Exam 1 Flashcards
a single quantum of response measured in a postsynaptic cell refers to…..
the fusion of a single vesicle in the presynaptic cell
an isolated nerve preparation treated with a moderate dose of curare would be associated with a decrease in the….
- curare mentioned in class blocks the ach receptors at neuromuscular junction in mammals so….
amplitude of MEPPs (spontaneous quantal synaptic events)
amplitude of the EPP (evoked synaptic response)
An isolated nerve muscle preparation exposed to a low concentration of extracellular ca2+ would be associated with a decrease in the….
- amplitude of the EPP due to fewer vesicle fusing
- release of transmitter from the terminal of the motor axon triggered by a presynaptic action potential due to fewer vesicles fusing
- influx of ca2+ into the presynaptic terminal….decreased driving gradient with reducaed ca2+
In humans a demylenating disease can cause many problems with regulation of
muscle coordination. Why is it that the early onset of the disease there is not so many problems but as the disease progresses skeletal muscle control becomes worse and sensory input is lost
in some cases. (Please explain the detail of the problem at the cell level or surrounding cell
environment and why the problems come about)
The insulation around the neuron is being lost and it is progressively getting worse. The neurons will impact each other and start to short circuit each other or have some impact on each other. The myelination keeps the capacitance lower so electrical signal can travel quickly along neurons. The more loss the slower the electrical signals will become.
In the complete metabolism of one glucose molecule, in the presence of oxygen, most ATP molecules are produced in which one of the following series of reactions or cycles listed
citric acid cycle and electron transport chain
The water that is produced from the end result of the electron transport chain is….
formed through a series of reactions involving molecular oxygen. during the final stage of the electron transport chain, electrons combine with oxygen and protons to form water.
What is the august krogh principle
for any physiological problem, there is an organism that is bets suited to study it.
how to test to understand whether a synapse between two neurons is electrical or chemical? you might describe an experiment to test. be sure to state what is expected for either a chemical or electrical transmission in your experiment or conditions you use
chemical:
block neurotransmitter release
- Administer a substance that interferes with the release of neurotransmitters. For example, use Botulinum toxin to block the release of acetylcholine.
-Observe whether the signal transmission between neurons is affected.
-If the synaptic transmission is impaired, it suggests a chemical synapse, as chemical synapses rely on neurotransmitter release to transmit signals.
-we can expect impaired signal transmission with the neurotransmitter release blockers or receptor antagonists.
electrical:
dye injection
-Inject a fluorescent dye into one neuron.
-Observe if the dye spreads to the connected neuron without a time delay.
-If the dye rapidly spreads to the connected neuron, it suggests an electrical synapse, as electrical synapses allow direct flow of ions and molecules between neurons.
- we can expect immediate and direct transmission of signals between neurons
during the relative refractory period for a neuron, explain the general mechanism behind WHY the responsiveness of the neuron to a stimulus is different.
the relative refractory period is mostly due to the continued presence of an elevated potassium concentration inside the neuron and the gradual repolarization of the cell membrane. in this period, the neuron is in a state where it can respond to stimulus, but the threshold for generating another action potential is elevated due to the hyperpolarization and ongoing repolarization processes.
explain and discuss the differences between the nernst equation and the goldman-hodgkins-katz equation. what information is gained from these equations
nernst equation is used to describe the equilibrium potential for a single ion across a cell membrane. This helps to determine the membrane potential at which the concentration gradient and the electrical gradient are balanced for a specific ion.
GHK equation is an extension of nernst, and takes into account the permeability of the membrane to multiple ions. the ghk provides more comprehensive model to consider contributions of multiple ions and their respective permeabilities.
a certain insect larvae thrives in small pools deep within a glacier. how might this insects cell membrane have evolved to function normally in these near freezing waters? list THREE factors associated with the membrane that are likely occurring and THE DIRECTION in which these factors alter the membrane.
- membrane fluidity: increased fluidity
- protein structure and function: increased flexibility and stability
- anti-freeze proteins or compounds: increased production of anti-freeze substances.
these would allow them to endure and survive in the harsh and cold conditions
define physiology and describe why it is important to study comparative physiology.
physiologists are constantly trying to answer key questions in areas ranging from the functions of single cells to the interactions between human populations and our environment here on earth;
Comparative physiology: 1. Appreciate diversity 2. Understand trade-offs & constraints 3. Universal vs. unique
examples of the august Krogh Principle
-Giant squid: action potential in the axon of the squid; voltage clamp was made bc of the info from the wide diameter of the axon
-Barn owl: relies on precise information on the time of arrival of sound in its ears. Info gathered from here helped with our understanding of how the brain maps sensory space, and how nervous systems encode timing information
Physiological example of feedback control system (body temperature)
Stimulus: body temperature falls below set point
Sensor: temperature-monitoring nerve cells
Integrator: temperature control center (humans hypothalamus)
Effector: skeletal muscles (and others) starts to shiver
Compensatory response: heat production increases through shivering
increases till body temp is at set point
positive feedback control system- physiological ex
signal from mature fetus
sensor: stretch sensors
integrator: mother’s hypothalamus
effector: pituitary gland
compensatory response: pituitary gland
oxytocin secreted and contractions enhanced
(loop stops bc baby delivers and no longer is a stimulus)
