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Do epithelial tissues always exhibit polarity?
Yes, epithelial tissues typically exhibit polarity, with distinct apical and basal surfaces. The apical surface faces the external environment or a body cavity, while the basal surface is anchored to a basement membrane. This polarity allows for the specialized functions of epithelial cells, such as secretion and absorption.
What is membrane polarity?
-70 mV this potential difference in a resting neuron (Vr) is called the resting membrane potential, and the membrane is said to be polarized.
Why does the polarity of a cell membrane reverse during an action potential?
The reversal of polarity during an action potential is due to the changes in ion concentrations across the cell membrane. When the membrane depolarizes, sodium ions rush into the cell and make the inside more positive. Repolarization occurs when potassium ions leave the cell, bringing the membrane potential back to negative.
What is a factor that determines whether molecule can cross a cell membrane?
size/ polarity can be the factors
What are 6 special characteristics of epithelium?
1. Cellularity: composed entirely of cells 2. Polarity: Apical vs. Basal Surface 3. Specialized Contacts: special cell junctions (Tight, Gap and Desmosomes) 4. Avascular but Innervated: contains NO blood vessels but has nerve endings 5. Regeneration: high regenerative capacity 6. Deep in Epithelia, there's always Connective Tissue
What are the characteristics of epithelia tissue?
Epithelia tissues consists of closely-packed cells arranged in one or more flat sheets. Their apical surface is exposed to the external environmental while their basal surface is attached to the tissue beneath it. The connective tissues link the epithelial cells to other structures. Nutrients travel to the epithelia tissues via diffusion through the capillaries.
Do epithelial tissues always exhibit polarity?
Yes, epithelial tissues typically exhibit polarity, with distinct apical and basal surfaces. The apical surface faces the external environment or a body cavity, while the basal surface is anchored to a basement membrane. This polarity allows for the specialized functions of epithelial cells, such as secretion and absorption.
Which of the following factors does not affect membrane permeability?
The presence of membrane proteins does not directly affect membrane permeability. Membrane proteins mainly play a role in transport, signaling, and cell recognition rather than impacting the permeability of the membrane itself.
What is a factor that determines of a molecule can cross a cell membrane?
Polarity
How is the cell membrane selectively permeable?
The pores of the cell membrane only allow objects of a certain size or polarity through. The lipids that make up the membrane have a certain polarity at the head and tail and only certain objects are allowed through because of this.
Which is a factor that determines wether a molecule can cross the cell membrane?
Polarity
What is membrane polarity?
-70 mV this potential difference in a resting neuron (Vr) is called the resting membrane potential, and the membrane is said to be polarized.
What is a factor that determines whether a molecule cross a cell membrane?
size/ polarity can be the factors
Why does the polarity of a cell membrane reverse during an action potential?
The reversal of polarity during an action potential is due to the changes in ion concentrations across the cell membrane. When the membrane depolarizes, sodium ions rush into the cell and make the inside more positive. Repolarization occurs when potassium ions leave the cell, bringing the membrane potential back to negative.
What is a factor that determines whether molecule can cross a cell membrane?
size/ polarity can be the factors
What are 6 special characteristics of epithelium?
1. Cellularity: composed entirely of cells 2. Polarity: Apical vs. Basal Surface 3. Specialized Contacts: special cell junctions (Tight, Gap and Desmosomes) 4. Avascular but Innervated: contains NO blood vessels but has nerve endings 5. Regeneration: high regenerative capacity 6. Deep in Epithelia, there's always Connective Tissue
What will happen in certain tissues without tight junctions?
Without tight junctions in certain tissues, there would be a large amount of molecules freely flowing around the epithelial tissue. These junctions keep the cells in there safe from flowing through the epithelium.
