Chapter 56: Nervous System Flashcards
Brain, spinal cord, cranial nerves I and II
Central nervous system.
Cranial nerves III to XII, spinal nerves, autonomic nervous system
Peripheral nervous system
Primary functional unit of the NS. Characterized by: excitability (ability to generate a nerve impulse), conductivity (ability to transmit an impulse), and influence (ability to influence other neurons, muscle cells, or glandular cells by transmitting nerve impulses to them).
Consist of: cell body, dendrites, and an axon
Neurons
Provide support, nourishment and protection to neurons; more numerous than neurons. Divided into two types.
Glial cells
Specialized macrophages capable of phagocytosis. Protect the neuron. Mobile within the brain and multiply when the brain is damaged
Macroglia
Most abundant type of microglial cell. Found primarily in the gray matter and provide structural support to neurons. Delicate processes form the blood-brain barrier with the endothelium of the blood vessels. When the brain is injured, they act as phagocytes for neuronal debris.
Astrocytes
Specialized cells that produce the myelin sheath of the nerve fibers in the CNS and are primarily found in the white matter of the CNS (Schwann cell myelinated the nerve fibers in the periphery). Type of microglial cell.
Oligodendrocytes
Line the brain ventricles and aid in the secretion of cerebrospinal fluid. Type of microglial cell
Ependymal cells
Nerve regeneration
If the axon of the nerve cell is damaged, the cell attempts to repair itself. Damaged nerve cells attempt to grow back to their original destinations by sprouting many branches from the damaged ends of their axons. Axons in the CNS are generally less successful than peripheral axons in their regeneration. Injured nerve fibers in the PNS can regenerate by growing within the protective myelin sheath of the supporting Schwann cells if the cell body is still intact.
Chemicals that affect the transmission of impulses across the synaptic cleft
Neurotransmitters
A decrease in the neurons that secrete this neurotransmitter is seen in Alzheimer’s disease. Myasthenia gravis results from a reduction in the receptors for the NT. Activates muscles.
Acetylcholine
Produced in several areas of the brain. Involved in emotions and moods and regulating motor control. Parkinson’s disease results from destruction of the neurons that secrete this NT.
Dopamine
Composed of right and left hemispheres and is divided into four lobes: frontal, temporal, occipital, parietal, and occipital. Functions are multiple and complex.
Cerebrum
A group of structures located centrally in the cerebrum and midbrain. Initiation, execution, and completion of voluntary movements, learning, emotional response, and automatic movements associated with skeletal muscle activity (e.g. swinging the arms while walking, swallowing saliva, and blinking)
Basal ganglia
Lies directly above the brainstem and is the major relay center for afferent inputs to the cerebral cortex
Thalamus
Located just inferior to the thalamus and slightly in front of the midbrain. It regulates the ANS and the endocrine system.
Hypothalamus
Located near the inner surfaces of the cerebral hemispheres and is concerned with emotion,a aggression, feeding behavior, and sexual response.
Limbic system
Includes the midbrain, pons, and medulla.
Brainstem
Coordinates voluntary movement and maintains trunk stability and equilibrium
Cerebellum