Epidermis
thin outer portion of skin
What is the epidermis made of?
layers of epithelial cells
Keratin
waterproofing protein coating outer layer of epidermis
Dermis
thick inner portion of skin
What is the dermis composed of?
primarily connective tissue
What do lysozymes do?
break down bacterial cell walls
The skin contains sebum secreted by oil glands containing
fatty acids that inhibit pathogens
Vesicles
small, fluid filled lesions
bullae
vesicles larger than 1cm in diameter
macules
flat, reddened lesions
pustules
raised lesions with pus
impetigo
Staphylococcal skin infection crusting (nonbullous) sores spread by autoinoculation
scalded skin syndrome
Staphylococcal skin infection. bulbous impetigo toxin B causes exfoliation
pemphigus neonatorum
impetigo of the newborn
toxic shock syndrome (TSS)
Staphylococcal skin infection Fever, vomiting, shock, and organ failure caused by toxic shock syndrome toxin 1 (TSST-1) in the bloodstream
Acne
most common skin disease in humans
inflammatory (moderate) acne
caused by propionibacterium acnes
metabolizes sebum; fatty acids produce an inflammatory response treated with antibiotics and benzoyl peroxide
nodular cystic (severe) acne
inflamed lesions with pus deep in the skin
otitis externa
Infection by pseudomonas "Swimmers ear" Opportunistic in burn patients Resistant to many antibiotics
necrotizing fasciitis
Streptococcal skin infection "Flesh- eating" strep disease Exotoxin A produced by S. pyogenes acts as a superantigen
measles (rubeola)
Viral disease transmitted by the respiratory route Cold like symptoms, macular rash Koplik's spots Encephalitis in 1 in 1000 cases Prevented by MMR vaccine
koplik's spots
red spots on the oral mucosa opposite the molars
Shingles (herpes zoster)
Reactivation of the latent varicella- zoster virus that moves along peripheral nerves to the skin. - due to stress or lowered immunity Follows the distribution of affected cutaneous sensory nerves. - limited to one side of the body Postherpetic neuralgia- very painful Prevention via the zoster vaccine Antiviral drugs may lessen symptoms.
Chickenpox (Varicella)
DNA virus, Herpes family Herpesvirus varicella- zoster (human herpesvirus 3) Transmitted via the respiratory route Causes pus-filled vesicles Virus becomes latent in the central nerve ganglia Reye's syndrome Prevented by a live attenuated vaccines -breakthrough varicella can occur if previously vaccinated
Reye's syndrome
Severe complications of chickenpox; vomiting and brain dysfunction -aspirin use increases risk
Warts
Papillomas Transmitted via contact Caused by papillomavirus -more than 50 types -some cause skin and cervical cancers Treated with cryotherapy, electrodesiccation, or salicylic acid Papilloma vaccine can prevent certain cervical cancers
papillomas
small skin growths
Rubeola
measles
varicella zoster
virus that causes chickenpox
Rubella
German measles Macular rash and light fever Transmitted via the respiratory route; 2-3 week incubation Prevented by MMR vaccines
Papillomavirus
Causes warts
Herpes simplex virus I and II (HSV I, HSV II)
DNA viruses, herpes family Usually develop as cold sores or fever blisters
HSV I
spread primarily by oral or respiratory routes
HSV II
spread primarily sexually
Conjuctivitis
Inflammation of the eye membrane (conjunctiva) Also called red eye or pinkeye Caused by bacteria or virus Commonly caused by Haemophilus influenzae Can be caused by pseudomonas associated with unsanitary contact lenses
CNS
Central nervous system Composed of the brain and spinal cord
Blood- brain barrier (BBB)
Formed by epithelial cells of the capillary wall, astrocyte end- feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. Shields the brain from toxins in the blood.
Encephalitis
Inflammation of the brain
Meningitis
Inflammation of the meninges.
Tetanus
Caused by Clostridium tetani Gram(+), endospore forming, obligate anaerobe Grows in deep wounds Tetanospasmin released from dead cell blocs relaxation pathway in muscles Prevented by vaccination with tetanus toxoid (DTP) and booster (dT)
Poliomyelitis
Poliovirus Transmitted by ingestions Initial symptoms: sore throat and nausea Viremia may occur; if persistent, virus can enter the CNS Destruction of motor cells and paralysis occurs in <1% of cases Prevention: vaccination (enhanced- inactivated polio vaccine)
Rabies
Caused by rabies virus Transmitted by animal bite
Furious rabies
Animals are restless then highly excitable
Paralytic rabies
Animals seem unaware of surroundings
Haemophilus influenzae Meningitis
Occurs mostly in children (6 months- 4 years) Gram(-) aerobic bacteria, normal throat microbiota Capsule antigen type B Prevented by Hib vaccine
Neisseria meningitidis
Also called meningococcal meningitis Caused by N. mengitidis: Gram (-), aerobic cocci with a capsule 10% of people are healthy nasopharyngeal carriers Begins as throat infection, rash
Streptococcus pneumoniae Meningitis
Also called pneumococcal meningitis Caused by S. pneumoniae (a gram+ diplococcus) 70% of people are healthy nasopharyngeal carriers Most common in children (1 month- 4 years) Mortality: 30% in children, 80% in elderly Prevented by vaccination
Listeria monocytogenes
Gram (+) bacillus pathogen causing listeriosis
Clostridium tetani
Gram (+) pathogen causing tetanus
Poliovirus
Causes poliomyelitis
Rabies virus
Causes rabies
Listeriosis
Caused by Listeria monocytogenes Gram(-) aerobic rod Usually foodborne; can be transmitted to fetus Reproduce in phagocytes
Cardiovascular & Lymphatic systems
Plasma leaves blood to become interstitial fluid Lymph capillaries: transport interstitial fluid to blood Lymph nodes contain: fixed macrophages, B cells, T cells
What do lymph nodes contain?
Fixed macrophages, B cells, T cells
What is the function of the lymphatic system?
Maintains fluid levels in body tissues by removing all fluids that leak out of blood vessels.
Septicemia
Persistent pathogens or their toxins in blood
Sepsis
Systemic inflammatory response
Septic shock
Sepsis + uncontrollable decreased blood pressure
Endocarditis
Inflammation of the endocardium
Anthrax
Bacillus anthracis: Gram(+), endospore- forming, aerobic rod Found in soil Cattle routinely vaccinated Treated with ciprofloxacin or doxycycline
Infectious mononucleosis
Epstein- Barr virus (HHV-4) Childhood infections are asymptomatic Transmitted via saliva Characterized by proliferation of monocytes
Cutaneous anthrax
Endospores enter through minor cut 20% mortality
Gastrointestinal anthrax
Ingestion of undercooked, contaminated food 50% mortality
Inhalational (pulmonary) anthrax
Inhalation of endospores 100% mortality
Staphylococcus aureus Streptococcus pyogenes Enterococcus faecium Streptococcus agalactiae/ Group B Streptococcus
Gram (+) pathogens associated with nosocomial infections
Bacillus anthracis
Gram (+), endospore- forming, aerobic rod Pathogen causing anthrax
Cytomegalovirus (CMV)
HHV- 5 Infected cells swell Latent in white blood cells May be asymptomatic or mild Transmitted across placenta; may cause mental retardation Transmitted sexually, by blood, or by translated tissue
Epiglottitis
Most life threatening disease of the upper respiratory system
Scarlett fever
Erythrogenic toxin produced by lysogenized S. pyogenes
Diphtheria
Caused by Corynebacterium diphtheriae Forms a tough grayish membrane in the throat -Fibrin and dead tissue -Blocks passage of air to the lungs Exotoxin produced by lysogenized bacteria: circulates in the blood; damages the heart and kidneys
Otitis media
Infection of the middle ear: formation of pus puts pressure on the eardrum Causes: Streptococcus pneumoniae, nonencapsulated Haemophilus influenzae, Moraxella catarrhalis, S. pyogenes, respiratory syncytial viruses Common in childhood due to smaller auditory tube Treated with broad-spectrum penicillins
Viral pneumonia
Occurs as a complication of influenza, measles, or chickenpox
Q fever
Caused by Coxiella burnetti
Pertussis (whooping cough)
Caused by Bordetella pertussis Produces a capsule: allows attachment to ciliated cells in the trachea: destroys ciliated cells and shuts down the ciliary escalator. Tracheal cytotoxin of cell wall damages ciliated cells. Pertussis toxin enters the bloodstream.
Tuberculosis
Caused by Mycobacterium tuberculosis
Acute Q fever
High fever, muscle aches, headache, coughing
Chronic Q fever
Endocarditis (may occur years after infection)
Pathogens that cause otitis media
Streptococcus pneumoniae Nonencapsulated Haemophilus influenzae Moraxella catarrhalis S. pyogenes respiratory syncytial viruses
Mycoplasma pneumonia
Pathogen causing Mycoplasmal pneumonia No cell wall Gram (-)
Coxiella burnetiid
Pathogen causing Q fever. Obligately parasitic, intracellular gammaproteobacteria. Gram (-)
Bordetella pertussis
Gram (-) coccobacillus pathogen causing pertussis (whooping cough)
Corynebacterium diphtheriae
Pathogen causing Diphtheria Gram (+) rod; pleomorphic
Legionella pneumonia
Pathogen causing Legionellosis Aerobic, gram (-) rod Grows in water and air conditioning, biofilms, and waterborne amebae
Mycobacterium tuberculosis
Gram (+) Pathogen causing Tuberculosis Acid- fast rod; obligate aerobe 20- hour generation time Lipids in the cell wall make it resistant to drying and antimicrobials.
Influenza virus
Contains 8 RNA segments and an outer lipid bilayer
Adenovirus
Causes mild cold or flu- like illness.
Rhinovirus
30%-50% of common cold Thrives in temperatures lower than body temperature.
Coronavirus
10%-15% of common cold
Respiratory syncytial virus (RSV)
Most common viral respiratory disease in infants and life-threatening pneumonia in older adults. -almost all children are infected by age 2 -14,000 deaths annually, mostly in older adults Causes cell fusion (syncytium) in cell culture Coughing and wheezing for more than a week Diagnosis: serological test for viruses and antibodies Treated with palivizumab
Cholera
Acute diarrheal illness caused by infection of the intestine with Vibrio cholerae bacteria.
Salmonella gastroenteritis
Caused by salmonella enterica Invades intestinal muscosa and multiples -passes through M cells and enters the lymphatics -replicates in macrophagesIncubation of 12-36 hours; fever, nausea, pain and cramps, diarrhea
Traveler's diarrhea
Most commonly caused by enterotoxigenic E. coli
Aflatoxin poisoning
Mycotoxins produced by Aspergillus flavus -likely to be found on peanuts -causes liver cirrhosis and liver cancer
Ergot poisoning
Mycotoxins produced by Claviceps purpurea -occurs in grains -restricts blood flow (gangrene) and causes hallucinations
Giardiasis
Caused by Giardia intestinalis Prolonged diarrhea, malaise, weight loss, flatulence, cramps. Hydrogen sulfide detected in the breath or stools. Diagnosed with microscopic examination of stool samples; CDC currently recommends serological fecal tests. Treated with metronidazole and nitazoxanide.
Amebic dysentary
Caused by Entamoeba histolytica
Vibrio cholera
Gram (-) pathogen causing cholera
Escherichia coli
Gram (-). E. coli.
Campylobacter jejuni
Gram (-) micro aerobic Causes campylobacteriosis
Helicobacter pylori
Gram (-) pathogen causing Helicobacter peptic ulcer disease. Infects 30–50% of the population in the developed world - grows in the stomach acid by producing urease: converts urea to alkaline ammonia - disrupts stomach mucosa, causing inflammation