PHGY 209 midterm

what percentage of body weight does water make up

45-75%

main reasoning for the big difference in water body mass between people

fat adipose tissue

what happens if body water content is seen as a fraction of lean body mass

the difference in percentage becomes insignificant among individuals

difference between obligatory and facultative losses

obligatory losses are required, facultative losses are necessary for balance

difference between insensible perspiration and sweating

insensible perspiration is passive and sweating is active

negative water balance causes

excessive loss from gut, excessive sweating, excessive loss in expired air excessive urine, reduced intake

water intoxication causes

excessive intake and renal system failure

2 major body water components

extracellular fluid and intracellular fluid

which of the 2 body water compartments divides into 2 major and 2 minor sub compartments

extracellular fluid

2 major compartments of ECF

plasma and interstitial fluid

2 minor compartments of ECF

lymph and transcellular fluid

how much of water body mass does ICF make up

2/3

how much of water body mass does ECF make up

1/3

what is interstitial fluid

the fluid that percolates between individual cells

difference in lymph from capillaries

fluid only moves on-way though blind-ended tubules

what is transcellular fluid

an aggregate of small fluid volume secreted by specific epithelial cells

indicators for measuring ECF compartment

inulin, sucrose, mannitol

indicators for measuring total body water

antipyrine, D2O, T2O

indicators for measuring plasma volume

Evan’s blue or I 131- albumin

how do you calculate ICF

total body water - ECF

how do you calculate ISF

ECF - plasma

ICF is high in ____ and low in ____

high in K+ and low in Na+ and Cl-

ECF is high in ____ and low in ___

high in Na+ and Cl- and low in K+

body fluids are essentially…

aqueous solutions of inorganic ions with variable amounts of protein

molarity

amount of solute in a specific amount of solution

molality

amount of solute dissolved in specific amount of solvent

calculate amount of body water

body water percentage/100 x weight (kg)

calculate concentration of medicine

dosage x weight = amount of medicine given
amount of medicine given/amount of body water = concentration

calculate hematocrit

(height of RBC column/height of total column) x 100

where does exchange of gases happen in the plasma membrane

between ISF and ICF

cell membrane

bimolecular phospholipid bilayer, 6-10nM thick, amiphipathic

how does cholesterol act as a buffer

prevents lower temps from inhibiting fluidity and higher temps from increasing fluidity

integral proteins

cross the membrane

peripheral proteins

found on both sides of the membrane

glycocalyx

gel, sugar-rich coating surrounding cell

what does glycocalyx contribute to

cell-cell recognition, communication, adhesion, protection

selective tranpsport

channels and transporters

enzymes

amino acid transport and Na-K pump

cell surface receptors

G-protein receptor, insulin receptor, ACh receptor

cell surface identity marker

CD4 T lymphocytes, CD45 Leucocytes, CD68 monocytes

cell adhesion

CAMs, cadherins, integrins

Attachment to cytoskeleton

actin, microtubules, septins

transmembrane pathways

vis phospholipid bilayer or via interaction with transmembrane protein

passive transmembrane mechanisms

diffusion, facilitated diffusion, osmosis

active transmembrane mechanisms

active transport, endocytosis and exocytosis

diffusion

movement of molecules from one place to another as a result of random thermal motion; driven by concentration gradient; only effective over short distances

ion channels

transmembrane proteins with ion selectivity

channel gating

ion channels can change between being open and closed

types of channel gating

ligand-gating, voltage gating, mechanical-gating

mediated transport

movement of ions and other molecules by integral membrane proteins

factors that determine mediated transport

solute concentration, affinity of transporters, number of transporters, rate of conformational change

characteristics of mediated transport

specificity, saturation, competition

facilitated diffusion

involves transporters or carriers enabling a solute to penetrate readily

methods of facilitated diffusion

transporter/carrier method, passive, net flux from high to low concentration

what do hormones do to transporters

increase number/affinity of transporters

primary active transport

hydrolysis of ATP by a transport

what does phosphorylation of transporters do

changes the confirmation and its solute binding affinity

Ca2+-ATPase

maintains low intracellular Ca2+ levels

H+-ATPase

maintain low lysosomal pH

H+/K+-ATPase

acidification of stomach

secondary active transport

movement of Na+ down its concentration gradient coupled with movement of another molecule up is concentration gradient

mechanisms of secondary transport

symport/cotransport and antiport/countertransport

symport/cotransport

solute is transported same direction as Na+

antiport/countertransport

solute is transported in opposite direction to Na+

Endocytosis

cell membrane invaginates and pinches off to form a vesicle (out to in)

types of endocytosis

pinocytosis and phagocytosis

exocytosis

an intracellular vesicle fuses with the cell membrane and contents released in ECF (in to out)

types of exocytosis

constitutive and regulated

receptor-mediated endocytosis

molecules in ECF bind with high affinity to specific protein receptors

types of receptor-mediated endocytosis

clathrin-dependant and potocytosis

diffusion of water

water diffuses through cell membranes via water permeable changes (aquaporins)

osmosis

net diffusion of water across a semipermeable membrane

osmotic pressure

pressure required to prevent movement of water across a semi-permeable membrane

osmolarity

total solute concentration of a solution

ismotic

solutions with same osmolarity

hypoosmotic

solutes with osmolarity lower than 300 mOsm

hyperosmotic

solutions with osmolarity higher than 300 mOsm

to be effective in sustaining osmotic pressure, particles must be..

non penetrating

isotonic

300 mOsm of non penetrating solute (no net movement)

hypotonic

less than 300 mOsm of non penetrating solute (cell will swell)

hypertonic

greater than 300 mOsm of non penetrating solute (cell will shrink)

capillary structure and permeability

water-soluble substances though pores

lipid-soluble substances through endothelial cells

exchangeable proteins moved by vesicular transport

bulk flow

flux

amount of solute crossing a surface area per unit time

one way flux

unidirectional rate of movement of a solute

net flux

overall rate of movement of solute

what does blood contain

ICF and ECF

in electrophoresis, the rate of migration is influenced by…

number and distribution of charges and molecular weight

where are plasma proteins synthesized

in the liver except for gamma globulin

renal disease

albumin levels decline

bacterial infection

gamma globulin levels increase

role of plasma proteins

determining distribution of fluid between plasma and ISF

of ECF how much does ISF and plasma make up

ISF is ¾ and plasma is ¼

what contributes to effective osmotic pressure

only non diffusible solutes like plasma proteins

colloidal osmotic pressure of plasma (COP)

25 mm Hg

COP increases

more water flows into plasma

COP decreases

more water flows into ISF

methods for transport across capillary wall

osmotic flow and filtration and bulk flow

starling forces

osmotic flow, filtration, bulk flow

what do starling forces determine

distribution of ECF volume between plasma and ISF

where do exchanges between plasma and ISF take place

capillary bed