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Flashcards in homeostasis Deck (13):
1

definition of steady state

maintenance of nearly constant conditions over time

2

definition of equilibrium

when a system's solute concentrations and other parameters are constant in time without requiring an input of energy

3

what is Basal metabolic rate?

energy expenditure at rest
kcal/hr/sq meter body surface area

4

what value is usually less; basal metabolic rate or resting metabolic rate?

the basal metabolic rate because RMR includes various daily activities in its value

5

list 5 factors that can influence metabolic rate

gender
age
hormones
temperature that you live in
malnutrition

6

what is the primary intracellular fluid cation?

K+

7

what does mass balance for a system in steady state mean?

it means that any substance taken in by the body is nearly equal to the amount leaving the body plus that removed by metabolism

8

what is the primary extracellular fluid cation?

Na+

9

how is the difference between the intra and extracellular fluid cations maintained?

by the basolateral Na+/Ka+ ATPases which transport 3 Na+ molecules out of the cell in exchange for two K+ molecules transported into the cell

10

in the system level example of endocrine control over thyroid function, where does thyroid hormone negatively inhibit?

thyroid hormone negatively inhibits the anterior pituitary gland to prevent too much or too little TSH release

11

what is a system's "gain"?

it is the capacity of the system to restore a controlled variable to its set point after a pertubation

12

what does a higher system gain imply?

a better ability to restore a controlled variable to its set point in response to a perturbation

13

give some examples of a USEFUL positive feedback systems?

-uterine contractions during birth
-blood clotting after vessel rupture
-estrogen effects on pituitary hypothalamus before ovulation
-generation of an all or none action potential via Na+ channel activation
-calcium inducted calcium release in the heart