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