and sympathomimetic drugs cause chronotropy to increase or decrease?
Increase
Name five ways to decrease chronotropy via parasympathetic nervous System stimulation
Valsalva’s maneuver Coughing Suctioning Vomiting Carotid stimulation
Is chronotropy increased or decreased in conduction abnormalities?
Decreased
Name three drug classes that effect chronotropy
Beta-blockers
Digoxin
Calcium-channel blockers
An increase in ventricular filling pressure (preload) will be met with a proportional increase in contractile force
Starling’s Law
Cardiac output
Stroke volume x heart rate
Normal range is 4.0-6.0 liters/minute
End diastolic volume, aka preload
Volume of blood in the heart at the end of diastole; when the heart is all done filling
End systolic volume
Volume of blood in the heart at the end of systole; normally 50-60 mL
Stroke volume
Amount of blood pumped by the heart per beat; EDV-ESV; normal = 60-130 mL
Name three conditions that increase preload
Heart failure
Hypervolemia
Bradydysrhythmias
Name 7 conditions that decrease preload
Hypovolemia Excessive vasodilation, I.e. shock Increased intrathoracic pressure Cardiac tamponade RT ventricular failure or infarction (decreases preload for LV) Tachydysrhythmias Loss of atrial contraction (A-fib)
Resistance to ejection of blood from ventricles
Afterload; McDonalds straw vs a coffee stirring straw
Name 5 conditions that increase afterload
Vasoconstriction Hypertension Aortic valve disease Hypercoagulability Pulmonary hypertension (RV)
Name three conditions that decrease afterload
Hypotension
Vasodilation
Vasodilators
Is rapid diastolic filling active or passive?
passive; AV valves open and blood rushes into ventricles
reduced diastolic filling is also called…
diastasis
during what phase of the Wigger’s diagram is coronary blood flow happening/optimal?
reduced diastolic filling/diastasis
What subphase is also known as “atrial systole” or “atrial kick”
Atrial contraction
Atrial contraction contributes what percentage of diastolic filling volume?
15-30%
Which subphase occurs after the P wave?
Atrial contraction
this contraction increases pressure in the ventricle, but there is no change in volume due to AV valves are closed and semilunar valves have not yet opened
Isovolumetric contraction
Which subphase accounts for two-thirds of oxygen consumption of the ventricle
Isovolumetric contraction
Which subphase follows the QRS complex
Isovolumetric contraction
This phase occurs when aortic and pulmonary arterial pressures increase rapidly and ventricular volume decreases rapidly
Rapid Ventricular Ejection
Rapid Ventricular Ejection occurs during what segment of the EKG?
ST segment
Reduced ejection is also called
protodiastole
What two subphase occurs during the T wave of an EKG?
Reduced ejection or protodiastole and isovolumetric relaxation
isovolumetric relaxation
relaxation occurs and pressure decreases; volume does not change because the semilunar valves are closed and the AV valves have not yet opened
Arteries carry blood
away from from the heart
veins carry blood
towards the heart
Blood vessel Tunica adventitia
aka tunica externa; outer fibrous layer composed primarily of connective tissue
blood vessel Tunica media
muscular layer; primarily responsible for blood pressure regulation via augmentation of vascular tone and resistance
blood vessel tunica interna
only layer that is present in capillaries
blood vessel lumen
hollow core within a blood vessel; diameter varies directly with blood flow (bigger diameter = greater flow)
ability to expand to accommodate blood ejected by the ventricle
arteriol elasticity
ability to recoil and thus send the bolus of blood forward to more distal aspects of the arteries and circulation
arteriol contractility
name four examples of elastic arteries
aorta, brachiocephalic, subclavian, femoral
name four examples of muscular arteries
axillary, brachial, radian, renal
arterioles
resistance vessels; major regulation of capillary blood flow and blood pressure
single layer of squamous epithelial cells surrounding a basement membrane
capillaries
regulate the flow of blood into the capillary bed; constriction decreases flow to the true capillaries = decreased blood delivery
pre-capillary sphincter
branches of arterioles that flow straight through the venules, called a thoroughfare channel
metarterioles
Rise from arterioles or metarterioles; allow for delivery of nutrients and oxygen to tissues and removal of waste products
true capillaries
regulates blood flow out of the capillary bed
post-capillary sphincter
What is the purpose of hepatic portal circulation
hepatic filtration and regulation of nutrient rich blood
What is the purpose of the Circle of Willis?
provide adequate circulation through its anastomoses (connection or opening)
oppostion to forward flow; friction between the vessel wall and blood
Total peripheral resistance (afterload)
How does stroke volume affect blood pressure?
Increases or decreases contractility
carbon-dioxide detecting cells in the carotid bodies and the aorta
chemoreceptors
secreted by the kidney and will stimulate the catalysis of angiotensin I in the lungs
renin
Name a very powerful vasoconstrictor.
Angiotensin II
Who converts angiotensin I to angiotensin II?
angiotensin converting enzyme (ACE)
secreted by the adrenal cortex; promotes sodium retention and potassium excretion
Aldosterone
What are the three main functions of the RAAS system
- increase blood volume
- vasoconstriction
- increase in blood pressure
What type of flow results in bruit
turbulent flow
Name four things that can cause turbulent flow
- narrowing
- shunt
- dilation
- increase metabolism or CO
Name 4 things that happen if venous return to the heart is hindered
- end-diastolic volume (preload) drops
- stroke volume decreases
- CO decreases
- BP and profusion may also decrease
Name four factors that can promote venous return
- contraction of skeletal muscle
- neg. inspiratory pressure in the chest
- RT ventricular relaxation
- total blood volume (like a crowd of 200 trying to leave a room when someone yells fire–people in the front of the doors will get pushed out)
any agent that alters the heart rate
chronotropy
any agent that affects the conduction speed at the AV node
dromotropy
