PU535 Public Health Biology Unit 1 Biological Perspective in Public Health

Question 1

What is homeostasis?

How is homeostasis maintained?

Answer 1

The body’s internal equilibrium.

Through negative and positive feedback loops.

Question 2

When does disease or illness develop?

Answer 2

Typically, when homeostasis is disrupted.

Injury, malnutrition, or invasion by pathogens can all disrupt homeostasis. Cells do check for imbalances and have ways to adapt but sometimes dividing cells fail to detect unwanted changed and results in mutations that may cause disease.

Question 3

What is the study that relates to the changes that occur in normal anatomy and physiology as a result of illness or disease?

Answer 3

Pathophysiology

Question 4

What are the factors considered in pathophysiology? (3)

Answer 4

Etiology - the study of the cause of disease

Pathophysiology - the study of the changes to normal anatomy and physiology

Clinical manifestations - the signs and symptoms of the disease or illness, along with diagnostics and treatments available

Question 5

Make the models with their correct terms (See attached; list below)

A - Hyperplasia
B - Severe dysplasia
C - Atrophy
D - Mild Dysplasia
E - Metastasis
F - Hypertrophy
G - Metaplasia

Answer 5

C1, F2, A3, D4, B5, G6, and E7

Question 6

What refers to the reversible reduction or shrinkage in cell size? It can happen when cells are no longer used, are malnourished, have insufficient blood supply, lack of innervation or sufficient hormonal stimulation.

Answer 6

Atrophy.

For example, thymic involution or the atrophy of the thymus gland, is a hallmark indicator of the aging process and shrinks at a rate of 1% beginning in the ages of 35-45 and very small in older adults. Its location is over the heart and it produces thymosin which is important hormone for T-cells
secretion in immune function.

-trophy refers to size usually.

Question 7

What describes an increase in cell size rather than increase in the number of cells?

Answer 7

Hypertrophy.

Question 8

What is an increase in the number of cells caused by increased workload, hormonal stimulation or decreased tissue?

Answer 8

Hyperplasia

-plasia refers to formation or growth.

Question 9

What describes abnormal growth or development of tissues or cells, leading to a change in size, shape, and appearance that is sometimes reversible but often precedes neoplastic (cancerous) changes?

Answer 9

Mild dysplasia.

Question 10

What is severe dysplasia (carcinoma in situ)?

Answer 10

It describes a group of abnormal cells that are found only in the place where they first formed (primary location) and have not spread to other parts of the body.

Carcinoma in situ is often considered to be the earliest form of cancer development.

Question 11

What is the replacement of one adult cell with another adult cell that can better endure some changes or stress? It is usually a response to chronic inflammation or irritation.

Answer 11

Metaplasia

Question 12

What do you call it when cancer cells break away from the site where they first formed (known as the primary tumor) and spread to other areas of the body, usually via the blood or lymphatic system, forming a new tumor (called a metastatic tumor) in other organs or tissues in other parts of the body?

Answer 12

Metastasis (invasive carcinoma)

The new, metastatic tumor is the same type of cancer as the primary tumor.

For example, if breast cancer spreads to the lung, the cancer cells in the lung are usually identifiable as breast cancer cells, not lung cancer cells. This is useful when diagnosing cancers and determining if a tumor is a primary or secondary neoplasm.

Question 13

T/F - There are four types of homeostatic feedback mechanisms.

Answer 13

False. There are two which are negative and positive feedback control.

Question 14

What is the difference between positive and negative feedback mechanisms in the body?

Answer 14

Positive feedback occurs when stimulus triggers an enhanced response exaggerating the original event.

Negative feedback mechanisms restore homeostasis by detecting and correcting changes to the normal homeostatic conditions in the body.

There are fewer examples of positive feedback mechanisms than there are of negative feedback mechanisms.

Question 15

What are some examples of positive and negative feedback mechanisms that strive for homeostasis within the body?

Answer 15

Positive feedbacks - platelet formation in the blood coagulation cascade (haemostasias) and oxytocin release during labor contractions in childbirth.

Negative feedbacks - secretion of insulin from the pancreas to reduce high blood sugar levels back to normal, control of body temperature by thermoreceptors in the hypothalamus (thermoregulation), and control of blood pressure and respiration rate.

Question 16

T/F - Disease can develop when homeostasis cannot be sustained.

Answer 16

True.

It is important to differentiate between illness and disease. An individual may live a reasonably normal life and not be considered ill, despite having a disease.

For example, an asthmatic person can live a normal life and not usually be considered ill because the body has adapted to the disease. However, disease may make them more susceptible to certain illnesses such as respiratory infections or pneumonia.

Question 17

T/F - The division of somatic cells involves three stages.

Answer 17

False.

Somatic cell division has two stages. Mitosis and cytokinesis.

Question 18

What are the two stages of somatic cell division and reproduction?

Bonus: For sex cells or gametes, what is the stage of cell division and reproduction called?

Answer 18

Mitosis is when the nucleus and genetic material of the cell divide.

Cytokinesis is when the cytoplasm divides and ends when the new cell’s contents divides into two daughter cells.

Meiosis.

Question 19

T/F - A biopsy is a medical procedure that involves a healthcare practitioner removing a small sample of body tissue for examination under a microscope.

Answer 19

True.

A sample can be excised from anywhere in the body. Biopsy tend to be more invasive than cytology, which is the study of a single cell typical in fluid extraction.

Question 20

T/F - Cancer is a condition that develops when cells die uncontrollably.

Answer 20

False.

Cancer develops due to excessive and uncontrollable cell growth. A cancerous (or neoplastic) cell develops due to mutation of a single gene which affects the control of normal function in the cell.

The mutation allows the cell to grow and proliferate without the normal regulatory controls of cell growth and replication and it loses the ability to enter apoptosis (programmed cell death). Initially, the uncontrolled growth of the cancerous cells is localized but because they have lost the ability to perform apoptosis, the cells do not die and so the mass of proliferating cells begins to invade nearby tissue and may eventually metastasize to other areas of the body.

Necrosis is an undesirable form of cell death usually caused by factors external to the cell, such as trauma, toxins or infection.

Question 21

T/F - During their lifetime, cells face constant challenges to their normal function.

Answer 21

True.

Question 22

T/F - When assessing pain, remember the acronym PQRST.

Answer 22

True.

Question 23

When assessing pain, PQRST, what does the acronym mean?

Answer 23

P = precipitation/palliation– what causes the pain and what relieves it?
Q = quality – how could the pain be described, is it crushing, dull, sharp or stabbing?
R = region/radiation – where did the pain start and has it spread elsewhere?
S = severity – how bad is the pain, using a scale of 0 = no pain to 10 = worst pain?
T = timing– when did the pain start and how long does it last?

Question 24

See attachment for question.

Answer 24

C

Question 25

See attachment for question.

Additional question - What are the components of the feedback mechanisms?

Answer 25

D

Every homeostatic feedback mechanism has three components:

Sensory mechanism - to detect deviations in the homeostatic equilibrium.

Control center in the CNS - regulates the body’s response to the change.

Effector mechanism - receives responses from the CNS that help restore homeostatic equilibrium.

Question 26

See attachment for question.

Answer 26

A

The pons is part of the brainstem and it is the structure that links your brain to your spinal cord. It handles unconscious processes and jobs like breathing and sleep-wake cycle. It also contains several junction points for nerves that control muscles and carry information from senses in your head and face.

Question 27

What are the three parts of the brain that are involved in maintaining homeostasis in the body?

Answer 27

Medulla oblongata - controls a number of vital functions such as circulation and respiration.

Pituitary gland - controls the function of other glands and is involved in regulation of growth, maturation and reproduction.

Reticular formation - group of nerve cells that control certain vital reflexes such as cardiovascular function and respiration.

Question 28

See attachment for question.

Answer 28

A

There is no single cause that triggers carcinogenesis and is likely induced by a number of triggers that interact together and the cell is unable to defend against.

These triggers can be genetic, lifestyle factors (smoking, diet, lack of exercise), hormonal, metabolic, viral, radiation or chemical in nature.

Carcinogenesis is a multi-stage process that involves a pre-clinical (latent) phase and a clinical phase. In some cancers, the latent phase can last for many years and in others it may be very short (weeks, months).

Question 29

What are the main stages of carcinogenesis? (4)

Answer 29

Initiation - the introduction of a spontaneous or induced genetic mutation

Promotion - confers a selective growth advantage that allows the abnormal cells to grow and proliferate

Progression - a series of additional mutations allow the mutated cell to continue to grow and evade apoptosis - cells may not be distinguishable from the parent cell

Metastatic spread - the movement of cancerous cells away from their site of origin

Question 30

Most solid cancerous tumors arise from which type of tissue?

a. glandular
b. skin
c. nervous
d. epithelial

Answer 30

D

All cancer derived from epithelial tissue is usually classified as a carcinoma.

Cancers derived from glandular tissue = adenocarcinomas
Cancers derived from muscle, bone, and connective tissues = sarcomas
Cancers derived from lymphatic and immune tissue = lymphomas
Cancers derived from white blood cells = leukaemias
Cancers derived from pigment cells = melanomas
Cancers derived from plasma cells = myelomas

Question 31

The ____________ of a disease can be intrinsic or extrinsic.

What do you call a disease that has no known cause?

Answer 31

Etiology.

Can be influenced by the individual’s biochemistry (intrinsic) or environmental (extrinsic) factors.

Idiopathic.

Question 32

The development of a disease is called its ____________.

Answer 32

Pathogenesis.

A self-limiting disease is one that clears up on its own, otherwise it is considered chronic. An example of disease that is chronic and undergoes periods of remission and exacerbation is rheumatoid arthritis, an inflammatory disease.

Question 33

Complete the stages of disease progression: (use the attached list to fill in blanks)

1. injury/exposure
2. _______ phase
3. prodromal period
4. _______ phase
5. _______
6. convalescence
7. recovery

Answer 33

2 = latent phase
4 = acute phase
5 = remission

Question 34

Cytology and histology are branches of _______________ .

Answer 34

Pathology.

Pathology is a branch of medicine that involves laboratory examination of cells in samples of body tissue or fluids for diagnostic purposes. Cytology usually involves examining individual cells or clusters of cells through a microscope. Pathologists usually need a very small sample of cells for cytology tests like a cervical smear test.

Histology is the examination of an entire section of tissue, which contains many types of cells. Depending on the tissue type, disease processes can affect tissues in distinctive ways.

Histopathology (the study of tissues affected by disease) tests are very useful for making a diagnosis and may also be helpful when determining the severity and progression of disease.

Question 35

The pain radiating along the left arm often reported by MI patients is called ____________ pain.

Answer 35

Referred (or reflective) pain.

Usually describes pain experienced in part of the body at a distance from its area of origin. These mechanisms are not fully understood, but it is thought to happen when nerve fibers from various regions or organs converge on the same levels of the spinal cord.

The best-known example is pain experienced during a myocardial infarction. Nerves from damaged cardiac tissue convey pain signals to spinal cord levels T1–T4 on the left side, which are the same levels that receive sensation from the left side of the chest and part of the left arm. This very close proximity of the converging nerve fibers confuses the brain, which interprets the heart pain as coming from the chest area and left arm (and sometimes the neck or jaw).

Question 36

A solid tumor is usually classified according to the ______ from which it originates.

Answer 36

Tissue.

The majority of solid tumors arise from epithelial tissue, which is the main type of tissue that lines the internal and external surfaces of the body’s organs (for example, the lungs, colon and breasts). Tumors arising from epithelial tissues are called carcinomas.

Question 37

Cancer cells can ___________ away from their origin.

Answer 37

Metastasize