Body Fluids and Homeostasis

Question 1

set point

Answer 1

value around which the normal value fluctuates around

Question 2

dynamic constancy

Answer 2

homeostasis relies on this principle; no rigidity in body processes allows for minor fluctuations since the internal environment is constant and can return to set point on their own

Question 3

disease

Answer 3

LOSS of homeostasis

Question 4

negative feedback

Answer 4

homeostatic mechanism that REDUCES a change in a regulated variable; inhibition of a variable further in the pathway leads to decrease in variable earlier in the pathway
(MORE COMMON)

Question 5

positive feedback

Answer 5

homeostatic mechanism that AMPLIFIES a change in a regulated variable; increase of a variable earlier in the pathway leads to increase in variable later in the pathway (LESS COMMON i.e blood clotting)

Question 6

Who coined the term “homeostasis”?

Answer 6

Walter Cannon

Question 7

Who developed the concept of compartmentalization of the internal environment of fluid surrounding tissues and organs?

Answer 7

Claude Bernard

Question 8

Define: body fluids

Answer 8

the water solutions within the body

Question 9

Functions of body fluids

Answer 9

thermoregulation, shock absorption, lubrication, transport of nutrients and waste

Question 10

Total body water (TBW) and ECF/ICF/IF contributions

Answer 10

body is 60% water and of that 60%:
- 2/3 (40%) intracellular fluid
- 1/3 (20%) extracellular fluid

–> of the ECF 80% interstitial fluid and 20% plasma

Question 11

blood vessel structure

Answer 11

capillaries= 1 endothelium cell thick with water-clefts
- allows for max diffusion of nutrients, gas exchange and waste disposal

Question 12

plasma membrane components

Answer 12

BILAYER of hydrophilic heads and hydrophobic tails, proteins and glycoproteins, and cholesterol

Question 13

calculate blood volume

Answer 13

plasma, buffy coat of WBCs (<1%) and RBCs
so BV= plasma + RBC volume

Question 14

hematocrit

Answer 14

volume of RBCs to total blood volume (BV)
= RBC Volume/BV x100%
NORMAL RANGE: 35%-50%

Question 15

Molarity

Answer 15

moles of solute per liter of solution
units: mol/L (M)
CaCl2= 1 mol CaCl2

Question 16

Normality

Answer 16

number of EQUIVALENTS of solute per liter of solution
CaCl2= 2Eq= 2 normal

Question 17

Osmolarity

Answer 17

number of osmoles (osmotically active particles) of solute per liter of solution
CaCl2= 3 osmolar

Question 18

Osmolality

Answer 18

number of osmoles per kg of solvent

Question 19

Ionic composition of: SODIUM

Answer 19

Na(in)= 12
Na(OUT)= 140
- [Na] higher OUTSIDE the cell

Question 20

Ionic composition of: POTASSIUM

Answer 20

K(IN)= 150
K(out)= 4
- [K] higher INSIDE the cell

Question 21

Ionic composition of: CALCIUM

Answer 21

Ca(in)= 10^(-4)
Ca(OUT)= 2.5
- [Ca] higher OUTSIDE the cell

Question 22

Ionic composition of: MAGNESIUM

Answer 22

Mg(IN)= 30
Mg (out)= 1
- [Mg] higher INSIDE the cell

Question 23

Ionic composition of: CHLORIDE

Answer 23

Cl(in)= 10
Cl(OUT)= 110
- [Cl-] higher OUTSIDE the cell

Question 24

Ionic composition of: PROTEINS

Answer 24

[Protein-]= higher INSIDE the cell

Question 25

Macroscopic electroneutrality

Answer 25

on the BROAD spectrum, the positive and negative charges in the ICF are equal; and the positive and negative charges in the ECF are equal

Question 26

Osmolality of most/all cells in the body

Answer 26

~285mOsm/kg solvent --> 300 mOsm/L

Question 27

Diffusion

Answer 27

the movement of molecules from an area of higher solute concentration to lower solute concentration d/t their thermal energy

Question 28

Simple Diffusion

Answer 28

the PASSIVE movement of molecules from an area of higher solute concentration to lower solute concentration d/t their thermal energy so no outside energy is required

Question 29

Facilitated Diffusion

Answer 29

the MEDIATED passive movement of molecules from high to low concentration with the help of channels and/or carriers

Question 30

Osmosis

Answer 30

the SIMPLE diffusion of water

Question 31

Fick's law of diffusion

Answer 31

determines the net flux of particles that will diffuse across a membrane equation: J= PA(C1-C2)

Question 32

Determinants of ion permeability across a membrane

Answer 32

- temperature (higher temp --> increased movement of particles) - molecular weight - B (lipophilicity; higher lipophilicity--> increased movement of particles - charge (charged particles cannot PASSIVELY cross the membrane)

Question 33

Limitations of diffusion

Answer 33

why we would need assistance getting particles across the membrane: - low permeability - uphill transport - long distances - small surfaces