BIOL373 UNITS 1-3 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
What is physiology?
the science of the function of living systems
What is our understanding of human physiology based on?
Animal experimentation (rats).
Function vs process
Function -> why
Process -> how
What is homeostasis?
Maintenance of a relatively stable internal environment (especially ECF) creating an
oscillation around a set point.
What is the father of homeostasis?
Walter Cannon (1929)
What happens when a homeostatic organism fails to compensate for change?
Disease
What is it called when the failure to compensate is studied?
Pathophysiology
Local vs reflex control
Local control: cells near site of change initiate response
Reflex control: Cells at a distance site control response (neural and endocrine)
,What is the response loop?
stimulus, sensor, input signal, integrating center, output signal, target, response
What are the 3 feedback mechanisms?
1. negative feedback
2. feedforward control
3. positive feedback
What does negative feedback do?
stabilizes variable and maintains homeostasis.
What is feedforward control?
anticipates change to maintain homeostasis.
What is positive feedback?
reinforces stimulus which is not homeostatic.
How is homeostasis achieved?
By nervous and endocrine systems with their combination of electrical and chemical
signals.
How do electrical signals contribute to homeostasis?
By changing membrane potential in nerve and muscle cells.
How do chemical signals contribute to homeostasis?
Responsible for communication when secreted into the ECF by all cells (most cell to cell
communication)
What are target cells?
Cells that respond to signals.
What are 3 methods of long range cell to cell communication?
,1. endocrine
2. neural
3. neuro endocrine
What is endocrine long range cell to cell communication?
A chemical (hormone) is released into the bloodstream from an endocrine cell via
diffusion and distributed throughout the body to a target cell with a receptor for that
chemical.
What is neural long range cell to cell communication?
The electrical signal travels down neuron and reaches the end and is translated to a
chemical signal (neurotransmitter) which transmits information to the next cell (another
neuron or to the receptor of the target cell).
What is neuro endocrine long range cell to cell communication?
The electrical signal travels down the neuron and reaches the end and is secreted into
the blood via diffusion and travels until it diffuses out to the target cell with a receptor to
elicit a response.
How can sending a signal throughout the entire body affect only certain cells?
Only cells that have receptors for that signal (ligand) will respond to it.
What is a ligand?
signal molecule that binds to a particular receptor.
What are receptors?
Proteins that project to outside of the membrane or are within the cytoplasm of the cell.
What determines what type a receptor a ligand will interact with?
Its chemical properties.
, What types of receptors do water-soluble ligands bind to?
Surface receptors as they are hydrophilic/lipophobic (majority).
What types of receptors do water-insoluble ligands bind to?
Intracellular receptors as they are hydrophobic/lipophilic (steroids).
Lipophilic ligand vs lipophobic ligand responses
Lipophilic: slower responses related to changes in gene activity
Lipophobic: rapid cellular response
What are 4 types of membrane receptors?
1. ion channel
2. enzyme-coupled receptor
3. G protein-coupled receptor
4. integrin receptor
What is signal transduction?
The transmission of molecular signals from a cell's exterior to its interior.
How do same signals have different effects in different cell types?
One ligand may have several different types of receptors.
What do receptors exhibit for their ligands?
Saturation, specificity, and competition as cells can change their response to signals by
changing receptor number or sensitivity.
How do cells increase receptor number?
Increase in gene expression (up-regulation).
How do cells decrease receptor number?
internalize surface receptors (down-regulation).
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
What is physiology?
the science of the function of living systems
What is our understanding of human physiology based on?
Animal experimentation (rats).
Function vs process
Function -> why
Process -> how
What is homeostasis?
Maintenance of a relatively stable internal environment (especially ECF) creating an
oscillation around a set point.
What is the father of homeostasis?
Walter Cannon (1929)
What happens when a homeostatic organism fails to compensate for change?
Disease
What is it called when the failure to compensate is studied?
Pathophysiology
Local vs reflex control
Local control: cells near site of change initiate response
Reflex control: Cells at a distance site control response (neural and endocrine)
,What is the response loop?
stimulus, sensor, input signal, integrating center, output signal, target, response
What are the 3 feedback mechanisms?
1. negative feedback
2. feedforward control
3. positive feedback
What does negative feedback do?
stabilizes variable and maintains homeostasis.
What is feedforward control?
anticipates change to maintain homeostasis.
What is positive feedback?
reinforces stimulus which is not homeostatic.
How is homeostasis achieved?
By nervous and endocrine systems with their combination of electrical and chemical
signals.
How do electrical signals contribute to homeostasis?
By changing membrane potential in nerve and muscle cells.
How do chemical signals contribute to homeostasis?
Responsible for communication when secreted into the ECF by all cells (most cell to cell
communication)
What are target cells?
Cells that respond to signals.
What are 3 methods of long range cell to cell communication?
,1. endocrine
2. neural
3. neuro endocrine
What is endocrine long range cell to cell communication?
A chemical (hormone) is released into the bloodstream from an endocrine cell via
diffusion and distributed throughout the body to a target cell with a receptor for that
chemical.
What is neural long range cell to cell communication?
The electrical signal travels down neuron and reaches the end and is translated to a
chemical signal (neurotransmitter) which transmits information to the next cell (another
neuron or to the receptor of the target cell).
What is neuro endocrine long range cell to cell communication?
The electrical signal travels down the neuron and reaches the end and is secreted into
the blood via diffusion and travels until it diffuses out to the target cell with a receptor to
elicit a response.
How can sending a signal throughout the entire body affect only certain cells?
Only cells that have receptors for that signal (ligand) will respond to it.
What is a ligand?
signal molecule that binds to a particular receptor.
What are receptors?
Proteins that project to outside of the membrane or are within the cytoplasm of the cell.
What determines what type a receptor a ligand will interact with?
Its chemical properties.
, What types of receptors do water-soluble ligands bind to?
Surface receptors as they are hydrophilic/lipophobic (majority).
What types of receptors do water-insoluble ligands bind to?
Intracellular receptors as they are hydrophobic/lipophilic (steroids).
Lipophilic ligand vs lipophobic ligand responses
Lipophilic: slower responses related to changes in gene activity
Lipophobic: rapid cellular response
What are 4 types of membrane receptors?
1. ion channel
2. enzyme-coupled receptor
3. G protein-coupled receptor
4. integrin receptor
What is signal transduction?
The transmission of molecular signals from a cell's exterior to its interior.
How do same signals have different effects in different cell types?
One ligand may have several different types of receptors.
What do receptors exhibit for their ligands?
Saturation, specificity, and competition as cells can change their response to signals by
changing receptor number or sensitivity.
How do cells increase receptor number?
Increase in gene expression (up-regulation).
How do cells decrease receptor number?
internalize surface receptors (down-regulation).
