Quiz 3 (Lecture 12)

Question 1

Defense mechanisms evolved as

Answer 1

modifications of normal physiology

Question 2

Homeostasis is

Answer 2

the stability of key variables in cells, tissues, and organisms controlled by feedback mechanisms

Question 3

Most maintenance and defense mechanisms were

Answer 3

evolutionarily derived by modifying homeostatic functions

Question 4

Maintenance mechanisms sustain normal function by

Answer 4

preventing, repairing, and reducing malfunctions that are byproducts of normal physiology

Question 5

Defense mechanisms protect against

Answer 5

specific hostile environmental perturbations that exceed homeostatic capacity

Question 6

Hostile factors with sufficient impact on

Answer 6

fitness lead to the evolution of specialized defense mechanisms

Question 7

The seven hostile factors

Answer 7

famine, dehydration, heat/cold stress, pain, predation, toxins, and infections

Question 8

When food deprivation persists, metabolism shifts

Answer 8

to a fasting response
- glycogen stores are used up
- gluconeogenesis becomes the main source of glucose (saved for brain)
- lipolysis is activated and most tissues fatty acids act as main metabolic fuel

Question 9

when starvation begins,

Answer 9

the liver starts synthesizing ketone bodies that become the main fuel for most tissues including the brain

Question 10

when starvation is extreme and fat stores are depleted,

Answer 10

the breakdown of protein in skeletal muscle starts to provide amino acids as fuel sources

Question 11

predation

Answer 11

flight or fight response
- controlled by a strong increase in the output of the sympathetic nervous system, it results in increased heart rate, respiration, and a shift in cardiac output to skeletal muscle
– is upregulated on existing sympathetic nervous system

Question 12

Allergens

Answer 12

Allergic defenses operate in barrier tissues: skin and mucosa of the upper respiratory, gastrointestinal, and urogenital tracts
- responses to noxious substances: venoms, irritants, and xenobiotics

Question 13

defenses always operate

Answer 13

at a cost
- but cannot interfere w/ reproduction
- costs include defensive organs and tissues

Question 14

evolutionary costs are measured as

Answer 14

negative covariances with other functions

Question 15

Deployment of defenses costs involve

Answer 15

both energy and physiological costs (interference with other functions)

Question 16

Should we treat symptoms that are defenses?

Answer 16

blocking symptoms that are defenses can temporarily alleviate suffering but can also interfere with defenses

Question 17

Fever proximate mechanism

Answer 17

when components of a bacterial cell are bound by macrophages, the macrophages produce fever-inducing signals
- fever has been documented in many vertebrates (including ecto- and endotherms)

Question 18

Fever example

Answer 18

iguanas develop behavioral fever
- showed that fever is adaptive bc iguanas who were sick and did not develop a fever died

Question 19

Anti-fever study

Answer 19

medicines prevented monocytes from moving from the blood to infectedtissues

Question 20

why are fevers common?

Answer 20

low cost and not detrimental to have it

Question 21

Principle of asymmetric harm

Answer 21

a false positive is a minor nuisance whereas a false negative can be a catastrophe

Question 22

smoke detector principle

Answer 22

no one wants a smoke detector that detects only some or even the majority of fires (detects ALL)