Sept 18 Lec 2.docx

Sept. 18, Lecture # 2 B64 Anatomical Directions: • You always need a point of reference (we generally use the spinal cord) • 90 degree twist in neuraxis • Proximal = closer to • Distal = far away • Lateral = towards the sides • Medial = towards the middle Planes of Section: • Horizontal/ Transverse: horizontal slices from bottom to top (slicing a hotdog bun) o Round part toward the left and hemis clearly split toward the right • Sagittal: down the nose, vertical slices from side to side (new hotdog buns) o You’re only really seeing one hemi (least amount of brain out of all of them) o Midsagittal cut = down the corpus collosum o Parasagittal cut = more towards a side • Coronal/ Frontal: regular slices of loaf bread, cutting vertical slices from front to back o You can see the round part of the brain at the top and the 2 hemis at the bottom + corpus in the middle clearly Protecting and Supplying the Nervous System: • Meninges: 3 layers, protects brain (also exist in the spinal cord!) *PNS has all these membranes except arachnoid membrane!* o Dura matter = just under the bone of skull, fairly thick, quite hard o Arachnoid membrane = more spongey, fibre-like arachnoid terabulae  Subarachnoid space = full of CSF, blood vessels course through o Pia matter = follows all the convolutions (all the gyri and sulci) of brain, not tough and rigid, similar to seram wrap, very thin delicate layer, closest to the cortex • Cerebrospinal fluid: secreted in ventricles (hollow spaces). Circulates through ventricles, subarachnoid space, and central canal of spinal cord o 2 very large lateral ventricles in each hemi rd o 3 ventricle o 4 ventricle o Ventricles all connect with cerebral canal and are filled with CSF o Avg. of 120 ml of CSF in our brain and it’s constantly being changed over o CSF produced in choroid plexus (a black, gummy structure) • Blood supply: brain receives nutrients through carotid and vertebral arteries o Brain can’t store its own glucose or energy, so it gets it from blood o 3 main cerebral arteries = anterior, middle, posterior o 3 mins of blood supply cut off = damage Organization of the Nervous System: Central • See slide for this!! • USE SUMMARY TABLES IN TEXTBOOK • Maybe go back and watch videos • Brain (“cephalon” = brain) o Hindbrain (damage often causes death bc controls vital fxns). Also called brainstem.  Includes reticular formation = sleep, arousal, temp reg, motor control  Metencephalon (pons and cerebellum)  Myelencephalon (medulla = reg of breathing, heart rate) o Midbrain (Mesencephalon)  Fairly small region of the brain  Know only 2 parts: • Colliculi o Superior = visual processing o Inferior = auditory processing o Forebrain  Telencephalon • Neocortex = o Lissencephalic = no convulutions i.e. rat o Gyrencephalic = has gyri, convultions i.e. human brain o 6 layers of cerebral cortex (outermost = 1 = closest to pia)  I: not many cells  II: most cells start here, few cell bodies, but we see axons, synaptic connections here  III: pyramidal cells, but smaller,  IV:  V: larger cells, pyramidal cells (motor activity)  VI: mixture of cell shapes, sizes, types (polymorphic in terms of the cells that exist here) • Basal ganglia = located deep within hemis. Disease of basal ganglia include Parkinson’s (progressive deterioration of dopamine-containing neurons in substantia nigra. Slow in initiating movement, jittery, tremors, rigid movement) and Huntington’s (progressive destruction of mainly the caudate and putamen)Composed of: o Globus pallidus o Putamen o Substantia nigria • Limbic System (overlap in other parts of brain) o Hippocampus: declarative memory o Amygdala: fear, aggression, memory o Hypothalamus: aggression, reg of hunger, thirst, sex, temp, circadian rhythms, hormones o Anterior Cingulate Cortex: decision making, error detection, reward, pain, empathy o Posterior Cingulate