Quizzes 201

Rearrange the following items to describe the proper steps in an action potential, from start to finish.

1. The membrane potential of the neuron shifts from resting membrane potential to threshold. 2. Voltage-gated Na+ channels open. 3. Na+ rushes into the cell and the cell depolarizes. 4. Voltage-gated Na+ channels inactivate. Voltage-gated K+ channels open. 5. K+ ions flow out of the neuron and the neuron repolarizes. 6. Voltage-gated K+ channels stay open beyond the resting membrane potential and the neuron hyperpolarizes. 7. Pumps return the neuron back to resting membrane potential.

Which of the following neuroglia cells help make the blood brain barrier?

Astrocytes

The kinetics of voltage-gated potassium channels mandate that they open and close in a proper order. Which of the following properly illustrates the kinetics of voltage-gated potassium channels.

At rest, voltage-gated potassium channels are closed. During the depolarization phase of the action potential, voltage-gated potassium channels are closed. At the peak of the action potential, voltage-gated potassium channels open. Because voltage-gated potassium channels are slow-acting, it takes a long time for them to close, so they stay open well into the hyperpolarization phase.

The kinetics of voltage-gated sodium channels mandate that they open/close/inactive in a proper order. Which of the following properly illustrates the kinetics of voltage-gated sodium channels.

At rest, voltage-gated sodium channels are closed. During the depolarization phase of the action potential, voltage-gated sodium channels are open. At the peak of the action potential, voltage-gated sodium channels inactivate. These channels MUST close again before reopening.

Which of the following is/are pathway(s) that CSF takes to get from the 3rd ventricle to the 4th ventricle?

Cerebral aquaduct

Postsynaptic potentials are:

Changes in membrane potential of the postsynaptic neuron in response to a neurotransmitter binding to a receptor on the postsynaptic neuron.

Which of the following influences the speed of action potential propogation?

Diameter of an axon Myelination

Two neurons synapse onto the dendrites of one neuron. One of these neurons is excitatory and causes EPSPs in the postsynaptic neuron and the other neuron is inhibitory and causes IPSPs in the postsynaptic neuron. If both presynaptic neurons fired at the same time, what would this cause in the postsynaptic neuron?

EPSP/IPSP cancellation

Cerebrospinal fluid flows through the ventricles of the brain and supplies nutrients to the brain while also offering the brain buoyancy. Which of the following neuroglia cells help make cerebrospinal fluid?

Ependymal cells

The Choroid Plexus is composed of which type of neuroglia?

Eppendymal cells

In unmyelinated axons, action potentials seemingly jump from node to node, in a process called "saltatory conduction."

False

Neurons communicate strength of signal by altering the amplitude of action potential deflection.

False

Voltage-gated Na+ channels and voltage-gated K+ channels do not exist within the axon terminal. Instead, the axon terminal has voltage-gated Cl- channels.

False

Muscarinic acetylcholine receptors are _________ receptors that cause the opening of ________.

G protein coupled; K+ channels

Multiple Sclerosis:

Is an autoimmune disease in which one's own immune system attacks the myelin sheaths, causing them to become sclerotic (hard) and then non-functional.

One of the ~100 billion neurons in your brain fires an action potential. During the repolarization phase of that action potential, while the voltage-gated sodium channels are still inactivated, your neuron decides it wants to fire another action potential. Can it do so? Why or why not?

No. The neuron is in absolute refractory period, so no additional action potentials can be fired.

You're washing dinner dishes and out of the corner of your eye, you catch a glimpse of something moving near the kitchen baseboard. You turn your head quickly so you can see what it is. It is a mouse. What part of the brain was activated for this visual reflex?

Superior colliculi

Your Aunt Selena is very considered about her wrinkles. Though you try assuring her that wrinkles are beautiful and are a sign of a life well lived, your aunt decides to get a botox treatment. How does botox work?

The botulinum neurotoxin from Claustridum botulinum is injected into skeletal muscle. Botulinum is endocytosed into the motor neuron and it cleaves the SNARE proteins. Because SNARE proteins have been destroyed, vesicles containing neurotransmitters can not dock and fuse, and no neurotransmitters are released. This then prevents muscle contraction and the skeletal muscle relaxes and softens, and wrinkles are minimized.

The falx cerebri is:

a dura mater extension that separates the two hemispheres of the brain, through the longitudinal fissure

The corpus callosum is:

a white matter axon tract that connects the two hemispheres of the brain

Which of the following factors affects force of muscle contraction? E. all of the above Answers:A. strength of stimulus B. muscle fiber thickness C. length of sarcomere prior to contraction D. frequency of stimuli E. all of the above

all the above

When a presynaptic neuron synapses on the axon of a postsynaptic neuron, it is called:

axoaxonic synapse

When a presynaptic neuron synapses on the cell body of a postsynaptic neuron, it is called:

axosomatic synapse

Which of the following is NOT a function of the cerebellum? A. Subconsciously provide precise timing and appropriate patterns of skeletal muscle contraction B. Emotional reactions such as fear C. Recognize and predict sequence of events during complex movements D. Balance

b. Emotional reactions such as fear

Which of the following is NOT true of the hypothalamus? A. It helps mediate autonomic nervous system function B. It is a control center for the pituitary gland C. It is part of the brainstem D. It regulates body temperature, food intake, water imbalance, thirst, and other homeostatic functions

c. It is part of the brainstem

If, in a laboratory, a skeletal muscle cell receives a single stimulus to contract, it produces a single muscle twitch. If we quickly fire multiple, continuous stimuli which cause the muscle to constantly contract, without being able to relax at all, then we have a condition of:

complete tetanus

The _________________ phase of the Sliding Filament Model of Contraction occurs when myosin and actin separate from one another.

cross bridge detachment

The _________________ phase of the Sliding Filament Model of Contraction occurs when myosin (in the cocked state) and actin bind together.

cross bridge formation

Nicotinic acetylcholine receptors are _________ receptors that cause the opening of ________.

direct ligand-gated; Na+ channels

The quadriceps are surrounded by a connective tissue called _____________. If we cut the quadriceps open, we see clusters of skeletal muscle cells. These clusters of cells are called _____________, and are wrapped in a connective tissue called _____________.

epimysium; fascicles; perimysium

Which of the following is NOT a function of the muscular system? A. hematopoiesis B. generation of heat C. production of movement D. maintenance of posture

hematopoiesis

Which of the following is/are pathway(s) that CSF takes to get out of the ventricular regions and into the subarachnoid space?

lateral and median aperture

During eccentric contraction, the length of the muscle __________

lengthens

Which ion channel type opens in response to chemicals binding to it?

ligand-gated channels

Motor neurons send information from the Central Nervous System to target organs and glands. Motor neurons can correctly be classified as which of the following?

multipolar neurons efferent neurons

Coming off of the M line are _________ fibers and extending off of the Z line are __________ fibers.

myosin; actin

Striations of muscle are due to alternating bands of dark and light. The dark band is due to the _________ myofilaments and the light band is due to ________ myofilaments.

myosin; actin

One motor unit, by definition, is

one motor neuron and all the muscle fibers it innervates

Aerobic respiration requires ________ to produce ATP. The utilization of glucose in this process creates ____ ATP and the byproducts CO2 and H2O

oxygen; 32

Melatonin is produced in the ______________, which is under the control of the Master Clock, also known as the _________, which regulates circadian rhythms.

pineal gland; suprachiasmatic nucleus

During contraction, the muscle shortens due to shortening of the _____________, which is the smallest functional unit of skeletal muscle.

sarcomere

During contraction, the bulk of calcium comes from:

sarcoplasmic reticulum

During isotonic contraction, the length of the muscle ______

shortens

Which of the following muscular tissues is not striated?

smooth muscle

During isometric contraction, the length of the muscle __________

stays the same

If, in a laboratory, a skeletal muscle cell receives a single stimulus to contract, it produces a single muscle twitch. If we quickly fire another stimulus for the muscle to contract, prior to the muscle fully relaxing, then we have a condition of:

temporal summation

The middle cerebellar peduncles connect

the pons to the cerebellum

Which of the following is/are true of myelination?

the spaces between myelination are called "nodes of ranvier" myelination protects and electrically insulates axons myelination increases speed of action potential propogation

Sensory neurons gather information from the external and internal environments, and send that information to the Central Nervous System for processing. Sensory neurons can also correctly be classifed as which of the following?

unipolar neurons afferent neurons

Which ion channel type opens in response to changes in membrane potential?

voltage-gated channels

The longitudinal fissure is

what separates the left and right hemispheres of the cerebrum

The central sulcus is

what separates the precentral gyrus from the postcentral gyrus