Chapter 1 Flashcards
Structures that make up the Central Nervous System
Brain
Spinal Cord
How many neurons does the brain have?
100 Billion
How many neurons does the spinal cord have?
100 Million
Number of cranial nerves
12
Number of spinal nerves
31 pairs
Specialized cells that monitor change in the internal and external enviroment
Sensory Receptors
Small masses of nervous tissue consisting of neuronal cell bodies that are located outside the brain and spinal cord
Ganglia
Extensive network of nerves that are located in the walls of the GI tract that help regulate the digestion system
Enteric Plexus
Name the tasks that the Nervous System carries out
- Smell
- Touch
- Temperature
- Speech
- Memory
- Body movement
- Operation of the internal organs
Three basic functions of the Nervous System
- Sensory Function
- Integrative Function
- Motor Function
Detect internal and external stimuli and carry information into brain and spinal cord via cranial and spinal nerves
Sensory function afferent
The ‘Information Processing’. Consist of Perception and Analyzing/Storing information to help lead to appropriate responses
Integrative Function
Once integration occurs the brain may elicit motor response to muscles or glands (effectors) via cranial and spinal nerves
Motor Function (Efferent)
Two cells that nervous tissue consists of
Neurons and Neuroglia
Provide most of the unique functions of the nervous system
Neurons
Function is to provide support, nourishment, and protection
Neuroglia
The parts of a Neuron
Cell Body
Dendrites
Axon
Axon Terminals
Highly branched structures that carry impulses to the cell body
Dendrites
Conducts away from the cell body toward another neuron, muscle, or gland
Axon
Contain synaptic vesicles that can release neurotransmitters
Axon Terminals
Structure Class:
Have several or many dendrites and one axon
Most common type in brain and spinal
Multipolar
Structure Class:
One Dendrite and one axon
Found in the retina of eye and inner ear
Bipolar
Structure Class:
Fused dendrite and axon
Sensory neurons of spinal nerves
Unipolar
Functional Classes of Neurons
Sensory
Motor
Interneurons
Convey impulses into CNS
Sensory
Convey impulses from brain or spinal cord out through the PNS to effectors (Muscles or Glands)
Motor
Located within the CNS
Transmit impulses between neurons, such as between sensory and motor neurons
Interneurons (association neurons)
Support, nourish, and protect neurons
Critical for homeostasis of interstitial fluid and neurons
Cells smaller but much more numerous than neurons
Make up half the volume of the CNS
Neuroglia
Functions of Neuroglia
- Do NOT generate or conduct nerve impulses
- Support, nourish and protect neurons
- In case of injury or disease, neuroglia can multiply to fill in space formerly occupied by neurons
Neuroglia that forms the blood brain barrier
Astrocytes
Neuroglia that produce myelin in CNS
Oligodendrocytes
Neuroglia that protects CNS cells from disease
Microglia
Neuroglia that forms CSF in ventricles
Ependymal cells
Neuroglia that produce myelin around PNS neurons
Schwann cells