Epithelia Flashcards
What is the shape of Squamous Epithelial Cells
Flat and thin
What is the function of Squamous Epithelial Cells
Squamous epithelial cells are involved in diffusion, filtration, and secretion. They line the air sacs of the lungs, blood vessels, and form the outermost layer of the skin (epidermis).
What is the shape of Cuboidal Epithelial Cells
Cube-shaped with a central nucleus.
What is the function of Cuboidal Epithelial Cells
Cuboidal epithelial cells are involved in secretion and absorption. They are found in kidney tubules, various glands (e.g., thyroid gland), and the lining of the small ducts in the pancreas.
what is the function of Columnar Epithelial Cells
Columnar epithelial cells are involved in absorption and secretion. They line the digestive tract (from stomach to intestines), respiratory tract (e.g., bronchi), and parts of the reproductive system
What is the function and importance of tight junctions
Function: Create a watertight seal between adjacent cells.
Importance: Prevent the leakage of substances between cells, ensuring selective transport across epithelial tissues.
What is the function and importance of Adherens Junctions
Function: Provide mechanical strength and stability to tissues.
Importance: Help cells resist separation during mechanical stress, maintaining tissue integrity.
What is the function and importance of Desmosomes
Function: Anchor cells together and distribute mechanical stress.
Importance: Enable tissues to withstand stretching and contraction, particularly in tissues subjected to mechanical forces (e.g., skin, heart muscles).
What is the function and importance of Gap Junctions
Function: Allow direct cell-to-cell communication.
Importance: Enable the rapid exchange of ions, small molecules, and electrical signals between adjacent cells, facilitating coordinated cellular activities.
What is the function and importance of Hemidesmosomes
Function: Attach epithelial cells to the underlying basement membrane.
Importance: Provide structural support, preventing the detachment of epithelial cells from the underlying connective tissue.
What is the function and importance of Basement Membrane
Function: Support and separate epithelial tissues from underlying connective tissues.
Importance: Acts as a selective filter, regulates the exchange of molecules, and provides structural support for epithelial cells.
What is Simple Diffusion
Passive movement of ions across a membrane down their concentration gradient.
No energy input required.
Small, non-polar ions can diffuse directly through the lipid bilayer.
What is Facilitated Diffusion
Passive movement of ions across a membrane through specific transport proteins.
No energy input required.
Larger or charged ions rely on transporters or channels to cross the membrane.
What is Active Transport
Movement of ions across a membrane against their concentration gradient.
Energy input, usually in the form of ATP, is required.
Ion pumps or carriers actively transport ions across the membrane.
what is Endocytosis
Process by which cells engulf substances from the extracellular environment.
Involves the formation of a vesicle around the material to be transported.
Allows for the uptake of large particles or bulk amounts of ions.
what is Exocytosis
Process by which cells release substances into the extracellular environment.
Involves the fusion of vesicles with the plasma membrane.
Allows for the secretion of large molecules or bulk amounts of ions.
what are ion channels
Protein-based pores in the cell membrane.
Allow selective passage of specific ions.
Can be gated (open or closed) based on various stimuli, such as voltage or ligand binding.
What is the Electrochemical Gradient
Combined effect of the concentration gradient and membrane potential on ion movement across a membrane.
Determines the direction and magnitude of ion flux
What is the Membrane Potential
Difference in electrical potential across a cell membrane.
Generated by the unequal distribution of ions across the membrane.
Plays a crucial role in various cellular processes, including ion transport.
What is the Concentration Gradient
Difference in ion concentration between the inside and outside of a cell.
Forms the chemical component of the electrochemical gradient.
Drives passive ion movement down the gradient from an area of higher concentration to an area of lower concentration
What is the Voltage Gradient
Difference in electrical charge across a cell membrane.
Forms the electrical component of the electrochemical gradient.
Results from the separation of positive and negative charges across the membrane, often maintained by ion pumps or channels.
Explain how the Sodium/Potassium ATPase works and its action in ion transport mechanisms
The Sodium/Potassium ATPase is a protein that uses ATP energy to transport sodium (Na+) and potassium (K+) ions across the cell membrane. It actively pumps three sodium ions out of the cell for every two potassium ions it brings into the cell. This process helps maintain the concentration gradients of these ions, which is essential for nerve impulse transmission, muscle contraction, and other cellular functions.
What is the structure and cell types of Nasal Epithelium
Structure: Pseudostratified columnar epithelium.
Cell Types:
Goblet cells: Secrete mucus to trap particles and pathogens.
Ciliated cells: Beat their cilia to move mucus and trapped particles towards the throat for removal.
Basal cells: Stem cells for epithelial cell regeneration.
What is the structure and cell types of Tracheal Epithelium
Structure: Pseudostratified columnar epithelium.
Cell Types:
Goblet cells: Secrete mucus to trap debris and pathogens.
Ciliated cells: Move mucus towards the throat for clearance.
Basal cells: Responsible for epithelial cell renewal.