Module 3 Flashcards
(26 cards)
What is negative feedback
Change in a factor that triggers an opposite reaction
- it shuts off on its own
What is positive feedback
Give examples
Change in a factor that triggers a response in the same direction
- contractions during birth
- outside factor needed to shut off
What is feedforward regulation?
Give examples
Response to smthg before the reaction is even made
- saliva in the mouth
- skin detects temp change and warms body
Ways of water loss
- evaporation
- sweat
- feces
- kidneys (urine)
Distribution of body water inside and outside
2/3 of body water inside the cell, 1/3 outside
The concentration of substances in the plasma and interstitial fluid is the same except plasma has …
Proteins
What is
-molarity
-molality
-osmolality
Respectively
- one mole of solute dissolved in 1 L solution
- one mole solution dissolved in 1 kg solvent
- total molality of solution
Direction of water flow in osmosis
Water flows from high to low concentration
- hypotonic to hypertonic
Direction of solute in osmosis
From low to high concentration
Difference btwn neurotransmitters and messengers
Neurotransmitters- communicate rapidly over a short distance
Messengers- communicate slowly over a larger distance
What are first and second messengers
First messenger: comes from extracellular fluid to bind to the receptor
Second messenger: produced in the cytoplasm of the cell and is formed bc of the receptor activation from the first messenger
Briefly explain cell signaling
The ligand first messenger binds to receptors which causes a change in shape. This activates JAK kinases which leads to the production of new proteins that help generate a response.
Rate of diffusion is determined by
- amount of substance (concentration)
- velocity
- available openings
- solubility
Differences btwn simple and facilitated diffusion
Simple: no carrier protein needed, rate of diffusion increases proportionately with amount of concentration
Facilitated: with carrier protein, after some time diffusion rate becomes constant bc there is a concentration limit.
Difference btwn primary and secondary active transport
Primary needs ATP, secondary uses na/k pump. The pump needs ATP
Net charge of cell inside and outside
Inside cell is negative, outside is positive bc 3 Na is pumped out, 2 K is pumped in
What is secondary active transport
The transport that is made with the energy released after primary transport
Which channel is responsible for depolarization of membrane in action potential
Voltage gated Na channel
What is the value of resting membrane potential?
-70
Its -55 when its open
When do voltage gated K channels open?
Opens when the membrane potential changes and then later repolarizes the membrane to -75, causing hyper polarization( membrane becomes more negative)
True or false:
Voltage gated K channels operate with positive feedback
False,
Na channels operate with positive feedback
K channels operate with negative feedback
What is relative refractory period?
Small period in which a second active potential can be produced, but the stimulus has to be greater than it usually is
Can you have a second active potential during absolute refractory period?
No
What is inhibitory post synaptic potential caused by?
Opening of Cl/K channels, causes hyperpolarization
- less likely to reach the threshold
