What type of molecules require help from channels or pumps to enter the cell?
Large, charged, or water-soluble molecules
These molecules cannot freely pass through the cell membrane due to their size or charge.
How do lipid-soluble molecules cross the cell wall?
They can easily cross the cell wall due to their small size
However, they do not perform well in water, which is primarily what blood consists of.
What are the two main diffusion processes mentioned?
Simple diffusion and facilitated diffusion
Simple diffusion allows molecules to pass directly through the cell wall, while facilitated diffusion requires transport proteins.
What do glucose transporters rely on to function?
Facilitated diffusion and concentration gradient
This process helps maintain blood sugar levels.
What is the significance of GLUT 4?
It is the most important insulin-dependent transporter
GLUT 4 is found in skeletal muscles and the liver.
What activates GLUT 4 transporters?
Insulin binding to insulin receptors
This activation leads to glucose transport into the cell.
What is glycogen?
The main storage form of glucose
Glycogen can be broken down into glucose to provide ATP for energy.
What happens in diabetes concerning glucose transport?
Communication with glucose transporters is impaired
This impairment typically leads to higher blood sugar levels.
What is the function of GLUT 2 transporters?
They allow pancreas cells to sense increased blood sugar
GLUT 2 transporters are always on and initiate the release of insulin.
What distinguishes GLUT 1 transporters?
They are present in red blood cells and the nervous system
GLUT 1 transporters are not insulin-dependent and are always active.
What is V max in facilitated diffusion?
The maximum rate of diffusion
It is limited by the binding and releasing process of transport proteins.
What is primary active transport?
A process that utilizes energy to move substances against their concentration gradient
Examples include the Na/K pump.
What is the stoichiometry of the Na/K pump?
2 K+ ions in and 3 Na+ ions out
This process consumes ATP and contributes to the cell’s negative charge.
What is ATP?
Adenosine triphosphate, the energy currency of the cell
ATP provides energy by cleaving phosphate groups.
What is secondary active transport?
A process that relies on the electrochemical gradient established by primary active transport
It often involves co-transport mechanisms.
What is a symporter?
A transporter that moves two or more substances in the same direction
An example is the sodium-glucose transporter (SGLT).
What is an antiporter?
A transporter that moves compounds in opposite directions
An example is the sodium-calcium exchanger (NCX).
What factors affect the diffusion rate?
Concentration gradient, lipid solubility, particle size, pore size, number of pores/channels, heat, electrical charge/membrane potential
Each factor influences how quickly substances can diffuse across the membrane.
What is osmosis?
The movement of water across a semi-permeable membrane down its concentration gradient
Water moves from areas of high water concentration (low solute) to low water concentration (high solute).
What generates osmotic pressure?
The movement of water into compartments with higher solute concentration
This can create significant pressure, as demonstrated in experiments with U-shaped test tubes.
What is resting membrane potential?
The electrical charge difference across the cell membrane at rest
Typically denoted as -mV, influenced by ion gradients and membrane permeability.
What is the Nernst equation used for?
To measure the voltage that will prevent ions from diffusing across the membrane
It helps determine the polarity of the cell based on ion concentration gradients.
What is the typical resting membrane potential for cells?
-80 mV
This value reflects the higher permeability of potassium ions at rest.
What happens if Na+ concentration builds up inside the cell?
It can cause intracellular edema
This condition occurs due to water following the electrolytes into the cell.
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Chapter One Guyton61
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Chapter 2 Guyton118
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Chapter 4 Guyton76
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Exam 1178
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Exam194
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LECTURE ONE109
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A And P Lecture 232
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A/P Normal Values33
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Lecture 3158
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Lecture 446
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Lecture 553
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Lecture 657
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Lecture 756
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Lecture 8110
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Lecture 960
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Lecture 1075
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Lecture 1154
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Lecture 1252
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Lecture 1346
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Lecture 1447
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Lecture 1538
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Lecture 1650
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Lecture 1758
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Lecture 1836
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Lecture 1931
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Lecture 2041
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Lecture 21 - Cardiac -ekg35
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Lecture 22 Cardiac Ekg 273
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Lecture 23 EKG 336
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Lecture 24 Ekg Plus Arrythmias40
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Lecture 25 Arrythmias And Blood Fluid Filtration38
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Lecture 26 Filtration And Absorbtion38
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Lecture 27 Filtration And Absorbtion 240
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Lecture 28 Renal Pressures/ ReAbsorption / Secretion35
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Lecture 29 Creatinine And Iv Fluids39
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Lecture 30 Kidney Anatomy38
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Lecture 31 - Proximal Tubule Transporters And Descending Loop Of Henle47
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Lecture 32 Ascending Loop Of Henle And Distal Tubule41
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Lecture 33 Rena Htn, Aldo54
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Lecture 340
