Homeostasis and Fluid Compartments

Question 1

Largest organ system

Answer 1

Integumentary

Question 2

Movement of fluid (blood) within circulatory system

Answer 2

Bulk flow

Question 3

Movement of fluid (lymph) between capillaries and cells

Answer 3

Diffusion

Question 4

Two fluid compartments separated by plasma membrane

Answer 4

Extracellular fluid (ECF) 
Intracellular fluid (ICF)

Question 5

Two divisions of ECF

Answer 5

Intravascular fluid (IVF) 
Interstitial fluid (ISF)

Question 6

K+ is tightly regulated in ECF - if you go too high, you start to mess with ____________ of excitable cells

Answer 6

membrane potential

Question 7

Surrounds cells and serves as an interface between cels and external environment

Answer 7

Extracellular fluid (ECF)

Question 8

Most of the body’s fluid is in the ______

Answer 8

ICF (intracellular fluid)

Question 9

\_\_\_\_\_\_\_\_\_\_\_\_\_: equal amount of substance 
No net transfer of substance or energy 
No barrier to movement 
No energy expenditure to maintain 
IVF = ISF

Answer 9

Equilibrium

Question 10

_____________: constant amount of substance in compartments
Input = output
Requires energy to maintain
ECF does not equal ICF

Answer 10

Steady state

Question 11

______________: maintenance of extracellular fluid (ECF) constituents as relatively constant
Central theme of physiology

Answer 11

Homeostasis

Question 12

Concentrations in _____ need to be compatible with life (can stop the heart by raising ECF K+ levels to even 7 or 8 mM) - buffer zone

Answer 12

ECF

Question 13

Homeostatic control where response is made at a distance from the target cell (endocrine, nervous)

Answer 13

Reflexes

Question 14

Homeostatic control that occurs at target cell (paracrine, autocrine, gap junctions)

Answer 14

Local response

Question 15

3 components triggered by a stimulus in a homeostatic reflex loop

Answer 15

Sensor (afferent)
Integration center
Effectors (efferent)

Question 16

___________ detect change imposed by the external environment and change that occurs/arises within the body
Usually negative controls

Answer 16

Reflex loops

Question 17

Has the set point, sends out effector response if it needs to be adjusted
(Usually the brain)

Answer 17

Integration center

Question 18

Thermal sensors detect a drop in body temperature and signal to the hypothalamus to trigger effectors that cause:

Answer 18

Muscle shivering

Vasoconstriction is skin (move vessels closer to the core)

Question 19

During ___________, the hypothalamus set point is reset to read and response as if the body were cold (shivering, vasoconstriction)

Answer 19

fever

Question 20

When sodium ingested = sodium excreted

Answer 20

Neutral mass balance

Question 21

When more sodium injected than excreted

Answer 21

Positive mass balance

Question 22

Why does being thirsty and drinking something after eating salty food help maintain steady sodium concentration?

Answer 22

Drink brings in volume (higher amounts but higher volume, maintains concentration)

Question 23

Increased volume in vasculature leads to:

Answer 23

increased blood pressure (hypertension)

Question 24

Insulin secretion is a ______ negative feedback loop

Answer 24

simple

Question 25

Thyroid hormone control is a ______ negative feedback loop that is regulated at many different steps

Answer 25

complex

Question 26

Accelerating response (negatively regulated - have to turn it off to prevent pathology)
Female reproductive tract
Clotting cascade

Answer 26

Positive feedback

Question 27

Anticipates change
Needed to “prime” the effector response because reflex control (peripheral nerve-brain-peripheral muscle/gland) takes too long to meet the need
Ex. GI tract (smell of food increases secretion of stomach acid)

Answer 27

Feed-forward control

Question 28

__________ activates the response, but does not accelerate the response or increases the sensitivity of the effector to the stimulus (not positive feedback)

Answer 28

Feed-Forward

Question 29

Smooth muscle sustains a given contractile state over time that can be increased or decreased depending on sympathetic nervous activity (alpha 1 adrenergic)

Answer 29

Tonic control

Question 30

______________ control of the heart
Sympathetic system increases heart rate through beta 1 adrenergic receptors
Parasympathetic system decreases heart rate through muscarinic ACh receptors

Answer 30

Antagonistic control

Question 31

_________ function in a predictable, timed manner

Govern daily biological functions (bp, temp, metabolism, urine output)

Answer 31

Circadian rhythms

Question 32

Circadian rhythms controlled by _______________
Sleep – temp drops about 1 degree C
Hormones also change
Growth hormone spikes in early sleep
Cortisol high in early morning (when you rise)
Growth hormone and cortisol sensitive to plasma glucose levels
Night owl – shifted so cortisol is as high early in morning

Answer 32

hypothalamus

Question 33

Why are many of the homeostatic control mechanisms in the body so complex?

Answer 33

Back-up systems in case one fails

Faster response