Nerve Tissue Flashcards
What are the 2 primary components of nerve tissue?
Neurons and glial cells
What are the 2 main divisions of the nervous tissue?
Central Nervous System and the Peripheral Nervous System
What are the main parts of a neuron?
Cell body (soma), dendrites and axon
Name the structural classifications of neurones
Multipolar, bipolar and unipolar (pseudounipolar)
Name the functional classifications of neurones
Sensory (afferent), motor (efferent) and interneurones
Name the glial cells found in the CNS
Astrocytes, oligodendrocytes, microglia and ependymal cells
Name the glial cells found in the PNS
Schwann cells and satellite cells
What are the two types of synapses?
Electrical synapses and chemical synapses
What is the role of neurotransmitters?
To facilitate communication between neurons at chemical synapses
Which cells myelinate axons in the CNS and PNS?
Oligodendrocytes in the CNS and Schwann cells in the PNS
What is the primary function of myelin?
To insulate axons and increase conduction velocity
What is the difference between gray and white matter?
Gray matter contains cell bodies, dendrites, and unmyelinated axons
White matter contains myelinated axons
What are the main components of the CNS?
Brain and spinal cord
What are the 3 connective tissue layers of a nerve
Epineurium, perineurium and endoneurium
What is a ganglion?
A cluster of neuron cell bodies in the PNS
Why is regeneration limited in the CNS?
Due to inhibitory factors and scar formation
What facilitates regeneration in the PNS?
Schwann cells
What are the components of a reflex arc?
Receptor —> Sensory Neuron —> CNS —> Motor Neuron —> Effector
How is the autonomic nervous system divided?
Into sympathetic and parasympathetic systems
What stain is used to visualise myelin?
Luxol fast blue
What does the silver stain highlight in nerve tissue?
Axons
What type of neuron is common in sensory pathways?
Unipolar (pseudounipolar) neurons
What type of neuron is most abundant in the CNS?
Multipolar neurons
Where are bipolar neurons commonly found?
In special sensory organs like the retina and olfactory epithelium
What is the function of astrocytes?
They maintain the blood-brain barrier and provide metabolic support
What is the role of microglia?
They act as the immune cells of the CNS, removing debris and pathogens
What do ependymal cells produce?
Cerebrospinal fluid
How do Schwann cells support axons in the PNS?
By forming myelin sheaths and aiding in axon regeneration
What ions are crucial for action potential generation?
Sodium (Na+) and potassium (K+)
What is saltatory conduction?
The jumping of action potentials between nodes of Ranvier in myelinated axons
What neurotransmitter is primarily involved in neuromuscular junctions?
Acetylcholine (ACh)
What is the difference in myelination between the CNS and PNS?
A single oligodendrocyte myelinates multiple axons in the CNS
Each Schwann cell myelinates only 1 segment of a single axon in the PNS
What are nodes of Ranvier?
Gaps between myelin sheaths where ion exchange occurs during nerve conduction
What is a monosynaptic reflex?
A reflex arc involving only one synapse between the sensory and motor neuron (e.g. patellar reflex)
What is a polysynaptic reflex?
A reflex involving one or more interneurons between sensory and motor neurons (e.g. withdrawal reflex)
What is the main function of the cerebrum?
Higher-order functions like thought, memory and voluntary movement
What is the role of the cerebellum?
Coordination of voluntary movements and balance
What does the brainstem control?
Basic life functions like breathing, heart rate and blood pressure
What is the role of sensory ganglia?
To house the cell bodies of sensory neurons
What are autonomic ganglia?
Ganglia that contains the cell bodies of postganglionic autonomic neurons
What is Wallerian degeneration?
The process of axon degeneration distal to a site of injury
What factors inhibit CNS regeneration?
The presence of myelin-associated inhibitors and astrocyte-driven glial scar formation
What disease is characterised by the demyelination of CNS neurons?
Multiple sclerosis (MS)
What is Guillain-Barré syndrome?
A disorder where the immune system attacks the myelin in the PNS, causing weakness
What is neuropathy?
Damage or dysfunction of peripheral nerves, leading to weakness, numbness, or pain
What does Nissl staining highlight in neurons?
Rough endoplasmic reticulum in the soma, known as Nissl bodies
What structures are visible in electron micrographs of synapses?
Synaptic vesicles, synaptic cleft, and postsynaptic density
