Proper Heart Function (5)
- Contractions must be synchronized
- Valves must open completely (no stenosis)
- Valves must not leak
- Myocardial muscle cells must provide enough force to move the blood
- Ventricles must be able to fill during diastole
The human circulatory system achieves the cellular needs such as ____________________________________.
Eliminating waste products providing metabolic substrates.
Cells of the human circulatory systems have ______________ contact with ______________.
Direct; interstitial fluid
Three essential mechanisms of human circulatory system:
- sufficient blood flow in the capillaries
- diffusion between capillaries and interstitial fluid must be small
- arterial blood must have the correct physiological parameters
Cardiovascular System Functions:
- Exchange of fluids, gases, electrolytes and large molecules
- Heat exchange with surroundings
Cardiovascular system may be viewed functionally as _____________.
TWO pumps
What are the "Two Pumps" of the cardiovascular system?
- Pulmonary Circulation
- Systemic circulation
Pulmonary Circulation is also considered as ______ pressure.
LOW pressure
Systemic Circulation is also considered as ________ pressure.
HIGH pressure
Describe Pulmonary circulation
Blood flow WITHIN THE LUNGS involving the O2 and CO2 gas exchange between the blood and the alveoli.
Describe Systemic Circulation
Blood flow INVOLVING ALL THE BLOOD VESSELS in the body EXCEPT FOR THE LUNGS
How are the pulmonary and systemic circuits aranged?
In series (a sequence of steps, A to Z)
The pulmonary and systemic circulation systems are constrained to pump essentially the SAME amount of blood; called the ________________ which is how much for a resting adult?
Cardiac output, 5-6 L/min for a resting adult

In-parallel arrangement concludes that blood flow changes in ONE organ __________ dramatically impact the blood flow in OTHER organs
WILL NOT
At what stage in the circulation does the heart receive its blood supply?
Immediately when blood is..... (rewatch this part)
What is the phase of ventricular relaxation and filling?
Diastole
What is the phase of ventricular contraction?
Systole
Describe Preload
- Ventricular wall tension @ the END OF DIASTOLE (relaxation)
- The STRETCH on the ventricular fibers just BEFORE contraction
- Approximated by the EDV or EDP
Describe Afterload
- Ventricular wall tension DURING CONTRACTION
- The FORCE that must be overcome for the ventricles to eject its contents
- Resistance
Describe Contractility
- Changes in the strength of contraction, independent of the preload and afterload
- Reflects chemical or hormonal influences on the force of contraction
What is Cardiac Output (CO)?
Quantity of blood pumped per minute from each of the ventricles
Cardiac Output Equation
CO = SV x HR
Stroke Volume Equation
SV = EDV - ESV
EDV
End Diastolic volume
ESV
End Systolic volume
Factors that affect STROKE VOLUME?
(SVCPA)

SVCPA
- Contractility (+)
- Preload (+)
- Afterload ( - )
Factors that affect CARDIAC OUTPUT?
COHS
- Heart Rate (+)
- Stroke Volume (+)
Describe the Frank-Starling Mechanism
correlates an INCREASE in venous return and ventricular preload to an INCREASE in stroke volume
What is Ejection Fraction (EF)?
- The FRACTION of the blood pumped out of the ventricle
- Should be > 0.55 (55%) in a normal heart
Ejection Fraction Equation
EF = SV / EDV
Chronotropy
Heart rate
Dromotropy
Conduction velocity
Inotropy
contractility
Lusitropy
relaxation
Norepinephrine released from sympathetic nerve terminals binds to post junctional adrenoreceptors ( ___, ____, and ___ ) resulting in ___________ chronotropy, dromotropy and inotropy.
- B2, B1, A1
- INCREASED
What inhibits NE release?
- Prejunctional A2 receptors; feedback mechanism (sympathetic)
- Prejunctional M2 receptors; Ach binds (parasympthathetic, Vagus)
Parasympathetic nerves release Acetylcholine, which binds to post junctional _____ receptors resulting in ___________ chronotropy, dromotropy and inotropy.
- M2
- DECREASED
B1 receptor couples to...
GS
B2 receptor couples to.....
GS
A1 receptor couples to......
Gq
M2 receptor couples to......
GI

Describe ANS role in Arterial Pressure Feedback control
A sudden fall in arterial pressure elicits a rapid BARORECEPTOR REFLEX that ACTIVATES the ANS to INCREASE CO and CONSTRICT BLOOOD VESSELS to restore arterial pressure.

Describe KIDNEYS role in Arterial Pressure Feedback control
A sudden fall in arterial pressure elicits the kidneys to respond by retaining Na+ and H2O to INCREASE BLOOD VOLUME

What is Atrial Natriuretic Peptide (ANP)?
28 amino acid polypeptide
Where is ANP made and stored?
Atrial Myocytes
When is ANP released?
In response to ATRIAL DISTENSION
ANP _________ blood volume and is a ____________________ system to the ____________________________ system.
- REDUCES
- Counter-regulatory
- Renin-angiotensin-aldosterone
ANP is hydrolyzed by what?
Neprilysin, neutral endopeptidase (NEP)
Entresto
- Combination therapy of Valsartan and Sacubitril
- Mortality reduced by 20% for patients compared to Enalapril
Valsartan is a.....
AT1 inhibitor
Sacubitril is a.....
Neprilysin inhibitor