SLCC PHYSIOLOGY EXAM- ESSAY
QUESTIONS AND ANSWERS
Define negative feedback - Answer-A reaction that occurs in response to some kind of
stimulus. If the variable decreased, the system responds to make it increase back to the
set point. It tends to be self-correcting.
Define positive feedback - Answer-It doesn't bring you back to the set point. If a
regulated variable increases, the system responds to make it increase more or faster. It
must have an end.
Give an example of negative feedback & label the receptor, integrating center, and
effector. - Answer-A home thermostat (heating system). The thermostat contains the
receptor (thermometer) and integrating control center. If the heating system is set at 70
degrees, the heat (effector) turns on if the temperature drops below 70 degrees. After
the heater heats the house to 70 degrees, it shuts off effectively maintaining the ideal
temperature.
Give an example of positive feedback & label the receptor, integrating center, and
effector. - Answer-Child birth. During labor, the cervix begins to stretch and receptor
cells send signals to the brain (sensors). The signals are received in the hypothalamus
(integrating center) which then releases oxytocin. Oxytocin makes contractions speed
up and become more intense (effectors). The increase in contractions cause more
oxytocin to be released and the cycle goes on until the baby is born. The birth ends the
release of oxytocin and ends the positive feedback mechanism.
Define passive energy - Answer-It needs a concentration gradient. It does not require
energy input. It goes from higher to lower energy.
Define active energy - Answer-It involves a pump (a protein) that moves something
against it's gradient. It requires energy to work. It goes from low to high concentration.
Simple diffusion - Answer-Type of passive transport, doesn't require energy. Unassisted
passage of small, hydrophobic, nonpolar molecules from high to low concentration.
Facilitated diffusion - Answer-Type of passive transport, doesn't require energy. Uses
integral membrane poteins to help larger, charged, hydrophilic, and polar molecules
across a concentration gradient.
In facilitated diffusion, what are the two proteins that help molecules cross a
membrane? - Answer-carrier proteins or channel proteins- one has an opening, one
changes shape
Different types of channel proteins - Answer-Aquaportins- allow water to cross
QUESTIONS AND ANSWERS
Define negative feedback - Answer-A reaction that occurs in response to some kind of
stimulus. If the variable decreased, the system responds to make it increase back to the
set point. It tends to be self-correcting.
Define positive feedback - Answer-It doesn't bring you back to the set point. If a
regulated variable increases, the system responds to make it increase more or faster. It
must have an end.
Give an example of negative feedback & label the receptor, integrating center, and
effector. - Answer-A home thermostat (heating system). The thermostat contains the
receptor (thermometer) and integrating control center. If the heating system is set at 70
degrees, the heat (effector) turns on if the temperature drops below 70 degrees. After
the heater heats the house to 70 degrees, it shuts off effectively maintaining the ideal
temperature.
Give an example of positive feedback & label the receptor, integrating center, and
effector. - Answer-Child birth. During labor, the cervix begins to stretch and receptor
cells send signals to the brain (sensors). The signals are received in the hypothalamus
(integrating center) which then releases oxytocin. Oxytocin makes contractions speed
up and become more intense (effectors). The increase in contractions cause more
oxytocin to be released and the cycle goes on until the baby is born. The birth ends the
release of oxytocin and ends the positive feedback mechanism.
Define passive energy - Answer-It needs a concentration gradient. It does not require
energy input. It goes from higher to lower energy.
Define active energy - Answer-It involves a pump (a protein) that moves something
against it's gradient. It requires energy to work. It goes from low to high concentration.
Simple diffusion - Answer-Type of passive transport, doesn't require energy. Unassisted
passage of small, hydrophobic, nonpolar molecules from high to low concentration.
Facilitated diffusion - Answer-Type of passive transport, doesn't require energy. Uses
integral membrane poteins to help larger, charged, hydrophilic, and polar molecules
across a concentration gradient.
In facilitated diffusion, what are the two proteins that help molecules cross a
membrane? - Answer-carrier proteins or channel proteins- one has an opening, one
changes shape
Different types of channel proteins - Answer-Aquaportins- allow water to cross
