Look at table of terms in book on pg 88 Methodology Major divisions of nervous system are the CNS brain and spinal cord and the PNS peripheral nervous system consists of the somatic and autonomic nervous system Somatic nervous system deals with sensory to motor kinds of information Autonomic nervous system is further broken down into the sympathetic and parasympathetic nervous systems Spinal cord communicates with the senses organs and muscles below the head On each side one has a sensory and a motor neuron The sensory neuron brings information to the spinal cord and is on the dorsal side of the cord The exiting ventral neuron carries motor information out of the cord Sensory information dorsal side motor information ventral side The dorsal root ganglia are where the cell bodies of the spinal cord are located this is outside the cord The motor neuron cell bodies are located inside the cord The H shape on the spinal cord consists of cell bodies dendrite the white surrounding it is myelin If the spinal cord is cut it cuts off all motor information to the area below the cut The autonomic nervous system is responsible for such things like the fight or flight response The brain has 3 major divisions The hindbrain is one Hindbrain consists of the medulla pons and the cerebellum Medulla is located just above the spinal cord and controls vital functions such as breathing damage to this area is typically fatal There are 12 pairs of cranial nerves some have a sensory and a motor component some don t The pons is the anterior and ventral to the medulla This is where a lot of crossing over of information occurs from the right side to the left and vice versa The medulla and pons also contain the reticular formation and the raphe formation The cerebellum is important for motor movements and is involved in fairly complex cognitive abilities like shifting attention it s also why you can t tickle yourself The midbrain is another division The midbrain in humans is not that a big of a deal it s more involved in birds reptiles and amphibians In the midbrain one sees the tectum which is the roof of the midbrain The superior and inferior colliculi are like swellings on either side of the tectum and are important routes for sensory information Superior is for vision and the inferior for auditory The tegmentum contains the third and fourth cranial nerves and part of the reticular formation Also the substantia nigra in the midbrain is important because it s an area rich in dopamine containing neurons and the area that is destroyed in Parkinson s disease Substantia nigra helps an individual s readiness in movement so in Parkinson s individuals have trouble initiating movements The largest of the three divisions is the forebrain The outer portion of the forebrain is the cerebral cortex The limbic system is in the forebrain The limbic system is a system in the brain it s in general important for emotional behaviors emotional center One of the structures is the thalamus center of the forebrain The thalamus is one s main source of sensory input to the cortex all senses except olfaction sense of smell go through the thalamus Olfactory information goes directly to cortex Ventral to thalamus is the hypothalamus Hypothalamus is a number of distinct nuclei that control stuff like drinking temperature regulation sex etc hypothalamus also involved in immune response The pituitary gland connects to the hypothalamus The basal ganglia are important for movement speech complex behaviors of all kind emotional expression learning behavior etc Basal ganglia have three separate components caudate and putamen receive sensory information from thalamus and globus pallidus which sends sensory information into the cortex The basal forebrain is also part of the limbic system contains the nucleus basalis important for attention and arousal The hippocampus is also part of the limbic system important for learning and memory and other things The back part of the brain is served by the vertebral arteries The front part is served by the carotid arteries The brain and spinal cord are covered by meninges a tough connective tissue that has three layers Outermost layer is the dura mater which is pretty tough and somewhat tough The middle layer is the arachnoid membrane which is pretty soft and spongy The innermost layer is the pia mater which is incredibly closely attached to the brain spinal cord Between the arachnoid membrane and the pia mater is the sub arachnoid space The sub arachnoid space is filled with cerebral spinal fluid CSF Human brain weighs about 3 lbs Brain tissue is very delicate but the skull and the cerebral spinal fluid do a good job protecting it Brain consists of several ventricles that also contain CSF Lateral ventricles are the largest chambers and are contained in each hemisphere The third ventricle is towards the back There s also the fourth ventricle which is further behind the third From the fourth ventricle through the central canal to the spinal cord travels the rest of the CSF There are special cells in the ventricles that produce the CSF These cells are choroid plexus cells The half life of the CSF is about 3 hours so there is continual production and reabsorption of the CSF Every now and then the production and release of CSF is interfered with like a blockage which leads to hydrocephaly This increases pressure on the brain because it accumulates within the ventricles or the subarachnoid space When it occurs in infants the skull bones spread causing an overgrown head Hydrocephalus is usually associated with mental retardation Cerebral cortex is 80 of the brain volume Consists of left and right hemisphere and covers all of the other forebrain structures It s convoluted because it s got grooves called sulci it s also got bumps called gyri Each hemisphere is designed to receive sensory information from and send motor information to the contralateral side of the body right to left left to right The cortex is primarily gray matter on the outside the myelinated axons are internal The two hemispheres communicate all the time one way to communicate is the corpus callosum a bundle of nerves between the two hemispheres The anterior commisure and hippocampus commisure is another way