Ch. 18 - The Heart Flashcards
What vessels does blood enter during ventricular systole?
Aorta & pulmonary arteries
How are cardiac muscle cells like skeletal muscle cells?
Is striated, have I and A bands, contracts by the sliding filament mechanism
What valves are supported by the chordae tendinae and what is its purpose?
AV valves. Keep valves from going into atria. Hold in place.
What is the function of coronary arteries?
Carries blood to myocardium
When is the tricuspid valve closed?
When the ventricles are in systole (contract)
What is ischemia?
Possible essay
“To hold back blood”. Deprivation of blood supply to any tissue.
What is pericarditis?
Possible essay
Inflammation of the pericardium. Roughens the serous membrane surface.
What is angina pectoris?
Possible essay
“Choked chest”. Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium.
What is myocardial infarct?
Possible essay
“Heart attack”. Prolonged coronary blockage can lead to this.
Heart sounds are made by what?
The closing of the heart valves
What is the foramen ovale?
“Oval door”. Connects the two atria in fetal lungs(stop) and allows blood entering the right heart to bypass the pulmonary circuit and the collapsed, nonfunctional fetal lungs. In adult heart, position is revealed by the fossa ovalis.
What are some factors that influence heart rate?
Temperature, anger, fever, epinephrine, age, gender, emotions, exercise, drugs and alcohol
Blood within the pulmonary veins returns to what chamber?
Left atrium
What fluid is found in the pericardial cavity?
Serous fluid
What are some age related changes that affect the heart?
Sclerosis an thickening of valve flaps, decline in cardiac reserve, fibrosis of cardiac muscle, and atherosclerosis
Why is fibrosis of the cardiac muscle serious?
Loses contraction capabilities
What are purkinje fibers? Be able to label them p. 694 (don’t need to know what they are)
Long strands of barrel-shaped cells with myofibrils. Complete pathway through interventricular septum, penetrate into heart apex, and turn superiorly into ventricular walls.
What valves contain chordae tendinae? Contrast them
Tricuspid and mitral (bicuspid) valves.
Tricuspid = 3 cusps (flaps), right AV valve
Bicuspid = 2 cusps (flaps), left AV valve
What membrane covers the heart?
Pericardium
What is the importance of intercalated discs?
Allows cells to communicate and contract in unison.
Fibrous skeleton reinforces heart (framework)
Contain anchoring desmosomes and gap junctions. Desmosomes prevent adjacent cells from separating during contraction. Gap junctions allow ions to pass from cell to cell.
How can you determine the left and right side of the heart?
size or thickness of ventricles (left is thicker)
Why is the left ventricular wall of the heart thicker than the right wall?
Pumps blood to the entire body. More pressure, stronger contractions.
What will hemorrhaging do to blood pressure?
Decrease it
What layer of the heart is responsible for its contractions?
Myocardium
What would happen tetanic contractions occur in the heart?
Heart would stop pumping
What does norepinephrine do to the heart?
Increases heart rate, help heart reach threshold (maximum) quickly
Where will pressure increase if stenosis of the mitral valve occurs?
Pulmonary circulation
What is systole and diastole? What sides of the heart are associated with each?
Systole = contraction
Diastole = relaxation
Ventricles
Systole is right, diastole is left
Blood flow within the heart.
Right atrium ➡️ tricuspid valve ➡️ right ventricle ➡️ pulmonary valve ➡️ pulmonary arteries ➡️ lungs ➡️ pulmonary vein ➡️ left atrium ➡️ bicuspid valve ➡️ left ventricle ➡️ aortic valve ➡️ aorta ➡️ body
Why is oxygen so critical to the heart?
Can’t go into anaerobic contraction without. Heart can’t store oxygen.
What valves do not have chordae tendinae attached?
Aortic and pulmonary valves
What is bradycardia?
Heart rate slower than 60 beats/min. May result from low body temp., certain drugs, or parasympathetic nervous activation. Is a known, and desirable, consequence of endurance training.
When would an artificial pacemaker be surgically implanted?
Essay
Fainting spell, shortness of breath, AV and SA nodes are not functioning correctly
