Anatomy and Physiology: Fluid Dynamics, Respiration, and Excretion

This essay provides a comprehensive overview of key concepts in anatomy and physiology. It explains the roles of hydrostatic and osmotic pressure in tissue fluid formation and reabsorption, details the causes and characteristics of oedema, and describes the structure and mechanisms of the respiratory system, including breathing, diffusion, and oxygen transport by haemoglobin. Furthermore, it discusses how diseases like asthma and emphysema compromise oxygen uptake and the negative effects of smoking on the respiratory system. The essay also defines excretion, emphasizes its importance for health, and provides examples of related organs and systems, such as the kidneys and their function in waste removal. The document is available on Desklib, a platform offering a wide range of study tools and solved assignments for students.

Anatomy and Physiology 1
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Anatomy and Physiology 2
Anatomy and Physiology
Explain the role of hydrostatic and osmotic pressure in the formation and
reabsorption of tissue fluid.
Hydrostatic pressure can be defined as pressure of a fluid that is in an enclosed space.
This is the pressure that is primarily responsible for the movement of fluids between the
capillaries and the tissues (Collins and Varmus, 2015). In other words, it is the pressure that
is mainly responsible for movement of fluid from the capillaries to the tissues. It follows that
the pressure plays a key role in the formation of tissue fluid. One kind of this pressure is the
blood hydrostatic pressure. It refers to the force that is exerted by blood which is enclosed by
the capillaries or the chambers of the heart (VanPutte, Regan and Russo 2017). There is also
capillary hydrostatic pressure. This refers to the pressure applied by blood to the walls of
capillaries. As seen above this pressure is responsible for the formation of tissue fluid through
movement of fluids from the capillaries to the tissues.
Osmotic pressure is antagonistic to the hydrostatic pressure. It is responsible for the
movement of fluids from the tissue fluid back to the capillaries (Lavie et al. 2015). This
process is referred to as reabsorption. It is also known as oncotic pressure. While the
hydrostatic pressure leads to movement of fluids from the capillaries, osmotic pressure causes
the fluids to move back to the capillaries. Osmotic pressure is dependent on the osmotic
concentration gradient. This refers to the difference between the concentration of water and
solutes. Water moves from a region where it is in high concentration to a region where it is in
low concentration across a semi-permeable membrane.

Anatomy and Physiology 3
Explain oedema and some possible causes.
Oedema refers to a condition where there is accumulation of body fluid in excessive
quantities. The fluid accumulation occurs in body tissues. Oedema may occur in almost any
part of the body. Although this is the case oedema may occur more in certain parts of the
body. These include the legs, hand, feet, arms and ankles. The condition is characterized by
swelling which occurs directly beneath the skin and especially in the legs. It may also lead to
stretching of the skin to the pressure applied by the swelling. Oedema may also cause the
abdomen to be swollen (Foster and Coetzee 2015). One common way of determining oedema
is through using the thumb to press the area suspected. In cases of oedema, a pit is usually
left. The pit disappears slowly. The condition may be given different names depending on the
area of the body that it affects. For instance, there is pulmonary oedema, peripheral oedema
etc.
There are several possible causes of oedema. The common mode of causation is
through leaking of fluid from the blood vessels in to the neighbouring environment. Mild
cases may be caused by such factors as: sitting in a place for a long period, consuming a diet
that is high in sodium and pregnancy (Smith 2014). Oedema could also present as a side
effect of certain medications. For instance, drugs used to treat hypertension, oestrogens,
thiazolidinediones (drugs for diabetes management) and steroid drugs. In some instances,
oedema may be a symptom of another serious condition (Waugh and Grant 2014). Such
conditions include congestive heart failure and kidney diseases.
Explain the structure of the respiratory system.
This is the system that carries out the proves of breathing/ gaseous exchange. The
process is fundamental to life and any illness affecting the system poses a significant threat to

Anatomy and Physiology 4
life. The process of breathing involves two main processes. The fist is inhalation which refers
to the absorption of oxygen from the air for respiration purposes. The second process is
exhalation. This is discarding of carbon dioxide from the body. Carbon dioxide is a by-
product of metabolism. The system is categorized in two: the upper part and the lower part.
The upper part is composed of the organs running from the nose to the trachea. The
mouth is also an organ of the upper part. The lower part is composed of the trachea, the
bronchi, bronchiole and the lungs. These organs (those of the lower respiratory tract) are
contained in the chest cavity. The trachea can be defined as tubular structure which bridges
the throat and the bronchi. The bronchi (singular bronchus) refers to two tubes that branch
from the trachea. These go to the lungs. The bronchi divide further in to tubular structures
called bronchioles. There are also the pulmonary alveoli. This refers to tiny air sacs that have
a single layer membrane and connect to blood capillaries. Gaseous exchange occurs at the
pulmonary alveoli. The lung refers to the organ including the air tubes from the bronchi each
ending to an alveolus. It is the organ at the centre of gaseous exchange.
Explain mechanisms of breathing, diffusion in the lungs, and how oxygen
combines with haemoglobin to be carried around the body.
Gaseous exchange refers to the process by which the oxygen is obtained from the
surrounding environment to the blood stream and the elimination of carbon dioxide. As
observed in the previous discussion, the lung is at the centre of this process. The process of
gaseous exchange between the blood and the pulmonary alveoli occurs through the process of
simple diffusion (Reed, Bayly and Sellon 2017). For the process of diffusion to occur
efficiently, it is necessary that a concentration gradient be maintained (Rizzo 2015). This
means that the oxygen concentration in the alveoli should consistently be lower than that in

Anatomy and Physiology 5
the blood while the level of carbon dioxide in the blood should be greater than that in the
alveoli. This is maintained by the continuous process of breathing which eliminates carbon
dioxide from the body while supplying air rich in oxygen and low in carbon dioxide.
The process of breathing is active and involves contraction and relaxation of muscles.
The muscles mainly involved in the process are internal and external intercostal muscles; and
the diaphragm. Haemoglobin is the protein that is mainly responsible for transport of blood to
most tissues of the body. Haemoglobin is contained in the red blood cells. Each contains four
groups of haem and each group contains iron. One haemoglobin group can carry four oxygen
molecules. Reaction between haem and oxygen leads to formation of oxyhaemoglobin.
Explain how diseases such as asthma and emphysema compromise the uptake of
oxygen, and the effect of smoking on the respiratory system.
There are certain disease conditions that may affect the integrity of the respiratory
system and pose significant threat to health. One of such conditions is asthma. Asthma is a
condition that causes the inflammation of the air passages (Asthma, 2014). The result of the
inflammation is a temporary narrowing of the airway. Symptoms of asthma include coughing,
chest tightness, wheezing and shortness of breath (Network, 2014). When the airway is
narrowed, the normal functioning of the respiratory system is altered (Lambrecht and
Hammad 2015). It becomes harder for oxygen to reach the lungs and for carbon dioxide to be
excreted. If the condition is severe, it may greatly deteriorate the quality of living.
Emphysema is another condition that may negatively alter the integrity of the
respiratory system. When one has emphysema, the alveoli get damaged (Bogner, 2018). This
causes the airway to collapse and makes the process of gaseous exchange difficult. The result
is inadequate exchange of gases which may pose a great threat to life. One cannot survive for

Anatomy and Physiology 6
long when the process of gaseous exchange is severely altered. The disease may cause a total
collapse of the airway which caused death. It can therefore be concluded that emphysema
severely affects the operations of the respiratory system in a negative way.
Smoking is another factor that may affect the integrity of the respiratory system in a
negative way. Extensive evidence has suggested that smoking increases the chance of
developing lung disease including lung cancer chronic bronchitis and emphysema. All these
reduce the ability of the respiratory system to carry out its function.
Define excretion, explain why excretion is vital for health and include examples
of structure and function of related organs and systems.
Excretion refers to the process by which the body gets rid of the waste products of
metabolism. The normal bodily processes such as metabolism lead to formation of by-
products which may be toxic to the body. It is therefore undesirable that these wastes
accumulate in the body for they could cause harm. The body has a complex system that
ensures homeostasis. Homeostasis simply refers to the process by which the body maintains
body concentrations at a relatively normal range. The excretory system is involved in getting
rid of the waste products. Removal of waste products is done by various organs. Some of
these are the sweat glands, liver, kidney and lungs.
The kidney carries the most excretory work (Scanlon and Sanders 2018). It is
composed of three parts. These are the renal medulla, renal cortex and renal; pelvis. The
kidney is used in eliminating waste products from the blood. The blood enters the organ
through the renal artery. The artery branches into many different arterioles. These further
divide in to tiny structures known as the nephrons. The nephron is the basic unit of a kidney.
When the blood flows to the bowman’s capsule of the kidney, pressure is applied, and this

Anatomy and Physiology 7
leads to filtration. The wastes are filtrated/taken out by the application of the pressure. There
are some capillaries (peritubular) that surround the nephron so that substances can move in
and out of the blood. The renal pelvis takes the urine (waste) away using the ureter. The
contents of the ureter are emptied in to the urinary bladder.

Anatomy and Physiology 8
References
Asthma, U.K., 2014. Asthma facts and FAQs. Routledge.
Bogner, M.S., 2018. Human error in medicine. CRC Press.
Collins, F.S. and Varmus, H., 2015. A new initiative on precision medicine. New England
Journal of Medicine, 372(9), pp.793-795.
Foster, M.N. and Coetzee, W.A., 2015. KATP channels in the cardiovascular system.
Routledge.
Lambrecht, B.N. and Hammad, H., 2015. The immunology of asthma. Routledge.
Lavie, C.J., Arena, R., Swift, D.L., Johannsen, N.M., Sui, X., Lee, D.C., Earnest, C.P.,
Church, T.S., O’keefe, J.H., Milani, R.V. and Blair, S.N., 2015. Exercise and the
cardiovascular system: clinical science and cardiovascular outcomes. Routledge.
Network, G.A., 2014. The global asthma report 2014. Routledge.
Reed, S.M., Bayly, W.M. and Sellon, D.C., 2017. Equine Internal Medicine-E-Book. Elsevier
Health Sciences.
Rizzo, D.C., 2015. Fundamentals of anatomy and physiology. Cengage Learning.
Scanlon, V.C. and Sanders, T., 2018. Essentials of anatomy and physiology. FA Davis.
Smith, B.P., 2014. Large Animal Internal Medicine-E-Book. Elsevier Health Sciences.
VanPutte, C.L., Regan, J.L. and Russo, A., 2017. Seeley's anatomy & physiology. McGraw-
Hill Education.
Waugh, A. and Grant, A., 2014. Ross & Wilson Anatomy and Physiology in Health and
Illness. Elsevier Health Sciences.

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