Central Nervous System Anatomy PDF

**Central nervous system** (**CNS**): the brain and spinal cord. **Peripheral nervous system** (**PNS**): all parts of the nervous system found outside the skull and spinal column. **Nerves**: a collection of axons bundled together outside the central nervous system. **Somatic nervous system:** c...

**Central nervous system** (**CNS**): the brain and spinal cord. **Peripheral nervous system** (**PNS**): all parts of the nervous system found outside the skull and spinal column. **Nerves**: a collection of axons bundled together outside the central nervous system. **Somatic nervous system:** connects brain and major muscles and sensory systems. **Autonomic nervous system:** Nerves that primarily control the viscera (internal organs) **Enteric nervous system:** local network of neurons that governs function of the gut **The cranial nerves:** a set of 12 paired nerves that emerge directly from the brain (including the brainstem) rather than the spinal cord. **The spinal nerves:** Spinal nerves are 31 pairs of nerves that emerge from the spinal cord and connect the spinal cord to the body. **Sympathetic nervous system:** activation prepares the body for action (fight or flight response-\>increased blood pressure, heart rate, pupils dilate). **Parasympathetic nervous system:** activation is often in opposition to sympathetic activity (rest and digest). **Horizontal plane**---divides brain into an upper (dorsal) and lower part (ventral) **Sagittal plane**---divides brain into right and left halves (medial towards midline, lateral away from the midline); midsagittal means directly in the center/middle **Coronal plane**---divides brain into front (anterior) and back (posterior) regions **White matter:** Consists mostly of axons with white myelin sheaths. **Fiber/Tract**---a bundle of axons **Gray matter**: Contains more cell bodies and dendrites, which lack myelin. **Nuclei**---a collection of neurons **Dura mater**--- (Latin "tough mother") tough outermost sheet **Arachnoid**---(Latin "spiderweb-like) substance between the dura mater and pia mater that cushions the brain **Pia mater**--- (Latin "tender mother) delicate innermost layer