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.
What is the function of the thalamus?
Intergrated and transmits sensory information to various cortical areas of the cerebral hemispheres via separate thalamic nuclei
What is the hypothalamus?
The master neurohormonal organ.
Which structures make up the brainstem?
Midbrain, pons, and medulla.
What is the recticular activating system (RAS)
Located in the brainstem and functions to maintain consciousness, arousal, and alter news.
What is contained in the medulla?
Ascending and descending fiber tracts, respiratory and cardiovascular control centers, and nuclei to CN VII, IX, X, and XI
What are the three functional areas of the cerebellum?
- Flocculonodular lobe (archeocerebellum) - maintenance of equilibrium
- Paleocerebellum (anterior lobe and part of vermis) - regulates muscle tone
- Neocerebellum (posterior lobe and most of vermis) - coordinating voluntary muscle activity
What are the three meningeal layers?
Dura mater, arachnoid mater, and Pia mater.
Describe the dura mater
Thickest outermost layer of the meningeal layers
What folds does the dura mater form?
Falx cerebri - functionally separates cerebral hemisphere
The teorium cerebelli - separates the occipital lobe and cerebellum.
Describe the arachnoid mater
Thin avascular membrane joining the dura mater. The subdural space is located between the dura and arachnoid mater.
Describe the Pia mater
Thin avascular membrane adherent to the brain and spinal cord. The subarachnoid space is between arachnoid and Pia mater.
What levels does the subarachnoid space extend to in the spinal cord?
S2 to S3
Describe the epidural space
Located outside the dura but inside the spinal canal. Contains a venous plexus and fat that provides protection from the neural structures.