RE CH28 Part 1 Flashcards
What is the peripheral nervous system composed of?
Cranial/spinal nerves and their receptors
What is the central nervous system composed of?
Brain and spinal cord
What are the divisions of the peripheral nervous system?
Somatic and autonomic
What is the somatic nervous system?
Sensory neurons for the control of skin, muscles and joints
What is the autonomic nervous system?
Consists of sympathetic, parasympathetic, and enteric subdivisions which are responsible for involuntary innervation of various organs.
What is gray matter of the CNS composed of? What is white matter composed of?
Gray - neuron cell bodies
White - myelinated axons
What are pseduounipolar neurons?
Neurons with one cytoplasmic process that exits the cell and decides into two branches, one serving as the dendrite, the other as the axon.
Give examples of pseduounipolar neurons
Dorsal root/cranial ganglia - they enable sensory impulses to travel from the dendrite directly to the axon without passing through the cell.
What are multipolar neurons?
Multiple dendritic processes but only one axon, constitute the majority of the CNS
What are the four types of glial cells?
- Astrocytes
- Oligodendrocytes
- Microglial cells
- Ependymal cells
What is the function of astrocytes?
- Provide structural support, group and pair neurons, regulate the metabolic environment, and active in neuronal repair after injury.
- Fibrous astrocytes are found in white matter and protoplasm if astrocytes are found in gray matter
What is the function of oligodendrocytes?
Forms the myelin sheath of axons in the brain and spinal cord. They are capable of myelinating more than one axon.
What forms the myelin sheath in the peripheral nervous system?
Schwann cells - myelinated only one axon
What is the function of microglial cells?
Proliferate and develop into large macrophages that phagocytize neuronal debris
What is the function of ependymal cells?
Line the roof of the 3rd and 4th ventricles of the brain and central spinal canal to form the choroid plexus which secretes CSF
What is the node of Ranvier?
Non-myelinated junctions between Schwann cells and the site of impulse propagation. Impulses in myelinated axons travels from one node to another (saltatory conduction)
Which brain structures lack a blood-brain barrier?
Circumventricular organs: area of poster a, pituitary gland, pineal gland, choroid plexus, and portions of the hypothalamus.
What may cause blood brain barrier disruption?
TBI, subarachnoid or Intracerebral hemorrhage, cerebral ischemia, brain lesions, inntracaroitd injection of hyperosmolar solution (shrinks endothelial cells of BBB).
What are gyri and sulci?
Gyri - elevated convolutions of the cerebral cortex
Sulci - shallow groves of the cerebral cortex
What is the somatosensory cortex?
Located in the postcentral gyrus of the parietal lobe controls the sensations of touch, pain, limb position and the perception of grasped objects.
What is the function of the basal ganglia?
Control of movement
What is the function of the amygdala?
Regulation of emotional behavior, response to pain, appetite, and forming the response to stressors.
What is the function of the hippocampus?
Essential for memory formation and learning.
What is the diencephalon?
Located midline between the two cerebral hemispheres and contains the thalamus and hypothalamus.