Dr. Fahim Ullah Khan provides an overview of disease, the immune system, and antibiotics in 3 pages of content. The document defines disease and its terminology, describes communicable and noncommunicable diseases, and explains how the immune system and different types of immunity protect the body. It also outlines what antibiotics are, how they work to destroy or slow bacteria, and common types including penicillin.

1. Every Day Science
Dr. Fahim Ullah Khan PhD Biology (Zoology)
Center for Biotechnology and Biomedicine, Division of Life and Health Sciences,
School of Life Sciences Tsinghua University, Beijing 100084, China
(World Ranking 10)

2. Contents
Disease Terminology
Immune System
Antibiotics

3. • Any harmful deviation from the normal structural or functional state of an
organism, generally associated with certain signs and symptoms and
differing in nature from physical injury.
• The study of disease is called pathology. It involves the determination of
the cause (etiology) of the disease, the understanding of the mechanisms of
its development (pathogenesis), the structural changes associated with the
disease process (morphological changes), and the functional consequences
of those changes.
• Humans, other animals, and plants are all susceptible to diseases of some
sort.
• Disease represents the consequences of a breakdown of the homeostatic
control mechanisms.
• Death in humans and other mammals, for example, often results directly
from heart or lung failure, but the preceding sequence of events may be
highly complex, involving disturbances of other organ systems and
derangement of other control mechanisms.
• Diseases Terminology

4. • Noncommunicable diseases generally are long-lasting and progress
slowly, and thus they are sometimes also referred to as chronic diseases.
• They can arise from environmental exposures or from genetically
determined abnormalities, which may be evident at birth or which may
become apparent later in life.
• The World Health Organization (WHO) has identified four major types of
noncommunicable disease: cancer, cardiovascular disease (e.g., heart
attack, stroke), chronic respiratory disease (e.g., asthma), and diabetes
mellitus.
• WHO estimates that, combined, these four groups of conditions account for
82 percent of all deaths from noncommunicable disease.
• Environmental hazards: The development of goitre is attributable to
iodine deficiency in the diet, which leads to compensatory growth of the
thyroid gland in a vain effort to overcome the deficiency.
• Noncommunicable disease

5. • Communicable, or contagious, diseases are those transmitted from one
organism to another.
• Infectious diseases are diseases caused in the host by infection with living,
and therefore replicating, microorganisms, such as animal parasites,
bacteria, fungi, or viruses.
• Lower respiratory infections, diarrheal diseases, and tuberculosis are
among the most common and deadliest types of infectious diseases.
• Epidemic : A prevalence of disease occurs in a wave, the number of cases
rising to a peak and then declining.
• ENDEMIC : A disease outbreak is endemic when it is consistently present
but limited to a particular region. This makes the disease spread and rates
predictable. Malaria, for example, is considered endemic in certain
countries and regions.
• Communicable disease

6. • PANDEMIC: The World Health Organization (WHO) declares a pandemic when a
disease’s growth is exponential. A pandemic cuts across international boundaries, as
opposed to regional epidemics. This wide geographical reach is what makes
pandemics lead to large-scale social disruption, economic loss, and general
hardship.
• Communicable disease

7. • The immune system is the body's defense against infections.
• The immune system attacks germs and helps keep us healthy.
• Many cells and organs work together to protect the body.
• White blood cells, also called leukocytes, play an important role in the immune
system.
• Macrophage is a type of white blood cell which is a phagocyte. They are
scavengers which constantly move around to remove dead cells and foreign bodies
such as pathogenic microbes; this occurs by the production of compounds such as
nitric oxide..
• Lymphocytes help the body remember the invaders and destroy them.
• Neutrophil which fights bacteria.
• The two kinds of lymphocytes are B lymphocytes and T lymphocytes.
• Lymphocytes start out in the bone marrow and either stay there and mature into B
cells, or go to the thymus gland to mature into T cells.
• B lymphocytes are like the body's military intelligence system they find their
targets and send defenses to lock onto them.
• T cells are like the soldiers they destroy the invaders that the intelligence system
finds.
• Immune system

8. • Antibodies

9. • Humans have three types of immunity.
• Innate immunity: Everyone is born with innate (or natural) immunity, a
type of general protection. For example, the skin acts as a barrier to block
germs from entering the body.
• And the immune system recognizes when certain invaders are foreign and
could be dangerous.
• Adaptive immunity: Adaptive (or active) immunity develops throughout
our lives. We develop adaptive immunity when we're exposed to diseases
or when we're immunized against them with vaccines.
• Passive immunity: Passive immunity is "borrowed" from another source
and it lasts for a short time. For example, antibodies in a mother's breast
milk give a baby temporary immunity to diseases the mother has been
exposed to.
• Types of immunity

10. • Antibiotics, also known as antibacterials, are medications that destroy or slow
down the growth of bacteria.
• Alexander Fleming discovered penicillin, the first natural antibiotic, in 1928.
• Antibiotics cannot treat viral infections, such as cold, flu, and most coughs.
• Fleming predicted the rise of antibiotic resistance.
• Antibiotics either kill or slow the growth of bacteria.
• Side effects can include diarrhea, an upset stomach, and nausea.
• They either stop bacteria from reproducing or destroy them.
• Before bacteria can multiply and cause symptoms, the immune system can
typically kill them.
• White blood cells (WBCs) attack harmful bacteria and, even if symptoms do
occur, the immune system can usually cope and fight off the infection.
• Sometimes, however, the number of harmful bacteria is excessive, and the
immune system cannot fight them all. Antibiotics are useful in this scenario.
• The first antibiotic was penicillin. Penicillin-based antibiotics, such as
ampicillin, amoxicillin, and penicillin G, are still available to treat a variety of
infections and have been around for a long time.
• Antibiotics

11. • Different Types of Bacteria

12. • A bactericidal antibiotic, such as penicillin, kills the bacteria. These drugs
usually interfere with either the formation of the bacterial cell wall or its
cell contents.
• A bacteriostatic stops bacteria from multiplying.
Side effects
• Antibiotics commonly cause the following side effects:
• diarrhea
• nausea
• vomiting
• rash
• upset stomach
• with certain antibiotics or prolonged use, fungal infections of the mouth,
digestive tract, and vagina
• Antibiotics

13. Thank you