NUR11O1 Integrated Human Anatomy and Physiology

Department of Biology
Institute of Arts and Sciences
Far Eastern University
LECTURE ACTIVITY NO. 12
CARDIOVASCULAR SYSTEM: HEART

Name: Santiago, Prancheska Abigayle P. Section: 12 Date Submitted: Nov. 12, 2020

I. INTRODUCTION

The heart is the major organ of the cardiovascular system which pumps oxygenated
blood to the different organs of the body through its systemic circuit and loads the
deoxygenated blood via the pulmonary circuit.

II. ACCOMPLISH THE ACTIVITY TABLE 1.

GUIDE QUESTIONS ANSWERS

12.01A. List the major functions of the 1. Pumping oxygenated blood to the other body parts.
heart. 2. Pumping hormones and other vital substances to different
parts of the body.
3. Receiving deoxygenated blood and carrying metabolic
waste products from the body and pumping it to the lungs
for oxygenation.
4. Maintaining blood pressure.
12.02A. Describe the size, shape, and The heart is a muscular organ about the size of a
location of the heart, and explain why fist, located just behind and slightly left of the breastbone.
knowing its location is important. The heart pumps blood through the network of arteries and
veins called the cardiovascular system.

12.03A. Describe the structure of the The pericardium is the membrane that encloses the heart and
pericardium. the roots of the major heart vessels, consisting of an outer
fibrous layer (fibrous pericardium) and an inner double
serous membrane layer (serous pericardium).
12.03B. Give the location and function of Coronary arteries supply blood to the heart muscle. Like all
the coronary arteries. other tissues in the body, the heart muscle needs oxygen-rich
blood to function. Also, oxygen-depleted blood must be
carried away. The coronary arteries wrap around the outside
of the heart.

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
12.03C. Describe the chambers of the The heart has four chambers: two atria and two ventricles.
heart. The right atrium receives oxygen-poor blood from the body
and pumps it to the right ventricle. The right ventricle pumps
the oxygen-poor blood to the lungs. The left atrium receives
oxygen-rich blood from the lungs and pumps it to the left
ventricle.
12.03D. Name the valves of the heart 1. Tricuspid valve: located between the right atrium and the
and state their locations and functions. right ventricle. Opens to allow blood to flow from the right
atrium to the right ventricle. Prevents the back flow of blood
from the right ventricle to the right atrium.
2. Pulmonary valve: located between the right ventricle and
the pulmonary artery. Separates the right ventricle from
the pulmonary artery. Opens to allow blood to be pumped
from the right ventricle to the lungs (through the pulmonary
artery) where it will receive oxygen. Prevents the back flow of
blood from the pulmonary artery to the right ventricle.
3. Mitral valve: located between the left atrium and the left
ventricle. Your mitral valve is located between the left atrium
and left ventricle of your heart. It regulates the flow of blood
from your lungs into the left ventricle, the main pumping
chamber. Oxygen-rich blood comes from your lungs and fills
the left atrium.
4. Aortic valve: located between the left ventricle and the
aorta. Opens to allow blood to leave the heart from the left
ventricle through the aorta and the body. Prevents the
backflow of blood from the aorta to the left ventricle.
12.03E. Describe the flow of blood The heart contains four chambers, two atria and two
through the heart, and name each of the ventricles. The blood that is returned to the right atrium is
chambers and structures through which deoxygenated and s passed into the right ventricle to be
pumped through the pulmonary artery to the lungs for
the blood passes.
reoxygenation and removal of carbon dioxide. The left atrium
receives newly oxygenated blood from the lungs through the
pulmonary veins, which is passed into the strong left
ventricle to be pumped through the aorta to the different
organs of the body.

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
12.04A. List the components of the heart The heart wall consists of three layers:
wall and describe the structure and 1. Endocardium - The endocardium is a thin, smooth
function of each. membrane which lines and gives the glistening appearance to
the inner surface of the heart; it assists in forming the valves
by its reduplications, and is continuous with the lining
membrane of the large bloodvessels.
2. Myocardium - Cardiac muscle tissue is a specialized,
organized type of tissue that only exists in the heart. It is
responsible for keeping the heart pumping and blood
circulating around the body. Cardiac muscle tissue,
or myocardium, contains cells that expand and contract in
response to electrical impulses from the nervous system.
3. Epicardium - The epicardium is a thin layer of elastic
connective tissue and fat that serves as an additional layer of
protection from trauma or friction for the heart under the
pericardium. This layer contains the coronary blood vessels,
which oxygenate the tissues of the heart with a blood supply
from the coronary arteries.
12.04B. Describe the structural and Cardiac muscle is striated muscle that is present only in
functional characteristics of cardiac the heart. Cardiac muscle fibers have a single nucleus, are
muscle cells. branched, and joined to one another by intercalated discs that
contain gap junctions for depolarization between cells and
desmosomes to hold the fibers together when
the heart contracts.
12.05A. Describe the characteristics of The cardiac action potential is a brief change in voltage
action potentials in cardiac muscle. (membrane potential) across the cell membrane of heart cells.
This is caused by the movement of charged atoms (called
ions) between the inside and outside of the cell, through
proteins called ion channels.
12.05B. Explain the structure and The conducting system of the heart consists of cardiac muscle
function of the conduction system of the cells and conducting fibers (not nervous tissue) that are
heart. specialized for initiating impulses and conducting them
rapidly through the heart (see the image below). They initiate
the normal cardiac cycle and coordinate the contractions
of cardiac chambers.

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
12.05C. Describe the waves of an The waves on an ECG include the:
electrocardiogram, and relate each of 1. P wave - The P wave represents the depolarization of the
them to contractions of the heart. left and right atrium and also corresponds to
atrial contraction.
2. The QRS Complex - refers to the combination of the Q, R,
and S waves, and indicates ventricular depolarization and
contraction (ventricular systole). The Q and S waves are
downward waves while the R wave, an upward wave, is the
most prominent feature of an ECG. The QRS complex
represents action potentials moving from the AV node,
through the bundle of His and left and right branches and
Purkinje fibers into the ventricular muscle tissue.
Abnormalities in the QRS complex may indicate cardiac
hypertrophy or myocardial infarctions.
3. The T Wave - it indicates ventricular repolarization, in
which the ventricles relax following depolarization and
contraction. The ST segment refers to the gap (flat or slightly
upcurved line) between the S wave and the T wave, and
represents the time between ventricular depolarization and
repolarization. An elevated ST segment is the classic indicator
for myocardial infarctions, though missing or downward
sloping sloping ST segments may indicate myocardial
ischemia.

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
12.06A. Describe the cardiac cycle and The cardiac cycle comprises a
the relationship among the contraction complete relaxation and contraction of both the atria and
of each of the chambers, the pressure in ventricles, and lasts approximately 0.8 seconds. Beginning
with all chambers in diastole, blood flows passively from the
each of the chambers, the phases of the
veins into the atria and past the atrioventricular valves into
electrocardiogram, and the heart
the ventricles. The atria begin to contract (atrial systole),
sounds.
following depolarization of the atria, and pump blood into
the ventricles. The ventricles begin to contract (ventricular
systole), raising pressure within the ventricles. When
ventricular pressure rises above the pressure in the atria,
blood flows toward the atria, producing the first heart sound,
S1 or lub. As pressure in the ventricles rises above two major
arteries, blood pushes open the two semilunar valves and
moves into the pulmonary trunk and aorta in the ventricular
ejection phase. Following ventricular repolarization, the
ventricles begin to relax (ventricular diastole), and pressure
within the ventricles drops. As ventricular pressure drops,
there is a tendency for blood to flow back into the atria from
the major arteries, producing the dicrotic notch in the ECG
and closing the two semilunar valves.
12.07A. Describe the heart sounds and The “ lub” is the first heart sound, commonly termed S1, and
their significance. is caused by turbulence caused by the closure of mitral and
tricuspid valves at the start of systole. The second sound,”
dub” or S2, is caused by the closure of aortic and pulmonic
valves, marking the end of systole. Specifically,
the sounds reflect the turbulence created when
the heart valves snap shut. In cardiac auscultation, an
examiner may use a stethoscope to listen for these unique and
distinct sounds that provide important auditory data
regarding the condition of the heart.
12.08A. Describe intrinsic and extrinsic 1. Intrinsic regulation of the heart rate (HR) includes the
regulation of the heart. myogenic sublevel and the sublevels of cell-to-cell
communication, the cardiac nervous system, and humoral
factors produced within the heart. Myogenic regulation is
considered to be the first sublevel in control of the cardiac
function.
2. Extrinsic controls of the cardiovascular system include
neuronal, humoral, reflex, and chemical regulatory
mechanisms. These extrinsic controls regulate heart rate,
myocardial contractility, and vascular smooth muscle to
maintain cardiac output, blood flow distribution, and arterial
blood pressure.

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
12.08B. Give the conditions for which 1. Anticoagulants (Also known as Blood Thinners.)
the major heart medications and What the Medication Does?
treatments are administered. Decreases the clotting (coagulating) ability of the blood.
Sometimes called blood thinners, although they do not
actually thin the blood. They do NOT dissolve existing blood
clots. Used to treat certain blood vessel, heart and lung
conditions.
2. Antiplatelet Agents and Dual Antiplatelet Therapy (DAPT)
What the Medication Does?
Keeps blood clots from forming by preventing blood platelets
from sticking together.
3. Angiotensin-Converting Enzyme (ACE) Inhibitors
What the Medication Does?
Expands blood vessels and decreases resistance by lowering
levels of angiotensin. Allows blood to flow more easily and
makes the heart's work easier or more efficient.
4. Angiotensin II Receptor Blockers (or Inhibitors) (Also
known as ARBs)
What the Medication Does?
Rather than lowering levels of angiotensin II (as ACE
inhibitors do) angiotensin II receptor blockers prevent this
chemical from having any effect on the heart and blood
vessels. This keeps blood pressure from rising.
5. Angiotensin Receptor-Neprilysin Inhibitors (ARNIs)
ARNIs are a drug combination of a neprilysin inhibitor and
an ARB.
What the Medication Does?
Neprilysin is an enzyme that breaks down natural substances
in the body that open narrowed arteries. By limiting the effect
of neprilysin, it increases the effects of these substances and
improves artery opening and blood flow, reduces sodium
(salt) retention, and decreases strain
12.09A. List the major age-related Normal changes in the heart include deposits of the "aging
changes that affect the heart. pigment," lipofuscin. The heart muscle cells degenerate
slightly. The valves inside the heart, which control the
direction of blood flow, thicken and become stiffer. A heart
murmur caused by valve stiffness is fairly common in older
people.

III. CONCLUSION: Make general statement (Maximum of three sentences on what you have
learned on this activity.
The cardiovascular system

©
Biofacultymember2020
NUR11O1 Integrated Human Anatomy and Physiology
Department of Biology
Institute of Arts and Sciences
Far Eastern University
particulary in the heart, is the most important of all other systems. Our heart is very small but it
has a big responsibility especially to all living organisms.

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Biofacultymember2020