Transport and Respiration in Biology

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Biology
Biology
Transport and Respiration
MAY 28, 2019
Student Details:

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Biology
Contents
Introduction......................................................................................................................................2
Transport and Respiration................................................................................................................3
Structures of the heart with their function...................................................................................3
Difference between the coronary, pulmonary and systematic circulation...................................4
Comparison of consequences of blockage in the circulatory system..........................................5
Cardiac cycle with electrical stimulation.....................................................................................6
Role of pacemaker.....................................................................................................................10
Difference between cardiac output and blood pressure.............................................................10
Similarities and differences in cardiac output and blood pressure at rest and exercise.............11
Components of Respiratory System..........................................................................................12
Explanation of the structure and function of the components of the respiratory system..........14
Mechanism of breathing............................................................................................................20
Pressure changes in the thorax during breathing at a higher place............................................21
Conclusion.....................................................................................................................................23
References.....................................................................................................................................24

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Biology
Introduction
The heart is a muscular organ of the body. It consists of muscle fibers, blood vessels named
arteries, veins, and blood capillaries. It works by the help of electric signals generated by sino-
atrial node (SA), atrioventricular node (AV) and Purkinje fibers. It functions for the circulation
of oxygenated blood throughout the parts of the body and deoxygenated blood from the different
parts of the body to the lungs. It is located behind the sternum in the chest above the diaphragm.
The size of the normal heart is equal to fist size and it is of 298 grams or 10.5 ounces in weight.
It has double circulation named pulmonary circulation and systematic circulation. Besides this
one more circulation named coronary circulation is also situated in the heart. Blockage in these
circulatory systems may lead to consequences like heart failure, stroke, arrhythmia, dyspnea,
chest pain and many more diseases (Junior, 2019).
The respiratory system includes many organs of the body like the nasal cavity, larynx, pharynx,
trachea, lungs, and diaphragm. By the help of these organs, inhalation and exhalation process of
breathing takes place (Zimmermann, 2018).

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Biology
Transport and Respiration
Structures of the heart with their function
The heart is the part of the body made up of muscles, 4 chambers, wall, valves, blood vessels,
two electric signal generating nodes and fibers. Four chambers of heart named as left atrium
(LA) carry oxygenated blood from the lungs, “left ventricle (LV)” carry “oxygenated blood from
LA”, right atria take away “deoxygenated blood” from the body parts and right ventricle (RV)
carry deoxygenated blood from right atria (RA) . The heart has four valves. One is “mitral valve
(bicuspid valve)” which is situated in between LA and LV through which oxygenated blood from
left atria to ventricle get passed. Second is “aortic valve” situated in between “left ventricle and
the aorta” by which “oxygenated blood” gets passed to different parts of the body. The third is
“tricuspid valve” stated in between “right atrium and right ventricle” and pass “deoxygenated
blood” from right atria to the right ventricle. The last one is “pulmonary valve” situated in
between pulmonary artery and right ventricle and pass “deoxygenated blood” to lungs to get
“oxygenated” (Newman & Sullivan, 2018). Heart consists of three kinds of blood vessels which
are named to be “arteries which carry out oxygenated blood except for pulmonary artery”, veins
named superior and inferior vena cava which carry out the deoxygenated blood except for
pulmonary vein, and capillaries helps in exchange of compounds like nutrients, water, waste and
oxygen from near about tissues (Lewis & Writer, 2016).
A wall of muscles named septum isolates LA and LV from RA and RV. Three layers of the
tissue named “epicardium, myocardium, and endocardium” combinedly form the wall of the
heart and covered by pericardium tissue layer. Sino-atrial (SA) lies in the top of RA and known
to be a pacemaker. It generates an electric signal for the contraction of atria and passes down of

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Biology
blood into the ventricles. AV node situated in the bottom of right atrium passed electric signals
to make the gap in the contraction of atria and ventricles. Then Purkinje fibers in the ventricle
walls and generate signal to heart muscle to produce contraction in the ventricles and causes
“diastole (relaxation of atria)”and ventricles filled with blood and “systole (contraction of atria)”,
ventricles get filled by the blood, contraction of ventricles and pumping of blood outside the
heart) to the heart (Beckerman, 2019).
Difference between the coronary, pulmonary and systematic circulation
Coronary Circulation Pulmonary Circulation Systematic Circulation
“Coronary circulation”
provide blood supply to the
right atrium, right
ventricle, SA node, AV node
and to the selected part of
LA of the heart, blood
supply provided by right
coronary artery (RCA). To
the LA and LV, the blood
supply is provided by left
circumflex artery (LCX)
and left anterior descending
artery (LAD) which are the
parts of left coronary artery
(LCA) (Rehman &
“Pulmonary circulation”
function for the circulation of
deoxygenated blood from the
RA to RV through the
tricuspid valve. Then from
here, deoxygenated blood
pumped into the pulmonary
artery that carries
deoxygenated blood into the
lungs (Boyette & Burns,
2019).
“Systematic circulation”
work to circulate oxygenated
blood from LA of the heart
passed into the left ventricle
through the bicuspid valve.
Then from here, blood
pumped into the aorta to
supply oxygenated blood
throughout the different body
parts (Lakna, 2017).

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Rehman, 2019).
It helps in coronary
vasodilation.
Inside the lungs
deoxygenated blood gets
oxygenated by releasing
carbon dioxide in the
pulmonary vesicles and by
addition of oxygen into the
bloodstream. Then this
oxygenated blood carried out
to the LA chamber of the
heart from the lungs by
pulmonary veins.
Deoxygenated blood carried
out from the different body
parts to the right atrium
chamber of the heart through
superior vena cava and
inferior vena cava.
It is composed of RCA and
LCA (Rehman & Rehman,
2019).
This circulatory system
consists of the pulmonary
artery and pulmonary vein
(Boyette & Burns, 2019).
In this circulatory system,
superior and inferior vena
cava, aorta takes place
(Lakna, 2017).
Comparison of consequences of blockage in the circulatory system
Coronary Circulation Pulmonary Circulation Systematic Circulation
Due to the occurrence of
blockage in the coronary
artery, narrowing and
Due to blockage in the
pulmonary artery and vein,
pulmonary hypertension takes
Due to blockage in the aorta,
superior and inferior vena
cava, it causes arrhythmia,