Practice exams and HW
In a neuron, sodium ions are typically more abundant
outside the cell
At rest, which way will potassium and sodium flow, assuming this cell is similar to the neurons we learned about in class.
potassium will flow out of the cell, but very little sodium will flow into the cell
Which of the following correctly identifies how messages are conducted through a reflex arc?
sensory - interneruon - motor
What type of signaling molecule binds to intracellular receptors?
sterorids
If you were attacked by a mountain lion, the _______ division of the nervous system would cause your heart to beat harder and your airways to expand in diameter.
sympathetic
In the spinal cord, interneurons are located in
the gray matter
In order to start an action potential, several graded potentials must sum to reach
threshold potential
Ectothermic animals
use heat from their environments to maintain body temperature
An organism that is a regulator for sodium concentration rather than a conformer
would expend energy to remove excess sodium from the body if needed
What type of signaling molecule would be stored in a vesicle rather than a micelle?
A hydrophilic molecule A protein
A mouse strives to maintain stable calcium concentrations in its blood. If the blood calcium concentrations decrease below a normal range, what would be the next step in the negative feedback pathway?
A sensor would detect the low calcium concentrations and send that information to an integrator.
Which statement is correct?
A signaling cell can also be a target cell
Pyrethrin, a pesticide derived from chrysanthemums, prevents Na channels from closing. What effect would this have on the action potential in an affected insect?
Action potentials are larger and take more time to repolarize.
Sensory pain neurons in the skin of a student's finger are activated after the student accidentally pinches his finger in closing door. The activated sensory neurons then relay this information to the central nervous system using _____________ nerve tracts.
Afferent
Glial cells associated with the _________ help to ______ the speed of conduction along a neuron.
Axon; increase
Which of the following comes first in the excitation- contraction coupling process in skeletal muscle?
Calcium binds to troponin, moving tropomysosin from actin
In the history of the animal lineage, the ability to interpret and create complex behavior patterns is only possible in animals that have _________________ type of nervous systems.
Centralized
Which statement is correct?
Chemical signals in the body can be lipids, proteins, or small molecules.
Which of the following describes the most common flow of information through a neuron?
Dendrite, cell body, axon
In the human retina, it was discovered that ions can move through channels in the membrane that connect two cells. What allows this to happen?
Electrical synapses
A doctor suspects he has a patient with a pancreatic tumor that is causing a hormone to be secreted into the blood even when its not needed. If the patients blood glucose levels are constantly too high, what hormone must the pancreas be secreting too much of?
Glucogen
If a drug caused the kidney cells to always detect low levels of oxygen, what would happen?
Greater than normal amounts of red blood cells would be made
Each of the following are fossils from around the time of the Cambrian explosion. Which following fossils shoe cephalization?
Haikouichthys, an animal with a head that contained a large ganglion
What type of signals are stored in vesicles?
Hydrophilic
If a toxin were to block voltage- gated potassium channels from opening, which part of the action potential would be most affected?
Repolarization would happen slower
Which organelle stores most of the calcium in skeletal muscle cells?
Sarcroplasmic reticulum
At a synapse, the neurotransmitter is the _______, while the postsynaptic cell is the _________.
Signaling molecule; responding cell
In endocrine signalling
Signaling molecules travel through the blood
Signaling through the somatic motor nervous system will stimulate contraction of ________________ muscle.
Skeletal
What type of muscle would you expect to find in the small intestine?
Smooth muscle
What functional division of nervous system is responsible for autonomic responses to stress?
Sympathetic
Right after activation of a G protein-coupled receptor, what happens next?
The G protein is activated by the intracelluar domain of the activated receptor.
If a mutation caused structure(s) A to not work properly, how might this mutation affect the ability of the cell to function?
The cell would be unable to detect incoming signals.
How would the structure of smooth muscle differ from skeletal muscle?
The muscle would have diamond shape and no striations
During the powerstroke:
The myosin head pivots forward, sliding the actin filament along.
Conotoxin, a toxin from snails, inhibits the voltage-gated calcium channels in neurons. What would this primarily affect in the above neurons?
The release of neurotransmitters at the synapse
Which of the following best describes the set point in a homeostasis system?
The target or "normal" value or range of values for the parameter being regulated
Which of the following best describes the set point in a homeostatic system?
The target or "normal" value or range of values for the parameter being regulated
What prevents electrical signals from moving backwards through a neuron, into an area they've already passed through?
The voltage-gated sodium channels need time to reset after inactivation.
When a skeletal muscle contracts, the _______ maximally overlaps.
Think and thin filaments
Efferent pathways conduct impulses:
Towards effectors such as muscle
What is the function of tropomyosin in skeletal muscle contraction?
Tropomyosin is moved from actin binding sites, allowing myosin to bind to actin.
What prevents action potentials from moving backwards?
Voltage- gated Na + channels inactivate
The absolute refractory period occurs primarily because of
Voltage-gated Na channels inactivating
All cell-to-ell communication pathways require
a signal and receptor
Which of these is a type of ligand or signaling molecule?
acetylcholine
Myelination of axon allows
an action potential to travel more quickly
In juxtacrine signaling, the cell signaling molecules
are physically attached to the signaling cell
Where would you expect to find the axon terminal of an interneuron?
attached to another neuron
What part of the nervous system includes the neuron is described above?
autonomic
The merging of many incoming electrical impulses, or signal integration, occurs at the
axon hillock
Each nerve contains a bundle of
axons
After contraction, _________ cause/causes calcium concentrations to decrease in the skeletal muscle
calcium pumps
Which of these animals shows the LEAST degree of cephalization?
coral
In skeletal muscles, tropomyosin
covers the actin until excitation- contraction coupling causes it to move
On what part of a neuron would you find the most ligand-gated Na+ channels to receive incoming signals?
dendrites
Even the simplest nervous systems have the ability to
detect sensory information such as temperature
Receptor kinase _________ when they are active
gain phosphate group
indidviduals can measure their heart rate by taking their pulse, but there are no biological heart rate sensor within the body. Based on this:
heart rate isn't maintained at a constant rate, even when the internal or external environment changes.
What type of receptor enters the nucleus and assists in transcription when activated?
intracellular receptor
One disadvantage of an endothermic lifestyle is that
it requires a high comsumption rate of metabolic fuels
As part of the termination step in this signaling pathway, what might happen to cAMP?
it would be destroyed by an enzyme
An oligodendrocyte is type of glia
located in the CNS where it provides electrical insultation
An astrocyte is a type of glia cell
located in the CNS where it provides support
A neuron that send information away from the CNS is a
motor neuron
The spinal cord is made up of
motor neurons interneurons glia axons
The nervous system in jellyfish is made up of
neurons that are connected by a network without a central nervous system
At rest in a neuron, there is
More positive charge on the exterior of a cell compared to the interior
A neuron that sends information away from the CNS is a(n):
Motor neuron
Smooth muscle differs from skeletal muscle in that
Muscle cells in the skeletal muscle are parallel fiber, while muscle cells in smooth muscle are interconnected diamonds
In crossbridge cycling, ATP binding to myosin causes
Myosin to unbind from actin
What is primarily responsible for the interior of the cell having more potassium and less sodium than the extracellular fluid?
Na/K/ATPase Pump
Resting membrane potential is maintained through the action of
Na/K/ATPase pumps and the K+ leak channels
Which of the following best describes the relationship between a nerve and an axon?
Nerves contain bundles of axons held together with connective tissue wrappings.
Which of the following best describes the relationship between a nerve and an axon?
Nerves contain bundles of axons held together with connective tissues wrappings
If you stimulate the neuron with an electrode. Assuming this is a chemical synaspe like the other ones we discussed in class, what would happen at the synaspe between neuron and muscle?
Neurotransmitter would be released from the neuron to the muscle
Smooth muscle gets a signal to begin contraction from
Neurotransmitters from a neuron Hormones circulating in the blood An action potential transmitted through gap junctions from another smooth muscle cell
You are studying a synaspe that has failure to transmit the neural signal. Which of the following might be a problem of the presynaptic neuron?
No neurotransmitter is released
How does a phosphorylation cascade amplify a signal?
One active kinase can phosphorylate multiple other kinases, which can in turn phosphorylate multiple kinases
What is phosphorylation cascade?
One protein phosphorylating another set of proteins which phosphorylate another set of proteins
The target cells of a steriod hormone such as cortisol, are able to respond to it because of which of the following?
Only target cells express appropriate intracellular receptors
At rest, our heart is quietly pumping away keeping your blood pressure stable. During this period of rest, the __________ branch of the ________ nervous system is dominant throughout your body.
Parasympathetic; autonomic
These hormones are produced from amino acid chains that are up to 50 amino acids long.
Peptide hormones
Second messenger systems refer to:
Proteins and molecules within a cell that help to relay a message to the appropriate target site.
Steroid hormones are lipids. Signaling by steroid hormones would be carried out by what type of receptor?
Intracellular receptor
One disadvantage of an endothermic lifestyle is that:
It requires a high consumption rate of metabolic fuels.
Cyclic cAMP is a second messenger what does this mean?
It sends a signal within the same sell
A target cell removes the receptors for insulin from its plasma membrane. In response, the pancreas produces and releases more insulin into the blood. How will the target cell respond to the increased concentration of insulin moving around the body?
It will not respond to the insulin
Suppose you changed the extracellular fluid concentration at 100 mM k + and 10 mM Na+, what would happen to the resting membrane potential?
It would go up
Continuing with the extracellular fluid concentration at 100 mM k + and 10 mM Na+, what would happen to an action potential?
It would not happen at all
Evolutionarily, the first (or earliest) animals that used neurons for cell communication were the:
Jellyfish
The chemical signal that travels from a signaling cell and binds to its receptor at a target cell is also known as a/an:
Ligand
