Unit 12A- Disease and Infections
Definition of disease:
A disease is an abnormal condition of an organism which interrupts the normal bodily functions
that often leads to feelings of pain and weakness and is usually associated with symptoms and
signs.
https://www.biology-online.org/dictionary/Disease
Definition of an infectious disease:
An infectious disease is a disease due to the presence of an infectious particle, especially a
microbial pathogenic agent that is capable of being transmitted to another host. Different
microbial agents can bring disease to their host. They include the pathogenic viruses, bacteria,
fungi, protozoa, prions etc.
https://www.biology-online.org/dictionary/Infectious_disease
Case study for patient presenting symptoms of an infectious disease (Hepatitis B);
A 31 year old male presented himself to his GP with symptoms of fatigue and abdominal pain.
The patient had a history of 4 sexual partners in the last 3 months with no protection. He had no
history of taking illegal drugs and his overall health was good with no other medical conditions.
Upon a physical examination his liver was noted to be slightly enlarged and the whites of his
eyes were of a yellow tinge, presenting symptoms of jaundice. A blood test was requested to be
taken to investigate any possible disease occurring in the liver or elsewhere in the body. After
reviewing the patient’s blood results, the male patient was diagnosed with acute hepatitis B.
M1. Assess the physiological effects of the disease on the structure and function of the
human body.
Hepatitis B is a type of infectious disease which is transmitted through blood or body fluid
contact of an individual infected with the hepatitis B virus infection (also known as hepatitis B
surface antigen positive). Once infected the hepatitis B virus mostly attacks the liver causing a
multitude of health problems. This happens because the hepatitis B virus attacks the liver cells
by binding to them. The cells in the liver (hepatocytes) engulfs the hepatitis B virus via
endocytosis. The body’s immune system then begins to attack the infected liver cells,
simultaneously damaging the liver and removing the hepatitis B virus from the body. Cytotoxic
lymphocytes (CTLs) are examples of the body’s immune response to the HBV infection. These
lymphocytes in particular cause a lot of liver damage as they kill cells which contain the hepatitis
B virus, hence killing the liver cells, reducing the function of the liver. Other inflammatory cells
and activated platelets at the site of infection further damage the liver and its function.
Definition of disease:
A disease is an abnormal condition of an organism which interrupts the normal bodily functions
that often leads to feelings of pain and weakness and is usually associated with symptoms and
signs.
https://www.biology-online.org/dictionary/Disease
Definition of an infectious disease:
An infectious disease is a disease due to the presence of an infectious particle, especially a
microbial pathogenic agent that is capable of being transmitted to another host. Different
microbial agents can bring disease to their host. They include the pathogenic viruses, bacteria,
fungi, protozoa, prions etc.
https://www.biology-online.org/dictionary/Infectious_disease
Case study for patient presenting symptoms of an infectious disease (Hepatitis B);
A 31 year old male presented himself to his GP with symptoms of fatigue and abdominal pain.
The patient had a history of 4 sexual partners in the last 3 months with no protection. He had no
history of taking illegal drugs and his overall health was good with no other medical conditions.
Upon a physical examination his liver was noted to be slightly enlarged and the whites of his
eyes were of a yellow tinge, presenting symptoms of jaundice. A blood test was requested to be
taken to investigate any possible disease occurring in the liver or elsewhere in the body. After
reviewing the patient’s blood results, the male patient was diagnosed with acute hepatitis B.
M1. Assess the physiological effects of the disease on the structure and function of the
human body.
Hepatitis B is a type of infectious disease which is transmitted through blood or body fluid
contact of an individual infected with the hepatitis B virus infection (also known as hepatitis B
surface antigen positive). Once infected the hepatitis B virus mostly attacks the liver causing a
multitude of health problems. This happens because the hepatitis B virus attacks the liver cells
by binding to them. The cells in the liver (hepatocytes) engulfs the hepatitis B virus via
endocytosis. The body’s immune system then begins to attack the infected liver cells,
simultaneously damaging the liver and removing the hepatitis B virus from the body. Cytotoxic
lymphocytes (CTLs) are examples of the body’s immune response to the HBV infection. These
lymphocytes in particular cause a lot of liver damage as they kill cells which contain the hepatitis
B virus, hence killing the liver cells, reducing the function of the liver. Other inflammatory cells
and activated platelets at the site of infection further damage the liver and its function.
