Written Assignment Unit 4
University of the People
HS 2211 Human Anatomy and Physiology
Shelly Watkins, Instructor
October 04, 2022
Name (Withheld for grading purposes)
Introduction
The heart is one of the most vital organs in the human body. It forms part of the cardiovascular
system along with veins, arteries, and capillaries. The heart is often called the pump as it pumps
the blood throughout the body carrying oxygen and nutrients to the cells while also removing
carbon dioxide and waste. Therefore, any structural change to the cardiovascular system is bound
to affect its functioning. This paper aims to explain one specific structural (anatomic) difference
and its physiological consequence.
The heart
The heart is a muscular organ in the thoracic cavity known as the mediastinum. The heart's center
is hollow and houses four separate chambers. Its main responsibility is to pump blood throughout
the body. The heart represents the most important organ in the cardiovascular system. The
pericardium, located outside the heart, comprises thick connective tissue that protects and
stabilizes the heart (OpenStax, 2018). An involuntary cardiac muscle called the myocardium
forms the heart wall (the outer membrane of the heart is called the epicardium, and the inner
membrane is called the endocardium). The four previously mentioned hearth chambers include
two upper chambers known as the right and the left atrium and two lower chambers known as the
left and the right ventricle (OpenStax, 2018). A septum is a dividing wall between the two atria
and ventricles. The right atrium receives the blood coming back to the heart from the systemic
circulation (deoxygenated blood) and passes it to the right ventricle through the tricuspid valve
(OpenStax, 2018). From the right ventricle, the blood flows into the pulmonary tract that
branches into the left and right pulmonary arteries that carry it to each lung for oxygenation.
Once full of oxygen, the blood flows back from the pulmonary tract into the left atrium via one
of the pulmonary veins, passing to the left ventricle through the mitral valve. The left ventricle is
the major pumping chamber that pumps blood into the aorta and the rest of the body. In addition
to the tricuspid and the mitral valve, the pulmonary and the aortic valve ensure the unilateral
flow of the blood, meaning the blood never flows back and forth between the atrium and
ventricle.
Atrial septal defect (ASD)
Congenital heart defects such as atrial septal disorders affect the heart's structure at birth. In other
words, an atrial septal defect indicates an opening or a hole in the septum that separates the two
upper chambers known as the atrium (Centers for Disease Control and Prevention, 2019). Minor
septal disorders have the potential to close shortly after birth or even during pregnancy, but some
are more severe and might require surgery. In atrial septal disorder, the blood does not follow the
natural flow from the right atrium to the right ventricle as regular deoxygenated blood does.
Instead, the oxygenated blood from the lungs in the