Module One, Lecture Seven Flashcards
Active Cellular Physiology (18 cards)
What are Excitable Cells?
Generate and conduct electrical signals, enabling the body to respond rapidly to stimuli
How do Excitable Cells transmit information?
Use chemical and electrical gradients for rapid signalling events. Neurons are responsible for transmitting
What are Neurons responsible for? ( 2 )
- Sending and receiving signals, facilitate communication between different brain areas, the spinal cord, and the entire body
- Crucial role in sensory input, motor commands, and relaying electrical signals which influence thoughts, feelings and behaviours
What are Muscle Cells responsible for?
- Contraction which leads to movement and other bodily functions
- Basic building blocks of muscle tissue and come in three types; Skeletal, Smooth and Cardiac
What is Diffusion?
The movement of molecules from a high to low concentration
What is the definition of Osmosis?
Passive transport of water molecules across a semipermeable membrane from a region of high water concentration to a region of low water concentration
What is a Semipermeable Membrane?
A barrier that allows some molecules ( like water ) to pass through
How does Osmosis work?
Osmotic force pushes water across the semipermeable membrane, trying to equalise the concentration of the two sides of the membrane
Define an Isotonic Solution…
A solution that has the same concentration of solutes as the cell’s cytoplasm or the extracellular fluid
Define a Hypotonic Solution…
Has a lower concentration of solutes than the cell, leading to water moving into the cell and potentially causing it to swell
Define a Hypertonic Solution…
Has a higher concentration of solutes than the cell, leading to water moving out of the cell and causing it to shrink
What does Equilibrium mean?
It is an isotonic solution, the water concentration inside and outside the cell is equal, resulting in no net movement of water
What is a Chemical Gradient?
A difference in the concentration of a substance across a membrane
What is the importance of a Chemical Gradient?
Plays a crucial role in the movement of molecules across cell membranes, nutrient transport, and waste removal
Describe the steps of a Chemical Gradient… ( 4 )
- A chemical gradient exists when there are varying concentration of substance in different locations
- Substances move from areas of high concentration to areas of low concentration
- The chemical gradient provides the driving force for the movement of substances ( passive diffusion or active transport )
- The movement of substances will continue until equilibrium is reached
What is an example of a Chemical Gradient and its steps? ( 5 )
- Sodium Ion Concentration
- The concentration of sodium ions is much high outside of the cell than inside the cell
- This difference creates a concentration gradient, which is a driving force for sodium ions to move into the cell
- The inside of the cell is negatively charged which creates an Electrical Gradient
- The Sodium-Potassium Pump helps maintain these concentration differences by pumping sodium ions out of the cell and potassium ions into the cell, against their concentration gradient ( active transport )
What is Resting Membrane Potential?
-70 mV, meaning the inside of the cell is negatively charged relative to the outside
When do Positive Ions enter the cell? ( 2 )
- During a depolarization, which acts as a signalling event for excitable cells
- The positive ions are then removed during repolarization to return to the resting membrane potential ( negatively charged )