CARDIOVASCULAR SYSTEM Flashcards
Location of the heart
between the two lungs, 2/3 to the left
Membrane that surrounds and protects the heart and holds it in place.
PERICARDIUM
tough, inelastic, dense irregular connective tissue layer. It prevents overstretching of the heart, provides protection, and anchors the heart in place.
Outer fibrous pericardium
a thinner, more delicate membrane that forms a double layer around the heart.
Inner serous pericardium
Two parts of the pericardium:
- Outer fibrous pericardium
2. Inner serous pericardium
Two parts of the inner serous pericardium:
a. Outer parietal layer
b. Inner Visceral Layer
Fused to outer fibrous pericardium
Outer Parietal Layer
Also known as epicardium. Adheres tightly to the surface of the heart
Inner Visceral Layer
thin film of fluid between the parietal and visceral layers. It reduces friction between the membranes as heart moves.
PERICARDIAL FLUID
space that contains the pericardial fluid.
PERICARDIAL CAVITY
inflammation of the pericardium.
PERICARDITIS
Chambers of the heart:
- Atria
2. Ventricles
two upper chambers
Atria
two lower chambers
Ventricles
partition between atria
◊ Contains fossa ovalis (remnant of foramen ovale)
INTERATRIAL SEPTUM
Deoxygenated blood pathway
- SVC, IVC, CS
- RA
- RV
- PT
- R&L PA
Oxygenated blood pathway
- Lungs
- PV
- LA
- LV
- AA
Prevents backflow of blood
VALVES OF THE HEART
Two types of valves
- Atrioventricular
2. Semilunar
2 types of atrioventricular valves
- Tricuspid valve
2. Bicuspid (Mitral) valve
2 types of semilunar valves
- Pulmonary valve
2. Aortic valve
lies between atrium and ventricle
ATRIOVENTRICULAR VALVES
prevent blood from flowing back into the heart
SEMILUNAR VALVES
valve from RA to RV
Tricuspid valve
valve from LA to LV
Bicuspid valve
valve from RV to PT
Pulmonary valve
valve from LV to Aorta
Aortic valve
TRUE OR FALSE
The blood flow of the heart comes from areas of LOW blood pressure to HIGH blood pressure
FALSE
The blood flow of the heart comes from areas of HIGH blood pressure to LOW blood pressure
Movement of blood controlled by
- contraction and relaxation of myocardium
2. opening and closing of valves
remnant of foramen ovale
fossa ovalis
separates the RV from LV.
INTERVENTRICULAR SEPTUM
wrinkled pouch-like structure at the anterior surface of each atrium. It increases the capacity of the atrium to hold greater volume of blood.
AURICLE
flow of blood through the numerous vessels in the myocardium.
CORONARY CIRCULATION
: Principal coronary arteries that originate as branches from the ascending aorta.
: Deliver oxygen and nutrients throughout the heart muscle.
Left and Right Coronary Arteries
: Large vein on the posterior surface of the heart.
: Collects deoxygenated blood with carbon dioxide waste.
: Empties into the RA.
Coronary Sinus
: Connections where 2 or more arteries supply the same region,
: Provide alternative routes for blood to reach a particular organ or tissue of the body.
: Provide detours for arterial blood if a main route becomes obstructed.
Anastomoses
% of the cardiac muscle fibers that are specialized – generate action potentials over and over and do so in a rhythmical pattern.
1%
maintains heart rhythm
Natural pacemaker
: set route of action potentials to ensure coordinated contraction of heart muscles
Conduction system
2 important functions of the conduction system of the heart:
- Natural pacemaker
2. Conduction system
5 components of the conduction system of the heart:
- Sinoatrial node (SA node)
- Atrioventricular node (AV node)
- Atrioventricular bundle / AV bundle / Bundle of HIS
- L&R Bundle Branches
- Purkinje Fibers
: Located at the right atrial wall, inferior to the opening of the SVC.
: Begins cardiac excitation; location where an action potential spontaneously arises.
: Natural pacemaker of the heart
: Action potentials about 100 times per minute
Sinoatrial node (SA node)
: Located in the interatrial septum, anterior to the opening of the coronary sinus.
: Action potential slows considerably, providing time for the atria to empty their blood into the ventricles.
Atrioventricular node (AV node)
: Located in the interventricular septum
: Only site where action potentials can conduct from the atria to the ventricles.
Atrioventricular bundle / AV bundle / Bundle of HIS
: Course through the interventricular septum toward the apex of the heart.
L&R Bundle Branches
: Has a large diameter
: Rapidly conduct action potential, first to the apex of the ventricles and then upward to the remainder of the ventricular myocardium.
Purkinje Fibers
action potential conduction are recorded by electrodes placed on the skin
Electrocardiogram/ ECG (or EKG)
3 components of the electrocardiogram:
- P wave
- QRS wave
- T wave
atrial depolarization (atrial contraction)
P wave
ventricular depolarization
QRS complex
ventricular repolarization (ventricular relaxation
T wave
downward deflection
Q
large upright triangular wave
R
downward wave
S
one cardiac cycle is equal to?
one heartbeat
TRUE OR FALSE
The two atria RELAX while the two ventricles CONTRACT
FALSE
The two atria CONTRACT while the two ventricles RELAX
phase of contraction
SYSTOLE
phase of relaxation
DIASTOLE
3 PHASES OF CARDIAC CYCLE:
- Relaxation period
- Atrial Systole
- Ventricular Systole
begins at the end of a cardiac cycle when the ventricles start to relax and all 4 chambers are in diastole.
Relaxation Period
contraction of atria
Atrial Systole
contraction of ventricles
Ventricular Systole
volume of blood ejected per minute
CARDIAC OUTPUT
The cardiac output is determined by the:
Stroke volume x heart rate
Average stroke volume of a resting adult
70 mL
Average heart rate of a resting adult
75 bpm
amount of blood ejected by the left ventricle during each contraction.
STROKE VOLUME
3 FACTORS THAT INCREASE SV AND HR:
- Degree of stretch
- Forcefulness of contraction
- Pressure required to eject blood
The nervous system regulation of the heart originates in the cardiovascular (CV) center in the medulla oblongata
AUTONOMIC REGULATION OF HEART RATE
4 Other regulators of heart rate:
Cardiac accelerator nerves
Vagus (X) nerves
Baroreceptors
Chemoreceptors
sympathetic neurons that reach the heart travel here. They innervate the conduction system, atria, and ventricles Releases norepinephrine that increases HR.
Cardiac accelerator nerves
parasympathetic neurons travel here. Extends to the conduction system and atria. Releases acetylcholine (ACh) that decreases HR.
Vagus (X) nerves