BIO 203 Lecture Notes - Lecture 16: Mucous Membrane, Thermostat, Anatta

12 views6 pages
Department
Course
The body’s defense system
The body generally defends you against anything that it does not recognize as
being part of or belonging inside you
Common targets of the defense system include
Pathogens
Disease-causing bacteria, viruses, prions, protozoans, fungi,
parasitic worms
Cancer cells
Once normal body cells whose genetic changes cause unregulated
cell division
Three lines of defense
Physical and chemical surface barriers
Nonspecific
Keep foreign organisms or molecules out
Internal cellular and chemical defenses
Nonspecific
Attack any foreign organisms or molecule that has gotten past the surface
barriers
Immune response
Specific
Destroy specific targets and remember them
Physical barriers
Skin
Nearly impenetrable
Waterproof
Resistant to most toxins and enzymes of invading organisms
Mucous membranes
Line the respiratory and digestive tracts
Sticky mucus traps microbes
Chemical barriers
Sweat and oil glands of the skin
Produce chemicals that slow or prevent the growth of bacteria
The lining of the stomach
Produces hydrochloric acid and protein-digesting enzymes that destroy
pathogens
Urine
Slows bacterial growth with acidity
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in
Washes microbes from the urethra
Saliva and tears
Contain lysozyme, an enzyme that kills bacteria
Second line of defense
Defensive cells
Defensive proteins
Inflammation
Fever
Defensive cells and natural killer cells
Phagocytes (WBCs) that engulf pathogens
Neutrophils: arrive first
Macrophages: develop from monocytes that leave the circulatory system
Eosinophils: attack pathogens that are too large for phagocytosis, such as
parasitic worms
Natural killer (NK) cells
Also a type of WBC
Search out abnormal cells, including cancer cells, and kill them
Interferons: slow viral reproduction
Small proteins secreted by a cell infected by a virus
Attract macrophages and natural killer cells that destroy infected cells
Stimulate neighboring cells to make proteins that prevent the viruses from
replicating
Complement system: assists other defensive mechanisms
Group of proteins that enhances both nonspecific and specific defense
mechanisms
Destroy pathogens, enhance phagocytosis, stimulate inflammation
Inflammation
Destroys invaders and helps repair and restore damaged tissue
Four signs
Redness
Heat
Swelling
Pain
Redness
Mas cells release histamine which causes blood vessels to dilate
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.