Flashcards in Chapter 11- Cardiovascular Deck (71)
What does the Cardiovascular system consist of?
Heart (a pump)
Vascular system (a collection of pipes making up a plumbing system)
What is its main function?
Supply oxygen and nutrients to the tissues
Remove carbon dioxide and waste products
Where is the heart located?
Behind the sternum just slightly to the left of midline of the body
Occupies a space called the thoracic mediastinum between the lungs
(Also in the mediastinum - esophagus, trachea, thymus)
Extends from the level of the second rib to about the level of the sixth rib
Inferiorly, rests on the diaphragm
What are the four borders of the heart?
Superior, inferior, medial, and lateral
Superior border is called the base and is wider than the inferior surface which is called the apex
What are the three surfaces of the heart?
Sternocostal, diaphragmatic, and pulmonary
What is the base of the heart?
The superior border (the top portion)
formed by the left atrium
What is the apex of the heart?
The inferior portion (the bottom portion where it kinda makes a point)
formed by the left ventricle
Describe the chambers of the heart
right and left atrium
right and left ventricle (pumping chambers)
Atria are separated by a septum or wall called the interatrial septum
Ventricles are separated by a wall called the interventricular septum.
Septum that separates the atria from the ventricles, the atrioventricular septum
The walls of the ventricles are thicker than the walls of the aorta
How does the right atrium receive blood?
Receives blood that is returning from the body to the heart and blood from the coronary sinus
Right atrium forms the right border
Blood being returned to the heart is deoxygenated so there is a depression in the inter atrial septum called fossa ovalis - this depression was a valve in the fetus which allowed the fetus to get blood
How does the right ventricle receive blood?
Receives deoxygenated blood from the right atrium and pumps into the lungs to be oxygenated
This chamber forms the anterior surface of the heart
It has three muscles that are attached to the tricuspid valve that prevent the valve from falling into the right atrium when pressure in the right ventricle builds
How does the Left atrium receive blood?
Forms most of the base of the heart
Four pulmonary veins carrying oxygenated blood enter the left atrium. They do not have valves
How does the left ventricle receive blood?
Receives blood from the left atrium
Works harder than any other chamber because it pumps oxygenated blood out of the heart via the aorta into the systemic circulation . Its myocardium is twice as think as that of the right ventricle.
What are the four valves of the heart
Pulmonary semilunar valve
Aortic semilunar valve
Describe the Tricuspid valve
Right AV or atrioventricular valve
Between the right atrium and right ventricle
Consists of three cusps or leaflets which prevent blood from flowing back into the right atrium when the right ventricle contracts
Cusps are anchored by cordlike structures called chordae tendinae to specialized cardiac muscle called papillary muscles . These muscles contract when the ventricles contract . Prevent the valve from falling into the right atrium and keeps blood from flowing back into the upper chamber
Describe the Pulmonary semilunar valve
Between the right ventricle and the trunk of the pulmonary arteries, prevent blood from flowing back into the right ventricle .
Its cusps are shaped like half moons which is why its called semi lunar valve
Describe the Bicuspid valve
Mitral valve (because its shaped like a hat) or the left AV valve
Between the left atrium and the left ventricle
Has Two cusps
Also has chordae tendinae attached to papillary muscles like the tricuspid valve
Prevents blood from flowing back into left atrium when the left ventricle contracts
Describe the Aortic semilunar valve
Between the left ventricle and the aorta
Prevents blood from flowing back into the left ventricle and also has halfmoon shaped cusps hence "semi lunar"
Describe the Innermost layer of the heart
Innermost layer is called the endocardium.
Very thin and lined with endothelium
Protects by lining the chambers, heart valves and large blood vessels
Describe the Middle layer of the heart
Middle layer is the muscular myocardium.
Cardiac muscle makes up 90% of the heart
responsible for pumping action of the heart
Thickest in the left ventricle
Describe the Outermost layer of the heart?
Outermost layer is the epicardium.
Also known as the visceral pericardium, contains fat
Cushions the heart if the chest experiences blunt trauma
What is the membrane that surrounds the heart?
Entire membrane around the heart is called the pericardium
Outer fibrous layer called the parietal pericardium
Innermost layer called the visceral pericardium
secretes a watery fluid that acts to reduce friction between the two membranes
Inflammation of the innermost lining of the heart and the valves
Bacterial infections are the most common cause
Weakness, fever, excessive sweating, general body aches, difficulty breathing, and blood in the urine
Treatment addresses the underlying cause
Inflammation of the muscular layer of the heart
Most common cause is a viral infection
Especially with Coxsackie B
Unexplained fever, chest pain that is, dyspnea, decreased urine output, fatigue, and fainting
Treatment normally includes steroids, bed rest, and a low-sodium diet
Inflammation of the pericardium
Most commonly caused by complications of viral or bacterial infections
Sharp, stabbing chest pains, fever, fatigue, and orthopnea
“Friction rub” may be heard.
Treatment includes analgesics for pain and diuretics are used to remove excess fluids around the heart.
Describe the cardiac cycle
Events from one heart beat to the next. There is more pressure on the left side of the heart than the right
Two atria of the heart contract and then relax simultaneously
Two ventricles also contract and relax simultaneously
Contraction - Atrial systole and ventricular systole
Relaxation - Atrial diastole and ventricular diastole
When atria contract the ventricles relax and vice versa
When the atria contract- Tricuspid and bicuspid valves open, and blood enters the ventricles
Right ventricle contracts, tricuspid valve closes- Pulmonary semilunar valve opens and blood enters the pulmonary trunk
Left ventricle contracts, the bicuspid valve closes- Aortic semilunar valve opens and blood enters the aorta
Number of cardiac cycles per minute - Same as the heart rate (pulse rate)
How does Strenuous exercise impact heart rate
Increases the heart rate because there is a greater demand for oxygen
How does Parasympathetic system impact heart rate
“Slows” things down
Vagus nerve, cranial nerve X, is the parasympathetic innervation to the heart
How does Sympathetic innervation impact heart rate
Increases heart rate, part of the “flight or fight” response
How does Cardiac control center impact heart rate
Medulla oblongata of the brain
Blood pressure rises, this control center ends impulses to decrease the heart rate