Action Potential and Nervous System Function

In the CNS, most neuronal ______ occurs in the gray matter

Axons are concentrated in the ______ matter

Cell bodies in the PNS are found in ______

Axons in the PNS are bundled in ______

Parkinson disease is caused by loss of dopamine-producing neurons in the CNS substantia ______

Parkinson disease is treated with l-dopa, a precursor of ______

The neuronal cell body contains the ______ and surrounding cytoplasm

The cell body acts as a trophic center, producing most ______ for the processes

This propagation, called the action potential, the depolarization wave, or the ______, is capable of traveling long distances along neuronal processes

By collecting, analyzing, and integrating information in such signals, the nervous system continuously stabilizes the intrinsic conditions of the body within normal ranges and maintains behavioral patterns

The functional unit in both the CNS and PNS is the ______

Some neuronal components have special names, such as “neurolemma” for the ______

Most neurons have three main parts: 1.The ______, which contains the nucleus and most of the cell’s organelles and serves as the synthetic or trophic center for the entire neuron

Cell bodies can be very large, measuring up to 150 µm in diameter. Other neurons, such as those in the cerebellar granular layer, are among the body’s smallest ______

The dendrites, which are the numerous elongated processes extending from the perikaryon and specialized to receive stimuli from other neurons at unique sites called ______

The ______ are the numerous elongated processes extending from the perikaryon and specialized to receive stimuli from other neurons at unique sites called synapses

Proximal regions of the astrocytic processes are reinforced with bundles of intermediate filaments made of glial fibrillary acid protein (GFAP), which serves as a unique marker for this ______ cell.

Distally the processes lack GFAP, are not readily seen by microscopy, and form a vast network of delicate terminals contacting ______ and other structures.

Terminal processes of a single astrocyte typically occupy a large volume and associate with over a million ______ sites.

Astrocytes originate from progenitor cells in the embryonic neural tube and are by far the most numerous ______ cells of the brain, as well as the most diverse, structurally and functionally.

There are two main morphological types of astrocytes: protoplasmic and ______ astrocytes.

Protoplasmic astrocytes have a ______ appearance due to their many radiating processes and are primarily found in the grey matter.

Functions attributed to astrocyte: Buffering extracellular K+ levels Regulating the extracellular ionic concentrations around ______.

Fibrous astrocytes have relatively few but longer cytoplasmic processes that align with the nerve axons and are mainly found in ______ matter.

The spinal cord shows bilateral symmetry around the CSF-filled central ______

In the spinal cord, the gray matter forms a roughly H-shaped structure with two posterior (sensory) horns and two anterior (motor) ______

The gray matter in the spinal cord contains abundant astrocytes and large neuronal cell bodies, especially those of motor neurons in the ventral ______

The white matter in the spinal cord contains primarily oligodendrocytes and tracts of myelinated axons running along the length of the ______

With H&E staining, the large motor neurons of the ventral horns show large nuclei, prominent nucleoli, and cytoplasm rich in Nissl substance, all indicating extensive protein synthesis to maintain the axons of these cells that extend great ______

In the white commissure ventral to the central canal, tracts run lengthwise along the cord, seen here in cross section with empty myelin sheaths surrounding axons, as well as small tracts running from one side of the cord to the ______

The skull and the vertebral column protect the CNS, but between the bone and nervous tissue are membranes of connective tissue called the ______

Three meningeal layers are distinguished: the dura, arachnoid, and pia ______

The middle meningeal layer is the thicker weblike ______ mater (A) containing the large subarachnoid space (SA)

The subarachnoid space is filled with ______ and the arachnoid acts as a shock-absorbing pad between the CNS and bone

Fairly large blood vessels (BV) course through the ______

The innermost pia mater (P) is thin and is not clearly separate from the ______; together, they are sometimes referred to as the pia-arachnoid or the leptomeninges

The space between the pia and the white matter (WM) of the spinal cord here is an artifact created during dissection; normally the pia is very closely applied to a layer of astrocytic processes at the surface of the CNS tissue

The blood-brain barrier (BBB) is a functional barrier that allows much tighter control than that in most tissues over the passage of substances moving from blood into the CNS tissue. The main structural component of the BBB is the capillary ______

The limiting layer of perivascular ______ feet, which closely envelops the basement membrane of the continuous capillaries in most CNS region, also contributes to the BBB and further regulates passage of molecules and ions from blood to brain

The cell body acts as a trophic center, producing most ______ for the processes