Nerve Flashcards
What are the 2 main parts of the nervous system?
- Central Nervous System
2. Peripheral Nervous System
What are the 2 principal cells of nerve tissue?
- Neurones
2. Neuroglial Cells
Name 5 types of neuroglial cells
- Astrocytes
- Schwann Cell
- Ependymal Cell
- Microglia
- Oligodendrocytes
What are the 3 main parts of a neuron?
- Body
- Dendrites
- Axon
What is an alternative name for a cell body?
Soma
What are 2 ways to classify neurons?
- Structurally
2. Functionally
What are 3 structural classifications of neurons?
- Bipolar
- Multipolar
- Pseudounipolar
What 3 senses are typically related to bipolar neurons?
- Sight
- Sound
- Balance
What is the typical function of multipolar neurons?
Motor neuronal function
What is the typical function of pseudounipolar neurons?
Sensory neuronal function
Where is 1 place that pseudounipolar neurons found?
Dorsal root ganglions
What are Nissl bodies?
Combination of free ribosomes and rough ER found in neuron cell body
Where are organelles found in the neuron?
Cell body - Can be in dendrite but never axon
What is the function of an axon?
Transmit an electrical impulse from cell body to axonal ending
What is the function of neurotubules?
Facilitate rapid transport of synaptic vesicles along axon
What produces the myelin sheath?
Schwann Cells / Oligodendrocytes
What is myelin?
Lipid rich insulator
What is the function of myelin?
Allows for increased conduction velocity of electrical impulse along axon
What is the gap between one myelinating cell and the next called?
Node of Ranvier
What is the epineurium?
Protective layer surrounding the entire nerve
What type of CT is epineurium?
Dense Irregular CT
What is the perineurium?
Protective layer surrounding the nerve fascicle
What type of CT is perineurium?
Loose CT
What is the endoneurium?
Protective layer which occurs between the nerve fibres within each fascicle
What type of CT is endoneurium?
Loose CT
What is the function of the dorsal root of peripheral nerves?
Receive sensory information
What is the function of the ventral root of peripheral nerves?
Send out motor signals
In what part of the nervous system do Schwann cells act?
Peripheral Nervous System
In what part of the nervous system do oligodendrocytes act?
Central Nervous System
Name 4 types of neuronal ending
- Synapse
- Motor End Plate
- Muscle Spindles
- Sensory Endings
What is a synapse?
Regions at the end of some axons which transmit nerve impulse from one neuron to another
How does a synapse communicate with another neuron?
Via transmitter substance
What is a motor end plate?
Junction between an axon and a muscle fibre surface
How does a motor end plate arise?
- Axon becomes unmyelinated
- Neuromuscular bulb rests on depression within muscle
- Transmitter acts similarly to synapse
What is muscle spindle?
Specialised muscle fibres lying within a CT capsule
What is the function of muscle spindle?
Detect stretch in a specific muscle
What is the function of motor neurons of muscle spindle?
Prevent overstretching of a muscle to prevent tear
Name 3 sensory endings
- Pacinian Corpuscle
- Meissner’s Corpuscle
- Nociceptors
Where is the Pacinian corpuscle found?
Deep in the dermis
What is the function of the Pacinian corpuscle?
Deformation
Name 3 locations where the Meissner’s corpuscle is found
- Fingertips
- Lips
- Just under epidermis
What is the function of Meissner’s corpuscle?
Touch receptor
What is the function of a nociceptor?
Detect pain
Name 1 area where nociceptors are found
Pulp cavity of teeth
Give 2 differences between how Schwann cells function and how oligodendrocytes function
- Unmyelinated axons in CNS have no support from oligodendrocytes
- Oligodendrocytes can myelinate several axons at once
What are 2 types of astrocytes?
- Fibrous - White matter
2. Protoplasmic - Grey matter
What are 2 functions of astrocytes?
- Blood-brain barrier
2. Restrain spread of electrical disturbance in areas surrounding synapses and unmyelinated axons
What happens when microglia cells are activated?
Become macrophage and antigen-presenting cells
What happens during MS with regards to microglia cells?
Degrade myelin debris
What is the function of ependymal cells?
Secrete cerebrospinal fluid
Describe ependymal cells
Low columnar, ciliated, epithelium-like cells which line cavities of CNS
What type of CT is dura mater?
Dense CT
What type of CT is pia mater?
Loose CT
Describe arachnoid mater
2 components
- Layer in contact with dura
- System of trabeculae connecting to pia mater
- Cavity between trabeculae is filled with CSF
What is the choroid plexus?
Invaginated folds of pia mater that penetrate ventricles of brain
What is the main function of CSF?
Hold brain in situ to reduce weight