Physiology Review for Midterm

Immune System

 Disease as a Failure of Homeostasis 

·         any condition that prevents the body from working as it should

·         body may fail to maintain homeostasis

·         may become apparent right away (birth defect or poisoning), or may not show up for many years (cancer)

   

 Infectious diseases: DISEASES CAUSED BY AGENTS THAT ENTER OR INFECT BODY

Transmitted by: PATHOGENS

 Immune system:  PRIMARY DEFENSE AGAINST PATHOGEN

Body’s 3 lines of defense

First Line	Second Line If gets through 1st line Infection	Third Line
Non-Specific – “fortress walls”	Non-Specific	Specific – “security guard”
·      Physical and Chemical barriers – skin, tears, sweat, saliva, mucus membranes, stomach acid	·         Inflammatory Response – increased blood flow	·      recognizes, attacks, destroys, remembers ·       T-cells  - killer T cells cause pathogen to burst ·       Memory T-cells and memory B cells cause a quicker response if infected with same pathogen again

Types of Immunity – ability of body to fight infection through the production of antibodies or cells that inactivate foreign substances or cells

Passive	Active
·         “borrowed” immunity ·         temporary ·         Maternal immunity – antibodies come to baby from mother before birth and from mother’s breast milk	·         Body produces its own antibodies or killer T cells to attach an antigen ·         Results from having the disease or getting a vaccination

Preparation and use of a vaccine

1.      Obtain Pathogen

2.      Treat pathogen to kill or weaken it

3.      Inject altered pathogen (vaccine) into organism

4.      Body responds to antigens present by making antibodies and having white blood cells attack invader

5.      Some white blood cells specific for this pathogen remain in the body for a long time to continue the protection from future attacks by the pathogen.

Problems Associated With the Immune Response

Allergies –

·         rapid immune system reaction to environmental substances that are normally harmless

·         immune system reacts by releasing excess histamines – leads to runny nose, sneezing, rash, swelling

·         ex. certain foods, pollen, chemicals from insect bites

Damage to the Immune System

AIDS – Acquired Immunodeficiency Syndrome caused by HIV (a retrovirus)

condition whereby the body's specific defense system against all infectious agents no longer functions properly.