Biology - Part 3 Flashcards
Where does absorption of the digestive system occur?
Absorption occurs in small intestines via finger-like projections called villi and microvilli
Remaining products of digestion that are not absorbed are transported into the colon.
What are the functions of the colon?
Water absorption, storage and formation of feces
What does the duodenum secrete?
Secretin: stimulates pancreas to release bicarbonate, neutralizing stomach acid and other pancreatic digestive enzymes
Cholecystokinin (CCK): stimulates bile (liver) release from gall bladder and acid production by the stomach
What is the function of the immune system?
Cells, tissues, and organs that fight of illness and disease; protects body from pathogens and foreign invaders
What is the innate immunity?
1st line of defense; non-specific; physical and chemical barriers (skin, mucous membranes, and digestive enzymes)
What are the types of 2nd line of defense?
Non-specific; fever, inflammation, phagocytosis, NK cells, interferons, chemotaxis, and cytokines.
What are the actual examples of the 2nd line of defense?
Fever helps to eliminate pathogens that grow better at lower body temperatures
Inflammation: redness, heat, swelling, and pain are the 4 cardinal signs
NK cells: produce perforins that target cancer and virus cells., causing lysis
Interferons: response to viral infection and prevents replication; activate macrophages and NK cells
Leukocytes (WBCs): responds to cytokines released by other immune cells or damaged tissues via chemotaxis
What is the adaptive immunity/3rd line of defense?
3rd line of defense; highly specific; lymphocytes (B-cells, T-cells, NK)
Includes humoral and cell-mediated response
Once the immune system has recognized a specific antigen, it is able to eliminate the pathogen more effectively in the future.
What is the cell-mediated response?
Macrophages phagocytose non-self cells and presents antigens to T-helper cells.
T-helper cells release cytokines that stimulate cytotoxic T-cells to destroy specified non-self cells
What is humoral immunity?
Antibody-mediated
B-cells are activated by T-helper cells to produce antibodies that are highly specific for the antigen
Active Immunity: a vaccine or antigen stimulates the production of antibodies
Passive Immunity: antibodies from another source (breast milk)
What are the two slides to review?
23 and 24
What is fertility rate vs. replacement rate?
Fertility Rate: average # of offspring a woman will have during her childbearing years (15-44 y.o.a.)
Replacement Rate: # of births needed to maintain current population
However, fertility rates for developed countries is 1, and 7 for less-developed countries. Population in less-developed countries will rise, straining resources, and vice-versa for developed countries
What is population growth and decline dependent on?
Dependent on the difference between birth and death rates as well as the # of people who immigrate to or emigrate from.
Crude birth rate: # of births per 1,000 people/year
Crude death rate: # of deaths per 1,000 people/year
What factors affect fertility and birth rates?
Religion, culture, economy, employment, government, education, literacy, infant mortality rates, abortions and accessibility to family planning
What is imigration vs. emigration?
Birth Rate > Death Rate; population will grow unless emigration occurs
Birth Rate < Death Rate; population will decrease unless immigration occurs
