Unit 1 Flashcards
what is physiology ?
the study of function of living things
what is difference between function and process?
function is why and process is how
what is homeostasis ?
the maintenance of a typical stable internal environment around a set point. mainly ECF
what are two pathway of an organism in homeostasis ?
an external or internal change occurs results in a loss of homeostasis and the organism tries to compensate when failed its illness or disease when succeeded its wellness
who is walter cannon? and what is he know for ?
‘the father of homeostasis’ ; know for flight or flight response
what is reflex control?
a response at a distant control centre involving the CNS
what is local (paracrine) control?
they diffuse at neighbouring cells
what is the 7 path response loop ?
Stimulus
sensor
input signal (afferent)
integrating center
output signal (efferent)
target cell
response
what does a negative feedback loop do ?
stabilizes variable if something goes up negative loop will go down
what does positive feedback loop do ?
enhances variable (increases stimulus)
what does feedforward do ? is it homeostatic ?
anticipates change; no its not homeostatic
how many cells are in the human body
75 trillions cells
how is homeostasis achieved ?
with both nervous and endocrine systems working with electrical and chemical signals
what are electrical signals?
changes in the membrane potential in the nerve and muscle cells
what are chemical signals?
majority of communication ; secreted in the ECF by all cells
what are 3 long range cell to cell communication ?
Endocrine,Neural & Neuroendocrine
what is the endocrine commincation?
a chemical hormone is released into the bloodstream and distributed throughout the body to multiple target cells
what is neural communication?
an electrical signal (AP) that travels down neuron when it reaches the terminal it becomes a chemical (neurotransmitter)
what is neuroendocrine?
combination of neural & endocrine communication electrical signal become chemical and secreted into the blood
what defines are a target cell ?
a cell that has a receptors for a specific signal that will respond to it
what is a receptor?
a protein that is outside on a membrane or within the cytoplasm or nucleus
what 3 things do you need to be a surface receptor ?
Water soluble,
Hydrophilic
lipophobic
what 3 things do you need to be to be a intracellular receptor?
Water insoluble
Hydrophobic
lipophilic
what are the 4 type of receptor ?
Ion channel
G protein-coupled receptor (GPCR)
Enzyme coupled receptor
integrin receptor
what is the signal transduction pathway? what is route 1 and route 2?
A signal molecule binds to a membrane receptor and initiates signal transduction by protein. Route 1: once signal transduction initiate protein kinases activate and phosphorylate proteins to get a response. Route 2: once signal transduction is initiated amplifier enzymes activate second messenger that either activate protein kinases that will phosphorylate or Calcium that binds and activates protein which give us a response
can i ligand have different type of receptors
yes
what is an agonist ?
a molecule that is similar that can activate a receptor
what is an antagonist ?
a molecule that is similar to ligand and binds to receptor and blocks it
what is chlorea ?
it produces at toxin that blocks the enzyme activities of G protein and the cell keep making c-amp where it is secreted to the lumen of intestiens
what is the GCPR and what activates
its a receptor protein that is activated by an alpha, beta and gamma subunit and a signal molecules
what two parts of the trimeric are always together ?
beta & gamma
when is GPCR. inactivated ?
when the alpha subunit is attached to GDP & beta gamma complex
where is chlorea found
in food and water
A given signal molecule…
a)
May elicit different responses in different target cells or after binding with different receptor types
b)
Will elicit the same response regardless of the target cell type
c)
Will elicit the same response regardless of the receptor type
May elicit different responses in different target cells or after binding with different receptor types
What event is common to ALL signal transduction pathways?
Question options:
a)
Calcium ions bind to/activate proteins
b)
Cyclic nucleotides are formed
c)
Proteins change in conformation/activity
d)
Phosphates are transferred between molecules
e)
Protons are transferred between molecules
Proteins change in conformation/activity
What is a key difference between a local (paracrine) regulator and a hormone?
a)
Local regulators are small, hydrophobic molecules; hormones are either large polypeptides or steroids
b)
Local regulators diffuse to neighbouring cells; hormones usually travel throughout the body to distant target cells
c)
The signal transduction pathways of local regulators do not involve second messengers; pathways triggered by hormones do involve second messengers
d)
Local regulators often open ligand-gated channels and affect ion concentrations in cells; hormones bind with intracellular receptors and affect gene expression
e)
Local regulators initiate short-term responses; hormones trigger longer-lasting responses
Local regulators diffuse to neighbouring cells; hormones usually travel throughout the body to distant target cells
A hormone traveling in the bloodstream…
Question options:
a)
Travels only to cells with receptors for that hormone
b)
Travels to all cells but elicits responses only in cells with receptors for that hormone
c)
Is drawn to cells bearing its receptors by chemical forces
Travels to all cells but elicits responses only in cells with receptors for that hormone
A signal molecule needs a second messenger if…
Question options:
a)
It travels to its target via the bloodstream
b)
It readily crosses the plasma membrane and binds to a receptor in the cytosol
c)
It cannot cross the plasma membrane
d)
Both (b) and (c) are true
It cannot cross the plasma membrane
Second messengers can be…
Question options:
a)
Modified nucleotides
b)
Produced from membrane phospholipids
c)
Ions
d)
All of the above
All of the above
A second messenger participates in a signal transduction pathway by…
Question options:
a)
Dampening the message once the signal molecule has left the receptor
b)
Transporting a signal molecule through the hydrophobic plasma membrane
c)
Relaying a signal from the outside to the inside of the plasma membrane
d)
Relaying a message from the cytosolic side of the membrane throughout the cytosol
e)
Relaying a message by phosphorylating downstream proteins
Relaying a message from the cytosolic side of the membrane throughout the cytosol
Glucagon, a protein hormone, acts via a G-protein coupled receptor (GPCR) that acts via increasing intracellular levels of cyclic AMP.
In the situation above, which components would be considered the first and second messengers, respectively?
Question options:
a)
G-protein coupled receptor, adenylyl cyclase
b)
G-protein, Gα subunit
c)
Glucagon, adenylyl cyclase
d)
G-protein, cyclic AMP
e)
Glucagon, cyclic AMP
Glucagon, cyclic AMP
Once it enters intestinal epithelial cells, cholera toxin will…
Question options:
a)
Act on a trimeric G protein to prevent dissociation of the α subunit from the βγ subunit
b)
Inhibit secretion of water into the intestinal lumen
c)
Inhibit adenylyl cyclase activity
d)
Block GTPase activity of the Gα subunit
e)
b and d
Block GTPase activity of the Gα subunit
Both norepinephrine (NE) and phenylephrine, a drug used as a decongestant, bind to alpha1 adrenergic receptors and elicit the same response. In this context, phenylephrine is _____ of NE.
Question options:
a)
An antagonist
b)
An antagonist and competitor
c)
An inhibitor
d)
An agonist
e)
An agonist and blocker
An agonist
When is G protein activated
when gtp ase occurs an GDP turns into GTP and beta gamma dissociates
when is the g protein inactivated
when adenylyl cyclase binds and hydroslysi (gtp ase) phosphate off and become GDP and beta gamma bind again
how does chlorea toxin affect the G protiein
it prevents hydrolyisis on the g alpha by adding ADP ribose and allows a persistant activation of adenylly cyclase
what are cannons 4 postulates
- the nervous system has a role in maintaining the internal environment
2.some systems are underr tonic control
- some systems are under antagonistic control
- one chemical signal can different responses in different tissues
what are the two things in tonic control control ?
when you increase norepinephrine you increase tone (APs)
when you decrease norepinephrine you decrease tonic ( APs)
what are the 2 the type of neurons in antagonistic control
Sympathetic neuron- increases rate
parasymtheic- decreases heart rate
which one is faster neural or endocrine control ?
neural
which signal last longer neural or endocrine?
endocrine
how is neural stimulus intensity based on ?
the frequency
what is endocrine stimulus intensity based on ?
the amount of hormone secreted
what is pathophysiology?
study of failure to compensate
what is disease
failure to compensate for change
what is local control?
its the regulation of a physical processes right at the site (local change and local response)
what are chemicals signals monitored in relax pathway
glucose, CO2 , O2, Na+, Ca 2+
what are central receptors
they are receptors in or close to the brain
