Anatomy of the heart
Card Set Information
Anatomy of the heart
nursing A&P Ch 18 review
Where does the heart lie?
In the mediastinum, between ribs 2-6.
2/3 to left of midline , 1/3 to right
Where does the apex lie?
On the diaphragm, pointing to the left
Where does the base lie?
just below the 2nd rib
Why are the heart boundaries clinically important?
It aids in diagnosing heart conditions
What is different about the heart at birth?
It is transverse and appears large in proportion to the chest cavity
When does the heart attain its adult size and weight?
Between the start of puberty and 25 years of age.
In an adult, the heart resembles what shape?
that of the chest (To fit into the chest cavity)
What is the function of the pericardium?
provides protection against friction
Which layer of the pericardium is tough, with a loose-fitting inextensible sac?
The fibrous pericardium (outer layer)
Which layer adheres to the outside of the heart?
visceral layer (epicardium)
The serous pericardium (inner layer) contains what two layers?
Parietal and visceral
Which layer lies inside the fibrous pericardium layer?
Where does the pericardial space lie and what does it contain?
Between the parietal and visceral layer. It contains pericardial fluid.
How many layers make up the wall of the heart?
three distinct layers
What is the name of the outer layer of the heart and what is its function?
What is the name of the thick, contractile, layer of the heart and what is its function?
Myocardium; compresses heart cavities, and blood within them with great force.
What is the name of the delicate inner layer of endothelial tissue and what is its function?
Endocardium; lines cavities, ventricles, and atria
How many chambers does the heart have?
What are the right and left chambers separated by?
What are the names of the superior chambers?
What are the names of the inferior chambers?
Which chambers are known as the "receiving chambers" and why?
Atria and because they receive blood from veins
Why is the myocardial wall of each atrium not very thick?
Because little pressure is needed to move blood such a short distance
What is an auricle?
earlike flap protruding from each atrium
Which chambers are known as the "pumping chambers" and why?
Ventricles and because they push blood into the large network of vessels
Why are the ventricular myocardium thicker then the atria myocardium?
Because great force must be generated to pump blood a large distance
Between the ventricles, which myocardium is thicker and why?
The left is thicker because it must push blood much further
Which valve has the most issues and leads to the most surgeries?
Right Atrioventricular (AV) valve is also known as?
Left Atrioventricular (AV) valve is also known as?
What connects the free edges of the endocardium (of valve) to the papillary muscles?
The mitral valve is also known as the?
Half moon-shaped flaps growing out from the lining of the pulmonary artery and aorta are called...
Which valve is at the entrance to the pulmonary artery?
Pulmonary semilunar valve
Which valve is at the entrance to the aorta?
Aortic semilunar valve
What is the skeleton ring and what is its function?
set of connected rings that serve as a semirigid support for the heart valves and for attachment of cardiac muscle of the myocardium. Serves as an electrical barrier
What does left ventricular failure usually cause?
congested heart failure (CHF)
Myocardial cells receive blood from which arteries?
right and left coronary arteries
Where does the most abundant supply of blood go?
To the myocardium of left ventricle
Which coronary artery is dominate in approximately 50% of all hearts?
What is the approximate percentage of all hearts that neither coronary artery is dominate?
What percentage is remaining for dominate left coronary artery hearts?
What are anastomoses?
joining of two things
How many anastomoses exist between the larger branches of the coronary arteries?
A few exist
The SA node, AV node, AV bundle, and Purkinje fibers make up what system?
Conduction system of the heart
Which node is known as the pacemaker?
What does the SA node do and where is it located?
initiates electrical charge that starts heartbeat. Located in right atrial wall near superior vena cava opening
What does the AV node do and where is it located?
initiates electrical pulse when SA node fails. Located in right atrium along lower part of interatrial septum
What is a sign that the AV node has taken over firing the electrical pulse?
When is an artificial pacemaker is implanted?
If SA node is firing less often causing slower or skipped heartbeats
What happens if both the SA and AV node fire simultaneously?
They will cancel each other out and the heart will not beat
What is the cardiac plexuses made of and where is it located?
made up of the combination of sympathetic and parasympathetic fibers and located near arch of aorta
Fibers from cardiac plexus accompany...
right and left arteries to enter heart
Which nerves are also known as accelerator nerves?
Vagus fibers are...
inhibitory or depressor nerves
Which vessels carry blood away from the heart?
Which arteries are the largest in the body?
Elastic arteries. Ex: aorta and its major branches
Which vessels carry blood from arterioles to venules?
What are the four types of capillaries?
True, continuous, fenestrated, and sinusoids
Which capillaries receive blood from flowing from metarteriole with inpit regulated by precapillary sphincters?
Which capillaries have both intercellular clefts and "holes" or fenestrations through plasma membrane to facilitate exchange functions?
What are the characteristics of sinusoid capillaries?
Large lumen and tortuous course
Absent or incomplete basement membrane
Very porous (permits migration of cells into and out of vessel lumen)
Which vessels carry blood toward the heart?
What are capacitance vessels?
Veins that act as collectors and reservoir vessels
"Building blocks" are...
What do "building blocks" do?
Line endothelial cells
What is the function of the lining of endothelial cells?
line the entire vascular tree
the only lining found in capillaries
provide a smooth luminal surface.
What is the function of the smooth luminal surface?
protects against intravascular coagulation
What is the route of the systemic circulation?
Blood flows from left ventricle of the heart through the blood vessels to all parts of the body (except gas exchange tissues of lungs) and back to right atrium
What is the route of the pulmonary circulation?
Venous blood moves from right atrium to right ventricle to pulmonary artery to lungs where gases are exchanged. Pulmonary veins carry O2 rich blood to left atrium then is dropped into left ventricle.
All arteries carry O2 except..
All veins carry deoxygenated blood except...
What is an end-artery?
An artery that eventually diverge into a capillary
What is the circle of Willis?
A protective mechanism that prevents clots from blocking blood flow in brain
How can you tell the difference between a arterial bleed and a venous bleed?
Arterial bleed will spurt and be bright red where as a venous bleed will be darker and ooze
What is the hepatic portal circulation?
Veins from spleen, stomach, pancreas, gallbladder, and intestines send their blood to the liver via the hepatic portal vein.
In a fetus, which two organs do not begin working until birth?
lungs and liver
What is the Ductus Venosus?
continuation of umbilical vein, drains into vena cava
What is the Foramen Ovale?
opening in septum between right and left atria
What happens to the Foramen Ovale after birth?
functionally closes shortly after first breath and pulmonary circulation begins. It can structurally take up to 9 months to close.