A&P1_Nrvs_Sys_Lab                             A&P I_Syllabus          (updated 10/18/05)

The following are structures located on the models available in the A&P Labs. (2 pages)

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The Peripheral Nervous System (PNS) consists of the nerves, whether they arise from the Central Nervous System (brain or spinal cord). Some of the cells below are found in the PNS, while others are found in the CNS or both. Motor  neuron in a spinal cord (part of the CNS. The lines (top to bottom) indicate: 1) dendrites (upper right), 2) neurofibril within axon hillock, and 3) an axon. Most of the axon, which will synapse with a skeletal muscle in the PNS.  

Schwann cells form the myelin sheath in the PNS.

In myelinated axons, Schwann cells (PNS) wrap around the neuron multiple times, adding a protective sheath. In unmyelinated axons, Schwann cells only partially surround or only surround the axon once. In the CNS, this process involves the oligodendrocytes. Myelinated fibers in the CNS form the white matter, while unmyelinated fibers form the gray matter.

Growth of the Schwann cell around a neuron will form the myelin sheath.

Photo of a myelinated axon  and an unmyelinated one (these also could be dendrites of sensory neurons).

Unmyelinated fibers.

Identify and give function and location of each neuroglial cell shown below. Shown are a multipolar neuron, oligodendrocytes, Schwann cell, astrocyte, microglia, and ependymal cells.

Identify synaptic knob, synaptic vesicles, mitochondria, neurotransmitters, synaptic cleft, and postsynaptic membrane receptors. See drawing and electron micrograph below.

Photo of synaptic knob.

Be able to explain an EPSP, IPSP, spatial summation, and facilitation from the diagram below. 

How does drug addiction occur? Compare the neurophysiological effects of neuroinhibitory versus neuroexcitatory drugs.

Identify the connective tissues of a nerve (epineurium, perineurium, and endoneurium.. Blood vessels, a nerve fasciculus, and several neurons are also shown.

The Central Nervous System (CNS) consists of the brain and spinal cord:

Identify the meninges and associated structures surrounding the CNS on the following three drawings.

Meninges near the superior sagittal sinus.

Spinal cord and associated meninges.

Identify the ventricles and associated structures of the brain and spinal cord, and be able to trace the production, flow, and reabsorption of cerebrospinal fluid (csf).  What disorders are associated with csf?

Lateral view of ventricles of brain.

Arrows indicate direction of flow of CSF in brain.

Arrows indicate direction of flow of CSF at end of spinal cord.

Be able to identify the parts of the spinal cord, and know number of spinal nerves in each region and major nerves of each region.

Identify all regions and associated structures in a spinal cord cross section.  Be able to identify and explain mechanisms of spinal reflexes.

Reflex arcs may contain two or more neurons.

Note typo on Lateral spinothalamic tract.  The reticulospinal tract is a descending tract.  Know the function of each of these tracts.

Descending tracts.

In which lobe and gyrus of the brain do these ascending neurons terminate? Note the number of neurons in ascending (3) and descending (2) tracts.

In which lobe and gyrus is the motor cortex located.  Which neurons cross (decussate) in the medulla and which cross in the spinal cord?  What are the symptoms of upper motor neuron injury vs. lower motor neuron injury?  Which type of injury is likely to heal? Why?

Be able to identify all major portions, lobes, and structures of the brain, and know their functions.

Development of the brain:

Evolutionary changes in brain from fish to birds and humans.

Fetal development of human brain from week 5 to week 8 of gestation.

Development from 11 week fetus to birth of child.

On the views below you should be able to identify: all four major lobes of the cerebrum, the cerebellum, corpus callosum, septum pellucidum, fornix, interventricular foramen (of Monroe), 3rd ventricle, choroid plexus (of 3rd vent.), pineal gland, thalamus, intermediate mass (of thalamus), hypothalamus, mammillary body, optic chiasma, midbrain (cerebral peduncle), cerebral aqueduct, tectum (and corpora quadrigemina), pons, 4th ventricle, medulla oblongata, and spinal cord.  The pituitary gland is missing from this view, but, is in the 2nd illustration below, just beneath the optic chiasma, and immediately to the left of the pons.  At the top of the photo, beneath the word "Inc.," is the central sulcus, which separates the frontal and parietal lobe. The folds (gyri) to the left and right of this sulcus are the precentral gyrus (somatic motor area) and postcentral gyrus (somatic sensory area) of the cerebrum, both of which are better viewed in a lateral view of the brain. Most of the surface and outer few millimeters is gray matter, while most of the inner tracts are composed of white matter (myelinated neurons).

Be able to name labeled parts of brain.

These illustrations show the lateral and longitudinal fissures (sulci) of the brain.

These illustrations show the lateral and longitudinal fissures (sulci) of the brain.

The temporal lobe is pulled away here, illustrating the insula (purple), an area that is involved in understanding spoken words, the sense of taste, and in integrating sensory information from visceral receptors.  The temporal lobe is involved in hearing, smell, learning, memory, visual recognition, and emotional behavior.

Precentral gyrus (upper brown area):

Central sulcus (left) and Postcentral gyrus (upper gold area on right). Note the insula (the football shaped shaded area labeled on the right side).

Functional areas of the human brain.

Functional areas of the human brain.

Functional areas of the human brain.

Be able to identify all nerves and structures from your list on the brainstem, and know their functions. Note differences in olfactory bulbs and olfactory tracts (lines 1 & 2 on left); also, be able to distinguish between the optic nerves (line 2 on right) optic chiasma (line 3 on left), and optic tracts (below the X, on either side of pituitary gland).

Although not labeled, the horizontal light area in middle of the medulla oblongata, represents the decussation of pyramids (the region where approx. 85% of descending motor tracts cross from one side of the brain to the other.  The remaining 15% of motor tracts cross over the spinal cord in the lower cervical region, where nerves to the arms arise.

The pineal body (gland), part of the epithalamus, is represented by the 1st line at upper right. This is the "3rd eye" of lower vertebrates, which responds to darkness by producing melatonin, and helps to regulate behavioral patterns related to night & day, as well as seasonal changes. Its location is visible on the head of lizards by a small scale between the frontal and parietal scales. The four rounded 'bumps' below (and labeled on the left) the pineal gland are the corpora quadrigemina, composed of a pair of superior colliculi and inferior colliculi, which control reflexes of neck and back muscles for turning in response to visual and audio signals, respectively. These structures are on the posterior of the midbrain, a portion known as the tectum. On the lateral view (second figure below), this part is between the 3rd and 4th ventricles.

The choroid plexus of the 3rd and 4th ventricles is illustrated here by the blue wavy areas. These are surrounded by ependymal cells, which form the blood/csf barrier.

What is the significance of the dermatomes? How can they be used to diagnose spinal cord or nerve injuries?

Posterior view of dermatomes.

Compare the dermatomes with the areas for referred pain.

For additional resources on the nervous system, please consult:

http://www.pbs.org/wnet/brain

http://www.vh.org/Providers/Textbooks/BrainAnatomy/TOC.html

http://medstat.med.utah.edu/kw/hyperbrain/

http://www.cid.ch/DAVID/head.html

http://www.neuroguide.com

http://www.kumc.edu/instruction/medicine/anatomy/histoweb/