Ch 1 - Cellular Physiology Flashcards
What is interstitial fluid?
It is an ultra filtrate of plasma
Is the larger of the 2 sub-compartments in Extracellular fluid (interstitial fluid vs plasma)
What is plasma?
The fluid circulating in the blood vessels
The smaller of the 2 sub-compartments in Extracellular fluid (interstitial fluid vs plasma)
These two items make up total blood volume
Interstitial fluid & Plasma
Interstitial fluid + Plasma =
Total Blood Volume
What is Extracellular Fluid?
Contained within the integument of the animal
Fluid which bathes the cell
Major Cation of Extracellular Fluid
Na+ & Ca2+
Major Anion of Extracellular Fluid
Cl- & HCO3-
Major Cations of Intracellular Fluid
K+ & Mg2+
Major Anions of Intracellular Fluid
Proteins & organic phosphate (AMP, ADP, ATP)
ECF + ICF =
Total Body Water (TBW)
ECF = ___ of body water
1/3
ICF = ___ of body water
2/3
Percentage of Total Body Water is highest in…and lowest in…
Percentage of TBW is highest in newborns & adult males, & lowest in adult females and adults with large amount of adipose tissue (fat)
60-40-20 Rule
TBW: 60% of body weight
ICF: 40% of body weight
ECF: 20% of body weight
Extracellular Fluid is broken down into these 2 subcompartments
Interstitial Fluid & Plasma
What is osmolality?
A measure of the number of osmotically active particles per KILOGRAM of H2O
“How much sugar is in my coffee”
What is an osmole?
The number of particles into which a solute dissociates in solution
If solutes are bound to a protein are they active or inactive?
If any solutes are bounded to a protein they are inactive
What is osmolarity?
The number of osmotically active particles per LITER of total solution
Can be used interchangeably w/ osmolality (usually differ by about 1%)
What is pH?
Determined by the [concentration] of H+ ions
As H+ ions increases, pH decreases
As H+ ions decreases, pH increases
-log10[H+]
As the [concentration] of H+ ions increases
pH decreases
What is required for electroneutrality?
Each compartment must have the same concentration, in mEq/L, of positive charges (cations) as of negative charges (anions)
Anion Gap Formula
Anion Gap(plasma) = [Na+]plasma - ([Cl-]plasma + [HCO3-]plasma)
Normal Range for Anion Gap
8 - 16 meq/L
What is the anion gap?
A measurement that is useful in the diagnosis of acid-base disorders. The anion gap is based on the principle of electroneutrality: For any body fluid compartment such as plasma, the concentration of cations and anions must be equal. It accounts for the ignored anions & cations. It increases in conditions such as DM type I.
Electrolytes imbalance may result in
K+; arrhythmia
Na+; abnormal ECF osmolality, with water being shifted into or out of brain cells; seizures, coma, death
Glycerol backbone of cell membrane
Hydrophilic
Water soluble/water liking due to glycerol back bone w/ phosphate
Fatty acid tails of cell membrane
Hydrophobic
They are esterified hydroxyl groups
Water insoluble/water hating due to fatty acid tails
Tails oppose each other
Permeability of cell membrane is based on
Lipid or Water Solubility
Lipid soluble molecules & cell membrane
Uncharged
Dissolves in the hydrophobic layer & are able to cross cell membrane
»O2, CO2, steroid hormones
Water soluble molecules & cell membrane
Charged
Dissolves in the hydrophilic layer
Unable to dissolve in lipid membrane, but are able to cross water-filled channels, pores, or are transported by carriers
»Na+, Cl-, K+, Ca2+, glucose, H2O
Integral Proteins
Embedded and anchored by covalent bonds. Cannot be easily removed from cell membrane.
Transmembrane proteins have contact w/ both ECF & ICF. Some integral proteins are embedded but may not cross the membrane.
Peripheral Proteins
Not embedded in the membrane. Loosely attached by electrostatic interactions.
Located on either intra or extra cellular surface of cell.
Hydrophilic due to location
Removed by mild treatments that disrupt ionic bonds
Pores & Channels allow for
Water & Ions
Carrier proteins allow for
Facilitated diffusion; transport glucose
Pumps in cell membranes allow for
Active transport
Glycocalyx
Carbohydrates loosely attached to surface membrane
- Glycoproteins
- Glycolipids
- Proteoglycans
Tight Junctions
Zona Occludens
Attachment between cells
Occludens means to prevent/occlude
Claudins - principal structural elements of the tight junction
Adhering Junctions
Belt that encircles an entire epithelial cell just below the level of the tight junction
Functions:
»provide epithelial cells with clues about the nature and proximity of their neighbors
»initiates the assembly of a subcortical cytoskeleton as they assist in the assembly of actin, myosin, etc. – cytoplasmic cytoskeleton
Defects can lead to loss of cell organization as seen in tumors
Gap Junctions
- Low resistant pathways
- Principal structural element
• Connexin - Allows for communication between cells
• Intercellular communication - Eg:
• Current flow & electrical coupling between myocardial cells
Desmosomes
- Holds adjacent cells together tightly at a single, round spot
- Characterized by dense plaques of intermediate filaments
Simple Diffusion
- Does not require any form of energy
• Passive - Non-carrier-mediated
- Occurs down an electrochemical gradient
• Downhill - Eg: Pack of red dye in water or sugar in water
Diffusion of Electrolytes is affected by
- Potential difference across the membrane
• Electrical gradient
• Eg: K+ & Na+ - Diffusion potential
• Charged solute diffuses down a concentration gradient, based a potential difference across a membrane
Calculating Diffusion
J = -PA (C1 - C2)
J = flux (flow) P = Permeability A = Area C1 = Concentration 1 C2 = Concentration 2