Lecture 1: Introduction

Question 1

What is a disease?

Answer 1

Any state in which the health of the human organisms is impaired. Disease is a consequence of a failure of homeostasis.

Question 2

Homeostasis

Answer 2

the biological process that maintains a physiological steady state.

Question 3

what is meant by “steady state” in homeostasis

Answer 3

Maintaining an appropriate steady state of the internal environment despite changes in the external environment.

Question 4

Why is homeostasis usually desirable?

Answer 4

Allows consistency (constancy) in function of organs, tissues, cells, organelles, proteins.

Question 5

Pathogenesis…

Answer 5

Biological mechanisms causing evident disease

Question 6

Aetiology…

Answer 6

the specific cause of a disease

Question 7

Predisposition…

Answer 7

A susceptibility or tendency to develop a disease, which depends on other risk factors to become clinically evident.

Question 8

Risk factor…

Answer 8

A risk factor is a variable exposure or biological characteristic which makes a disease more likely

Question 9

Genotype & Environment–>

Answer 9

Phenotype

Question 10

Phenotype…

Answer 10

a physical or behavioural characteristic

Question 11

Genotype…

Answer 11

the inherited, genetic constitution of an organism

Question 12

Environment…

Answer 12

food availability, predators, competitors, climate, mate choice, environmental toxins, drugs

Question 13

intrinsic =

Answer 13

natural

Question 14

Genetic disease caused by intrinsic factor:

Answer 14

Sickle cell disease, CF

Question 15

Metabolic disease caused by intrinsic factor:

Answer 15

Diabetes, gallstones

Question 16

Cellular disease caused by intrinsic factor:

Answer 16

Autoimmune e.g. rheumatoid arthritis. Degenerative & raging e.g. Alzheimer’s

Question 17

Structural disease caused by intrinsic factor:

Answer 17

Congenital e.g. spina bifida, Epstein’s anomaly

Acquired e.g. atheroma, osteoarthritis

Question 18

Physical disease caused by extrinsic factor: (agent + Example)

Answer 18

Agent: Trauma, Radiation, Temperature.
Example: Bone Fracture, Cancer, Burns/Frostbithe (respectively)

Question 19

Chemical disease caused by extrinsic factor: (agent + Example)

Answer 19

Agent: Toxic substances, Inflammatory agents. Example: Tobacco lung damage, Asthma

Question 20

Biological disease caused by extrinsic factor: (agent + Example)

Answer 20

Agent: Bacterial, Virus, Fungi & Parasites.
Example: Various infections, AIDs, hepatitis, Athletes foot

Question 21

Nutritional disease caused by extrinsic factor: (agent + Example)

Answer 21

Agent: Various
Example: Malnutrition

Question 22

List diseases (CF, diabetes, traumatic head injury, breast cancer) from most affected by genetic factors to those affected by environmental factors

Answer 22

(Genetic) CF, diabetes, breast cancer, traumatic head injury (environmental)

Question 23

Disability Adjusted Life Years (DALYs)…

Answer 23

the sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability.

Question 24

e.g of disease pathogenesis (skin abscess) steps.

Answer 24

Aetiology - artiologic agent e.g. bacterium
Pathogenesis - pathogenic mechanism
Morphological and functional features - pathological process
Complications and sequelae - Overt disease ad secondary consequences

Question 25

Pathologic changes: What are the specific changes in function and structure that characterise each disease?

Answer 25

• Gross/macroscopic changes in organs
• Light microscopic level
• Electron- microscopic (EM) level
• Molecular level

Question 26

What are the manifestations of disease?

Answer 26

the functional consequences of the morphologic changes that occur in the disease process

Question 27

How would you detect manifestations of disease?

Answer 27

Clinical signs and symptoms 
tests may be needed such as 
-examination of urine/blood 
- X-ray, ultrasound, nuclear medicine 
- Examination of tissue samples (biopsies)

Question 28

Pathobiology…

Answer 28

how does the disease process PRODUCE the morphologic changes?

Question 29

Understanding the pathogenetic mechanisms…

Answer 29

provides the knowledge base for rational development and evaluation of interventions to PREVENT OR TREAT disease

Question 30

To understand disease we need to:

Answer 30

• Understand the process for maintaining homeostasis
• Identify the agents and events that disrupt homeostasis
• Understand why homeostasis fails
• Understand the sequence of events that causes the development of a disease state
• Then we can evaluate the effectiveness and mechanisms of action