LEC 13-14 - General neuroanatomy ANSCNS neuraxis Flashcards
(84 cards)
Describe the two main cell types in the nervous system.
neurons and glia
Define neurons and their primary functions.
Neurons are excitable cells that generate action potentials in response to stimuli.
They conduct information as electrical signals.
Neurons are among the largest cells in the body.
How do glial cells support neurons in the nervous system?
support neurons by:
Protecting and nourishing them.
Electrically insulating them.
Removing waste and neurochemical debris.
Assisting in injury repair.
What is the renewal capacity of neurons compared to glial cells?
Neurons usually do not renew or divide, except for a little bit of new growth in adults.
Glial cells are more numerous and can multiply.
Describe the types of connections neurons have.
Synapses with another neuron
Neuromuscular synapses - w/muscles
Neuroglandular synapses - w/ glands
Define the main parts of a neuron.
cell soma (cell body), axon hillock (initial segment), axon, dendrite, dendritic spines, synapse, and terminal axonal boutons.
How do neurons communicate with each other?
Neurons communicate with each other through synapses, where neurotransmitters are released from terminal axonal boutons.
Describe the characteristics of nerve cells.
have a large nucleus and a prominent nucleolus
- contain a large amount of rough endoplasmic reticulum, which is relevant for making proteins.
What is the structural classification of neurons?
-Anaxonic neuron
-Bipolar neuron
-(Pseudo) unipolar neuron
-Multipolar neuron
What are anaxonic neurons?
- no axon
- in the brain and special sense organs
What are bipolar neurons?
- In special sense organs e.g. eye, ear, nose
What are (Pseudo) unipolar neurons?
- Sensory neurons e.g. dorsal root ganglia
What are multipolar neurons?
- motor neurons and interneurons
Explain the impulse direction in neurons.
In neurons, the impulse direction follows the pathway from dendrites to axons.
Describe the central nervous system (CNS) terminology.
nuclei = collection of neuronal cell bodies
tracts = are bundles of nerve fibers (axons/dendrites).
Define the peripheral nervous system (PNS) terminology.
ganglia = are collections of neuronal cell bodies
nerves = are bundles of nerve fibres (axons/dendrites).
What glial cells are in the CNS?
- Oligodendrocytes
- Microglia
- Astrocytes
- Ependymal cells
What glial cells are in the PNS?
- Schwann cells
- Satellite cells
What are the supporting cells (glial cells)?
Astrocytes (CNS): Provide physical/nutritional support, regulate extracellular fluid, form blood-brain barrier.
Satellite Cells (PNS): Provide physical support for neurons.
What are the phagocytic cells (glial cells)?
Microglia (CNS): Main phagocytic and antigen-presenting cells.
Macrophages (PNS): Main phagocytic and antigen-presenting cells.
What are the cells of the ventricular system (glial cells)?
Ependymal Cells (CNS): Line the ventricular system.
What is the myelin producing cells (glial cells)?
Oligodendrocytes (CNS): Form myelin sheaths around multiple axons.
Schwann Cells (PNS): Form myelin sheaths around individual axons.
What are the functions of astrocytes?
Provide structural support
Regulate ion concentration
Remove wastes
Clear excess neurotransmitters
Form the blood-brain barrier
Participate in synapses
What is the role of the blood-brain barrier (BBB)?
Maintains homeostasis of the microenvironment in the CNS.