The Heart (Lecture 16) Flashcards
How long does it take to circulate all your blood?
about 1 minute
What does the heart serve as a pump for?
the pulmonary and systemic circuits
What is the average cardiac output?
5.25 L/min
Where is the heart found?
the mediastinum
Where does the heart lie?
on the diaphragm and posterior to the sternum
Where is the base of the heart?
posterior and superior surface of the heart
Where is the apex of the heart?
anterior and inferior, points to the left hip
How many layers of the pericardium are there?
three
What are the layers of the pericardium?
fibrous, parietal, and visceral pericardium
What is the visceral layer also known as?
epicardium
What does the pericardial cavity contain?
serous fluid
What are the functions of the pericardium?
prevents undesired movement, prevents overfilling of the heart, reduces friction
What are the layers of the heart wall?
epicardium, myocardium, endocardium
What epithelium is the epicardium made of?
simple squamous
What is the epicardium layer of the heart?
visceral layer of serous pericardium
What is the myocardium of the heart?
cardiac muscle
What makes up the bulk of the heart wall?
myocardium
What does the endocardium of the heart do?
lines chambers and covers valves
What epithelium is the endocardium made of?
simple squamous epithelium
What is the pulmonary circuit?
carries blood to and from the lungs
What is the pump for the pulmonary circuit?
right ventricle
What is the systemic circuit?
transports blood to and from the body tissues
What is the pump for the systemic circuit?
left ventricle
Which ventricle is bigger?
left
What does the right atrium do?
receives oxygen-poor blood from systemic circuit
What does the right ventricle do?
ejects oxygen-poor blood into the pulmonary trunk
What is special about the pulmonary valve?
the shape of it allows it to open when the ventricle contracts and prevents blood from returning to the ventricle
What does the left atrium do?
receives oxygen-rich blood from lungs through pulmonary veins
What does the left ventricle do?
ejects oxygen-rich blood into the aorta
What chamber of the heart is the most muscular?
left ventricle
What is the structure of the heart valves?
composed of dense connective tissue, two or three cusps
What are the functions of the heart valves?
permit passage of blood in one direction, prevent back flow of blood
What is the fibrous skeleton of the heart?
dense connective tissue located between the atria and the ventricles
What are the functions of the fibrous skeleton of the heart?
separates the atria and ventricles (structurally and electrically), anchors heart valves, provides a framework for cardia muscle attachment
What does cardiac muscle tissue look like?
short cells, branched, striated, contain 1-2 nuclei
What are cells joined by?
intercalated discs
What do gap junctions do for the heart?
increase the flow of electrical current
What do desmosomes do for the heart?
prevent cardiac muscle from pulling apart
Does skeletal or cardiac muscle have more mitochondria and ATP?
cardiac muscle
What is coronary circulation?
brings nutrient and oxygen to the heart wall
What does inadequate circulation cause?
heart attack/myocardial infarction
What is heart failure?
progressive weakening of the heart
What happens during heart failure?
heart can’t pump enough blood to meet the needs of the body, ventricles don’t empty completely so they become overfilled and blood backs up into veins behind the ventricle
What may result from heart failure?
edema (congestion) in tissues outside the pulmonary or systemic circuits
