Nerve Tissue - Histology (L1)

Question 1

Nerve tissue

Answer 1

AKA conductive tissue. Highly specialized for the capacity for action potentials. The nerve cells, or neurons, are easily stimulated to transmit action potentials, impulses of ions flowing along their cell surfaces very rapidly.

Question 2

Neuron

Answer 2

Each Neuron consists of a cell body (or soma) and several fiber-like processes extending from the cell body.

Question 3

Soma

Answer 3

Cell body. The soma contains the nucleus and is located inside the central nervous system (CNS). Thin tubes of the cell branch off each soma: dendrites which connect to other neurons, and a longer axon.

Question 4

Glial cells

Answer 4

The purple dots throughout the section are the nuclei of glial cells, the nutritive and support cells that surround neurons in the CNS.

Question 5

Axon

Answer 5

The axon of a motor neuron may be several feet long, and the axon exits the CNS to send an outgoing signal to a synapse with a skeletal muscle cell. Afferent neurons by contrast, have an axon that receives an incoming signal to the CNS from a sensory ending.

Question 6

Peripheral nerves

Answer 6

Peripheral nerves exit the central nervous system of a mammal to communicate with the rest of the body. A peripheral nerve consists of a large number of axons, each insulated by Schwann cells, and grouped together into cable-like bundles.

Question 7

Three levels of connective tissue organizing peripheral nerve

Answer 7

Endoneurium, perineurium and epineurium.

Endoneurium is next to the Schwann cells and contains connective tissue and capillary blood vessels.

The perineurium forms collagen-rich connective tissue layers wrapping bundles of axons.

Epineurium is the outermost connective tissue layer surrounding the many bundles of axons in the whole structure of a peripheral nerve.

Question 8

Small neurovascular bundle

Answer 8

Composed of an artery, vein and nerve. The vessels supplying and draining a particular area of tissue tend to pass together, frequently accompanied by a peripheral nerve and surrounded by connective tissue which forms an ill-defined protective sheath.

Question 9

Artery

Answer 9

Has a rigid wall and the lumen of the artery often has a scrunched appearance compared to the flat and smooth lumen in the vein. This is because the inner walls of the artery are have a large proportion of elastin and smooth muscle to provide for the expansion and recoil necessary for the maintenance of the blood pressure. In many specimens you may see a darkly staining layer right at the edge of the arterial lumen; this is elastin-rich endothelium. In many arteries and arterioles, the diameter of the lumen is regulated by smooth muscle in the arterial walls to control local blood flow and pressure, under the control of the sympathetic nervous system.

Question 10

Vein

Answer 10

Have a grainy appearance to their wall structure, and are under very low pressure compared to arteries.