Ch. 7 The Nervous System: Neurons and Synapses Flashcards
What is included in the Central Nervous System (CNS)
Brain and spinal cord
What is special about the CNS?
It is encased in the spine and skull
What is included in the Peripheral Nervous System (PNS)
Cranial and spinal nerves
Define Neurons
Conduct impulses but generally cannot divide
–but can repair if severed
Define Glial Cells (neuroglia)
Support the neurons and cannot conduct impulses, but can divide
–work together
Neurons
Respond to chemical and physical stimuli
–pain, pressure, heat…
Conduct electrochemical impulses (action potential)
Release chemical regulators (at synapse)
Neurons enable perception of?
- Sensory stimuli
- Learning
- Memory
- Control of muscles (voluntary and involuntary) and glands
Can neurons divide? Can neurons repair?
Most neurons cannot divide, but can repair
What is included in the structure of a neuron?
Cell body
Dendrites
Axons
Neuron Structure: Cell Body
Contains the nucleus and other organelles; cluster in groups
Clustered groups of cell bodies in the CNS are called ____.
Nuclei
Clustered groups of cell bodies in the PNS are called ____.
Ganglia
Neuron Structure: Dendrites
Receive impulses and conducts a graded impulse toward the cell body
Shorter projections than axon; project off cell body
Neuron Structure: Axon
Conducts action potentials away from the cell body
Axon is a long projection (can be up to 1 meter long)
Neuron Structure: Axon Hillock
Area where axon meets cell body; action potentials generate here then propagate out
What is Axonal Transport?
An active process needed to move organelles and proteins from the cell body to axon terminals
Require energy (b/c it’s an active process)
Axonal Transport: Fast
Component moves vesicles (neurotransmitters)
In vesicles, so it’s exocytosis bulk transport
Axonal Transport: Slow
Components move microfilaments, microtubules, and proteins
aka Cytoskeleton
Axonal Transport: Anterograde Transport
From cell body to dendrites and axon
Cell body –> away
Axonal Transport: Retrograde Transport
From dendrites and axons to cell body
The functional classification of neurons is based on?
The direction impulses are conducted
Sensory Neurons
Conduct impulses from sensory receptors to CNS
Motor Neurons
Conduct impulses from CNS to target organs (muscles or glands)
2 branches:
Somatic motor neurons
Autonomic motor neurons
Somatic Motor Neurons
Responsible for reflexes (which are involuntary) and voluntary control of skeletal muscles