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Host Defenses. Microbiology 2314. A Healthy Host Has a Variety of Defenses to Prevent Infection. Definitions. Resistance - Ability to ward off disease. Susceptibility - Lack of resistance. Two Types of Resistance. Nonspecific Resistance / Defense Against All Invaders.

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Host defenses

Host Defenses

Microbiology 2314



Definitions
Definitions Infection

  • Resistance

    - Ability to ward off disease.

  • Susceptibility

    - Lack of resistance.



Nonspecific resistance defense against all invaders
Nonspecific Resistance / Defense Against All Invaders Infection

  • First Line of Defense

    1. Skin

    2. Mucus Membranes

  • Second Line of Defense

    1. Phagocytes

    2. Inflammation

    3. Fever


Specific resistance defense against specific microorganisms
Specific Resistance / Defense Against Specific Microorganisms

  • Antibodies

  • Lymphocytes (B and T Cells)


Skin Microorganisms

Structure and Composition (Waterproof Keratin) Provide Resistance to Infection.

It is not a great place for bacteria to live…

Dries

Sheds

Secretes


Epidermis of the skin
Epidermis of the Skin Microorganisms

  • Epidermis consists of four layers.

  • Top layer is dead

  • 15-40 Rows of Dying Cells

  • Keratin a waterproof protein

  • pH of 3-5

Symbiotic bacteria living on the skin decompose dead skin cells.

The process results in a strong odor as the number of bacteria increase.



Best Areas for Organisms to Occupy are Excessive Moisture is Present

Scalp

Ears

Underarms

Genital Regions

Why?


Lachrymal apparatus
Lachrymal Apparatus Excessive Moisture is Present

Protects the eyes from irritating substances and microorganisms.

The conjunctiva has only a small number of bacteria present due to continuous blinking and lachrymal secretions which contain bactericidal substances.


The lacrimal glands underneath the skin of the upper eyelids make a fluid that is mostly salt and water. This salty water gets to the eye through small openings inside the upper eyelids.


When the eyelid blinks, the watery liquid is spread across the eye. There are other glands on edges of the eyelids that make oils. The most important of these glands are called the meibomian glands. The oils from these glands actually float on top of the watery fluid in the tears. This keeps the water from evaporating too quickly.


Some of the oils stay along the edge of the eyelid, and they help keep the tears from "leaking" over the eyelashes. If there is not enough of these oils, tears will keep overflowing from the eyes. Oddly enough, a problem with the meibomian glands can lead to overflowing tears and dry eye syndrome at the same time


Salivary Glands Produce Saliva help keep the tears from "leaking" over the eyelashes. If there is not enough of these oils, tears will keep overflowing from the eyes. Oddly enough, a problem with the meibomian glands can lead to overflowing tears and dry eye syndrome at the same time

Saliva Washes Microorganisms from Teeth and Gums


Saliva isn’t always enough. help keep the tears from "leaking" over the eyelashes. If there is not enough of these oils, tears will keep overflowing from the eyes. Oddly enough, a problem with the meibomian glands can lead to overflowing tears and dry eye syndrome at the same time

S. mutans Secretes Sticky Polysaccharide  Plaque


Tooth decay (dental caries) was not a major problem before the fateful year of 1886. Do you remember why 1886?



European teeth
European Teeth marketed.

Teeth in skulls from Europeans prior to the 1500’s showed remarkably well-reserved teeth. Once sugar was introduced into the European diet, teeth deteriorated quickly and tooth decay became a widespread disease.


Defensive body secretions
Defensive Body Secretions marketed.

  • Tears

  • Saliva

  • Mucus

  • Vaginal Secretions

  • Nasal Secretions

  • Sebum

  • Perspiration


Mucus traps many microorganisms that enter the respiratory and gastrointestinal tracts.

Snotty noses are a result of the body trying to rid the system of the trapped microorganisms.



The flow of urine moves microorganisms out of the urinary tract.

The kidney and bladder are usually sterile.


What is Sebum? tract.

Sebum is an oily/fatty substance secreted from the sebaceous glands (unsaturated fatty acids) that inhibits the growth of pathogenic bacteria.

Constituent % by weight

Glycerides and free fatty acids 57.5

Wax esters 26.0

Squalene 12.0

Cholesteryl esters 3.0

Cholesterol 1.5



Perspiration
Perspiration Sebum

  • Washes Microorganisms Off Skin

  • Maintains Body Temperature

  • Eliminates Cellular Wastes

  • Contains Lysozyme

  • Lysozyme is Most Effective Against Gram Positive Bacteria



Lysozyme
Lysozyme Bacteria.

  • Found In

    1. Tears

    2. Salava

    3. Nasal Secretions

    4. Perspiration


The acidity of gastric juice prevents most microbial growth in the stomach
The Acidity of Gastric Juice Prevents Most Microbial Growth in the Stomach

  • Mucus, HCl, Enzymes

  • pH 1.2 - 3.0

  • No effect on Clostridium botulinum

  • No effect on Staphylococcus aureus


Helicobacter pylori and ulcers
Helicobacter pylori in the Stomachand Ulcers


Ulcers
Ulcers in the Stomach

  • 4 Million Americans Have Ulcers Annually

  • H. pylori is Found in Almost 50% of the Population

  • That 50% Could Either Have Gastritis or Ulcers


Why is h pylori able to survive in the acidic environment of the stomach if it isn t an acidophil
Why is H. pylori able to survive in the acidic environment of the stomach if it isn’t an acidophil?


Phagocytosis the ingestion of microorganisms or particulate matter by a cell
Phagocytosis of the stomach if it isn’t an acidophil?The Ingestion of Microorganisms or Particulate Matter by a Cell

We frequently see this when WBC’s engulf bacteria.


Phagocytosis
Phagocytosis of the stomach if it isn’t an acidophil?

  • Attraction (Chemotaxis)

  • Attachment (Opsonization / Coating with Protein)

  • Ingestion

  • Digestion (Lysosomal Enzymes and Oxidizing Agents)

  • Expulsion


The Mechanism of Phagocytosis of the stomach if it isn’t an acidophil?

Chemotaxis is the process by which phagocytes are attracted to microorganisms.



Removing Pus From an Infected Liver and white blood cells.


An accumulation of pus in the front of the eye. In this image, the pus is seen as a pool of whitish fluid between the iris and cornea.


Blood is a Fluid with Formed Elements image, the pus is seen as a pool of whitish fluid between the iris and cornea.


White Blood Cells (Leukocytes) image, the pus is seen as a pool of whitish fluid between the iris and cornea.

Macrophages are Mature Monocytes that are Phagocytic in Nature

Histiocytes are a special type of macrophage fixed in a particular tissue

1. Kupffer Cells / Liver

2. Alveolar macrophages / Lungs


Wbc neutrophils
WBC - Neutrophils image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Increased / Bacterial Infection

  • Normally 50-70

  • Two Types

    1. Segmented (Mature)

    2. Banded (Less Mature)


Wbc basophils
WBC - Basophils image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Allergic Reactions

  • Leukemias

  • Normally 0-1


Wbc eosinophils
WBC - Eosinophils image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Worm Infections

  • Skin Disorders

  • Scarlet Fever

  • Normally 1-5


Wbc lymphocytes
WBC - Lymphocytes image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Viral Infections

  • German Measles

  • Whooping Cough

  • Syphilis

  • Normally 20-30


Wbc monocytes
WBC - Monocytes image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Recovery from Infections

  • Fungal, Rickettsial, Protozoal, Infections

  • Normally 2-6


Differential wbc count 100 cells
Differential WBC Count (100 Cells) image, the pus is seen as a pool of whitish fluid between the iris and cornea.

  • Neutrophils 50-70

  • Lymphocytes 20-30

  • Monocytes 2 - 6

  • Eosinophils 1 - 5

  • Basophils 0 - 1

Wright's stain is a technique that is used to make the differences between cells visible under light microscopy.

It is used in the examination of peripheral blood smears and bone marrow aspirates.




Concentrate your examination in areas where the cells are individually separated from one another and fairly uniformly dispersed


(Segmented) individually separated from one another and fairly uniformly dispersed


Neutrophils individually separated from one another and fairly uniformly dispersed

Banded Segmented


Lymphocyte individually separated from one another and fairly uniformly dispersed


Monocyte individually separated from one another and fairly uniformly dispersed


Eosinophil individually separated from one another and fairly uniformly dispersed


Basophil individually separated from one another and fairly uniformly dispersed


Mononucleosis
Mononucleosis individually separated from one another and fairly uniformly dispersed


Leukemia individually separated from one another and fairly uniformly dispersed


Sickle Cell Anemia individually separated from one another and fairly uniformly dispersed


Can we diagnose from a blood smear
Can We Diagnose From a Blood Smear? individually separated from one another and fairly uniformly dispersed


Slits alcoholic liver disease
Slits / Alcoholic Liver Disease individually separated from one another and fairly uniformly dispersed


Target cells decreased iron
Target Cells / Decreased Iron individually separated from one another and fairly uniformly dispersed


Thorn cells severe burns
Thorn Cells / Severe Burns individually separated from one another and fairly uniformly dispersed


Stippling heavy metal poisoning
Stippling / Heavy Metal Poisoning individually separated from one another and fairly uniformly dispersed


Teardrops bone marrow malfunction
Teardrops / Bone Marrow Malfunction individually separated from one another and fairly uniformly dispersed


Wbc hypersegmentation chronic infection or liver disease
WBC Hypersegmentation / Chronic Infection or Liver Disease individually separated from one another and fairly uniformly dispersed


Wbc ringed nucleus acute myeloid leukemia
WBC Ringed Nucleus / Acute Myeloid Leukemia individually separated from one another and fairly uniformly dispersed


Holes in cytoplasm of granulocytes toxic effect of ethanol
Holes in Cytoplasm of Granulocytes / Toxic Effect of Ethanol individually separated from one another and fairly uniformly dispersed






D hle bodies small pale blue cytoplasmic inclusions tuberculosis
Döhle with Bodies – Small pale blue cytoplasmic inclusions / Tuberculosis



  • Howell-Jolly bodies are spherical blue-black inclusions of red blood cells seen on Wright-stained smears. They are nuclear fragments of condensed DNA, 1 to 2m in diameter, normally removed by the spleen. They are seen in severe hemolytic anemias, in patients with dysfunctional spleens or after splenectomy.



Case study 1
Case Study 1 the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

  • This 16 year old male came to the emergency room complaining of severe abdominal pain in the right lower quandrant. He had a fever of 101 F. On physical examination, he had a rigid, board-like abdomen and rebound tenderness in the right lower quandrant. There were no other abnormalities.


What is the predominant white blood cell present? the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

What does this indicate?


Case study 2
Case Study 2 the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

  • This 15 year old female was sent home from summer camp because of weakness, lassitude, and sore throat. As her family physician, you found that on physical examination she had an inflamed pharynx, enlarged tonsils, several enlarged and slightly tender lymph nodes in the neck, a palpable spleen, and a tender palpable liver edge.


What is the predominant white blood cell type? the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

What is your diagnosis in this case?


Case study 3
Case Study 3 the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

  • This 65 year old male was in good health except for mild hypertension. At his last check-up, a CBC showed a markedly elevated white blood cell count and physical examination revealed several slightly enlarged lymph nodes in the neck and the axillae, and the spleen was palpable.


What is the predominant white blood cell type present? the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

What is the differential diagnosis?


Case study 4
Case Study 4 the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

This 52 year old male had gradually increasing fatigue together with discomfort in the left upper quandrant. Physical examination revealed an easily palpable spleen and liver edge. A few slightly enlarged lymph nodes were palpable in the neck.


Inflammation is a bodily response to cell damage. the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

Inflammation

1. Redness

2. Pain

3. Heat (Local Fever)

4. Swelling

5. Possible Loss of

Function


  • Vasodilation the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

    Increase in blood vessel diameter to increase blood flow

    1. Histamine / Body Cells

    2. Kinins / Blood Plasma

    3. Prostaglandin / Damaged Cells

  • Margination

    Adherence of phagocytes to vessel walls.

  • Emigration

    Phagocytes leaving blood vessels and

    entering tissues.

  • Pus

    Accumulation of damaged tissue, dead

    microbes, and white blood cells (phagocytes).


Tissue repair
Tissue Repair the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

  • Stroma (Supporting Tissue)

  • Parenchyma (Functioning Tissue)


Fever
Fever the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.

  • Abnormally High Body Temperature

  • Can Be Induced by Bacterial Endotoxins

  • Chills  Increased Temperature

  • Crisis  Decreasing Temperature

  • Temperature is Controlled by the Hypothalamus


How Do We Treat a Fever? the stages of a red blood cell before it matures. Cells of this stage are usually seen in newborn infants, and in patients with iron deficiency anemia.


  • Do not force food. If diarrhea is present, limit the intake of fruits and juice.

  • Sponging the body with a wet compress, especially keeping it on the forehead, temples and the feet is a very effective method of bringing down the temperature. Use lukewarm water; cool water may cause shivering, which actually raises body temperature. Don't use rubbing alcohol, since it can be toxic. Sponging can be repeated as often as required.

  • Overheating due to overdressing can aggravate the fever so dress lightly, and make sure bedclothes too are light.

  • Temperatures lower than 102 degrees F (38.9 degrees C) usually do not require medication.

  • Give acetaminophen or ibuprofen based on the package recommendations for age or weight. If you don't know the recommended dose call your doctor. Aspirin is not recommended for children under age 12.


The Complement System of fruits and juice.

The complement system consists of a group of serum proteins that activate one another to destroy invading microorganisms.


The of fruits and juice. complement system helps clear pathogens from an organism. It is derived from many small plasma proteins that form the biochemical cascade of the immune system. Activation of this system leads to cytolysis, chemotaxis, opsonization, immune clearance, and inflammation, as well as the marking of pathogens for phagocytosis. The complement system consists of more than 35 soluble and cell-bound proteins, 12 of which are directly involved in the complement pathways


Interferons
Interferons of fruits and juice.

  • Antiviral Proteins Produced in Response to Viral Infection

  • Alpha

  • Beta

  • Gamma


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