Heart Flashcards
What are the aortic semilunar ventricular valves between?
The left ventricle and aorta
What does the pulmonary semilunar ventricular valve separate?
The right ventricle and pulmonary arteries
What is the thickest part of the heart?
The left ventricle
What happens when the bicuspid ventricle is open?
The aortic semilunar ventricle is closed, tension on the chordae of low, and blood flows from the LA to the LV
What’s the order in which blood flows?
Right a, tricuspid, right ventricle, pulmonary semi, pulmonary arteries, lungs, pulmonary vein, left a, bicuspid, left v, aortic semi, aorta
What are the 4 main functions of the heart?
Route blood, generate blood pressure, ensure one-way blood flow, and regulate blood supply
How big is the heart?
Slightly larger than a closed fist and less than 1 pound
Where is the heart located?
In the thoracic cavity (mediastinum)
What is the heart between?
The 2nd and 5th intercostal spaces
What is the orientation of the heart?
The apex is inferior and it’s overall left and anterior
What is the pericardium?
A double-layered closed sac surrounding the heart
What is the double-layered closed sac surrounding the heart?
The pericardium
What is the parietal pericardium?
The outside layer
What’s the outside layer of the heart?
The parietal pericardium
What’s the visceral pericardium?
It covers the hearts surface
What covers the heart’s surface?
The visceral pericardium
What is the pericardial cavity?
The space surrounding the heart
What forms the pericardial cavity?
The visceral and parietal pericardium
What do the visceral and parietal pericardium form?
The pericardial cavity
What are the 4 coverings of the heart?
The pericardium, parietal pericardium, visceral pericardium, and the pericardial cavity
What are the 3 layers of the heart? (Superficial to deep)
Epicardium, myocardium, and endocardium
What is the epicardium?
The membrane forming the smooth outer surface
What type of cells is the epicardium?
Simple squamous tissue over fat/connective tissues
What is the outer layer of the heart called?
Visceral serous
What layer forms the smooth outer surface of the heart?
The epicardium
What is the myocardium?
The thick middle layer of the heart
What does the myocardium do?
It makes the heart able to contract via cardiac muscle
What layer allows the heart to contract?
The myocardium
What is the endocardium?
The inner surface of the heart chambers
What layer forms the thick middle layer of the heart?
Myocardium
What is the inner surface of the hearts chambers called?
The endocardium
What allows blood to flow easily through the heart?
The endocardium
What does the endocardium do?
It allows blood to flow easily through the heart
Describe cardiac muscle
It has 1 nucleus, its striated, and has lots of mitochondria
What type of disks does cardiac muscle have?
It has intercalated disks
What are intercalated disks?
Cell-to-cell contacts binding cells, and it’s folded to increase surface area
What does cardiac muscle contain?
It contains gap junctions
What do gap junctions do?
It reduces electrical resistance between cells, allowing both action potentials to pass easily and cells to contract in unison
What allows cells to contract in unison?
Gap junctions
What are the 3 phases of action potentials?
Depolarization, plateau, and repolarization
What causes action potentials?
Changes in membrane channel permeability
What do changes in membrane permeability cause?
Action potentials
What are changes in membrane channel permeability called?
Pacemaker potential
What is pacemaker potential?
Changes in membrane channel permeability
What happens during depolarization?
Na+ channels open briefly, then rapidly. K+ channels are closed and Ca+2 channels begin to open.
What happens during the plateau phase?
Na+ channels are closed, few K+ channels are open, slow Ca+2 channels remain open
What happens during the repolarization phase?
Voltage-gated Na+ channels remain closed, K+ channels are open, Ca+2 channels are closed.
When are Na+ channels open?
During depolarization
When are K+ channels partially or totally open?
K+ is partially open during plateau and fully open during repolarization
When are Ca+ channels open?
They open during depolarization and remain open during plateau
How long do cardiac action potentials take?
200 milliseconds
What prolongs cardiac action potentials?
The plateau phase prolongs it by keeping Ca+2 channels open
What do cardiac muscle cells coordinate?
The contraction of atria and ventricles
What causes the contraction of atria and ventricles?
The coordination of cardiac muscle cells in the wall of the heart
Where are cells that coordinate contraction located?
In the wall of the heart
What is the SA node?
The pacemaker of the heart
What is the pacemaker of the heart?
The SA node
What does the SA node do?
It initiates action potentials
What do action potentials caused by the SA node do?
They cause the contraction of atria
What causes the contraction of atria?
The action potentials caused by the SA node
What is the party of action potentials through the heart?
SA node, to AV node, to AV bundles, to left and right bundle branches, to purkinji fibers
Where are purkinji fibers located?
In the ventricles
What’s in the ventricles?
Purkinji fibers
Where does the action potential go from the SA node?
The AV node
Where does the action potential go from the AV node?
AV bundles
What are the two main parts of the cardiac cycle?
The atria and ventricles
Where is the atria?
On the top
Where are the ventricles?
On the bottom
What do cardiac muscle contractions do?
They produce pressure changes in the heart chambers, moving the blood
What does atrial systole do?
It contracts the atria and forces blood into the ventricles
What does systole mean?
Contraction
What does diastole mean?
Relaxation
What forces blood into the ventricles?
Atrial systole
What does ventricular systole do?
It forces blood out of the heart
What forces blood out of the heart?
Ventricular systole
What does atrial diastole do?
It fills with blood from the vena cava
What causes the atria to be filled wth blood from the vena cava?
Atrial diastole
What does ventricular diastole do?
It causes the ventricles to fill with blood from the atria
What causes the ventricles to fill with blood from the atria?
Ventricular diastole
What is stroke volume?
The volume of the blood pumped per ventricle with each heart contraction
What is the name for the volume of blood pumped with each heart contraction?
Stroke volume
What is cardiac output?
The volume of blood pumped by either ventricular each minute
What is the formula for cardiac output?
CO = SV x HR
What is the volume pumped by either ventricle each minute called?
Cardiac output
What regulates heart rate?
The automatic nervous system and chemical regulation
What does chemical regulation do?
It regulates hormones and ions to keep your heart rate normal
What does the automatic nervous system do for the heart?
It responds to emotional and physical stressors
What are the symptoms of a CO imbalance?
Coronary artherosclerosis, persistent high blood pressure, multiple MI, and dismayed cardiomyopathy
What is persistent high BP a symptom of?
A CO imbalance
What are the three tunics of the lumen called?
Tunica intima, media, and externa
What makes up the tunica intima?
Squamous tissue
What makes up the tunica media?
Mostly smooth muscle
What makes up the tunica externa?
Colleges fibers
What is made up of squamous tissue?
Tunica intima
What is made up of mostly smooth muscle?
Tunica media
What is made up of collagen fibers?
Tunica externa
What are the two types of arteries?
Elastic and muscular
What do elastic arteries do?
They absorb some of the pressure from the heart
Where are elastic arteries located?
Near the heart
What is a characteristic of elastic arteries?
They have no significant amount of dilation or construction
What has no significant amount of dilation and constriction?
Elastic arteries
What do muscular arteries do?
They deliver blood to specific organs
What delivers blood to specific organs?
Muscular arteries
What has a thick tunica media?
Muscular arteries
What do muscular arteries have?
A thick tunica media
What affects the arterioles flow?
Vaso events
