BIOL 373 Midterm 1 (Unit 1, 2 and 3)
What is physiology? - correct answer ✔✔the science of the function of living systems
What is homeostasis? - correct answer ✔✔the maintenance of a relatively stable internal environment
(especially ECF)
-oscillation around a set point
Who is Walter Cannon? - correct answer ✔✔the father of physiology
coined the term "homeostasis"
What is the difference between local and reflex control? - correct answer ✔✔Local control = cells near
site of change initiate response
Reflex control = cells at a distant site control response
What is negative feedback? - correct answer ✔✔stabilizes variable (correction in opposite direction of
change)
What is feedforward mechanism? - correct answer ✔✔control anticipates change
What is positive feedback? - correct answer ✔✔reinforces stimulus (NOT homeostatic)
What are the 3 ways cells can communicate long range? - correct answer ✔✔endocrine - chemical
released in blood and distributed throughout the body
neural - electrical signal travels down neuron then becomes chemical which travels to target cell
neuroendocrine - electrical signal travels travel down neuron then becomes chemical signal that is
secreted into the blood
What determines what type of receptors ligands will interact with? - correct answer ✔✔chemical
properties of the ligands
,surface receptor = hydrophillic/lipophobic/water soluble
intracellular receptor = hydrophobic/lipophillic/water insoluble
How can cells change their response to different signals? - correct answer ✔✔change receptor number
or sensitivity
increase = increase expression of gene that codes for receptor or increase expression of receptor
proteins on cell surface
decrease = internalize surface receptors
change receptor sensitivity = phosphorylation
How is a GPCR activated? - correct answer ✔✔-signal molecule binds to receptor and causes
conformational change
-activates G protein by exchanging GDP for GTP
-when GTp binds alpha subunit+GTP dissociates from the B and gamma subunits
-G alpha subunit turns itself off by hydrolizing GTP
What affect does Cholera Toxin have on the inactivation of G alpha subunit? - correct answer ✔✔-blocks
GTP hydrolysis (GTPase activity)
-results in persistent activation of adenylate cyclase
What are Cannon's Postulates? - correct answer ✔✔-the nervous system has a role in maintaining the
'fitness' of the internal environment
-some systems under tonic control
-some systems are under antagonistic control
-one chemical signal can have different effects in different tissues
Specificity of neural vs. endocrine control - correct answer ✔✔neural = single target cell or limited
number of adjacent target cells
endocrine = exposed to all cells but only those which receptors responsd
, Nature of signal for neural vs. endocrine control - correct answer ✔✔neural = electrical signal that turns
chemical (neurotransmitter)
endocrine = chemical signals
Speed of neural vs. endocrine control - correct answer ✔✔neural = very rapid
endocrine = much slower than neural responses
Duration of action in neural vs. endocrine control - correct answer ✔✔neural = usually very short
endocrine = longer than neural responses
Coding for stimulus intensity in neural vs endocrine control - correct answer ✔✔neural = each signal is
identical in strength. Increase intensity by increasing frequency
endocrine = intensity proportional to amount of hormone secreted
What are the evolutionary trends in the nervous system? - correct answer ✔✔bilateral symmetry ->
cephalization -> consolidation of PNS -> nerves -> ventral nerve cord -> dorsal nerve cord -> spinal cord -
> increasing role of forebrain
Describe the development of the Human CNS - correct answer ✔✔4 weeks: anterior end of neural tube
specialized into 3 regions (forebrain, midbrain, hindbrain) and spinal cord
6 weeks: neural tube differentiates into major brain regions present at birth
forebrain -> diencephalon, cerebrum
midbrain
hindbrain -> medulla oblongata, cerebellum, and pons
11 weeks: growth of cerebrum much more rapid than that of other regions
birth: cerebrum covers most of other brain regions; convoluted surface due to rapid growth in confined
space
What structures provide protection and support for CNS? - correct answer ✔✔-surrounded by bony
cage: cranium
-3 layers of connective tissues: meninges
What is physiology? - correct answer ✔✔the science of the function of living systems
What is homeostasis? - correct answer ✔✔the maintenance of a relatively stable internal environment
(especially ECF)
-oscillation around a set point
Who is Walter Cannon? - correct answer ✔✔the father of physiology
coined the term "homeostasis"
What is the difference between local and reflex control? - correct answer ✔✔Local control = cells near
site of change initiate response
Reflex control = cells at a distant site control response
What is negative feedback? - correct answer ✔✔stabilizes variable (correction in opposite direction of
change)
What is feedforward mechanism? - correct answer ✔✔control anticipates change
What is positive feedback? - correct answer ✔✔reinforces stimulus (NOT homeostatic)
What are the 3 ways cells can communicate long range? - correct answer ✔✔endocrine - chemical
released in blood and distributed throughout the body
neural - electrical signal travels down neuron then becomes chemical which travels to target cell
neuroendocrine - electrical signal travels travel down neuron then becomes chemical signal that is
secreted into the blood
What determines what type of receptors ligands will interact with? - correct answer ✔✔chemical
properties of the ligands
,surface receptor = hydrophillic/lipophobic/water soluble
intracellular receptor = hydrophobic/lipophillic/water insoluble
How can cells change their response to different signals? - correct answer ✔✔change receptor number
or sensitivity
increase = increase expression of gene that codes for receptor or increase expression of receptor
proteins on cell surface
decrease = internalize surface receptors
change receptor sensitivity = phosphorylation
How is a GPCR activated? - correct answer ✔✔-signal molecule binds to receptor and causes
conformational change
-activates G protein by exchanging GDP for GTP
-when GTp binds alpha subunit+GTP dissociates from the B and gamma subunits
-G alpha subunit turns itself off by hydrolizing GTP
What affect does Cholera Toxin have on the inactivation of G alpha subunit? - correct answer ✔✔-blocks
GTP hydrolysis (GTPase activity)
-results in persistent activation of adenylate cyclase
What are Cannon's Postulates? - correct answer ✔✔-the nervous system has a role in maintaining the
'fitness' of the internal environment
-some systems under tonic control
-some systems are under antagonistic control
-one chemical signal can have different effects in different tissues
Specificity of neural vs. endocrine control - correct answer ✔✔neural = single target cell or limited
number of adjacent target cells
endocrine = exposed to all cells but only those which receptors responsd
, Nature of signal for neural vs. endocrine control - correct answer ✔✔neural = electrical signal that turns
chemical (neurotransmitter)
endocrine = chemical signals
Speed of neural vs. endocrine control - correct answer ✔✔neural = very rapid
endocrine = much slower than neural responses
Duration of action in neural vs. endocrine control - correct answer ✔✔neural = usually very short
endocrine = longer than neural responses
Coding for stimulus intensity in neural vs endocrine control - correct answer ✔✔neural = each signal is
identical in strength. Increase intensity by increasing frequency
endocrine = intensity proportional to amount of hormone secreted
What are the evolutionary trends in the nervous system? - correct answer ✔✔bilateral symmetry ->
cephalization -> consolidation of PNS -> nerves -> ventral nerve cord -> dorsal nerve cord -> spinal cord -
> increasing role of forebrain
Describe the development of the Human CNS - correct answer ✔✔4 weeks: anterior end of neural tube
specialized into 3 regions (forebrain, midbrain, hindbrain) and spinal cord
6 weeks: neural tube differentiates into major brain regions present at birth
forebrain -> diencephalon, cerebrum
midbrain
hindbrain -> medulla oblongata, cerebellum, and pons
11 weeks: growth of cerebrum much more rapid than that of other regions
birth: cerebrum covers most of other brain regions; convoluted surface due to rapid growth in confined
space
What structures provide protection and support for CNS? - correct answer ✔✔-surrounded by bony
cage: cranium
-3 layers of connective tissues: meninges
