Human Anatomy: Nervous System, Spinal Cord, Brain, and Spinal Tracts

Comprehensive review flashcards covering neural tissue histology, spinal cord gross anatomy, spinal nerves and plexuses, cerebral and brainstem anatomy, cranial nerves, and ascending/descending spinal tracts.

The central nervous system (CNS) consists of the brain and the spinal cord, whereas the peripheral nervous system (PNS) includes all neural tissue located _______ the CNS.

outside

In the peripheral nervous system, the _______ division brings sensory information to the CNS, whereas the efferent division carries motor commands away from the CNS.

afferent

Within the autonomic nervous system, stimulation of _______ nerves causes pupil dilation, increases heart rate, and relaxes the urinary bladder.

sympathetic

Neuroglial cells that maintain the blood–brain barrier, regulate ion and chemical concentrations, and provide structural support in the CNS are called _______.

astrocytes

In the central nervous system, cytoplasmic extensions of _______ contact somas or axons to tie them together in a sheath of myelin.

oligodendrocytes

The neuroglia that line the ventricles of the brain and the central canal of the spinal cord to monitor and assist in producing cerebrospinal fluid are _______ cells.

ependymal

In the peripheral nervous system, _______ cells surround all peripheral axons and are responsible for myelination.

Schwann

In a neuron soma, clusters of rough endoplasmic reticulum (RER) and free ribosomes are termed chromatophilic substance or _______ bodies.

Nissl

Identify the four structural classes of neurons shown from left to right: (a) _______, (b) bipolar neuron, (c) pseudounipolar neuron, and (d) multipolar neuron.

anaxonic neuron

Sensory receptors that monitor the position and movement of skeletal muscles and joints are classified as _______.

proprioceptors

Action potential propagation can reach speeds of up to _______ in myelinated axons with a large diameter.

$$140\,\text{m/sec}$$

A neuronal pool circuit in which information spreads from a single presynaptic neuron to several postsynaptic neurons is known as _______.

divergence

In the adult, the spinal cord measures approximately _______ in length and extends from the brain down to the level of vertebrae $L_1-L_2$.

$$45\,\text{cm}$$

The tapered, conical inferior end of the spinal cord located at the $L_1-L_2$ level is called the _______.

conus medullaris

In the lower vertebral canal, the subarachnoid space inferior to the conus medullaris that contains the cauda equina is designated as the _______.

lumbar cistern

Specialized longitudinal extensions of the spinal pia mater that connect to the dura mater and anchor the spinal cord laterally are the _______ ligaments.

denticulate

In a cross section of the spinal cord, somatic motor nuclei that send commands to skeletal muscles are located specifically in the _______ gray horns.

anterior

The human body possesses _______ pairs of spinal nerves, including 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal pair.

31

The connective tissue sheath that wraps around an entire peripheral nerve and becomes continuous with the dura mater is the _______.

epineurium

Branches of spinal nerves $T_1$ to $L_2$ that carry sympathetic motor fibers to and from sympathetic ganglia are collectively called _______.

rami communicantes

The phrenic nerve, which innervates the diaphragm, arises primarily from the ventral ramus of spinal nerve _______, with minor contributions from $C_3$ and $C_5$.

$$C_4$$

The largest nerve in the human body, arising from the ventral rami of $L_4-S_3$ of the sacral plexus, is the _______ nerve.

sciatic

A patellar stretch reflex is an example of a _______ reflex circuit because it involves a single synapse between a sensory neuron and a motor neuron.

monosynaptic

Compression of the nerve roots in the lower lumbar and sacral spinal canal leading to bladder/bowel dysfunction and sciatica is called _______ syndrome.

cauda equina

During embryonic development, the primary brain vesicle prosencephalon divides into the telencephalon and the _______.

diencephalon

The metencephalon of the secondary brain vesicles develops into both the pons and the _______.

cerebellum

The primary motor cortex is anatomically situated on the _______ gyrus of the frontal lobe.

precentral

The motor speech center located on the frontal lobe that regulates breathing and vocalization patterns for speech is known as _______ area.

Broca's

The cerebral cortex lobe lying deep within the lateral sulcus that contains the olfactory cortex and gustatory cortex is the _______.

insula

The thick tract of commissural fibers that interconnects the left and right cerebral hemispheres is the _______.

corpus callosum

In the mesencephalon, visual reflexive movements of the eyes and head are integrated by the _______ colliculus.

superior

The fold of the dura mater that projects into the longitudinal fissure between the two cerebral hemispheres is the _______.

falx cerebri

Cerebrospinal fluid re-enters the venous bloodstream via finger-like extensions of the arachnoid mater called _______ granulations.

arachnoid

The specialized vascular structure consisting of ependymal cells that actively produces and maintains CSF in each brain ventricle is the _______.

choroid plexus

Parkinson's disease results from the degeneration of dopamine-producing neurons located within the _______ of the midbrain.

substantia nigra

This coronal section illustrates the neuropathological changes seen in _______, including severe cortical shrinkage, extreme hippocampal atrophy, and enlarged ventricles.

Alzheimer's disease

According to the cranial nerve assessment diagram, the Roman numeral assigned to the nerve tested by shrugging the shoulders (trapezius) is _______.

XI

Cranial Nerve VII (facial nerve) passes through the internal acoustic meatus and exits the skull via the _______ foramen.

stylomastoid

Sensory innervation to the posterior one-third of the tongue and motor innervation for the gag reflex are provided by Cranial Nerve _______.

IX

Within the posterior column pathway, sensations originating from areas inferior to $T_6$ are carried upward by the fasciculus _______.

gracilis

Pain and temperature sensations are transmitted to the primary sensory cortex via the _______ spinothalamic tract.

lateral

In ascending somatosensory tracts, the cell body of the _______-order neuron resides in a dorsal root ganglion or cranial nerve ganglion.

first

The anatomical rule stating that sensory fibers entering the cord at more inferior levels travel more medially within a tract than fibers entering at superior levels is the _______ rule.

medial-lateral

The descending motor pathway that carries conscious motor commands through the pyramids of the medulla is the _______ tract.

corticospinal

Subconscious motor control of upper limb position and muscle tone during voluntary movements is mediated by the _______ tract.

rubrospinal