Circulatory system Flashcards
Heart Location
- The heart is located in the mediastinum (prosteriorly extends
from the sternum anteriorly to the vertebral column, and lies medially
between the two lungs and the pleural membranes that
cover them)
Heart Angle
The base of the heart is
tipped up medially and
posteriorly, while the apex
projects inferiorly and
laterally.
The Pericardium
- membrane that
surrounds and
protects the heart - helps retains its
position in the
mediastinum,
while allowing for
some freedom of
movement
The Pericardium - structure
- The pericardium is composed of a tough
outer fibrous layer lined by a delicate serous membrane. - The fibrous pericardium is a very dense
and non-flexible connective tissue that
helps protect and anchor the heart. - The inner serous pericardium is
subdivided into a parietal layer which
adheres to the outermost fibrous layer
and a visceral layer which is also viewed
as the outer surface of the heart wall. - A thin pericardial fluid lubricates the
space between the visceral and parietal
pericardium.
Layers of the Heart Wall
- The epicardium, the thin, transparent
outer layer of the heart wall, is also called
the visceral layer of the serous pericardium. - The myocardium, the thick middle layer, is
composed of cardiac muscle. - The endocardium is a simple squamous
epithelium that is known throughout the
circulatory system as endothelium
Chambers of the Heart
- The heart has 4 Chambers:
- The upper 2 are the right
and left atria. - The lower 2 are the right
and left ventricles.
The right heart consists of the
right atrium and right
ventricle, taking venous blood
from the body and pumping it
to the lungs for oxygenation.
The left heart consists of the
left atrium and left ventricle,
taking freshly oxygenated
pulmonary
blood and pumping it
systemically to the body.
Arteries
- always conduct blood
away from the heart
– mostly contain oxygenated blood. - Mostly thick-walled
- exposed to high pressures
and friction forces.
Veins
- Veins are vessels that always bring blood back to the heart
- mostly contain deoxygenated blood.
- thin-walled
- exposed to low pressures
- minimal friction forces.
major arteries attach to…
attach to the heart are the arch of the aorta ,the
pulmonary trunk and the coronary arteries
major veins that attach to…
attach to the heart
are the superior and inferior vena cava,
the four pulmonary veins and the coronary sinus.