Video Praktikum Textus Nervosus

Summary

This video script from a histology practicum delves into the nervous system's structural components. It explains the roles of neurons and neuroglia cells, which support and protect neural activity. The script distinguishes between the central nervous system, comprising the brain and spinal cord, and the peripheral nervous system, which includes cranial and spinal nerves. It also covers the regeneration capabilities of peripheral nerves versus the central ones. The focus is on studying the spinal cord and peripheral ganglia, highlighting structures like the dorsal root ganglion and the myelin sheath. The video script provides a detailed look at neuron cell bodies, axons, and the supportive role of glial cells, all crucial for understanding neural function.

Takeaways

• 🧠 The video discusses the nervous tissue, specifically the textus nervosus, which is composed of neurons and neuroglial cells.
• 🔬 Neuroglial cells, such as astrocytes, oligodendrocytes, ependymal cells, satellite cells, and microglia, support, protect, and nourish neurons.
• 🌿 The nervous tissue is anatomically divided into the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which includes cranial and spinal nerves.
• 🌱 Peripheral nerve cells have a better regenerative capacity compared to central nervous system cells.
• 🧪 The lab focuses on studying the spinal cord as part of the CNS and the spinal ganglion and peripheral nerves as parts of the PNS.
• 🏠 Spinal ganglia are clusters of sensory neuron cell bodies located in the PNS, enveloped by a connective tissue capsule.
• 🔬 The preparation of the spinal ganglion shows structures like the capsule, neuron soma, and axon, with unipolar neurons having a T-shaped axon.
• 📚 The video also covers the preparation of the myelin sheath from the very-very fine nerve, showing the myelination of nerve fibers.
• 🧬 The structure of the nerve includes the epineurium, perineurium, and endoneurium, which are layers of connective tissue surrounding the nerve fibers.
• 🧬 The central nervous system has two main substances: the gray matter (substantia grisea) and the white matter (substantia alba), with the spinal cord having gray matter in the center and white matter around it.
• 🧬 The gray matter contains neuronal cell bodies and appears blue to purple due to the presence of neuromelanin, while the white matter contains myelinated axons, giving it a white appearance.

Q & A

What is the textus nervosus and its primary components?

Textus nervosus is one of the human body's tissues, composed of neurons and neuroglial cells. Neurons are the primary cells responsible for transmitting signals, while neuroglial cells provide nutrition, protection, and support for neuronal activity.

What are the two main types of neuroglial cells mentioned in the script?

The script mentions astrocytes and oligodendrocytes as examples of neuroglial cells.

How is the nervous tissue anatomically classified?

The nervous tissue is anatomically classified into two systems: the central nervous system, which consists of the brain and spinal cord, and the peripheral nervous system, which includes the cranial nerves from the brain and the spinal nerves from the spinal cord.

What is the difference in regeneration capability between peripheral and central nervous system cells?

The script indicates that peripheral nervous system cells have a better ability to regenerate compared to central nervous system cells.

What are the structures observed in the preparation of the spinal cord medulla?

The structures observed in the spinal cord medulla preparation include the capsule, soma of neurons, and axons of neurons.

What is the function of the dorsal root ganglion in the peripheral nervous system?

The dorsal root ganglion, also known as the spinal ganglion, is a collection of cell bodies located in the peripheral nervous system, encased in a capsule of connective tissue containing adipose tissue and blood vessels.

What are the characteristics of the neurons observed in the ganglion?

The neurons observed in the ganglion have a spherical or round shape with a nucleus in the center and a nucleolus in the middle, which appears as a dense purple dot. They also have an anisolic substance in the soma, surrounded by a glial cell layer resembling a flat epithelium with a round nucleus, known as satellite cells.

What is the appearance of the axons in the spinal ganglion when stained with hematoxylin-eosin?

The axons in the spinal ganglion appear magenta in color and are seen branching out from the soma with a T-shaped extension, one branch heading towards the central nervous system and the other towards the peripheral nervous system.

What is the structure observed in the preparation of the nerve fibers?

In the preparation of nerve fibers, structures such as axons, myelin sheaths, and Schwann cells are observed. The axons appear as pale lines, the myelin sheaths appear clear and colorless, and the Schwann cells have a spherical and larger nucleus compared to the fibrous cells surrounding them.

What are the three layers that make up the nerve sheath as described in the script?

The three layers that make up the nerve sheath are the epineurium, perineurium, and endoneurium. The epineurium is the outer fibrous sheath composed of dense irregular connective tissue. The perineurium surrounds the fascicles or groups of nerve fibers, composed of circularly arranged connective tissue with fewer fibers. The endoneurium surrounds each individual nerve fiber, composed of loose connective tissue.

What are the two main substances found in the central nervous system, and how do they differ in the brain and spinal cord?

The two main substances in the central nervous system are the gray matter (substantia grisea) and white matter (substantia alba). In the brain, white matter is found in the center with gray matter surrounding it, while in the spinal cord, gray matter is in the center and white matter is around it. Gray matter contains neuronal cell bodies and appears blue to purple due to the presence of neuroglia, while white matter contains myelinated axons, giving it a white appearance.

What is the central canal and its location in the spinal cord?

The central canal is a structure in the spinal cord that is lined by the ependymal cells, which form a simple columnar epithelium. It is located in the center of the spinal cord and is surrounded by gray matter.