1. Disease & Disease-Producing Organisms
Chapter 5
Anatomy & Physiology I

2. Disease
Any abnormality of the structure or function of a part, organ or system
Diseases fall into 7 different, but often overlapping categories
7 Predisposing factors increase the probability of a person becoming ill
The study of disease

3. Categories of Disease Infection: Degenerative diseases
Nutritional disorders
Metabolic disorders
Immune disorders
Neoplasms
Psychiatric Disorders

4. Infection
Believed to play a part in at least 50% of all human illnesses
Cause:
Many diseases are caused by infectious organisms
Example
cold, AIDS, tuberculosis etc

5. Degenerative Diseases
Involve degeneration (breaking down) of tissues in any system of the body
Causes
Hereditary
Wear and tear
Infection
No known causes
Example:
Alzheimer, osteoporosis, and arthritis

6. Nutritional Disorders
Caused by:
dietary lack (deficiency) of essential vitamins, minerals, proteins, or other substances
Excess alcohol, caloric intake
Example
Scurvy – lack of Vitamin C
Rickets – lack of Calcium
Beriberi- lack of thiamine
Kwashiorkor- lack of protein
Goiter: lack of iodine

7. Nutritional Excesses

8. Metabolic Disorders
A disturbance in the buildup, breakdown, or excretion of substances
Causes
Disruption in the reactions of cellular metabolism
Hormone imbalance regulate many metabolic activities
Hereditary errors of metabolism
Examples
diabetes,
gout (a disorder of the joints), >> uric acid
digestive disorders, and
hereditary dysfunctions.

9. Immune Disorders Caused by
Immune deficiencies: The decreased ability of the body to fight infection and disease. Caused by genetic or infection
Example: AIDS
Hypersensitivity – overactive immune system
Allergies
Animals, pollen, medicine, nuts etc
Autoimmune disorders
Example: rheumatoid arthritis, multiple sclerosis (MS), and systemic lupus erythematosus (SLE)

10. Neoplasms
The word neoplasm means “new growth” and refers to cancer and other types of tumors.
An abnormal and uncontrolled growth of tissues
Benign
Metastatic

11. Psychiatric Disorders
A health condition that changes a person’s thinking, feelings, or behavior (or all three) and that causes the person distress and difficulty in functioning

12. Predisposing Factors
May not cause a disease, but does increase the probability of a person becoming ill
Age: measles is more common in children, Alzheimer in elders
Gender: heart disease to men, diabets to women
Heredity: diabetes, allergies, and certain forms of cancer.
Living conditions & habits: sleep, exercise, diet, drugs, alcohol, and tobacco
Emotional disturbance: stress, anxiety, anger, sensitivity
Physical & chemical damage – Injuries & chemical exposure
Preexisting illness: high blood pressure or diabetes, increases one's chances of contracting another disease.

13. The Study of Disease Pathophysiology:
Is the study of close relationship of each disease's pathologic and physiologic aspects and the understanding of these fundamentals in treatment.

14. Disease Terminology Etiology – study of the cause of disease
Epidemiology: the study of diseases in populations. Epidemiology statistics include:
Incidence – The number of new disease cases, occurence and tendency to affect certain groups of individuals more than other groups
Morbidity – the proportion of a population with a specific disease
Mortality – the proportion of a population that dies from a given disease

15. Disease Terminology Cont.
Diseases are classified based on severity and duration as:
Acute – relatively severe but last a short time
Chronic – may be less severe but likely to be continuing or recurring
Subacute – between acute and chronic diseases

16. Disease Terminology Cont.
Based on origin:
Idiopathic – disease without known cause
Iatrogenic – disease caused by adverse effects from medical treatment
Communicable – disease that can be transmitted from one person to another
Epidemic – many people from a certain region acquire a certain disease at the same time
Endemic – a disease found to a lesser extent, but continuously in a particular region
Pandemic – a disease prevalent throughout the world

17. Example of Endemic Disease: The Goiter Belt in the US

18. Treatment and Prevention
of Disease
Medical process
History, including signs and symptoms
Sign – objective evidence (observed by physician or other healthcare professional
Symptoms – subjective evidence (conditions noted by the patient). For example: imaging studies, blood tests, and study of tissues removed in biopsy.
Syndrome – a characteristic set of signs and symptoms that accompany a disease; PMS, AIDS
Diagnosis – a conclusion as to the nature of the illness
Prognosis – prediction of probable outcome of disease
Therapy – course of treatment

19. Treatment: Complementary and
Alternative Medicine
Methods of disease prevention or treatment that can be used along with or instead of traditional modern medical practices

20. Alternative Medicine Naturopathy: healthy life style
Chiropractic: correcting misalignment for treatment of musculoskeletal disorder
Acupuncture: insert needle to relief pain
Biofeedback: electronic devices monitor changes and feed info back to a person
Herbal medicine

22. Disease Prevention
Modern medicine’s major focus is on treating patients who currently have a disease
Wellness movement focuses on preventing the occurrence of disease by promoting health
Health – an optimal physical, mental and emotional state of being, not merely the absence of disease
Health-promoting practices
Massage
Diet
Exercise
Stress management

24. Infectious Disease
Invasion of the body by disease-producing microorganisms
Microorganisms –
Aka microbes, germs
A tiny living thing too small to be seen by the naked eye
Most are harmless, many are beneficial, a few cause illness (are pathogenic)
Parasite – a living organism that lives on or in a living host at the host’s expense
Pathogen – disease-producing organism

25. Types of Infection
Infection – pathological state resulting from the invasion of the body by pathogenic microorganisms
Local – infection restricted to a small area
Systemic – infection throughout the whole body
Opportunistic infection – an infection that takes hold because the body has been weakened by disease or injury

26. Modes of Transmission Direct Contact Indirect Contact
Touching
Sexual activity
Indirect Contact
Touched objects
Vector – an insect or animal that transmits a pathogen from one host to another (mosquito)
Atmosphere

27. Portals of Entry & Exit Skin Respiratory tract Digestive system
Urinary system
Reproductive system

28. The Common Cold 1 billion Americans “catch” a cold every year
Leading cause of doctor visits & missed days of work & school
Caused by over 200 different types of viruses
One sneeze can send hundreds of thousands of particles several feet, where they live for 3-6 hours
To prevent
Avoid close contact
Wash hands
Do not touch your face
Clean surfaces frequently

29. Microbiology
Microorganisms- simple, microscopic, usually single-cell, forms of life. The group includes bacteria, viruses, fungi, protozoa, and algae. Book: table 5.1
Microbiology – The study of these microscopic organisms
Bacteria – single-celled organisms which grow in many environments
Viruses- composed of nucleic acids & protein; can only multiply inside of living cells
Fungi – plantlike organisms
Single celled – yeasts
Filamentous - molds
Protozoa – single-celled animals
Aka parasites
Includes worms

30. Microorganisms
Most are harmless to humans and are essential to all of life on earth
Normal flora – population of microorganisms that normally grow on or within our bodies
Beneficial
If normal flora are destroyed it can cause overgrowth of normally harmless bacteria, rendering them pathogenic

31. Bacteria Single celled organisms
One of the most primitive forms of life on earth
Their genetic material is not enclosed by membrane
Do not have a true nucleus
Lack most organelles

32. Bacteria Cont. Classification
Aerobic – require oxygen to grow
Anaerobic – grow in the absence of oxygen
Facultative anaerobes – use oxygen if present but are also able to grow without oxygen – e. coli
Endospores – resistant forms of bacteria that can tolerate long periods of dryness or other adverse conditions. Endospores can be become airborne
Resistant to ordinary methods of disinfection
Particularly dangerous – tetanus, botulism, anthrax

33. Bacteria Movement Flagella: helps them to swim rapidily
Pili – short “hairs” that help bacteria to glide across solid surfaces & anchor it to surfaces

34. Bacteria Cont. Largest group of pathogens to humans
Can divide every 20 minutes or every 24 hours
Cause damage to humans in 2 ways
Produce toxins
Growing in human tissues

35. Human defence mechanism
Physical barriers – skin, mucus membranes
Immune system

36. Shape & Arrangement of Bacteria
Three groups of bacteria based on their shape
Cocci
Diplococci
Streptococci
Staphylococci
Bacilli
Curved rods
Vibrios
Spirilla
spirochetes

38. Cocci & Bacilli Cocci – round Bacilli – straight rods
Diplococci – in pairs – causes gonorrhea, and meningitis
Streptococci – in strings – strep throat
Staphylococci – in clusters - pneumonia and fever.
Bacilli – straight rods
All endospore-forming bacteria are bacilli
TB, typhoid fever, Legionnaire’s disease

39. Curved Rods Vibrios – short curved rods, like a comma
cholera
Spirilla – resemble a corkscrew
Spirochetes – similar to spirilla but capable of waving & twisting motions. Casues syphilis

40. Obligate Intracellular Parasites
Bacteria that are much smaller than normal
Also include viruses, which are not bacteria
They only grow within the cells of their hosts
Chlamydia
Ricksettia
Transmitted through insect bites
Rocky Mountain spotted fever, typhus

41. Viruses
Extremely small in comparison to bacteria: seen by electron microscope
Have some characteristics of living matter but not all
Contain genetic material & are able to reproduce
Contain only DNA OR RNA
Generally made of genetic material surrounded by a protein coat
Are not cellular
Do not have enzyme systems
Can only grow within a host’s cell (obligate)

42. Virus size comparison. A chlamydia and a staphylococcus are shown for reference

43. Viruses

44. Classifying and naming Viruses
Classified according to:
type of nucleic acid they have: DNA or RNA
whether that nucleic acid is single stranded (ss) or double stranded (ds).
The diseases they cause: common cold, hepatitis, measles
where they were isolated : West Nile
the symptoms they cause: yellow fever
the host : Chickenpox, HIV, Swine influenza

45. Other Agents Smaller than Viruses
Prions (proteinaceous infectious )-made solely of proteins
Slow growing and hard to destroy
Mad cow disease
Viroids
Composed solely of RNA with no protein coat
So far have only been discovered to cause plant diseases

46. Fungi Types Simple plant-like organisms Very few cause diseases
Yeast – single celled
Molds – long & filamentous
Simple plant-like organisms
Do not contain chlorophyll
Grow in dark, damp places
Very few cause diseases

47. Mycotic (Fungal) Infections
Diseases caused by fungi are called mycotic
Can affect skin
Ringworm – tinea corporis or capitis
Athlete’s Foot
Can affect those with compromised immune systems
Candidiasis

48. Protozoa Single-celled animal-like organisms
Amebas – a “blob” that can move
Ciliates – tiny hairs propel this organism
Flagellates – a tail propels this organism
Sporozoa – cannot propel themselves
Obligate parasites, unable to grow outside host
Carried by mosquitos
malaria

49. Protozoa Movement

50. Parasitic Worms (Helminths)
Roundworms
Ascaris – intestinal; hard to control & eliminate
Pinworm – intestinal; hard to control & eliminate
Hookworms – intestinal; suck blood & cause anemia; larvae enter body through foot
Trichinea – live in muscles of animals & people; enter body through undercooked meat
Filaria – live in lymphatic system

51. Hookworm

52. Roundworms Ascaris & Filaria

53. Filaria Infection

54. Parasitic Worms (Helminths) Cont.
Flatworms
Tapeworms – can be 50 feet long in intestines, spread through undercooked meat
Flukes – can infect many body parts

55. Tapeworm

56. Microbial Control Infectious diseases are increasing
Increased population, travel, food processing
Public health measures help control microbes
Sewage/garbage disposal
Water purification
Prevention of food contamination
Milk pasteurization

57. Aseptic Techniques & Methods
Sterilization – kills EVERY living microorganism on an object
Disinfection – kills all pathogens (except spores) but does not necessarily kill harmless microbes
Antisepsis – pathogens not necessarily killed but prevented from multiplying

58. Universal Precautions to Control Infection
Healthcare workers MUST use barriers for any contact with moist substances, non-intact skin, & mucous membranes –REGARDLESS of whether or not blood is visible & REGARDLESS of a patient’s diagnosis
Soiled linen and trash are treated as contaminated
Needles are not recapped after blood draws
Handwashing – goal of 100% compliance

59. Handwashing
The single most important measure to prevent the spread of infection in ALL settings
Gloves are not a substitute for handwashing

60. Areas Missed During Handwashing

61. Antimicrobial Agents Antibiotics
Penicillin
Danger of opportunistic infections developing due to loss of normal bacteria
Danger of resistant strains of pathogens developing
Antiviral agents – very few and they have a limited range of effectiveness
Viruses mutate rapidly to become resistant
Antiviral agents are often used in combinations

62. Antibiotics