T/F: 52% of men with heart attacks die within a year, making men more likely to die than women of a hear attack.
List the 5 critical points that should be considered when discussing the heart
- Contractions must be synchronized
- Valves must open completely (not stenotic)
- Valves must not leak (not insufficient/regurgitant)
- Myocardial muscle cells must provide enough force to move blood
- Ventricles must be able to fill during diastole
What three essential mechanisms are required for cells to maintain homeostasis?
- Sufficient blood flow in capillaries
- Diffusion b/w capillaries and interstitial fluid must be small
- Arterial blood must have correct parameters
What are some functions of the CV system?
- Exchange of fluids, gases, electrolytes, large molecules
- Heat exchange
Blood flow w/in the lungs involving O2 and CO2 gas exchange b/w the blood and alveoli is part of __________ circulation
Blood flow involving all the blood vessels in the body except for the lungs is part of __________ circulation
T/F: the CV system may be viewed anatomically as two pumps
Which functional pump is considered low pressure (Pulmonary / systemic)?
Which functional pump is considered high pressure (Pulmonary / systemic)?
T/F: The pulmonary and systemic circuits are arranged in-series
What is the CO for a resting adult?
At what stage in the circulation does the heart receive its blood supply?
Immediately when blood is projected out of the aorta
Darcy's Law Equation:
F = (PA - PV) /R
The phase of ventricular relaxation and filling is known as:
The phase of ventricular contraction is known as:
The ventricular wall tension (force) at the end of diastole is known as:
Clinically, ________ is the stretch on the ventricular fibers just before contraction, often approximated by the end-diastole volume (EDV) or end-diastole pressure (EDP)
The ventricular wall tension (force) during contraction is known as:
Clinically, _________ is the force that must be overcome for the ventricles to eject its contents. Often approximated by the systolic ventricular (or arterial) P.
Property of heart muscle that accounts for changes in the strength of contraction, independent of the preload and afterload.
________ reflects chemical/hormonal influences on the force of contraction
EDV - ESV
What factors affect SV?
EDV and ESV
What factors affect CO?
SV and HR
T/F: The Frank-Starline mechanism correlates an increase in venous return and ventricular preload and a decrease in SV
What can be used clinically to define preload rather than calculating the wall stress?
LVEDP or LVEDV
What does the ejection fraction (EF) represent?
Fraction of the blood pumped out of the ventricle
T/F: In the normal heart, the EF >0.55 (55%)
How does NE affect chronotropy, dromotropy, and inotropy of the heart?
How does ACh affect chronotropy, dromotropy, and inotropy of the heart?
NE is released from the ___________ system
ACh is released from the ________
Which receptors does NE act on?
β2, β1, α1
Which receptors does ACh act on?
How does the body respond if there is a drop in arterial P (AP)?
- ANS = Quick Cardiac stimulation and Vascular constriction
- Kidneys = slowly increase blood volume
Reduces blood volume in response to atrial distension, found in heart failure (HF)
Atrial Natriuretic Peptide (ANP)
T/F: ANP is a counter-regulatory system to the renin-aldosterone system
Where is the heart positioned?
Thoracic cavity (aka Mediastinum)
Describe what structures are located around the heart
- Lungs (R and L of heart)
- Sternum (anterior to heart)
- Spine (posterior to heart)
- Diaphragm (inferior to heart)
Where does the apex of the heart point?
Inferiorly, anteriorly, and to the left
Where is the Long axis of the heart located?
Distance from LV to the root of the aorta
Superior border is comprised of:
RA and LA
Left border is comprised of:
LV and some LA
Inferior border is comprised of:
RV and some LV
Right border is comprised of:
Protective border of the heart:
Role of the Pericardium:
- Viscous fluid reduces frictional forces
- Constrains the amount of blood filling
The cell bodies for the preganglionic vagal efferents innervating the heart are found in which region of the brain?
- Nucleus tractus solitarius
Norepinepherine released by sympathetic nerves:
- Binds preferentially to β2-adrenoceptors on cardiac myocytes
- Constricts blood vessels by binding to α1-adrenoeptors
- Inhibits its own release by binding to prejunctional β2-adrenoceptors
- Decreases renin release in the kidneys
Stimulating efferent fibers of the right vagus nerve
- Decreases systemic vascular resistance
- Increases atrial inotropy
- Increases HR
- Releases ACh, which binds to M2 receptors
The CV system
- Aides in the transfer of heat energy from organs deep w/in the body to the outside environment
- Comprises pulmonary and systemic circulations that are in parallel w/ each other
- Transports CO2 from the lungs to tissues w/in organs
- Transports O2 from individual cells to the lungs
Which of the following statements concerning the heart is true?
- CO is the product of ventricular SV and HR
- The right and left ventricles are in parallel
- The right ventricle generates higher P than the left ventricle
- The right ventricle receives blood from the pulmonary veins
A patient complains of becoming "light headed" when he is standing upright. BP measurements reveal a significant fall in AP upon standing. Which of the following is a likely explanation of this patient's condition?
- Excessive activation of baroreceptor negative feedback mechanisms
- Excessive fluid retention by the kidneys
- Increased HR
- Reduced CO
Simple squamous epithelium that lines the inner chambers of the heart as well as the valve and is indistinguishable from the lining of the blood vessels
Composed of cardiac myocytes that form the contractile layer for the ejection of blood.
The ____________ are the contractile units of muscle w/ specific arrangements of the ptns (myosin, actin, and troponin)
They myocardium is divided into the ____________ and ______________ areas
The serous membrane on the outside of the middle layer of the heart.
The epicardium consists of _____________ cells that overlay connective tissues
The epicardium is synonymous with:
What is the fibrous skeleton and its role in the heart?
Help keep tissue in place
There is a 3D topology of the endocardial surface, which is interlaced with _____________
Describe the appearance of the endocardium
Smooth w/ sponge-like appearance
List the partitioning structures of the heart:
- Interatrial septum
- Interventricular septum
RA pressure range:
2-8 mm Hg
Approximately 10% of the blood in the normal heart at rest is delivered via ___________ aka _________
Atrial contraction; atrial kick
During exertion, as much as ______% is delivered via atrial contaction
RV pressure range:
2-8 mm Hg
RV pressure increases to __________ during contraction
15-30 mm Hg
LA pressure ranges:
2-10 mm Hg
T/F: the LV wall is approximately 2 times thicker than the RV
T/F: During diastole, the LV is spheroid shaped, but during systole, it is cone-shaped
LV pressure range (filling phase)
3-12 mm Hg
LV pressure range (Contraction)
100-140 mm Hg
T/F: Due to P differences, the interventricular septum is pushed to the right
In the fetal heart, this is the area where there was once an opening called the foramen ovale
Hole in the heart
Atrial septal defect (ASD)
Flap-like opening b/w RA and LA caused when the foramen ovale does not close properly
Patent Foramen Ovale (PFO)
Approximately _____% of people have a PFO
Cause of Afib
Disorganized electrical conduction pathways in the atria = less efficient pumping of atria
Afib causes blood to stagnate which can lead to clots. Where do the majority of these clots form?
Left atrial appendage (left auricle)
Treatment options for Afib
- Blood thinners
- Surgical procedures and implantable devices
Outflow obstruction in HCM can lead to _______
Function of heart valves:
Give unidirectional flow of blood w/o backflow
List the inlet valves
Atrioventricular valves (Tricuspid and Mitral (biscuspid)
List the outlet valves
Semulunar valves (Pulmonic and Aortic)
Which valves have 2 flaps
Which valves have 3 flaps
Obstruction of valve leading to decrease in forward blood flow:
Leaky valve leading to backflow of blood
What happens during aortic stenosis?
- Elevated LV P
- Secondary ventricular hypertrophy
- Murmur (systolic)
Which heart sound is the result of the mitral and tricuspid valves closing at the beginning of systole?
First sound (S1 "lub")
Which heart sound is the result of the aortic and pulmonic valves closing at the beginning of diastole?
Second sound (S2 "dub")
During expiration there is one sound, but may be audibly distinct during inspiration (physiologic splitting). Why does this happen?
- When you breathe in, more blood fills in R side of heart, pushing blood into pulmonary artery
- Pulmonary artery is more flexible = expands more = takes longer to get extra blood through