PHGY 215 Finals Questions and Answers Fully Solved 100%
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Course
PHGY 215
Institution
PHGY 215
Name and describe the 3 parts of a homeostatic control system - ️️Sensor: Detects
the environmental variable
Integrator: Determines if the variable is differing from the set point and by how much
Effector: If required, it changes the variable to restore it to its set point
What is facilitat...
PHGY 215 Finals
Name and describe the 3 parts of a homeostatic control system - ✔️✔️Sensor: Detects
the environmental variable
Integrator: Determines if the variable is differing from the set point and by how much
Effector: If required, it changes the variable to restore it to its set point
What is facilitated diffusion? - ✔️✔️Movement of specific molecules across cell
membranes through protein channels (no energy required)
Define homeostasis - ✔️✔️Maintaining a stable internal environment regardless of
external environment
Define set point - ✔️✔️Range/point where a variable state stabilizes
Define intrinsic control - ✔️✔️The homeostatic controllers are all contained in one fibre
or organ which monitors itself
Define extrinsic control - ✔️✔️Homeostatic controllers are external from the fibre or
organ being controlled
Define negative feedback and give an example - ✔️✔️- Change in variable causing the
effector to initiate an opposite response
- Blood glucose levels are monitored by the pancreas, when they get too high the liver
works to decrease it
Define positive feedback and give an example - ✔️✔️- Change in variable that causes
the effector to augment the original signal
- Oxytocin released during birth is augmented as the baby presses more against the
cervix
How is the lipid membrane a mosaic? - ✔️✔️It is a mosaic due to the interactions of
lipids, proteins, and carbohydrates working together
How does the plasma membrane act as a semi-permeable barrier? - ✔️✔️Size: only
small molecules are able to diffuse through the membrane
Solubility: only lipid soluble molecules can diffuse through the membrane
, Describe diffusion with an example - ✔️✔️Diffusion occurs as molecules move from
areas of high concentration to lower concentration depending on membrane
permeability (ion channels)
Describe osmosis with an example - ✔️✔️Osmosis occurs as water moves from areas
of high concentration to low concentration depending on the amount of water and the
solute within it
What is active transport? - ✔️✔️Movement of specific molecules against their
concentration gradients using ATP (eg. Na+-K+ ATPase)
What is pinocytosis? - ✔️✔️The ingestion of liquid into a cell by the budding of small
vesicles from the cell membrane.
What is phagocytosis? - ✔️✔️The ingestion of bacteria or other material by phagocytes
and amoeboid protozoans.
What is receptor-mediated endocytosis? - ✔️✔️Binding of receptors on a cell triggering
a phagocytic response
What is the electrochemical gradient? - ✔️✔️The combined impact of concentration
and ion gradients producing a "total" gradient
Describe the impact of the electrochemical gradient on K+. - ✔️✔️The electrochemical
gradient is made up of concentration and ionic graidents
Concentration: There are more K+ inside the cell then outside, meaning the K+ wants to
leave
Ionic: There are more negative anions inside the cell, drawing K+ in.
The total electrochemical gradient is the combined impact of these two forces.
Define depolarization - ✔️✔️Depolarization of a cell membrane occurs as the
membrane potential moves towards 0 mV
Define hyperpolarization - ✔️✔️The cell is polarized beyond the resting membrane
potential
How is resting membrane potential calculated? - ✔️✔️The Goldman Equation
How is membrane potential calculated? - ✔️✔️The Nernst Equation
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