BIOL 3401 1st Edition Lecture 6Human Anatomy Overview of the nervous system - Nervous system has 2 major anatomical subdivisions o Central nervous system (CNS) o Peripheral nervous system (PNS) Sensory and motor o Ganglion- swelling where nerve bodies come together - Soma- cell body - Dendrites- receiving signals down to other structures - Myelin sheath- send impulse faster, protective structure Types of Neuroglia - Four types occur in the CNS o Oligodendrocytes- forms myelin sheaths in CNS o Pendymal cells- lines cranial cavity, secretes cerebrospinal fluid (CSF) o Microglia- small, wandering macrophages, helps clean CSF o Astrocytes- have perivascular feet that contact blood capillaries, blood brain barrier - Two types in PNS o Schwann cells- produce myelin sheath similar to the one produced by the oligodendrocyetes in the CNS o Satellite cells- surround the neurosomas in the ganglia of the PNS, provide electrical insulation around soma The brain - 3 major regions of the the brain o Cerebrum is 83% of the brain o Cerebellum contains 50% of the neurons o Brainstem- what remains  Diencephalon Midbrain  Pons Medulla oblongata Cerebrum- Largest - 2 hemispheres separated by a longitudinal fissure - 5 lobes o Frontal- mood, emotion, voluntary motor function o Parietal- interpreting of general senses o Temporal- special senses, emotiono Occipital- visual center o Insula- deep to temporal and frontal, spoken