Biopsychology Notes 8 28 9 2 9 4 Structural Functional Organization of the Nervous System Neuraxis imaginary line use to orient the labeling of the nervous system In humans the neuraxis makes a 90 degree turn from brain to spinal cord These words can be used to identify location of neurons and pathways Medial a part of the brain or a pathway that is more towards the center neuraxis Lateral a part of the brain or a pathway that is more towards the outside away from the neuraxis Dorsal any position that is toward the top back plane relative to the horizontal neuraxis think of dolphin s dorsal fin remember back top of brain Ventral abdominal surface chest area bottom of the brain points towards chin bottom of brain Anterior or Rostral towards the front front of the brain nose mouth upper part of chest points towards face in brain Posterior or Caudal towards back side the tail or back of head back of brain To remember position of neuraxis in humans take your hand make a fist and put thumb on side of index finger and label anterior posterior dorsal ventral and then bend wrist keeping in mind the orientation Frontal Plane separates the front of the brain frontal lobe from the back of the head Sagittal Plane blade or orientation from the front of the head to the back of the head right half vs left half Mid Sagittal separates the two hemispheres directly in between them Horizontal Plane oriented horizontally to the ground separates top of the brain dorsal from the bottom ventral Cross Section Cross Plane refers to cutting through any kind of tubular formation spinal cord a nerve etc Contralateral a structure or control that crosses the neuraxis example right hemisphere has primary motor cortex but the firing of the motor cortex produces movement in the left side of the body Ipsilateral a structure or control that stays on the same side of the neuraxis example olfactory bulbs in each nostril project axons and neurons to the same side of the brain The nervous system is broken up into the central nervous system brain spinal cord and the peripheral nervous system everything else Peripheral Nervous System controls most of the body somatic and autonomic nervous system Somatic nervous system part of the nervous system that is under your voluntary control controls all of the skeletal muscles tongue hands feet movements you can initiate Autonomic nervous system autonomous outside of your primary control operates on its own to control your respiratory system heart rate digestion and all internal organs you can do things to indirectly change these things but your body will make you breathe etc again eventually Sympathetic nervous systems Parasympathetic nervous systems A Afferent and Efferent Neuronal Pathways Afferent label for neuron nerve or pathway that has sensory function input transfers information from organs and body periphery further into the nervous system and eventually into the central nervous system feeling pain sensation etc remember Affect Affect is Emotion Emotion is a Sensation Afferent is a sensory pathway Efferent label for neuron nerve or pathway that has motor output carries information from CNS to periphery body movement heart rate digestion etc remember the word Exit This information is exiting the brain and going to the rest of the body B Cranial and Spinal Nerves bundle of neurons make up nerves Information makes it in and out of the CNS through cranial or spinal nerves Cranial these exit out of the ventral surface of the brain and not through the spinal cord as most nerves do We have 12 cranial nerves 11 that stay in the head and brain Olfactory nerve transmits smell input others that transmit information on sight taste throat and mouth position etc The Vagus Nerve one of the cranial nerves exiting the ventral surface of the brain that leaves the head and neck region important function of autonomic control and regulation All sensory outputs of organs transmit information to the Vagus Nerve and then it takes information back to CNS Spinal 31 pairs of spinal nerves they exit out in between the vertebrae on right and left Cervical nerves 8 pairs control arms hands movement Thoracic nerves 12 pairs that primarily control movement trunk region lower back and mid range Lumbar nerves 5 pairs that control sensory input and motor output to legs Sacral nerves 5 pairs in hip region that control genital organs reproductive organs and bladder C Autonomic Nervous Systems Sympathetic nervous systems the part of the autonomic nervous system that is often said to regulate the fight or flight response the arousal part of the autonomic nervous systems increased heart rate sweating nervousness adrenaline respiration increases eyes dilate cotton mouth digestive system slows down endorphins release and reduce potential pain o Sympathetic ganglion groups signals and sends them out during sympathetic activation o Epinephrine Adrenaline Parasympathetic nervous systems opposes the behaviors of the sympathetic nervous system the rest and digest part of the autonomic nervous system o Parasympathetic activation constricts pupils stimulates salvation constricts airways slows heartbeat and stimulates the digestive system Not a light switch between the sympathetic and parasympathetic nervous systems a see saw between the two They can both be activated at the same time just to opposing degrees Central Nervous System encased in bone skull and vertebrae includes the brain and spinal cord has meninges and cerebrospinal fluid unlike anywhere else in the body Meninges group of connective tissue only found in the CNS protects and buffers the brain and spinal cord from any damage that could result from typical everyday movements Dura mater tough outer membrane the outer most layer of protection very tough and not flexible thickest layer unstrechable once it develops Arachnoid membrane web like softer than dura mater and kind of spongy within the web like sub arachnoid space flows the cerebrospinal fluid acts like an additional layer of buffering or a shock absorber to reduce the amount of pressure that would be placed on the brain tissue Pia mater adheres to CNS surface adheres directly to the brain and spinal cord so that the meninges stay in place thinnest layer and very pliable contours exactly to fill every space of brain tissues think of it like plastic wrap purpose is to attach the other two layers to the brain and spinal cord Cerebrospinal fluid CSF in the arachnoid space cerebral ventricles and