Nervous system Flashcards
Which systems play the most important roles in maintaining homeostasis?
The nervous and endocrine systems
What is neurology?
The branch of medical science that deals with the normal functioning and disorders of the nervous system.
What are the 3 basic functions of the nervous system?
- detecting stimuli (sensory function);
- analyzing, integrating, and storing sensory information (integrative function);
- responding to integrative decisions (motor function).
What does the central nervous system include?
The brain and spinal cord.
What does the peripheral nervous system include?
Cranial and spinal nerves.
Which two divisions of the PNS are there?
- Afferent (brings sensory information to CNS)
- Efferent (carries motor commands from CNS to muscles/glands/etc
Which two subdivisions of the motor (efferent) PNS are there?
Somatic (voluntary control over skeletal muscles)
Autonomic (involuntary control over cardiac + smooth muscles, glands)
What two types of cells does nervous tissue consist of?
Neurons and neuroglia
What are neurons?
Cells specialized for nerve impulse conduction and provide most of the unique functions of the nervous system, such as sensing, thinking, remembering, controlling muscle activity.
What are neuroglia?
They support, nourish, and protect the neurons and maintain homeostasis in the interstitial fluid that bathes neurons.
What three parts do most neurons consist of?
Dendrites (main input region)
Cell body (integration occurs)
Axon (main output, usually one per neuron)
Which three classifications of neurons are there?
Multipolar, bipolar and unipolar.
What are the functional classifications of neurons?
- Sensory (~10^6): carry sensory information to CNS
- Motor (~500k): carry information from CNS to effectors
- Interneurons(~2*10^10) Located within CNS between sensory and motor neurons
What is the function of neuroglia?
They support, nurture, and protect neurons and maintain the interstitial fluid that bathes them. (~50% of CNS volume)
What do neuroglia include in the two nervous systems?
In CNS: strocytes, oligodendrocytes, microglia and ependymal cells.
In PNS: Schwann cells and satellite cells.
Which two types of neuroglia produce myelin sheaths?
Oligodendrocytes and Schwann cells.
What is the function of astrocytes?
- Control the chemical environment of the brain
- Brace neurons and form barrier against capillaries
- Abundant, star-shaped cells
What is the function of microglia?
- Spiderlike phagocytes
- Dispose of debris
What is the function of ependymal cells?
- Line cavities of the brain and spinal cord
- Cilia assist with circulation of cerebrospinal fluid
What is the function of oligodendrocytes?
- Wrap around nerve fibers in the central nervous system
- Produce myelin sheaths
What is the function of satellite cells?
Protect neuron cell bodies
What is the function of Schwann cells?
Form myelin sheath in the PNS
How do neurons communicate?
By means of nerve action potentials, or nerve impulses.
How are action potentials generated?
The existence of a membrane potential and the presence of coltage-gated channels for NA+ and K+.
