PSL300 EXAM Questions and Answers
Graded A+
Homeostasis - Correct answer-Stability of the body's internal environment
Local control - Correct answer-Homeostatic signalling restricted to the region
where the change takes place
Reflex control - Correct answer-Homeostatic signalling which involves a long-
distance pathway that uses the nervous system, endocrine system, or both
Negative feedback loop - Correct answer-This is a homeotic pathway in which the
response opposes or removes the signal (Eg. Heater in aquarium turns on/off once
past a certain temperature threshold)
Positive feedback loop - Correct answer-This is a feedback loop response which
sends the regulated variable even farther from its normal value. It initiates a
vicious cycle of ever-increasing responses and sends the system temporarily out of
control until an event outside the loop stops the response (Eg. The cervix
continually stretches due to oxytocin releases which increases uterine contractions
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,and pushes the baby through the cervix until the baby is delivered, releasing the
cervical stretch)
Feedforward Control - Correct answer-A reflexive response that has evolved to
enable the body to predict that a change is about to occur and start the response
loop in anticipation of the change (Eg. Salivation in expectation of eating food)
Biorhythm - Correct answer-Regulated variables that change predictably and create
repeating patterns or cycles of change; coincides with predictable environmental
changes such as daily light-dark cycles or the seasons (Eg. Circadian rhythm)
Acclimatization - Correct answer-The natural adaptation of physiological processes
to a given set of environmental conditions
Acclimation - Correct answer-The adaptation of physiological processes to a given
set of environmental conditions set in an artificial laboratory environment
Target cells - Correct answer-These are cells that respond to chemical or electrical
signals
Local communication - Correct answer-A type of cell to cell communication that
involves gap junctions, contact dependent signals, and chemicals that diffuse
through the extracellular fluid to act on cells close by
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,Long distance communication - Correct answer-A type of cell to cell
communication that involves the use of electrical signalling in nerve cells and the
transfer of molecules in the blood stream
Connexin - Correct answer-These are the membrane spanning proteins that make
up the individual segments of the gap junction
Paracrine signal - Correct answer-This is a signalling chemical that acts on cells in
the immediate vicinity of the cell that secreted the signal
Autocrine signal - Correct answer-This is a signalling chemical that acts on the cell
that secreted it
Neurocrine - Correct answer-This is a chemical signal secreted by neurons
Neurotransmitter - Correct answer-These are neurocrines that diffuse out of the
neuron through a narrow extracellular space and contribute to a rapid effect
Neuromodulator - Correct answer-These are neurocrines that acts slowly as a
paracrine/autocrine signal
Neurohormone - Correct answer-These are neurocrines that are released into the
bloodstream for distribution
Cytokine - Correct answer-Any of a number of cell signalling molecules, such as
interferon, interleukin, and growth factors, that are secreted by certain regulatory
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, peptides and have an effect on other cells - These control cell development, cell
differentiation, and the immune response
Specifically cells of the immune system
Tonic control - Correct answer-A physiology-associated control system where the
response is always present but can be increased or decreased depending on the
state of the internal environment
Antagonistic control - Correct answer-A physiology-associated control system
where antagonistic pathways that have opposing effects can be changed to
maintain homeostasis
Stimulus - Correct answer-A component of the response loop described as the
disturbance or change that sets the pathway in motion
Sensor - Correct answer-A component of the response loop that continuously
monitors its environment for a particular variable
Input (afferent) Signal - Correct answer-A component of the response loop sent by
the sensor to the integrating centre
Integrating centre - Correct answer-A component of the response loop that
compares the input signal with the setpoint, or desired value of the variable
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Graded A+
Homeostasis - Correct answer-Stability of the body's internal environment
Local control - Correct answer-Homeostatic signalling restricted to the region
where the change takes place
Reflex control - Correct answer-Homeostatic signalling which involves a long-
distance pathway that uses the nervous system, endocrine system, or both
Negative feedback loop - Correct answer-This is a homeotic pathway in which the
response opposes or removes the signal (Eg. Heater in aquarium turns on/off once
past a certain temperature threshold)
Positive feedback loop - Correct answer-This is a feedback loop response which
sends the regulated variable even farther from its normal value. It initiates a
vicious cycle of ever-increasing responses and sends the system temporarily out of
control until an event outside the loop stops the response (Eg. The cervix
continually stretches due to oxytocin releases which increases uterine contractions
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,and pushes the baby through the cervix until the baby is delivered, releasing the
cervical stretch)
Feedforward Control - Correct answer-A reflexive response that has evolved to
enable the body to predict that a change is about to occur and start the response
loop in anticipation of the change (Eg. Salivation in expectation of eating food)
Biorhythm - Correct answer-Regulated variables that change predictably and create
repeating patterns or cycles of change; coincides with predictable environmental
changes such as daily light-dark cycles or the seasons (Eg. Circadian rhythm)
Acclimatization - Correct answer-The natural adaptation of physiological processes
to a given set of environmental conditions
Acclimation - Correct answer-The adaptation of physiological processes to a given
set of environmental conditions set in an artificial laboratory environment
Target cells - Correct answer-These are cells that respond to chemical or electrical
signals
Local communication - Correct answer-A type of cell to cell communication that
involves gap junctions, contact dependent signals, and chemicals that diffuse
through the extracellular fluid to act on cells close by
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,Long distance communication - Correct answer-A type of cell to cell
communication that involves the use of electrical signalling in nerve cells and the
transfer of molecules in the blood stream
Connexin - Correct answer-These are the membrane spanning proteins that make
up the individual segments of the gap junction
Paracrine signal - Correct answer-This is a signalling chemical that acts on cells in
the immediate vicinity of the cell that secreted the signal
Autocrine signal - Correct answer-This is a signalling chemical that acts on the cell
that secreted it
Neurocrine - Correct answer-This is a chemical signal secreted by neurons
Neurotransmitter - Correct answer-These are neurocrines that diffuse out of the
neuron through a narrow extracellular space and contribute to a rapid effect
Neuromodulator - Correct answer-These are neurocrines that acts slowly as a
paracrine/autocrine signal
Neurohormone - Correct answer-These are neurocrines that are released into the
bloodstream for distribution
Cytokine - Correct answer-Any of a number of cell signalling molecules, such as
interferon, interleukin, and growth factors, that are secreted by certain regulatory
©COPYRIGHT 2025, ALL RIGHTS RESERVED 3
, peptides and have an effect on other cells - These control cell development, cell
differentiation, and the immune response
Specifically cells of the immune system
Tonic control - Correct answer-A physiology-associated control system where the
response is always present but can be increased or decreased depending on the
state of the internal environment
Antagonistic control - Correct answer-A physiology-associated control system
where antagonistic pathways that have opposing effects can be changed to
maintain homeostasis
Stimulus - Correct answer-A component of the response loop described as the
disturbance or change that sets the pathway in motion
Sensor - Correct answer-A component of the response loop that continuously
monitors its environment for a particular variable
Input (afferent) Signal - Correct answer-A component of the response loop sent by
the sensor to the integrating centre
Integrating centre - Correct answer-A component of the response loop that
compares the input signal with the setpoint, or desired value of the variable
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