Steady State Condition
the normal condition of a system, normal flow/exchange of molecules. many variables but within normal limits. (Na+/K+ exchange in a cell)
Equilibrium
when two environments are truely equal. same value. (same water inside of cell and outside). different than steady state.
Negative Feedback (loop)
major control system in the body. it senses a change and reacts to Reverse it (negative to stimuli). example: thermostat sesnes temperature change and activates Heating/cooling to return to desired temperature.
Sensor->Integration->Effectors
sensors monitor variables (aorta) > Integrators attached to the sensor some way and process the change (heart) > Effectors cause the change (SNS; Vasopressin/kidneys)
Postive Feedback (loop)
stimulus causes a change, the body responds by increasing this change. (Severe hemorrhage: body keeps increasing cardiac output until heart failure) (Clotting: activates clotting cascade, TXA2, vasospasm, until bleeding stops)
Decompensated/Compensated Shock
positive feedback leads to death, or negative feedback insufficient/negative feedback works well
Cell membrane
composed of a phospholipid bilayer; protective ring of the cell.
Cytoplasm
The fluid within the cell.
Nucleus
composed of a DOUBLE phospholipid bilayer. DNA synthesis, reading/translation done here. Only small molecules can pass through membrane (hormones, small ions, protiens)
Endoplasmic Reticulum (rough)
Surrounds the nucleus. contains ribosomes, translates mRNA and creates proteins/peptides.
Endoplasmic Reticulum (smooth)
connected but distal to rough ER. does NOT contain ribosomes (smooth). lipids are created here. Transport vesicles are created for products.
Golgi Apparatus
modifies proteins and secretes them to the cell surface.
ICF
Intracellular fluid (inside the cells). makes up 2/3 of bodily fluid. ~28L
ECF
extracellular fluid (plasma, interstitial, and campillary membranes). 1/3 total body fluid ~14L
Na+
Sodium ion is EXTRACELLULAR.
Ratio is 10:1, normal values = 142 mOsm/Liter H2O
K+
Potassium ion is INTRACELLULAR.
Ratio is 35:1, normal values = 4.0 mOsm/Liter H2O
Ca++
Calcium ion is EXTRACELLULAR. It is used as a signaling ion (rushes into cell) to turn the cell on/off.
Ratio 10,000:1
HCO3-
Bicarbonate is EXTRACELLULAR. it primarily circulates in the blood as a buffer.
HPO4-
Phospate ion is INTRACELLULAR. It mainly functions with ATP production in the cell and can be used by the kidney as an intracellular buffer.
Phosphocreatine
intracellular compound that has a lot of potential energy.
Amino Acids
intracellular. used in the cell to make proteins/peptides.
Lactate
slighty more intracellular. it is a byproduct of cellular metabolism and is excreted by the cell. Seen in ECF during pathologic conditions.
Glucose
Usually extracellular. used for energy by the cell, needs insulin to cross membrane.
Proteins
intracellular. very large (bunch of amino acids) and needs transport system to leave the cell. negatively charged
Osamolarity
Usually in equilibrium because water tries to be the same on the inside and outside of the cell.
normal value = 283
simple diffusion
movement of molecules through the membrane (or intermolecular spaces) without the use of carrier proteins.
two pathways: watery channels/interstices of lipid bilayer
facilitated diffusion
a passive process. travel of molecules/ions through a membrane by chemically binding to them and carrying them through the membrane. (carrier-mediated diffusion) EX: Glucose uses this.
voltage gating
diffusion by open/closing of ion gates based on electrical charges on the inside and outside of the membrame
chemical gating
(diffusion) open/closing of channels by ligand binding to protein. The bind confirms to open/close gate.
primary active transport
when a molecule/substance is moved against a concentration by (a carrier protein) energizing the molecule so it passes the electrochemcial gradient. Ex: Na+/K+ pump
carrier protein
complex of two separate globular proteins (alpha/beta subunits) that facilitate the transfer of molecules through the membrane. they are used in facilitated diffusion and active transport. negatively charged.
Na+/K+ pump
uses active transport (ATP). has three binding sites for Na+ and two binding sites for K+. this removes 3 Na+ ions from the cell and brings 2 K+ ions into the cell. results is a net negative charge (-1) intracellularly. primary function is to regulate cell fluid volume.
GLUT-1
transport protein that helps deliver glucose (facilitated diffusion) in the nervous system/brain. does not require insulin, always on.
GLUT-2
transport protein (facilitated diffusion) in the pancreas that senses glucose level in the body. does not require insulin to activate.
GLUT-4
transport protein (facilitated diffusion) in insulin dependent tissues (fat, skeletal muscle). requires insulin to activate.
Goldman equation
shows us that resting membrane potential (Vrm) of any cell is dependent on the concentration gradients of the permeant ions and their relative permeabilities.
Vrm
Resting membrane potential of a cell measured in volts or mili-volts (mv).