Neuroanatomy Lecture Notes - PDF

Neuroanatomy -​ CNS vs PNS -​ Central nervous system (CNS) -​ Comprised of Brain and Spinal cord -​ Interpret sensory information and issue commands based on experience -​ Peripheral nervous system (PNS) -​ Cranial and spinal nerves...

Neuroanatomy -​ CNS vs PNS -​ Central nervous system (CNS) -​ Comprised of Brain and Spinal cord -​ Interpret sensory information and issue commands based on experience -​ Peripheral nervous system (PNS) -​ Cranial and spinal nerves -​ Includes sensory neurons that link receptors on the body surface with processing from the CNS -​ Division of the PNS -​ Somatic (control of body movements) -​ Autonomic (involuntary function of internal organs) -​ -​ Cranial Nerves (PNS) -​ Twelve pairs of nerves at the base -​ Olfactory and optic are CNS -​ 10 axons of PNS -​ Single nerve = multiple functions -​ Used for identification of neurological disorders -​ Cranial nerves have nuclei associated with midbrain, pons, and medulla -​ Covering of the brain (Meninges) -​ CNS encased in bone does not make direct contact -​ Brain covered by a three-layered membrane called meninges -​ Dura mater, arachnoid membrane, and pia matter -​ Dura mater -​ Outermost covering (tough like leather) -​ Arachnoid membrane  -​ Under the dura mater -​ Spider web consistency (hence arachnoid) -​ No space between dura and arachnoid (subdural hematoma: blood pools between dura and brain) -​ Pia mater -​ Thin membrane near surface -​ Many blood vessels -​ Sub area has CSF -​ Brainstem (Midbrain) -​ Serves as a transport center for information coming from spinal cord and forebrain (ascending and descending tracts meet here) -​ Red nucleus: associated with motor control -​ Periaqueductal gray: somatic pain sensation -​ Superior colliculus: direct input from the eye; control eye movement -​ Inferior colliculus: sensory input from the ear (auditory information to thalamus); sound localization -​ Core of the midbrain is the cerebral aqueduct -​ Connects the third and fourth ventricle -​ Brainstem (Medulla) -​ Process sensory information, control voluntary movement, and regulate autonomic system -​ Medullary pyramids: bundle of axons descending to the spinal cord -​ Very bottom of medulla -​ Name for shape -​ Contain corticospinal tracts; voluntary movement -​ Nuclear clusters: associated with hearing -​ Dorsal and ventral cochlear nuclei and superior olive -​ Inferior olive: role in motor control -​ Raphe nucleus: modulation of pain, mood, and wakefulness -​ Medulla (Spinal Cord) -​ Fourth ventricle disappears; beginning of the spinal cord -​ Dorsal column nuclei: somatic sensory information -​ Axons from dorsal column cross to the other side (decussate) to the thalamus -​ Spinal cord -​ Situated within vertebral column -​ Neck - cervical​ -​ C1-C7 -​ Ribs - thoracic -​ T1-T2 -​ Lower back - lumbar  -​ L1-L5 -​ Perlvic - sacral -​ S1-S5 -​ Major conduit of information from skin, joints, muscles -​ Transection of the spinal cord -​ Anesthesia, lack of feeling, in skin -​ Paralysis of muscles caudal to cut -​ Muscles cannot be controlled by the brain -​ Spinal nerves communicate with the cord -​ Somatic PNS -​ Spinal nerves adopt the names of vertebrae -​ 8 cervical nerves for 7 cervical vertebrae -​ Spinal cord ends at L3 -​ Does not grow after birth; column does -​ Cauda equina: Bundle of nerves down the lumbar and sacral column -​ Ventral-Lateral Surface -​ Organization of spinal nerves attached to the spinal cord (with meninges) -​ Nerves split into two roots at the vertebral notch -​ Dorsal root carries axon within the dorsal root ganglia -​ Ventral root carries motor axons from the ventral gray matter -​ Butterfly shape core is gray matter while the outside is white matter -​ Outside is highly myelinated -​ Gray matter is divided into 3 groups -​ Dorsal, lateral and ventral horns -​ White matter is divided into 3 columns -​ Dorsal, lateral, and ventral columns -​ Cross-sectional anatomy -​ Ascending and descending -​ -​ Major ascending sensory pathways  -​ Dorsal column consists of sensory axons to the brain -​ Conscious appreciation of touch -​ Spinothalamic tract -​ Painful stimuli and temp -​ -​ Descending tracts for control of movement -​ Names and tracts describes their origins and terminations -​ Dorsal column consists of sensory axons to the brain -​ Conscious appreciation of touch -​ Two descending tracts: -​ Lateral: Controls muscle tone and antigravity -​ Ventromedial: Maintain orientation in space and equilibrium -​ Autonomic PNS -​ Regulation of internal organs, glands, and vasculature -​ Regulation occurs automatically -​ ANS divisions: -​ Sympathetic: Stimulate fight or flight response -​ Parasympathetic: Stimulate rest-and-digest or feed and breed -​ Sympathetic ANS -​ Sympathetic Ganglia form a chain -​ Begins at the thoracic to lumbar -​ Thoracolumbar outflow -​ Runs along the vertebral column -​ Spinal nerves emerging from the column -​ Chemical signaling - Acetylcholine -​ Nicotinic receptor and norepinephrine -​ Parasympathetic ANS -​ Nerves arise from the CNS -​ Craniosacral outflow -​ Cranial nerves - preganglionic parasympathetic nerves -​ Trigeminal branches -​ Ophthalmic nerve, maxillary nerve, mandibular nerve -​ Vagus nerve -​ Paired but normally referred to as singular -​ Supplies motor fibers to all organs from the neck down to the colon -​ Heart rate, sweating, and muscle movements -​ Pelvic splanchnic -​ Innervation to hindgut -​ Regulates bladder, sphincter, and sexual function -​ Parasympathetic ANS signaling -​ Nicotinic receptors are channels while Muscarinic are G-Proteins -​ Main end-receptor stimulated from postganglionic fibers -​ Enteric Nervous System (ENS) -​ Division of the ANS -​ Located in the lining of the esophagus, stomach, intestines, pancreas, and gallbladder -​ Controls processes associated with transport and digestion of food -​ 500 million neurons -​ Makes use of 30 different neurotransmitters -​ 90% of serotonin and 50% of domaine -​