Chapter 10 Nervous System Flashcards
Central Nervous System (CNS)
Containing the brain and spinal cord the main functions are sensory function, integrative function and motor.
Peripheral Nervous System (PNS)
Located outside the CNS and consists of the nerves that connect the CNS with the rest of the body
Sensory Function
Gathering information from inside the body and outside environment where it is then carried to the CNS.
Integrative Function
Interprets sensory information brought to the CNS where the brain makes a plan.
Motor Function
Gathering information from the CNS toward the muscles and glands. They convert the plan to a action. Motor nerves carry out plans made by the CNS.
Nervous System Cells
Neuroglia aka Glial Cells and Neurons.
CSF
Cerebrospinal Fluid
Two common types of glial cells.
Astrocytes and Ependymal cells.
Glial cells functions.
They are the most abundant of nerve cells and are mostly in the CNS. They act as nerve glue but do not conduct impulses. Some participate in phagocytosis (ingestion of bacteria) and help in the secretion of the CSF.
Astrocytes
Star shaped and are the most abundant of glial cells with many functions they support neurons structurally, cover the structure of the brain, and help form a barrier called the blood-brain barrier.
Ependymal Cells
Ependymal cells are inside the cavity of the brain and help in the formation of the CSF.
Neurons
Help in the transmission of electrical signals and help the nervous system act as a communication network. Neurons are also nonmitotic meaning they cant replicate or be replaced.
Three parts of neurons.
Dendrites, Cell Body, and Axon
Dendrites
Treelike structures that receive signals from other neurons and then transmit the signals toward the cell body.
Cell body
Contains the nucleus and is essential for the life of the cell. Receives signal from the dendrites and sends it to the axon.
Axon
- ***
- *Long extensions that transmits signals away from the cell body.**
Structures of the axon.
Myelin Sheath, Neurilemma, and Nodes of Ranvier.
Myelin Sheath
It protects and insulates the axon. Myelination begins of the fourth month of fetal life and continues to the teenage years. Immature axons lack myelination and affect the motor neurons. This is why movement from infants are slow and uncoordinated. Formation of myelin sheath differs in the PNS to the CNS.
Schwann Cells
Schwann cells surround the axon of neurons in PNS and form the myelin sheath. The nuclei and cytoplasm of schwann cells lie out myelin sheath and are called neurilemma.
Oligodendrocytes
A type of glial cell that forms the myelin sheath of neurons only found in the CNS unlike schwann cells in the PNS. Because there is no schwann cells there is no neurilemma.
Nodes of Ranvier
Areas on axons not covered by myelin sheath, they appear in regular intervals.
Tissues of CNS.
There is white and gray matter.