Ch. 11-14 DSMs

Which type of neuron carries impulses from the CNS to an effector

Motor neuron

The period of time when a second action potential can be generated with a very strong stimulus

Relative refractory period describes

Do all graded potentials lead to action potentials

No

Action potentials are propagated along which portion of a neuron?

Axon

Do myelinated axons undergo continuous conduction?

No

Immediately after an action potential has peaked, which cellular gates open

Volate-gated K+ channels

Resting membrane potential of a neuron

-70 mV

Synaptic vesicles that contain neurotransmitters are located in what portion of a neuron

Axon terminals

Which glial cell in the CNS acts as a macrophage and phagocytizes bacteria and cell debri

Microglia

Anterior/visceral horns contain:

Somatic motor cell bodies

Which brain structure regulates overall body homeostasis

Hypothalamus

If the caudal portion of the neural tube failed to develop properly, what will be affected

Spinal cord may be affected

The arbor vitae refers to

Cerebellar white matter

The primary somatosensory area/cortex is located in the:

parietal lobe

The diencephalon includes:

Epithalamus, hypothalamus, and thalamus

What structure connects the hypothalamus to the pituitary gland

Infundibulum

Which area of the cerebral cortex controls voluntary contraction of muscles

Primary motor cortex

The somatic nervous system:

conducts impulses from the CNS to the skeletal muscles

Which cell types influence neuronal function by “mopping up” leaked potassium ions and by recapturing and recycling released neurotransmitters? These cells also participate in information processing in the brain.

Astrocyte

Which type of glial cells line the central cavities of the brain and spinal cord, where they help circulate the cerebrospinal fluid?

Ependymal cells

diseases such as multiple sclerosis, that damage the myelin sheath of neurons, likely affect which of cells?

Oligodendrocyte

Which type of glial cells are the most abundant and versatile and aid in making exchanges between capillaries and neurons?

Astrocytes

Which neuroglia are most responsible for helping determine capillary permeability in nervous tissue?

Astrocytes

Which division of the nervous system is also known as the involuntary nervous system?

Autonomic nervous system

Sensory and motor output are: PNS or CNS

PNS

Visceral sensory (afferent) fibers carry information from the

organs in the ventral body cavity to the CNS

Somatic motor fibers carry information from the

CNS to skeletal muscles

Based on your understanding of this cell’s function, you might expect this cell to be active in neurodegenerative disorders like Alzheimers where this cell removes damaged neurons. Additionally, this cell is active in preventing encephalitis and meningitis due to its ability to phagocytize microorganisms.

Microglial cell

Visceral sensory (afferent) fibers carry information from the

organs in the ventral body cavity to the CNS

Visceral motor fibers carry information from the

CNS to smooth muscles, cardiac muscles, and glands

Somatic sensory (afferent) fibers carry information from the

skin, skeletal muscles, and joints to the CNS

2 types of nervous tissue

neuroglia and neurons

Which two glial cells produce myelin sheath

oligodendrocytes and schwam cells

Glial cell that regulates chemical environment

Astrocyte

Glial cell that is phagocytic and engulfs micro-organisms

Microglial cell

Glial cell that produce & circulates CSF

Cilia

Glial cell that regulates chemical environment around nerves

Satellite cells

Region where cell body and axon meet

Axon hillock

Receives info (neuron)

dendrite

Communicates w/ neuron, gland

Axon terminals

One process extends from the cell body and forms central & peripheral processes, which together comprise an axon

Unipolar

Two processes extend from the cell body. One is a fused dendrite, the other is an axon

Bipolar

Many processes extend from the cell body. All are dendrites except for a single axon

Multipolar

Myelinated axons (white or grey matter)

White matter

Passive channels

Leakage (nongated) channels

Open in response to a chemical

Chemically gated (ligand-gated) channels

Open in response to mechanical vibration

Mechanically gated ion channels

Open in response to a direct change in membrane potential

Voltage-gated channels

Membrane potential becomes more positive

Depolarization

Membrane potential becomes more negative

Hyperpolarization

If we consider neurons to be carrying on conversations, which portion(s) of the neuron “listen(s)?”

Dendrites and cell body

Most common neuron type

Multipolar

Fibers that convey signals away from the CNS to the internal viscera such as the heart are considered

Visceral motor

Fibers that convey signals towards the CNS from the skin are considered

Somatic sensory

What is the role of astrocytes

Support neurons (brace and guide them)

Does myelin sheath increase impulse speed

yes

Which cells form myelin in the PNS

Schwann cells

Function of ependymal cells

Secrete CSF

Do dendrites transmit signals away from the cell body?

No

Is the interior of a nonconducting neuron positive

No

Threshold value for a neuron

-55mV

resting membrane potential for a neuron

-70mV

What happens during depolarization

Sodium enters and exits the cell

During repolarization

Sodium inactivates and potassium exits the cell

What type of refractory period results when no stimulus of any strength will trigger an action potential

Absolute

What type of action potential propagation would take place in a myelinated axon

Saltatory

What do neurotransmitters do

Transmit signals

Which autoimmune disease occurs when the immune system attacks and destroys the myelin sheath of the CNS

Multiple sclerosis

True/False: Calcium flows into the axon terminal and causes exocytosis of neurotransmitter when the AP arrives

True

Which type of synapse is most common

Chemical

Do graded potentials decay quickly

Yes

True/False: Myelinated axons conduct faster than nonmyelinated

True

A bundle of axons in the CNS is called:

A tract

A bundle of axons in the PNS is called:

A nerve

Which type of axonal transport allows certain viruses to circumvent the barrier created by astrocytes to enter into the CNS?

Retrograde transport

A neuron with a distal peripheral process and a central process that extends to the CNS is most likely:

A sensory neuron

Organelles for degradation or recycling are moved through the axon by:

Retrograde movement

Which type of axonal transport allows certain viruses to circumvent the barrier created by astrocytes to enter into the CNS?

Retrograde transport

If we consider neurons to be carrying on conversations, which portion of the neuron “speaks” by releasing neurotransmitters?

Axon terminal

Interneurons and motor neurons are: (uni, multi, or bipolar)

Multipolar neurons

Most sensory neurons are:

Unipolar neurons

Most interneurons are:

Multipolar

In axonal transport, retrograde movement is transport toward the cell body. Which of the following move in this direction?

Worn out organelles

Which type of ion channel opens when a neurotransmitter binds to it?

Chemically gated (ligand-gated) channels

All voltage-gated Na⁺ and K⁺ channels are closed during which stage:

The resting state of a neuron

What begins with the opening of the Na⁺ channels and ends when the Na⁺ channels begin to reset to their original resting state?

The absolute refractory period

Which statement best describes the role of leakage (nongated) channels?

Leakage channels help maintain the resting membrane potential.  

The movement of which ion through leakage (nongated) channels plays the most important role in generating the resting membrane potential?

Potassium

The sodium-potassium ion pump will:

pump three sodium ions out of the cell for every two ions of potassium it brings into the cell

Which type of ion channel opens when a neurotransmitter binds to it?

Chemically gated (ligand-gated) channels

What could cause a graded depolarization

Na⁺ entering the cell through chemically gated channels

Excessive potassium efflux as a result of relatively slower closure of the potassium gates corresponds to what part of an action potential curve?

The hyperpolarization phase of an action potential

Which fiber type consists of small diameter, unmyelinated axons, that propagate nerve impulses slowly?

C fibers

Which channels open during depolarization?

Na⁺

Saltatory conduction refers to:

a conduction process in myelinated axons where the electrical signal appears to jump from gap to gap along the axon

A stimulus that fails to generate an action potential is called

subthreshold stimulus

What begins with the opening of the Na⁺ channels and ends when the Na⁺ channels begin to reset to their original resting state?

The absolute refractory period

Describe voltage-gated channels

Membrane channels open and close in response to changes in the membrane potential.

All voltage-gated Na⁺ and K⁺ channels are closed during which stage

The resting state of a neuron

Which event begins with opening of potassium gates and the rushing out of K⁺?    

The repolarization phase of an action potential