Heart Flashcards
The cardiovascular system consists of (3x)
1) Heart
2) Blood
3) Vascular System
Is the heart a hollow muscular organ?
Yes
How many chambers does the heart have? And what are they?
1) Right atrium
2) Right ventricle
3) Left atrium
4) Left Ventricle
The flow of blood is left ventricle –> _______ –> _______ –> _______ –> _______ –> _______ –> _______ –> _______ –> _______ –> _______ –> _______
Left ventricle –> artery –> systemic circulation –> vein –> right atrium –> right ventricle –> pulmonary artery –> lung –> pulmonary vein –> left atrium –> left ventricle
What type of blood does the pulmonary circuit carry?
Oxygen-poor blood
What type of blood does the systemic circuit carry?
Oxygen-rich blood
The heart pumps oxygen-poor (_______) blood to the ______ (the ______ circuit) and oxygen-rich (_______) blood to the ______ (the ______ circuit)
1) deoxygenated, lungs, pulmonary
2) oxygenated, rest of the body, systemic
Would the midsagittal section be completely symmetrical? and Why?
No, it would not be completely symmetrical because the base of the heart is slightly to the left of the midline.
What is connected to the superior end of the heart at its base?
The great vessels, both veins, and arteries
Red on heart diagrams mean?
Oxygen rich
Blue on heart diagrams mean?
Oxygen poor
The Endocardium includes
- Connective tissue (Areolar Tissue)
- Endothelium
The Myocardium includes
- Bundles of cardiac muscle cells
- Connective tissue
The Serous Pericardium includes
Visceral and Parietal
1. Mesothelium (BOTH)
2. Areolar Tissue (BOTH)
3. Dense fibrous layer (Parietal ONLY)
The Fibrous Pericardium includes
Dense network of collagen fibers
The base of the heart includes (2 layers)
Endocardium and Myocardium
The Epicardium is the ___________ layer of the Serous Pericardium
Inner (Viseral)
From inner to outer layers of the heart & pericardium Name the 4 layers
- Endocardium
- Myocardium
- Serous Pericardium (Visceral & Parietal)
- Fibrous Pericardium
The Epicardium includes
Mesothelium and Areolar Tissue
The chambers of the heart is separated by what?
Muscular partitions called septa (singular septum, wall)
The atria are separated by __________
The interatrial septum
The ventricles are separated by __________
A much thicker interventricular septum
What are heart valves?
Covered openings that direct the flow of blood between chambers and vessels
What are the types of valves in the heart?
- AV valves
- Semilunar valves
What are the two types of AV valves?
- Tricuspid valve
- Mitral valve
The Pulmonary valve is located?
On the right of the heart, between the Right ventricle and Pulmonary artery (great vessel)
What are the two types of Semilunar valves?
- Pulmonary valve
- Aortic valve
The Aortic valve is located?
On the left side of the heart, between the Left ventricle and Aorta
The Mitral valve is located?
On the left side of the heart, between the Left atrium and Left ventricle
The Tricuspid valve is located?
On the right side of the heart, between the Right atrium and Right ventricle
Blood flow can flow both ways in heart valves (T/F)
False
The Right atrium receives blood from which two veins
The superior vena cava and inferior vena cava (systemic circuit)
The superior vena cava delivers blood from _____________
From the head, neck, upper limbs, and chest
The inferior vena cava delivers blood from ________________
From the rest of the truck, the viscera, and the lower limbs
Are there valves between the venae cavae and the right atrium?
No
How do the heart valves prevent the backflow of blood?
When the heart contracts the heart valves close so blood can not backflow
How does blood flow through the heart valves?
When the heart relaxes the heart valves open and the blood flow towards their intended location
The pulmonary valve consists of ________
three semilunar (half moon shaped) cusps of thick connective tissue
Where does the pulmonary circuit start?
Right Atrium
Where does the pulmonary circuit end?
Left atrium or Pulmonary vein
Where does the systemic circuit start?
Left ventricle
Where does the systemic circuit end?
Superior and Inferior vena cavae
Cardiac muscle cells need reliable supplies of oxygen and nutrients to ensure heart works continuously (T/F)
True
What part of the heart has its own separate blood supply?
Myocardium
What is the Myocardium blood supply called?
The coronary circulation
During max exertion, the blood flow to the myocardium may increase to 9x the rate during resting (T/F)
True
The coronary circulation includes
An extensive network of coronary blood vessels, both arteries and veins
Coronary Artery Disease is
The build of plaque in the coronary circulation which will eventually lead to a complete blockage of the circulation
Myocardium Infaraction is
(aka Heart Attack) is when the coronary circulation is blocked and the cardiac muscle cells die from lack of oxygen
The Heart has its own command center (T/F)
True
In a single cardiac contraction, the four chambers contract in what sequence?
First the 2 atria and then the 2 ventricles
What are the 2 types of cardiac muscle cells?
1) Specialized cells (pacemaker and conducting)
2) Contractile cells
What are the two types of Specialized heart muscle cells?
1) Pacemaker
2) Conducting
What do Contractile cells do?
Contractile cells produce the powerful contractions to
propel blood.
The electrical impulses initiated by the conducting system
spread and cause the contraction of the heart chambers. (T/F)
True
Do heart cells need to convert action potential into a chemical signal?
No, because the membranes are similar enough
What starts each heartbeat?
Action potential generated by cells of the conducting system
Propagate means
To spread
How does the action potential spread to contractile cells?
Other cells then propagate and distribute this electrical impulse
to contractile cells.
The electrical impulse at a cardiac contractile cell’s plasma
membrane produces an action potential that is similar to an
action potential in a skeletal muscle fiber (T/F)
True
What do the action potential triggers?
contraction of the contractile cells of the heart and the release of Calcium
Because of the way action potential is conducted, _______________________
the atria contract first, driving blood into the ventricles, and then theventricles contract next, driving blood out of the heart to the systemic circuit and pulmonary circuit.
The Function of Pacemaker Cells are
To Generate and Maintain the Action Potential
The Location of Pacemaker Cells are
Located in (1) The Sinoatrial (SA) node and (2) the atrioventricular node (AV) node
The Function of Conducting Cells are
To Interconnect the SA node and the AV node, and Distribute the Action Potential throughout the myocardium
The Location of Conducting Cells are
Located in the Internodal Pathways, AV Bundles, Bundle Branches, and Purkinje Fibers
* In between the Pacemaker Cells*
The heart knows when to contract when
they receive stimulus from action potential
Why are Pacemaker cells of the SA and AV nodes unique?
They do not have a stable resting membrane potential.
Not having a stable resting membrane potential means
Each time a pacemaker cell repolarizes, it then spontaneously and gradually depolarizes. Such autonomic depolarization is called autorhythmicity.
A continuous heartbeat is maintained because
Pacemaker cells of the SA and AV nodes are unique: they do not have a stable resting membrane potential.
Where is the rate of spontaneous depolarization the fastest
At the SA node
What is the function of the SA node
The SA node establishes the baseline heart rhythm or sinus rhythm. The SA node also generates an action potential
Starting at the SA node generating action potential, what happens next
the action potential spread across the atrial surface and causes atrial contractile cells to contract ➠ contraction of the atria
In the meantime of the AP traveling to the atrium, it also
travels via the internodal pathway to the AV node, where the conduction of the action potential slows down (a brief delay to allow the atrial contraction to occur before the ventricular contraction begins)
After the brief delay at the AV node,
The action potential is conducted along the AV bundle and the bundle branches to the Purkinje fibers.
What happens after the Purkinje fibers receive the AP
The Purkinje fibers then distribute the action potential to the ventricular myocardium. Purkinje fibers radiate from the apex toward the base of the heart ➠ the ventricles contract in a wave that begins at the apex of the heart and spreads toward the base ➠ pushing blood toward the base, into the aorta and pulmonary trunk.
Electrocardiogram, also known as
ECG OR EKG
The procedure to monitor the electrical events in the heart is called
Electrocardiography.
A recording of these electrical events is called
Electrocardiogram,
Are there standard ways to place the electrodes? Results?
Yes, which results in a standard EKG/ECG
What does the P wave show?
atrial depolarization
What happens immediately after atrial depolarization?
Atrial contraction
The atrial contraction occurs during what segment
P-R segment
The P-R segment shows
conduction through AV node and AV bundle
The Q wave shows
the beginning of ventricular depolarization
The QRS complex shows
The completion of ventricular depolarization and contraction
Ventricular contraction occurs shortly after what
the R peak from the apex toward the base
The T wave shows
The ventricular repolarization
Before the cardiac cycle begins, what occurred?
The heart is relaxed and all four chambers are partly filled with blood
Why is there a brief resting phase before each heartbeat
for the chambers to relax and prepare for the next heartbeat.
The period between the start of one heartbeat and the beginning of the next is
a single cardiac cycle.
For any one chamber in the heart, the cardiac cycle can be divided into
two phases: systole and diastole.
During systole
the chamber contracts and pushes blood into an adjacent chamber or into an arterial trunk.
During Diastole
the chambers fills with blood and prepares for the next cardiac cycle.
The basic principle od the cardiac cycle is
that Fluids flow from an area of higher pressure to an area of lower pressure.
Blood flows from one chamber to another
only if the pressure in the first chamber exceeds that in the second.
The first step of the cardiac cycle is
Atrial systole begins
Additional small amount of blood is pushed into the ventricles
The second step of the cardiac cycle is
Atrial diastole begins
Atria begin and remain relaxed till the end of this cardiac cycle
The third step of the cardiac cycle is
Ventricular systole begins
This is the first/early phase - AKA isovolumetric phase. The contraction is mild, only enough to close the AV valves, but not enough to push the blood into the great arteries.
The fourth step of the cardiac cycle is
Ventricular ejection
This is the second/later phase - AKA ventricular
ejection phase. The contraction becomes strong, enough to push the blood into the great arteries.
The fifth step of the cardiac cycle is
Ventricular diastole
All four chambers relax, blood flows in
The sixth step of the cardiac cycle is
Ventricular diastole begins
Ventricles begin to relax, ventricular pressure drops ➠ blood flows back ➠ closure of the semilunar valve. Blood begins to fill atria.
When considering cardiac function over time, physicians generally are most interested in
cardiac output
Cardiac output (CO) is
the amount of blood pumped by the left ventricle in 1 minute.
cardiac output (CO) is an indication
of the blood flow through peripheral tissues - and without adequate blood flow, homeostasis cannot be maintained.
The cardiac output provides a useful indication
of ventricular efficiency over time.
The body precisely adjusts cardiac output to
supply peripheral tissues with enough blood as conditions change.
