Overview of the Nervous System Flashcards
(41 cards)
What is a neuron?
Excitable cell specialised for rapid signal transmission via action potentials.
Define neuroglia (glial cells).
Non-neuronal cells that provide structural, metabolic, and immune support to neurons.
What is a synapse?
Functional connection between neurons (or between a neuron and an effector cell), where neurotransmitters mediate communication.
Where are action potentials initiated in a neuron?
Axon hillock.
What are nodes of Ranvier?
Gaps in the myelin sheath that facilitate saltatory conduction.
What is the resting membrane potential typically around?
~–70 mV.
Define action potential.
Rapid depolarisation and repolarisation of the neuronal membrane that propagates signals along the axon.
What does the Central Nervous System (CNS) consist of?
Brain + spinal cord.
What is the primary function of the Central Nervous System (CNS)?
Integrating sensory information and coordinating responses.
What is the Peripheral Nervous System (PNS)?
All neural structures outside the CNS.
What are the two subdivisions of the Autonomic Nervous System (ANS)?
- Sympathetic (“fight or flight”)
- Parasympathetic (“rest and digest”)
List the key structural components of a neuron.
- Dendrites
- Cell body (soma)
- Axon
- Axon terminals
What characterizes unipolar neurons?
Single process extending from the soma that branches into two.
Where are bipolar neurons commonly found?
Specialised sensory structures (e.g. retina, olfactory epithelium).
What is the most common type of neuron in the CNS?
Multipolar neurons.
What do sensory (afferent) neurons do?
Transmit sensory input from receptors to CNS.
What is the function of motor (efferent) neurons?
Carry commands from CNS to effectors (muscles/glands).
Where are interneurons located?
Entirely within the CNS.
What is the function of astrocytes?
Maintain blood-brain barrier, regulate extracellular ion balance, provide metabolic support.
What do oligodendrocytes do?
Produce myelin sheaths for CNS axons.
What is the role of microglia?
Act as immune cells; phagocytose debris and pathogens.
What is the function of ependymal cells?
Line ventricles; help circulate cerebrospinal fluid (CSF) via cilia.
What do Schwann cells do?
Form myelin sheath around PNS axons; aid in axon regeneration.
What is the role of satellite cells?
Surround neuron cell bodies in ganglia; regulate microenvironment.
