Ch 20. The Heart Flashcards
What is an artery?
carries oxygenated blood away from the heart
What is a Vein?
a blood vessel that carries deoxygenated blood toward the heart
Capillaries
blood vessels that connect arteries to veins. Smallest vessels where exchange of gases, nutrients, waste products occur.
Where is the Heart Located?
In the mediastinum, left midline, behind sternum
Shape of the Heart
Is determined by the shape of the thoracic cavity
What is the pericardium?
surrounds the heart with a double layer serous membrane
Visceral pericardium
Stuck to the surface of the heart
Parietal Pericardium + Visceral Pericardium make…
Serous Pericardium
Coronary Sulcus
between right and left ventricle
What is the job of ventricles?
To pump blood
What is the job of ventricles?
To pump blood
The pulmonary trunk branches out to where?
To the left and right pulmonary arteries
What are the three layers of the heart? Describe their function.
Endocardium (inner most layer): Epithelial lining that lines the heart and forms the valves of heart; continuous w/ endothelial to line blood vessels
Myocardium (thickest layer): made of cardiac muscle; connected with intercalated discs
Epicardium (outer most layer): on the heart;
Explain the order of blood flow in the heart.
SVC/ IVC > RA > Tricuspid Valve > RV > Pulmonary V > Pulmonary Trunk > R & L Pulmonary arteries > Lungs > R & L Pulmonary Veins > LA > Bicuspid Valve > LV > Aorta
Cardiac Muscle is a
function syncytium ( to allow cardiac muscles to contract at the same time)
What are intercalated discs?
They connect myocardial cells
What happens during action potential in cardiac muscles?
SA Node > Inter-nodal Bundle > Bundle of His
What is the visceral layer and parietal layer?
Visceral pericardium wraps around the heart and parietal pericardium is the lining of the fibrous pericardium.
Functions of connective tissue are….
Stores fat, transports substances, binds structures together, form a framework and support for organs and body, protects against disease, help repair tissue damage
Where is the heart located?
In the mediastinum toward left midline
How is pericardial fluid formed and what is it’s importance?
Visceral pericardium and parietal pericardium secrete pericardial fluid in the pericardial space to lubricate the expansion and contraction of the heart.
Auto-rhythmic means…
It does not need to be innervated to contract
What determines when valve opens/closes?
The pressure of blood flow
What separates the Left and Right Ventricle?
Interventricular septum
What is the purpose of having valves in the heart?
To guarantee the direction of blood flow in the heart
How does the chordae tendineae help the valves?
They are string-like chords that keep the valve from opening backwards and pull against the pressure in the blood.
What are papillary muscles?
Pulls on cordae tendineae for it to pull against pressure of blood
What is trabeculae carneae?
Pulls the wall of the ventricle during a contraction
Electrical signal is carried…
From the interventricular septum to right ventricular free wall
Why is the left free wall thicker than the right free wall?
More muscle is needed to move blood at a greater distance. Right pumps blood to lungs and Left pumps to rest of body.
The left ventricle also has to work against higher pressure.
