The heart Flashcards
How many times does the heart contract in the average lifetime?
About 2.5 billion times
What does the pulmonary circuit do?
It sends oxygen-depleted blood (deoxygenated) to the lungs to pick up O2 and unload CO2.
What does the systemic circuit do?
It sends oxygenated blood and nutrients to all body cells and removes waste.
What encloses the heart?
The parietal pericardium
What is the parietal pericardium?
A sac like structure that holds the heart in place and contains a small volume of serous fluid that reduces friction as the heart moves
How many layers is the wall of the heart?
3 distinct layers
What is the epicardium?
The outer layer of the wall of the heart which protects the heart by reducing friction
What is the myocardium?
The thick middle layer of the wall of the heart which consists mostly of cardiac muscle tissue that pumps blood out of he heart chambers
What is the endocardium?
The inner layer of the wall of the heart which is continuous with the inner linings of blood vessels attached to the heart
How many chambers is the heart divided into? What are they called?
4 chambers
The upper chambers are atria while the lower chambers are ventricles
What are the atria like and what do they do?
They are thin walled and receive blood returning to the heart
What do the ventricles do?
They receive blood from the atria and contract to force blood out of the heart into arteries.
What separates the left and right atria and ventricles?
A solid wall-like septum
What does the right atrium receive blood from?
Two large veins, the superior and inferior vena cava
Where is the large tricuspid valve located? What does it allow?
Between the right atrium and right ventricle
The passage of blood from the atrium to the ventricle without backflips
What are the atrioventricular valves (A-V)?
The tricuspid valve and the mitral valve
Which ventricle wall is thinner? Why?
The right ventricle muscular wall is thinner because blood must only be pumped to the lungs, not to the entire body.
The right ventricle pumps blood to ____
While the left ventricle pumps blood ______.
The lungs
Throughout the body
When the muscular wall of the right ventricle contracts,
Blood inside its chamber exits through the pulmonary valve into the pulmonary trunk.
The pulmonary trunk divides into
The left and right pulmonary arteries
What does blood from the pulmonary valve do?
It picks up oxygen in the lungs and deposits CO2.
What does blood from the lungs travel through and where does it go to?
Four pulmonary veins, two from the right lung and two from the left lung, transfer oxygenated blood from the lungs to the left atrium
Blood passes from the left atrium into
The left ventricle through the mitral (bicuspid) valve
When the left ventricle contracts,
The mitral valve closes and the only exit for blood is through the large aorta artery.
A heartbeat heard through ______ sounds like _____.
A stethoscope
A lubb-dupp
What produces the sound of the heartbeat?
The vibration of the heart tissue associated with the closing of the heart valves
The “lubb” occurs when?
During ventricular contraction when the A-V valves, mainly the tricuspid, are closing
The “dupp” occurs when?
During ventricular relaxation, when the pulmonary and aortic valves are closing
What do blood vessels consist of?
Arteries, arterioles, capillaries, venules, and veins
What are arteries?
Strong elastic vessels that are adapted to carry blood away from the heart under high pressure
The inner wall of an artery is made of simple squamous epithelium called endothelium.
What does endothelium do?
Releases nitric oxide, which relaxes the smooth muscle of the vessel
What is atherosclerosis?
An arterial disease in which deposits of fatty materials like cholesterol form plaque within the walls of arteries that restrict blood flow
What are the risk factors for developing atherosclerosis?
A fatty (saturated), high sodium diet, elevated blood pressure, tobacco smoking, obesity, and lack of physical exercise
How is pulse pressure calculated?
By subtracting diastolic pressure from systolic pressure
What is normal blood pressure? What is the diastolic number? Systolic?
120/80
Diastolic is the denominator
Systolic is the numerator
The lowest heart rate recorded was ____ and belonged to _____.
25 beats per minute
An athlete
What artery feeds the large intestines? Where is it located?
The superior mesenteric
Down the center of the body
What artery do you feel for your pulse?
The radial artery
What is the longest vein in the body? Where is it located?
The great saphenous
In the leg
What artery can cause strokes if both of its branches are blocked? Where is it located?
The common carotid
In the neck
Where is the external jugular vein located?
On the left side of the face
How much blood does the heart pump through the body each day?
7,000 liters
