Portals and parts Flashcards
Integumentary system
Skin
Forms the extertrnal body covering, and protects deeper tissues from injury
Many microbes live on the skin
Damage to the skin almost always results in some type of infection
The surface layer of skin is what
Densely packed layers of dead cells
Sebum
Secretion from skin
Oil from sebaceous glands
High lipid content but low PH (acidic)
LIPID BREAKDOWN products are toxic to some bacteria
Characteristics of sweat from sweat glands
Containers lysosome
High salt content
Low PH
Popular bacteria on skin
Staphylococcus - causes staph
Streptococcus- causes strep
Nervous system
Brain, nerves, spine
Fast acting control system of the body
It responds to internal and external changes by activating appropriate muscles and glands
Immuno privelaged- kept largely separate from rest of body— only certain chemicals can get through
The heart pumps blood, bone marrow, producers blood cells
The nervous system is split into what two systems
Central
Brain
Spinal chord
Peripheral shstem
Nerves
Ganglia
Cerebrospinal fluid
Derived from blood
Circulates around brain and meninges
Contents are selected from blood by blood brain barrier, other materials not allowed in brain
Brain is an immuno-privelaged site
Synapse structure
Nerves carry electrical signal- impulses
They result in the production and release of synaptic vesicles (bubble of cell membrane that contains something)
Electrical signal travels down nerve
Encourages the release of synaptic vesicles
And the nerve sends that signal
Endocrine system
Glands secrete hormones rhat regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells
Relates to the circulatory system
Cardiovascular system
Heart, blood vessels
Pump blood, bone marrow
Lymphatic system
Picks up fluid from tissues and returns it to blood
Houses white blood cells involved in immunity
Lymphatic capillaries
Suck fluid back up
Viremia
Viruses in the bloodstream
Example: HIV
Septicemia
Bacteria in the bloodstream
Sepsis
A large scale innate immune response (usually inflammation) as a result of septicemia
Can occur when an infection from elsewhere breaks into the blood vessels and spreads throughout the body
Where do bacteria get into bloodstream with septicemia
Some sort of lung infection
Urinary tract infections
Most likely ^^
Respiratory system
Allows for aerobic respiration
Keeps blood and cells of body constantly supplied with oxygen
Immune system of the respiratory system
Highly specialized
Produces mucus and cilia
They make a surface that make it hard for bacteria to attach to
Alveoli
Site if gas exchange between air and blood
Highly vascularized, some pathogens can cross into bloodstreams here
Alveoli are protected by a resident macrophage population that engulf and destroy foreign invaders
What happens during a gastroinestrincal infection
If the symptoms are in the higher part of digestive system, then this causes vomiting
If I’m the lower part then diarrhea is mkre cmmin
For both, this leads to dehydration
Urinary system
Eliminates nitrogen waste from body
Regulates water, electrolyte, acid base balance of blood
Urinary tract constituents of
Kidneys -removed small molecules from blood and converts to urine
Ureters
Urinary bladder
Where the urine is stored
Triangle shaped musicalar organ
Urine contains
Lysozime, lactoferrin
Lactoferrin is an iron sequestration molecule that limits the growth of bacteria usually found in secretory substances and secreted by immune cells
We get an infection when
Microbes cross to a new previously uncolonized area
Example UTI
when microbes acquire new disease causing traits
Ex. E.coli food poisoning
Microbes grow in higher numbers than usual
Ex: yeast infections
New microbes
Defenses are down
Pathogenicity
A potential capacity of a pathogen to cause disease
Virulence
A pathogens ability to infect or damage a host
Virulence factors
Features of pathogens that help them overcome our defenses
Opportunistic pathogens vs primary pathogens
Opportunistic- not necessarily a problem UNTIL they cause disease. Example: staf infection
Primary- always cause disease
Toxins as a virulence factor
Chemical products of microbes that are poisonous to host organism
This means the pathogen doesn’t necessarily cause the disease but what they produce
Endotoxins
Refers specifically to a component of the bacterial cell wall, triggers inflammation and fever
Exotoxins
Refers to any type of toxin released by a pathogen secreted away from the cell
3 types of exotoxins
Signal propagated inside cell
Break membrane apart
Pull the whole toxin itself into the cell
5 stages of infection
Entry Adhesive to host tissue Invade tissues to obtain nutrients Evade immune response and replicate Spread to new host
Step 1: entry of infection
Portals of entry
The way the infection gets in is how we identify them
Pathogens can get in through blood
Vectors
Blood sucking insects or Arthropoda like ticks and mosquitos
Infectious dose
How many microbes it takes to initiate an infection
Varies by pathogen
TB requires only 10 cells
Cholera requires 1 billion
How are enzymes sometimes used in invasion
Some pathogens secrete tissue digesting enzymes to break down barriers
Motility
Helps to make invasion possible, after moving
How do we try to evade infection or infectious pathogens
Host cells (immune cells) will try to eat pathogens, disable pathogens etc
3 methods for evading the immune response
- Antigen masking: pathogen steals own membrane and puts them all over itself to pretend to be a host cell so when immune cell comes along it jusr seee another host cells
- Antigen mimickery: pathogens own factors look like others in advance
- Antigen variation: in the process of infection, pathogen switches disguise so that the immune system can’t keep up easily
Pathogens can cause damage in 2 ways
Directly by secreting damaging chemicals
Indirectly inducing the hosts immune defenses (particularly if immune response is excessive or inappropriate)…
Things to look for if there are no detectable symptoms
Changes to immune cell populations
Presence of antibodies specific to
If pathogens gain access to blood: septicemia or viremia
Portals of exit
The way that diseases leave the body to infect others
Example, through urine, through feces, through skin warts or bumps, coughing, sneezing, etc
Norovirus
Vomiting bug that spreads in places like cruise ships cuz they can stay on surface for up to two weeks
Incubation period
No symptoms but pathogen is in the host initiating damage
The time between an infectious takes route and you take to see symptoms
Latency
Symptoms subside, but pathogen is still hanging out
Example: mono
Horizontal transmission
One person to another
Vertical transmission
Mother to child
Fomites
Indirect method of getting a disease (doorknobs, phones, handles)
Non living surfaces rhat transfer disease
Zoonoses
Diseases transmitted from animals to humans
Dead end transmission
Human to human can’t happen only animal to human for example rabies
Spillover event
The moment the disease transfers from one species to another
