anatomy chap 14 quiz

Mature neuron mitosis

A mature neuron typically cannot undergo mitosis because it does not have centrioles.

Effector function in nervous system

Respond to information.

CNS neurons

Interneurons are neurons located only within the CNS.

Neurolemmocyte function

Increases the propagation rate of a nerve impulse by forming myelin in the PNS.

CNS CSF production

Ependymal cells help produce cerebrospinal fluid (CSF) in the CNS.

Non-CNS cell

Neurolemmocytes are NOT part of the CNS.

Neuron function

Transmits, transfers, and processes nerve impulses.

Reverberating circuit

A neural circuit that is repeatedly stimulated by nerve impulse feedback.

Electrical synapse interaction

Gap junctions facilitate interaction between presynaptic and postsynaptic membranes.

Epineurium description

A thick, dense irregular connective tissue layer enclosing the nerve.

Structural types of neurons

Unipolar, bipolar, and multipolar.

Neuronal structural classification

Determined by the number of processes extending directly from the cell body.

Unipolar neuron

A neuron with a single process that divides into a peripheral and central process, most sensory neurons are unipolar.

Bipolar neuron

A neuron with one axon and one dendrite, found mainly in some special senses.

Multipolar neuron

A neuron with many dendrites and one axon; it is the most common structural type.

Functional types of neurons

Sensory, motor, and interneurons.

Sensory neuron function

Transmits nerve impulses from sensory receptors to the CNS.

Motor neuron function

Transmits nerve impulses from the CNS to muscles or glands.

Interneuron function

Processes information within the CNS and facilitates communication between sensory and motor neurons.

CNS glial cells

Astrocytes, ependymal cells, microglial cells, and oligodendrocytes.

Astrocyte function

Helps form the blood-brain barrier, regulates tissue fluid, provides structural support, replaces damaged neurons, and changes synapse numbers.

Ependymal cell function

Lines the ventricles and central canal and assists in production and circulation of CSF.

Microglial cell function

Defends against pathogens and removes debris through phagocytosis.

Oligodendrocyte function

Myelinates and insulates CNS axons.

PNS glial cells

Satellite cells and neurolemmocytes.

Satellite cell function

Surrounds neuron cell bodies in ganglia and regulates nutrient and waste exchange.

Neurolemmocyte function

Myelinates and insulates PNS axons.

CNS vs PNS myelin

Oligodendrocytes form myelin in the CNS; neurolemmocytes form myelin in the PNS.

PNS axon repair

If the cell body remains intact, the distal portion undergoes Wallerian degeneration, macrophages remove debris, and a regeneration tube forms.

Wallerian degeneration

Breakdown of the distal portion of a severed axon and its surrounding myelin sheath.

Connective tissue coverings of a nerve

Endoneurium, perineurium, and epineurium.

Endoneurium function

Surrounds an individual axon.

Perineurium function

Surrounds a fascicle, or bundle of axons.

Epineurium function

Surrounds the entire nerve.

Difference between neuron, axon, and nerve

A neuron is an individual nervous-system cell; an axon conducts impulses away from the cell body; a nerve is a bundle of many PNS axons.

Types of synaptic communication

Electrical and chemical.

Electrical synapse information transmission

Ions pass directly between cells through gap junctions.

Chemical synapse information transmission

Presynaptic neuron releases a neurotransmitter that binds to receptors on the postsynaptic cell.

Common synapse type in humans

Chemical synapses.

Similarity of converging and parallel-after-discharge circuits

Both involve multiple pathways converging on a common postsynaptic neuron.

Converging vs parallel-after-discharge circuit

Converging circuit receives several inputs that converge, while parallel-after-discharge sends information through several pathways simultaneously before converging.

Basic events of neurulation

Neural plate forms, neural groove develops, neural folds elevate, neural crest cells form and separate, neural folds fuse to form the neural tube.

Multiple sclerosis symptoms

Progressive demyelination and destruction of oligodendrocytes in the CNS, disrupting nerve impulse conduction.

Circulation vs movement and sensation after amputation

Circulation can be restored much more quickly than nerve regeneration, which requires axon regrowth.

Regenerating PNS axon growth speed

About 2–5 mm per day.

Nerve regeneration duration compared to circulation

Regeneration takes longer because nerve axons must physically reconnect with receptors or effectors.

Neuroplasticity after brain trauma

Nervous system remodels existing connections and can sometimes form new connections to compensate for lost function.

Neurogenesis definition

The development of new neurons.

Neurogenesis locations in CNS

Occurs in areas such as the olfactory bulb and hippocampus.

Neuroplasticity vs neurogenesis distinction

Neuroplasticity involves remodeling existing connections, while neurogenesis involves development of new neurons.

Key terms and definitions

Afferent = sensory = toward CNS; Efferent = motor = away from CNS; Interneurons = CNS only.

Myelination differences

Neurolemmocyte = PNS myelin; Oligodendrocyte = CNS myelin.

Glial cells functions

Ependymal = CSF; Microglia = phagocytosis/defense; Astrocytes = BBB/support/synapses.

Connective tissue surrounds the nerve

Endoneurium = axon; Perineurium = fascicle; Epineurium = entire nerve.

Signal transmission types

Saltatory = myelinated + fast; Continuous = unmyelinated + slower.

Synaptic communication types

Electrical synapse = gap junctions; Chemical synapse = neurotransmitter.

Circuit types

Converging = many → one; Diverging = one → many; Reverberating = feedback/repeating; Parallel-after-discharge = multiple pathways.

Neurulation process

Neurulation → neural plate → neural groove/folds → neural tube → CNS.