Nervous System 1 - Neurons & Neuroglia - 5a Flashcards
What cells use their entire structure to myelinate axons?
Schwann cells
What do Schwann cells assist with following axon injury?
Regeneration and regrowth of the axon
What are neuropeptides?
Relatively large molecules consisting of 3-40 amino acids linked by peptide bonds
Examples include endorphins and substance P
What is the size comparison between neuropeptides and small molecule neurotransmitters?
Neuropeptides are relatively large, consisting of 3-40 amino acids, whereas small molecule neurotransmitters are small organic molecules.
What are the two main components of the nervous system?
Central (CNS) and Peripheral (PNS) nervous system
What are the three major parts of a neuron?
- Soma (cell body)
- Dendrites
- Axon
What is the function of the soma in a neuron?
Contains plasma membrane, nucleus, and cytoplasm with organelles
What is the role of dendrites in a neuron?
Receives chemical messengers via receptor sites
What is the axon responsible for?
Transmits nerve impulses away from the cell body
Which part of the neuron is known as the trigger zone?
Axon hillock
What are the three structural classifications of neurons?
- Unipolar neurons
- Bipolar neurons
- Multipolar neurons
What type of neuron carries sensory information towards the CNS?
Sensory/afferent neurons
What is the primary function of motor/efferent neurons?
Carry nerve impulses from the CNS to effectors
What is the role of inter/association neurons?
Integrate incoming sensory impulses and elicit motor responses
What are neuroglia?
Support cells that provide nourishment, protection, and maintain homeostasis for neurons
Which type of neuroglia forms the blood-brain barrier?
Astrocytes
What is the function of ependymal cells?
- Produce and assist in the circulation of CSF
- Form part of the blood-CSF barrier
What do oligodendrocytes do?
Wrap around axons in the CNS to form the myelin sheath
What are Schwann cells responsible for?
- Myelination in the PNS
- Surround unmyelinated axons for protection
Fill in the blank: Myelin is a _______ covering around some axons.
[multilayered lipid and protein protective]
What is resting membrane potential?
Electrical gradient across the plasma membrane of a cell under resting conditions
What is the typical resting potential of a neuron?
-70mV
What is an action potential?
Series of rapidly occurring events that changes and restores the membrane potential
What is the difference between continuous propagation and saltatory conduction?
- Continuous propagation: unmyelinated neurons, slower
- Saltatory conduction: myelinated axons, faster
