WEEK 1 Flashcards
define physiology
- physiology is the science of life.
- a branch of biology that aims to understand the mechanisms of living things.
- it has roots in physics, chemistry and math
- it covers cell function at the ionic and molecular level to how organisms behavior and the influence of the external environment
- it is a experimental science
why is physiology important?
- describes how the body works, how it responds and adapts to challenges
- describes disease processes
- helpful for developing treatment
- promotes healthy living
- helps develop healthy environments
describe the levels of biological organization and understand physiology’s scope
levels of biological organization:
atoms > molecules > Genes > organelles > cells > tissues > Organs > organ system > organisms > pop. of one species > ecosystem (community of species) > biosphere
physiology’s scope: ranges from molecules to organisms and the influence of the external environment
what are the recurrent themes in physiology
Biological energetics
physiological compartments
communication
homeostasis
describe biological energetics
- refers to the energy economy of the cell
- cells need energy to work
- two forms of energy: Kinetic and potential
describe the different types of kinetic energy
Kinetic energy is the energy that powers movement.
- mechanical- directly powers the movement of matter
- thermal - the energy of the motion of molecules
- radiant- kinetic energy of photons
- electric- energy of moving ions. the movement of ions create a current
describe the different types of potential energy
Potential energy is stored energy
chemical bonds- energy stored in bonds that assemble atoms into molecules
concentration gradients- difference in concentration of substance on either side of permeable barrier
electrical potential- the energy of charge separation
define the difference between kinetic and potential energy
- kinetic energy is the energy that powers movement and is not stored
- potential energy is stored energy found in chemical bonds, concentration gradients and electrical potential
How many liters make up interstitial fluid?
13
what separates the intracellular compartment and the extracellular compartment?
plasma membrane
what makes up the extracellular compartment?
Blood plasma
interstitial fluid
transcellular fluid
what are the concentrations of the interstitial fluid?
Na+ = 145 mM
K+ = 4.5 mM
Cl-= 116 mM
what are the concentrations of the blood plasma?
Na+= 142 mM
K+= 4.4 mM
Cl-= 102 mM
protein= 1 mM
how many liters make up the blood plasma?
3 liters
how many liters make up the transcellular fluid
1 liter
what are the concentrations of the transcellular fluid
its variable
how many liters make up the intracellular fluid
25 liters
what are the concentrations of the intracellular fluid compartment
Na+= 15 mM
K+= 120 mM
Cl-= 20 mM
protein= 4 mM
what is the total body water
42 liters
what is the difference between plasma and the interstitial fluid
plasma is rich in plasma proteins, whereas interstitial fluid has none
what are the three processes of thermoregulation
- heat production
- heat loss
- heat transfer
most dietary fat is in the form of what?
triglycerides
fatty acids found in animal triglycerides are _____
saturated ones
fatty acids found in plant triglycerides are ______
unsaturated ones. except tropical oils
what is the energetically favorable form of phospholipids
sealed compartment
what is found on the outerleaflet of the phospholipid bilayer (non-cytosolic leaflet)
phosphatidyl choline (PC)
sphingomyelin
glycolipids
what is found on the inner leaflet of the phospholipid bilayer (cytosolic leaflet)
phosphatidylethanolamine (PE)
phosphatidyl serine (-)
characteristics of the fluid mosaic model
bilayer is a viscous fluid
lipids and proteins can diffuse freely
proteins provide specific functional properties
possible lipid movement in the bilayer includes
flexion
rotation
lateral diffusion
flip flops
factors that influence membrane fluidity
saturated vs. unsaturated hydrocarbon tails
cholesterol (low temps= more fluid; high temp= less fluid)
describe tight junctions
seal adjacent cells together
function as selective permeability barriers
utilize Claudins and occludins that are anchored to actin filaments
describe adhering junctions
seal cell-cell junctions
utilize cadherin proteins that are linked to the actin filaments of the cytoskeleton
describe desmosomes
cell-cell junctions
utilize desmosomal cadherins that are linked to intermediate filaments of the cytoskeleton
describe hemi-desmosomes
cell-matrix junctions
formed from intergrins and linked to intermediate filaments
what are the functions of the glycocalyx?
protection
mechanosensing
regulating cell signaling
regulating of membrane protein diffusion
immune regulation and checkpoint inhibition
define brownian motion (aka pedesis)
the random motion of particles suspended in a gas or liquid medium
- causes diffusion and osmosis
- driven by the kinetic motion of the system
- solutes move and collide, then ricochet in random directions but overtime does not travel very far
how to calculate concentration gradient
dC/dX
C= concentration
X= distance
the rate of diffusion through a solvent is dependent on _____
the concentration gradient
size of the molecules
and possible interactions of solvent with the solute
* diffusion will continue until the solute molecules are evenly distributed throughout the volume of solvent (aka equilibrium)
calculate diffusion in a bulk fluid
J = D * (dC/dX)
J= flux
D= diffusion coefficient
define flux
flux; the number of particles moving past a given region divided by the area of that region per unit time.
larger concentration = larger flux
larger distance = smaller flux
the rate of diffusion across a membrane depends on _____
surface area of the membrane
diffusion coefficient
concentration gradient
thickness of the membrane
calculate diffusion across a membrane
J = D * A * (dC/dX)
J= flux
D= diffusion coefficient
A= surface area
C= concentration gradient
X= thickness of the membrane
lipophilic membrane= large surface area
non-lipophilic membrane= smaller surface area
membrane proteins that mediate simple diffusion across a membrane
pores (non-gated channels) - always open
ion channels
essential components of ion channels
the gate
sensor
selectivity filter
channel pore
what are the mechanisms for gating or opening ion channels
- a change in voltage across the plasma membrane
- binding of a specific ligand to a ligand binding domain. there is no conformation change induced
- application of mechanical force
lipophilic molecules require a membrane protein to cross the membrane? true or false
false
permeability coefficient is
the flow of solute in moles per second per square cm membrane
what do aquaporins do
permit the flow of water across a membrane
water transport helps regulate ____
cell volume
the Na-K ATPase pumps Na out of the cell, K into the cell and keeps ______
water from entering the cell
Km (binding constant) equals
1/2 Vmax
In facilitated diffusion the transport of the solute is sped up across the membrane true or false?
true
two types of glucose transporters are
GLUTs (glucose transporters) and SGLTs (sodium-linked transporters)
what does GLUT2 do
facilitates transport of glucose and galactose across the membranes of many tissues especially the liver and Beta cells of the pancreas
glucose is transported across the membrane through
facilitated diffusion
what does GLUT5 do
transports fructose
example of primary active transport
Na-K ATPase
3 Na out ; 2 K in
-1 charge for every cycle of the pump.
this transport maintains the electrochemical gradient needed for secondary active transport
glucose concentration is higher where compared to other fluid compartments
- epithelial cells
scientist who founded the fluid mosaic model
Jonathan Singer & Garth Nicolson
gap junctions allow water, ions, and small molecules to pass through. True or false
True
