Lecture 5 (Nervous system, Neuron, Neuroglia, AP) Flashcards
What is the main function of the Nervous System?
Transmit messages in our body by linking sensory receptors that detect stimuli and motor effectors that respond to those stimuli.
What are the 2 parts of the nervous system?
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
What are the 2 parts of the Central Nervous System (CNS) ?
- The Brain
- The Spinal Cord
What are the 2 parts of the Peripheral Nervous System (PNS)?
- Sensory pathway
- Motor pathway
What are the 2 subdivisions of the Motor pathway? What do they do?
- Somatic Nervous System (SNS) : Stimulates skeletal muscles
- Autonomic Nervous System (ANS): Stimulates smooth and cardiac muscle, and glands)
What are the 2 subdivisions of the Autonomic Nervous System?
- Sympathethic nervous system
- Parasympathetic nervous system
What are the 2 types of cells of the nervous system?
1) Neurons
2) Neuroglia
What are the 3 types of neurons according to their function?
- Sensory Neurons (afferent neurons)
- Motor Neurons (efferent neurons)
- Interneurons (association neurons)
What is the function of sensory neurons (afferent neurons)?
Sensory neurons carry impulses to the Central nervous system.
What is the function of the motor neurons (efferent neurons)?
Motor neurons carry impulses from CNS to effectors (muscles and glands)
What is the function of interneurons (association neurons)?
Interneurons provide more complex reflexes and associative functions (learning and memory)
What are the 3 types of neurons according to their structure? How do they differ form each other?
- Multipolar (multiple extensions)
- Bipolar (two extensions)
- Unipolar (one extension)
Explain the basic structure of a neuron
- Cell body : enlarged part containing nucleus and other organelles
- Dendrites: short, cytoplasmic extensions that receive stimuli
- Axon: single, long extension that conducts impulses away from the cell body
How many neurons are there in the human brain?
100 billion neurons
What is the main function of schwann cells?
Schwann cells are cells that support neurons.
Where are myelin sheaths found?
Surrounding axons
What is the main function of astrocytes?
- Support neurons
- Remove waste
- Help maintain environment
- Help form blood brain barrier
What is the main function of microglia?
- White blood cells of the brain
- Clear away infection or dead cells
- Protect brain from disease
What are the 3 types of neuroglia?
- Astrocytes
- Microglia
- Schwann cells
What is the main function of neurons?
Neurons can initiate and conduct signals called nerve impulses
How can you describe a nerve impulse?
As a wave of electrical fluctuation that travels along the plasma membrane (action potentials)
What are the 4 functional regions of the neuron?
- Input zone
- Summation zone
- Conduction zone
- Output zone
What is located in the input zone? What does it do?
The dendrites and body cell (soma) are located in the input zone.
It receives input from other neurons or from sensory stimuli.
What is located in the summation zone? What does it do?
The axon hillock is located in the summation zone.
Serves as the site where the nerve impulses combine and possibly trigger an impulse that will be conducted along the conduction zone (axon)
Give the definition of an action potential?
Impulse or electrical signal that propagates (moves) along the surface of the membrane of a neuron.
What are the 2 major functions of action potentials?
1) Method for rapid information transmission over relatively long distances in neurons
2) Control neural activity by causing release of chemical transmitter at synaptic junction.
What are the 2 required factors to generate action potential?
- Existence of a resting membrane potential
- Presence of specific types ion channels
