Anatomy and Physiology: Inflammation, Immune System, Heart and Blood Pressure Regulation

1. Nathan is fixing a fence and scrapes his leg along a length of barbed wire. He manages to
stop the flow of blood by applying pressure and wraps his t-shirt around his leg while he
drives home from the paddock. At home, Nathan gives the wound a good clean but calls the
hospital for information and advice because he has noticed swelling and his leg is a bit sore.
a) Explain the four signs of inflammation and include the purpose (benefit) of each
response. In your answer, make it clear how pain serves a protective function (6 marks).
Inflammation is known as the response triggered as a result of damage cause to a living
tissue. There are commonly four signs associated with inflammation which involves the
following:
Pain: It results from inflammatory chemicals which attempts to stimulate nerve endings
and accordingly causes affected areas to feel more sensitive. Pain can arise in both
muscles and joints and in the event of chronic inflammation, a person feels high level of
stiffness and pain sensitivity making the area sensitive to touch. A severe injury causes
higher pain as compared to less severe injury and accordingly, pain serves as a protective
function. A person usually behaves in certain manner after sensing a noxious stimulus to
minimize injury, thus promote healing for the injury.
Heat: With the flow of more blood to the inflamed areas of the body, that part of the
body became warm. People affected with arthritic condition have inflamed joints which
results in that area becoming warm to touch. In the event of whole body inflammation, a
person feels fever as a result of infection or illness. This is helpful in avoiding big injury or
infection.
Redness: The purpose of the inflamed area becoming red is the blood vessel getting filled
with more blood than usual which triggers the need for treatment.
Swelling: It takes place as a result of fluid accumulating in tissues which may be only
restricted to the affected area or may be affecting the entire body.
b) Name and briefly discuss the first and second-line defenses in place to resist pathogens
entering the body and to stop the spread of the pathogen and potential infection. Name
two phagocytic cells and outline the importance of phagocytosis during the inflammatory
process (5 marks).
The first line of defense in place are the surface barriers. Mucus, tears and skin are the
surface barriers that fight against the infection and thus protects from invading
pathogens. There are beneficial bacteria grown over the human skin, bowel and other
parts of the body like mouth & gut that prevents harmful bacteria to take over. The
second line of defense are the non-specific phagocytes as well as other mechanism lying
internally which are having innate immunity that prevents the entry of pathogens into the
body. They destroy invaders in general manner and not target specific individual.
The name of two phagocytic cells are macrophages and neutrophils. Phagocytosis is
regarded as complex process where cells in most of the organ systems eliminate cell

debris and pathogens. This process is followed by inflammatory pathway activation which
in turn promotes elimination of pathogens as well as inhibits growth in it.
c) The adaptive (specific) immune system is activated when innate defenses are
unsuccessful in capturing and destroying a pathogen, such as bacteria or virus. Briefly
describe the role T-cells have in protecting the body against substances that infect body
cells (3 marks).
Human body is highly exposed to pathogens like viruses, bacteria & fungi. In the absence
of T cells such exposure is life threatening because these cells are helpful wiping out the
cancerous or infected cells. T cells are a part of immune system and plays the role of
coordination and focuses on particular foreign particles. Instead of attacking any antigens
generically, T cells keep in circulation till encountering their specific antigen.
d) Which steps are involved in haemostasis? Briefly describe the importance of the second
step of haemostasis (3 marks).
There are four steps involved in the mechanism of haemostasis which are as follows:
1. Blood vessel constriction
2. Temporary platelet plug formation
3. Coagulation cascade activation
4. Final clot formation.
The second step involve formation of temporary platelet plug which is important in
preventing blood loss with the accumulation of platelets around a breakage. Therefore,
more loss of blood from the body can be prevented alongside preventing any
contaminants from the outside getting into the body.

2. You are working in a hospital where you see numerous patients with respiratory illnesses
every day. Patients who have chronic obstructions in their airways run the risk of retaining
carbon dioxide in the body because they cannot exhale it properly from their lungs. A
healthy respiratory system helps regulate carbon dioxide levels in the body as part of the
acid-base balance. The kidneys also regulate acid base balance in the body and help
maintain stable plasma pH levels.
a) What effect does an increase in plasma carbon dioxide levels have on hydrogen ion
concentration? Does this result in an increase or decrease of plasma pH? (2 marks).
Respiratory acidosis takes place with the occurrence of CO2 not getting out with
breathing which results in overly acidic blood and thus respiratory problem like COPD
arise. With the rise in CO2, the concentration of hydrogen ion in the bloodstream rises
alongside lowering the ph level which in turn sets the state of acidosis. On the other hand,
with the lowering of CO2, the concentration of hydrogen ion in the bloodstream falls
resulting in alkalotic state.
b) What role do the kidneys play in maintaining the acid base balance in the body? (2
marks).
The role of kidney in maintaining the acid base balance in the human is quite major which
involves reabsorption of bicarbonate filtered by the glomeruli along with excreting the
titratable acids & ammonia through the urination process. Therefore, two roles does the
kidney play in maintaining the acid base balance that is, excretion of hydrogen ion into
the urine and reabsorbing bicarbonate from the urine.
c) Explain in detail the respiratory negative feedback loop activated when an increased level
of carbon dioxide is detected in the bloodstream. Include in your answer the names of the
general components of a negative feedback loop and identify by name the specific parts of
the body involved in regulating carbon dioxide levels. Make it clear how a change in
ventilation rectifies the imbalance and what makes the whole process an example of
homeostasis (8 marks).
On detecting the rise in carbon dioxide in the bloodstream, the lungs are signaled
resulting in rise in its activity & exhaling more carbon dioxide which is experience by a
person with the increase in breathing rate. The body respond to the rise in carbon dioxide
through hyperventilation or hypoventilation. A negative feedback loop facilitates self
regulation of the human body like regulation of O2 and CO2 levels in the blood in an
attempt to make sure that sufficient O2 is delivered for meeting the needs of cells for
cellular respiration as well as sufficient amount of CO2 has been removed from the body
for the prevention of harmful effects.
There are four basic components of the negative feedback loop which involves stimulus,
control, censor and effector.
Specific parts of the body involved in regulating carbon dioxide levels are airways, blood

vessels and lungs which works together for moving or cleaning out unwanted gases like
CO2 from the body. Also, the brain performs the function of regulating the amount of
carbon dioxide during exhalation by controlling the depth & speed of breathing known as
ventilation.
With the change in ventilation (speed or depth of breathing) that is, the breathing rate
increases results in the reduction of the amount of CO2 in the blood leading to rise in
blood ph and then comes to normal level. In case of blood ph becoming too alkaline, the
rate of breathing decreases leading to rise in carbon dioxide in the blood. Therefore, the
increase or decrease in breathing rate (ventilation) is helpful in balancing the levels of
CO2 and O2 in the blood and acts as an example of homeostasis which is the process
through which body reacts to the changes for keeping the condition inside the body in
order.