Neuroanatomy PDF

Directional terms - Dorsal: back - Ventral: front - Lateral: away from middle - Medial: toward middle - Proximal: near trunk - Distal: away trunk - Ips: same - Contra: crossing - Rostral: front - Caudal: back Anatomical planes - Sagittal: left and right...

Directional terms - Dorsal: back - Ventral: front - Lateral: away from middle - Medial: toward middle - Proximal: near trunk - Distal: away trunk - Ips: same - Contra: crossing - Rostral: front - Caudal: back Anatomical planes - Sagittal: left and right - Frontal or Coronal: Front and Back - Transverse: Top and bottom Neurological system - Cellular structure - Brain and spinal cord - Cranial and spinal nerves Classes of molecules - Carbohydrates: primary source of energy - Sugar - Starch - Nucleic acids - Proteins: building structure - Structural proteins - Globular proteins - Lipids: energy source - Support hormones - Provide insulation Animal cells - Bilipid membrane - Protein-lipid-protein openings +channels - Semi-permeable - Nucleus - Carries DNA - Nucleolus - RNA (blueprint plan) - Cytosol - Inside cells - Liquid soup - Mitochondria - Use oxygen to generate energy - Metabolism of the cell  - Other organelles - Endoplasmic reticulum - Protein production - Golgi apparatus - Transport system - Lysosomes - Takes care of garbage and cleans - Cytoskeleton - is a network of filaments and tubules that extends throughout a cell, through the cytoplasm **nervous cells need more mitochondria because they have no lipids for extra energy Cell function 1. Store energy (mito) 2. Build larger molceuels (endo ret) 3. Move materials out of cells (golgi) 4. Recycle (lysosomes) Neuroglial cells Support and protect nerve cells 40:1 glial to neurons epen : line the ventricle spaces in our brain. Where CSF is produced astro : help with plasticity makeup blood barrier ○ stimulate growth of new synapses ○ make up half of the glial cells Oligo: produce myelin within CNS Micro: scavengers they got to site of lesion and have an immun response, defend CNS Neurons - Nissl substance - Special protein that helps with upkeep - Mitochondria - Producing energy - soma/perikaryon - Body - Dendrites - Receive info from other neurons (afferent directing info toward body) - Axon - Transmits impulse (efferent exiting away from the body) - Axon hillock: beginning of the axon - Telodendria - finger like structures are the branching extensions of a neuron that help transmit signals to other neurons or muscles. - Terminal bouton - Button and wherenuerotransmittewil be released Myelin - CNS: oligodendrocytes - PNS: Schwann cells - Nodes of ranvier - Increased efficiency and speed *the thicker the myelin the faster *increasing temp increases speed Multi sclerosis when the body destroys the myelin Different kinds of neurons Unipolar Neurons: Have a single extension that branches into two parts; commonly found in sensory neurons. (PNS) Bipolar Neurons: Have two extensions (one axon and one dendrite); typically found in sensory organs like the retina. (PNS CNS sensory system) Multipolar Neurons: Have one axon and multiple dendrites; the most common type in the central nervous system, including motor neurons (most common) Psuedounipolar: rare Sensory: outside to inside the body motor : deliver message from CNS out to gland or muscle interneurons : extension cords (usually no myelin Golgi 1 long axons Golgi 2 short axons Neuronal connections - Axodendritic synapse: axon interfacing dendrite - Axosomoatic synapse - Axoanxonic synapse - En passant synapse: loosely connected - Somatsomatic synapse - Dendrodendritic synapse Neural transmission requires us to know about - Electrochemical gradient: positive and negative attract - Concentration gradient: move from high to low - Selective permeability: certain molecules are allowed to pass through channels, opening with energy passive Permeability - Plasma membrane: protein, lipid, protein - Double layer - Selective permeability - Channels and gates - Non gated - Gated  - Insoluble to water - Lets the + and - ions to pass 4 types of gates - voltage : respondes to the action potential (chnage in electric charge) - Ligand: operate based on chemical cues - Thermal: operated by temp - Mechanical: inner ear hair cells Soduim potassium pump Special physiology of nerve cells - Resting potentials: -70mV - Graded (local potentials) - Depolarization: making it more positive (-30mv) - Hyperpolarization: making it more negative less likely to trigger (-90mv) - Action potentials “all or none” → make it more positive - Series of depolarization along the axon Neural transmission - Polarization: loading the gun - Slightly negative at rest - Depolarization: channel firing - Sudden change in polarity triggers the action potential (depolariz along the axon) - Less negative getting ready and firing - Repolarization: reloading - Sodium potassium pump ative process - Going back to resting state Neural operation: - Principle of convergence: a single neuron can receive impulses from multiple other neurons which making it summative (more neurons stronger the response) - Principle of divergence: a single neuron can activate many other neurons and thereby creating limitless pathways this allows for groupin of activities - Degeneration: loss of neurons (stroke tbi) from loss of blood flow - Primary neuronal loss: immmediate loss - Secondary neuronal loss: overtime loss - Regeneration - PNS: regrow new neurons at the site of injury because of trophic facotrs produced by schwann cells - CNS: slower regrowth because we have scar tissue that will impede the regeneration Depolarization: less neg; closer to threshold (inside of cell is less -) Hyperpolarization: more neg further from threshold Refractory: incapable of producing action potential Resting state: slightly negative Neurotrans get produced and put in vesicle Neurotransmission in 5 steps 1. Synthesis of neurotransmitter (in the cell body and some in cytoplasm) 2. Concentration and packing of neurotransmitter into synaptic cleft 3. Release of neurotransmitter into synaptic cleft (certain amount of calcium) 4. Binding to receptor molecules to post-synaptic membrane 5. Termination of action a. Uptake picked up on post syn  b. Clean up c. Diffusion absorbed by othe cells Major neurotransmitters in Brain - ACh: acetylcholine (excitatroy) - Pns and cns - NE: norepinephrine ex and in - Neuromuscular and nueroglandular junctions - Inhib and excit - In brainstem - Deactivated by cont and mao - Neuropeptides: amino acids - Moderates response of neurotransmitter, pain killer - dopamine : inhib substantial nigra (motor activity) - Serotonin: (ihib) excitation in hypothalamus, sleep, temp, and mood - GABA: most common - Inhib - superior , inf colliculli, thalamus, hypothal, occipital lobe - Anti-anxiety meds CNS: brain and spinal cord - Perceive and discriminate sensory stimulus, and express emotions, responsible for repsiration, heartbeat, organizes and regulates behavior, thinking, rmemebring and understanding Organizational principles - Interconnectivitiy - Centrality of decision making (movement of hand) - Hierarchical organziation - More complex requires more complex inter - Higher in the brain - Laterality of brain organzation - Right and left hemi different roles - Left lang and right abstract thinking - Structural and functional specialization (specialized pathways) - Topographical organization - Spacial arrangement - Plasticity - Brain can modify function lessen as we age - Culturally neutral - No differences in brains Meninges (surrounds brain and spinal cord) superior to inferior - Duramater - Tough adheres to skill - Arachnoid  - No blood vessels spider web like - Pia mater - Most fragile, many arteries Why is meningitis so dangerous? Compresses the brain infection to the brain could happen Spinal tap - Extract csf and check for infection at L1 and L2 Subarachnoid hemmorage : ruptured blood vessel Ventricles (interconnected cavities) - Within these we have a structure called the chroid plexus and within this CSD is formed - CSF produced and circulates (replensih 3 times a day) Hydrocephalus - Obstructive (non-communciating): occurs when the flow of CSF is blocked along one or more of narrow passages connecting ventricles - Communicating: impaired absorption - Hypersecretory: producing too much CSF - Normal pressure: pressures are q=equal process of circulating is not happening - Congenital/acquired: born with or get an infection CSF - Regulation of intracranial pressure - Cleanses and nourishes CNS - Shock absorber - Produced in choroid plexus - Reabsorbed through venous system (arachnoid granulations) Surface features of the cerebrum - cortex : higher level-fucntioing sensory, perception, language - Lobes - Fissures (grooves); sulcus - Gyri (bumps) - White matter (axons) - Grey matter (cell bodies) CNS basics - Cerebrum (hemisphere and cortex) - Higher level functions; sensorimotor integration, perception - Basal ganglia - Regulates efferent (motor) system - Impacted in parkinsons - Diencephalon - Thalamus - Sensory - Hypothal - Memory  - Epithal - Melatonin - subthal - Motor planning CNS basics - Cerebellum (little brain) - Coordination - Equilibrium - Brain stem - Midbrain - Pons - Medulla oblongata - Spinal cord - Links with PNS Fiber tracts (axons and interneurons running between CNS and PNS) - Projection fibers - CNS to PNS long distance - Association fibers - Intrahemisphere within same hemi - Comissural fibers - Interhempheric corpus callosum PNS Cranial nerves 1. Olfactory 2. Optic 3. Oculmotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear 9. Glosspharyngeal 10. Vagus 11. Spinal accessory 12. Hypoglossal Designations - efferent=exit the CNS - afferent=towards the CNS - visceral= smooth muscles, glands, heart, trachea - somatic = skeletal muscles, motor General vs Special General - General Spinal column and cord (superior to inferior) - Cervical - Thoracic - Lumbar - Sacrum - Coccyx Spinal cord - 18 inches - Protected by vertebral column - Three meninges: dura mater, arachnoid, pia mater - Cervical: thoracic, lumbar, sacral, coccyeal C3, C4, C5= phrenic nerve (high risk) (paralysis) - Cervical enlargement - Lumbo-sacral enlargement - Nerves for the legs - Intervertebral foramen Spinal nerves - 31 pairs - Dorsal: sensory - Ventral: motor - Central canal: CSF Gross anatomy The brain - Develops from three swellinhs at the anterior end of the neural canal of the embryo - Prosencephalon (forebrain) - Telencephalon - Diencephalon - Mesencephalon (midbrain) - RHombencephalon (hindbrain) - Metencephalon - Myelencephalon The forebrain-Telencephalon - Major landmarks - Cerebral hemispheres - Lobes - Frontal - Parietal - Occipital - Temporal - Insular - Central sulcus (fissure rolando) - Lateral sulcus (sylvian fissure) - parieto -occipital sulcus Sulci increase surface area of the brain The forebrain- hemispheres - Dorsolateral - Convex - Outer surface - Inverted bowl - Mid-saggital - Midline - Smooth - Internal deep structures - Inferior - Underside - Irregular - Anterior, middle, posterior The forebrain lobes - Frontal lobe - Lateral surface= 4 gyri - Precentral gyrus - Superior, middle, inferior frontal gyri  - Medial surface - Medial aspects of the precentral and superior frontal gyri - Inferior surface - Gyrus rectus - Olfactory sulcus - Precentral gyrus= primary motor cortex - Responsible for initiating motor movements (voluntary) - Premotor cortex - Motor planning - Supplemental motor area - Planning and initiating - Prefrontal cortex - Attention, problem solving, executive function - Inferior frontal gyrus - Pars opercularis - Pars triangularis - Pars orbitalis Primary cortex - Primary motor cortex - Initiating motor movements (voluntary) Primary somatosensory (parietal lobe) ○ Receives info from skin and joints - Primary auditory (heschals gyrus) - Receives info from temporal lobes - Primary visual (on medial surface) - Receives info from occipital lobes - Primary olfactory (deeper in the brain) Association cortex (all the connections) - Frontal association cortex (plans) - Parietal assoc cort: take tactical and spacial info - Temporal assoc cort: take aud, language, and memory - Parieto-occitpal assoc cort: visual ingo **agnosia: damage to association cortex Tactical agnosia: cant name things with eyes closed Functional categories of the cortex - Sensory - Primary somatosensory cortex (post-central gyrus) - Primary auditory cortex (temporal lobe) - Primary visual cortex (occiptal lobe) - Motor  - Primary motor cortex (pre-central gyrus) - Pre-motor area (frontal lobe) - Supplementary motor area (frontal lobe) - Association cortex - Unimodel assoc cort - Visual, auditory, somatosensory - Multimodal assoc cort - Parietal assoc cort - Pre-frontal cort The forebrian- parietal - lateral surface - Post central gyrus (primary somatosensory) - Primary motor cortex for sensory info - Superior parietal lobule - Integrate in awareness of sensation - Inferior parietal lobule - Reading, writing, calculating - Spatial attention - Medial surface - Precuneus: memory and expression of emotion - Lower vis field Occiptal lobes - Lateral surface - Secondary visual cortex - Medial surface - Primary visual cortex - Cuneus and lingual gyrus - Resp lower visual field - Resp upper visual field - Divided by calcarine sulcus - Inferior surface - Lingual gyrus (top visual field) - Occipitotemporal gyrus Temporal lobe - Superior (dorsal) surface - Heschl’s gyri: primary auditory cortex - Lateral surface - Superior (wernicke’s), middle, temporal gyri - Inferior surface - Inferior temporal gyrus - Occipitotemporal gyrus Insula - Central lobe  - 3 short and 2 long gyri - Concealed by frontal, parietal and temporal OPERCULA - Gustatory and autonomic control - Maybe pain management and wellbeing Left hemi - Sensory stimulus from right side of body - Motor control of right side of body - Speech, language and comprehension - Analysis and calculations - Time and sequencing - Recognition of words letters and numbers Right hemi - Sensory stimulus from left side of body - Mtoro control of left side of body - Cretivitiy - Spatial ability - context / perception - Recognition of faces, places and objects Lateralization - Hemisphere dominance false - Handedness false - Anatomical differences true Limbic system (emotional regulation) - Meidal surface or two hemispheres - Old or primitive brain - Defined by function not structure - Connections to the hypothalamus - Behavioral reactions to sensory input - Emotions Limbic system consists - Cingulate gyrus - Amygdala (PTSD) - Parahippocampal gyrus - Hippocampus (memory) - In conjunction with hypothalamus Olfacurtory bubs: smells that have memory and emotions Cingulate gyrus (calming area) - Upper part of limbic pobe - Anteriorly related amygdala - Posteriorly related to hippocampus at the Isthmus - Medial surface-non convoluted Amygdala - Flight or fight; memory (ptsd) - Receives info from parahippocampus, olfactory, hypothalamus, thalamic nuclei - Sends info to parahippocampus, thalamus and prefrontal cortex - PTSD Parahippocampal gyrus - Part of limbic system - Connects to cingulate gyrus at the isthmus - Adjacent to hippocampus - Uncus Diencephalon - Thalamus - Everything goes through thalamus except smell**** - Great relay station - Gates and filters info - Focusing on one thing like a conversation at an event - Hypothalamus - Control center for autonomic nervous system - Epithalamus - Subthalamus Basal ganglia - Invovle in motor coordination - Parkingon’s disease this is damaged Thalamatic nuclei important for communication - Lateral genicualte body - Vision (reading, writin) - Medial genicualte body - Audition - Ventral anterior nucleus - Basal ganglia - Initiates voluntary movements - Ventrolateral nucleus - Pulvinar Thalamic pain syndrome - Increased or decreased thresholds ofr sensation of touch, pain, and temp, ants pants - Contralateral to site of lesion - Paranesthesias (crawling ants) - Inapprippriate emotional response Language dsiturbance - Anomia (word finding) - Reading and writing  - Dysarthria Epithalamus (posterior) - function : endocrine (hormones)/limbic system - Parts - Habenular nucleus - Pineal gland: no known neural output where melatonin is subthaalmus (ventral thalamus) - function : contributes to motor function - Regulating motor movements - Visuomotor coordination - Parts - Subthalamic nucleus - Fields of forel - Zona incerta - Connect to basal gang and cerebellum and visual motor Hypothalamus 4F - Function (involuntary) - Controls ANA fight or flight - Homeostatic control - Major parts - Optic chiasm - Mammilary bodes - Pituitary gland - Infundinulum - Fornix - Dmanage cause damage to body temp and sleep cycle Corpus callosum: connects the hemis Internal capsule links diencephalon and cerebrum - cortex : grey matter - All fiber tracts: white matter - Axons running to and from up through brainstem come in the cortex - Gets backed up more likely to effect if the person has a stroke The midbrain: mesencephalon - Most rostral portion of brainstem - External features - Crus cerebri (bundle of axons) - III oculomotor nerve (come off midbrain) - IV trochlear nerve (come off midbrain) - Inferior and superior collcoli (aud movement) sup (vis eye movement and vestibular) - Internal features - Tectum (roof, top of midbrain) - Superior colcillui  - Inferior colliculi - Periaquaductal gray→PAG (starts at tectum, regulates pain) - Tegmentum - PAG - Red nucleus - Crain nerve 3 and 4 nuclei - Reticular formation: regulates level of counciousnness - Basis pedunculi - Substantia nigra - Crus cerebri Functions of the brain stem - Conduit: ascending and descending tracts - House cranial nerve nuclei except CN I and CN II integrative : complex motor patterns, respiration and cardio activity, level of consiocuness - Pathway for ascending descending tracts - Injury with brainstem is very dangerous and life threatening PAG - Fucntions - Regulation of heartrate and bllood pressure - Pain response - Bladder control and contraction - Vocalizations - Fearful response Metencephalon - Pons - Two dvisions - Pontine tengmentum - Basilar pons - Connected to cerebellum (coordination, balance, motor movement) via middle cerebellar peduncle - Origin of trigeminal nerve and abducens nerve