Cardiopulmonary - Anatomy and Physiology Flashcards
Lecture #1
What areas are supplied by the circumflex arteries?
- Inferior wall of left ventricle (when it’s not supplied by the right coronary artery)
- Left atrium
- Sinoatrial node (around 40% of humans)
What areas are supplied by right coronary artery?
- Right atrium
- Right ventricle
- Inferior wall of left ventricle (in most humans)
- Atrioventricular (AV) node
- Bundle of His
- Sinoatrial (SA) node (around 60% of humans)
What areas are supplied by the left anterior descending artery?
- Left ventricle
- Interventricular septum
- Right ventricle
- Inferior areas of the apex
- Inferior areas of both ventricles
What percentage of humans does the circumflex artery supply the SA node?
around 40% of humans
What percentage of humans does the right coronary artery supply the SA node?
around 60% of humans
In order from the outside, what are the tissue layers of the heart?
Fibrous pericardium
Parietal pericardium
- with pericardial cavity in between
Visceral pericardium (also known as epicardium)
Myocardium
Endocardium
What is identified as the heart muscle?
the myocardium
How is the myocardium different from skeletal muscles?
Due to automaticity
- there are pacemaker cells that keep the heart moving without conscious voluntary control
What influences the myocardium?
Both sympathetic and parasympathetic pathways of the autonomic nervous system
External factors also play a role (stress, exercise, caffeine, elicit and Rx drugs)
What bundle influences the parasympathetic nervous system and what does it do?
Vagus nerve bundle
Some voluntary control over the HR to help it slow down
What other elements are associated with the myocardium?
Conductive and contractile elements
How is the blood supply of the myocardium?
Heavily reliant and demanding of O2
What are the structures that are lined by the endocardium?
myocardium, valves and atria
What is the structure of the endocardium?
Thin, smooth layer of cells which has some connective tissue and some elastic fibers and muscle tissue
What is the function of the endocardium?
- has a smooth surface to allow blood and platelets to flow freely and not adhere to heart walls
- strengthens the valves and support other heart tissue
- supports the subendocardial layers
What structures are found in the subendocardial layer?
Purkinje fibers
What valves are within the atrioventricular valves?
Tricuspid and mitral
Where is the tricuspid valve located?
From the right atrium to the right ventricle
Where is the mitral valve located?
From the left atrium and left ventricle
What valves are within the semilunar valves?
Aortic and pulmonary
Where is the pulmonary valve located?
From the right ventricle and pulmonary artery (to lungs)
Where is the pulmonary valve located?
From the left ventricle and aorta
What is the pathway for deoxygenated blood from the body?
Vena cava
Right atrium
Tricuspid
Right ventricle
Pulmonary valve
Pulmonary artery
Lungs
What is the pathway for oxygenated blood?
Through the pulmonary veins
Left atrium
Mitral valve
Left ventricle
Aortic valve
Aorta
Body
What is the equation for cardiac output?
CO = HR x SV
What is cardiac output?
Amount of blood ejected out of the left ventricle into the systemic vasculature per minute
How many liters of blood is ejected at rest?
4-5 L/minute
How long does it take for blood to travel through the pulmonary and system circuits?
About 1 minute
What happens when one of the cardiac output is compromised?
Compensation occurs which will need outside intervention to compensate
What is stroke volume?
Amount of blood ejected out of the left ventricle/beat
How much blood is ejected per beat?
55-100 mL/beat
What is stroke volume affected by?
left ventricular end diastolic volume and end systolic volume
What is left ventricular end diastolic volume?
Amount of blood left in ventricle at the end of diastole
What is end systolic volume?
Volume returning to the heart
What is preload?
The amount of stretch experienced by cardiac sarcomeres pre-contraction
What is Starling’s law?
The greater the LVEDV - the greater the stretch and volume pumped
What is DIRECTLY proportional to stroke volume?
Preload
What affects preload?
Affected by venous return and volume of returning blood
What is afterload?
the force the left ventricle must generate to overcome aortic pressure to open aortic valve
What is INVERSELY related to stroke volume?
Afterload
What is contractility?
The squeezing pressure of the left ventricle
What is ejection fraction?
The percentage of blood emptied from the ventricle during sytole
clinically useful way to understand left ventricle function
What is the equation of ejection fraction?
SV/LVEDV
The volume of blood ejected (SV) in relation to the amount of blood received before contraction (LVEDV)
What are the normal averages of ejection fraction?
> 55% (60-70%)
What does a lower ejection fraction percentage mean?
more impaired the ventricles
What does a low EF indicate?
indicator of cardiomyopathy or heart failure
What produces a rate pressure product?
HR x SBP
Which increases with activity and with HR and/or BP
What does the sympathetic system stimulate?
Also called the adregenic
- Increase HR and force of myocardiaal contraction = increase in myocardial in myocardial O2 demand
- coronary artery vasodilation
What controls the adrenergic stimulation?
or sympathetic stimulation
The medulla via T1-T4
What is an example of a sympathetic blockers?
Antihypertensives
What nodes do the adrenergic innervate?
- SA node
- AV node
- Conduction pathways
What controls the parasympathetic stimulation?
or the cholinergic
The medulla via vagus nerve (X) and the cardiac plexus