Chapter 14, Neural tissue Flashcards
What are the two subdivisions in the nervous system?
Central and Peripheral nervous system
The central nervous system consists of
Brain + Spinal cord + the cluster or nerves called nuclei
The peripheral nervous system consists of
Cranial + spinal + ganglia nerves
What are the three general functions CNS and PNS provide:
Collecting information, Processing and evaluating information, Responding to information
How does CNS collect information?
Receptors detect changes and pass the information to CNS
How does CNS evaluate information?
CNS determines the response that is required
How does CNS respond to information?
CNS initiates the nerve impulses to react to the changes in the body
Sensory Nervous system
Known as the afferent nervous system. This system receives information from the receptors in the PNS and transmits it to the CNS.
Motor Nervous system
Known as the efferent system. Sends impulses from CNS to muscles and glands. Divided into two regions: Somatic motor, Autonomic motor.
Somatic motor
Causes the contraction of skeletal muscles
Autonomic motor
Regulate smooth and cardiac muscle, as well as glands
Two distinct types of cells in the nervous system
Neurons(Electrically excitable cells that initiate, transmit, and receive nerve impulses). Glial cells(Nonexcitable cells that support and protect the neurons)
Neurons
The basic structural unit of the nervous system. High metabolic rate, Extreme longevity, Nonmitotic.
Glial cells in the CNS
Astrocytes, Ependymal cells, microglial cells, Oligodendrocytes
Astrocytes
Helps form the blood-brain-barrier(BBB), Replaces damaged neurons, Assisting neuronal development.
Ependymal cells
Ciliated cuboidal epithelial cells. Lines the ventricles of the brain and the central canal of the spinal cord. Produces cerebral spinal fluid.
Microglial cells
Small cells that are motile, wander through the CNS.
Oligodendrocytes
Only associated with CNS axons. Wraps around axons like electrical tape.
Glial cells of the PNS
Satellite cells, Neurolemmocytes/Schwann cells
Satellite cells
Flattened cells are arranged around neuronal cell bodies in ganglia. Maintains the environment.
Neurolemmocytes
Associated with PNS axons only, produce myelin. Have the same structure and function as Oligodendrocytes.
Myelination
The process of wrapping the axon with a myelin sheath. Serves as insulation.
How do axons regenerate
If the cell body is intact, depends on the extent and site of damage. Neurolemmocytes play an important role in this regeneration
Synapses
Specialized junctions between one axon and another neuron, muscle, or gland.
Electrical Synapses
Used to communicate with muscles, uses as messengers through ions
Chemical Synapses
Used by most of the body to communicate, also used as a messenger through hormones
