BIOL 562 Exam 1 Study Guide
BIOL 562 Exam 1 Study Guide BIOL 562
Popular in Neural Systems
Popular in Biology
verified elite notetaker
One Day of Notes
verified elite notetaker
verified elite notetaker
verified elite notetaker
One Day of Notes
verified elite notetaker
verified elite notetaker
This 13 page Study Guide was uploaded by Kathryn Chaffee on Tuesday February 2, 2016. The Study Guide belongs to BIOL 562 at Purdue University taught by Dr. Sahley in Spring 2016. Since its upload, it has received 44 views. For similar materials see Neural Systems in Biology at Purdue University.
Reviews for BIOL 562 Exam 1 Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/02/16
Neuroanatomy Exam Review Bio 562 1. Focus on general themes summarized in the 4 neuroanatomy lectures. 2. Know the major parts of the CNS. 3. Define the basic nomenclature used to describe the major anatomical features of the CNS 4. Recognize in the gross brain specimen the major surface landmarks that distinguish the major divisions of the brain and spinal cord. 5. Describe the vasculature of the brain and spinal cord and the general anatomical and functional territory supplied by each major artery . Review the types of hematomas. 6. Describe the anatomy and functions of the ventricular system and the dynamics of cerebrospinal fluid flow from formation to absorption. Review the meninges of the brain. 7. Describe the blood-brain barrier, including its anatomical basis, physiological role, and clinical significance 8. Be able to define common neuroanatomical terms (i.e. peduncle, nucleus etc.) 9. Review the cell types of the nervous system sand their general functions 10. From images of the gross brain you should be able to identify the major parts. (similar to the kinds of things you saw in the lab). 11. You should know general function associated with the major brain structures 12. Review the study notes that correspond to the specific topics covered in the PowerPoint slides. 13. Know the general functions associated with the prefrontal cortex. 14. Know the basic anatom y of the cerebellum. 15. Use the PowerPoint slides as your general guide as to what to review. Visual animals have a lot of visual brain area (visual cortex). Tactile animals have a lot of sensory brain area (sensory cortex). The cortical cytoarchitecture is not the same over the entire brain . There are 3 types of cortex (neocortex, hippocampus, and olfactory cortex) – not all are 6 layered. The majority of the human brain is association cortex. Association cortex is related to higher intellectual function. Most of the human cortex is made up of association areas that integrate information from t he primary areas. Brodmann divided the cerebral cortex into 52 different areas based solely on cytoarchitectural criteria. The 52 areas are defined by anatomical criteria (cell size, shape…). Motor output arises primarily from layer 5 of the cortex. The primary motor area (Area 4 of Brodmann) is much thicker than adjacent areas. Primary motor cortex – Area 4 Layer 4 of the cortex receives input from sensory areas. Thus, layer 4 is the thickes t in Brodmann areas devoted to sensory function. Mammals have similar brain parts but differ in complexity. The degree of folding increases in the following way: rat < rabbit < cat < sheep < chimp < human < dolphin. Folding the human brain into gyri and sulci increases the cortical surface area. Human have large brains proportional to their body size, but not all brains are proportional to body size. Central Nervous System Peripheral Nervous System Brain Cranial nerves and ganglia Spinal cord Spinal nerves and dorsal root ganglia Sympathetic and parasympathetic nerves and ganglia Enteric nervous system The brain starts out as a tube that gives rise to the entire CNS. The brain is encased in a protective compartment. The brain is nestled into bony compartments that help protect it. The lobes of the brain are defined by anatomical landmarks on the surface. Motor and sensory pathways travel in parallel. Cerebral hemispheres: Gray matter is on the outside Brainstem: Gray and white matter is mixed throughout Spinal cord: Gray matter is on the inside The distribution of gray and white matter varies depending on location. Nissl stains gray matter. Myelin stains are used to label the white matter tracts black. The stripes in the internal capsule are called striatum. There are changes in gray matter volume along the spinal axis. In the cervical and lumbar regions, the volume of gray matter is larger because these areas are where the limbs are located. Nucleus: a group of functionally related nerve cell bodies in the CNS Column 1) In the cerebral cortex, a group of nerve cell bodies that are related in function and in the location of the stimulus that drives them and that form a column oriented perpendicular to the plane of the cortex 2) In the spinal cord, a group of functionally related nerve cell bodies that form a longitudinal column extending through part or all of the length of the spinal cord 3) Also refers to bundl es of axons Clarke’s column: dorsal columns in the spinal cord Layer/lamina/stratum: a group of functionally related cells that form a layer oriented parallel to the plane of the larger neural structure that includes it Tract: a bundle of parallel axons in the CNS Lemniscus: tract that looks like a ribbon Peduncle: a group of several parallel tracts or fasciculi Ganglion: a group of nerve cell bodies located in a peripheral nerve or root; it forms a visible knot/ group of sensory neurons Nerve: a peripheral structure consisting of parallel axons plus associated cells The sensory nerve fibers enter the spinal cord in the dorsal roots. Motor axons leave the cord via the ventral roots. Schwann cells in the PNS myelinate axons. Nerve: bundles of axons Neuroscientists use several imaging techniques to assess brain structure and function: 1) Angiography 2) MRI 3) 3D Reconstructions 4) CT 5) fMRI 6) Diffusion tensor tractography Golgi: reticular view Cajal: Neuron view There are drawings of the nervous system by Ramon y Cajal. They came up with “The Neuron Doctrine.” Note the arrows indicating flow of information through the nervous system. Cajal was incredibly accurate in his drawings despite having only a crude microscope to view the Golgi stained tissue. The Human Connectome Project is a project to construct a map of the complete structural and functional connections in vivo within and across individuals. Processes = axons +dendrites Types of Neurons: • Multipolar – irregularly shaped cell body with more than 2 cell processes (with 1 the axon and the other dendrites); Ex: motor and interneurons • Bipolar – with 1 dendrite & axon • Pseudounipolar – single process close to the cell body divides into 2 branches; 1 branch extends to the CNS and the other to a peripheral ending • Unipolar neurons – true unipolar neurons are rare in vertebrates; found in embryonic tissue Neuron Classification - *Classified as efferent (motor) and afferent (sensory) • Motor neurons – control effector organs (i.e. muscle fibers, glands) [both visceral and somatic] • Sensory neurons – receive stimuli (touch, pain, thermal) from the body wall (somatic) or from organs (visceral) • Interneurons – form links between neurons; typically involved in modulation – often chemically defined Myelin increases conductance velocity. Oligodendrocytes are the cells in the CNS that myelinate axons. Schwann cells are the cells in the PNS that myelinate axons. Cell Body (perikaryon, soma) • Spherical, large, pale staining, centrally located nucleus with pro minent nucleolus • Highly developed RER (“Nissl bodies or Nissl substance) • Abundant neurofilaments & microtubules • Nissl stains elucidate cell bodies Axons • Conduct information away from cell body • Axoplasm contains abundant microtubules and neurofilaments • Transport of metabolites in the axon may be orthograde (away from cell body to nerve endings) or retrograde (nerve ending to cell body) • Retrograde flow can carry viruses and toxins along the axon into the CNS Molecular motors in the axon are used to trans port molecules toward the cell body (retrograde) and toward the axon terminal (anterograde). Axons can have synaptic terminals anywhere along the axon. Dendritic spines increase the surface area for synaptic contacts. Synapses are contact of one axon wi th the dendrites (axodendritic), perikaryon (axosomatic), or another axon (axoaxonic). Neuroglia (the “other” brain) • Function in mechanical & metabolic support of neurons • CNS - Astrocytes: contact neuronal cell bodies, dendrites, and axons and form a comple te lining around the external surfaces of the CNS and around CNS blood vessels; can engulf up to 100K synapses - Oligodendrocytes: myelinating in CNS (100:1) - Microglia: non-neural origin – enter brain early • PNS - Schwann cells: myelinating, non -myelinating, an d terminal forms in PNS Function of glial cells: • Neuronal precursor cells during development and in adult • Control extracellular environment – transporters of ions, neurotransmitters, solutes • Quantal release of transmitter – signaling function? • Myelination = impulse conduction, learning • Respond to pathological stimuli – cytokine production • Contributes to the blood-brain barrier • Scaffolding for migration and placement of the developing neurons • Scavenge extracellular potassium ions • Astrocyte neurotransmitter uptake • Participate in tripartite synapses - affect neuronal excitability • Growth factor production for neuronal deafferentation and survival • Axon guidance • Microglial activation in brain injury • Regeneration (CNS vs PNS) • Sleep? • Closes “critical periods” of development • Communicate among themselves (calcium waves) • Senses neural activity • Controls information flow through synapses • Chronic pain – release substances that excite neural pathways • Maintains homeostasis among neurons • Related to plasticity • Rhythmicity – regulating circadian clock in Drosophila • Vasomotor control of hippocampal vasculature • Synaptic connections (with cerebellar climbing fibers) Radial glia provide a scaffold for migrating neurons during development. Blood-Brain Barrier= endothelial tight cell junctions Astrocytic end feet may “contribute” to the blood -brain barrier. There are various ways that clinicians use to get drugs across the blood brain barrier: • Hyperosmotic solution • Microcatheterization • Microbubbles • Trojan Horses Anatomical Visualization Techniques • Golgi staining • Dye injection via intracellular recording electrodes • Immunocytochemistry • Nissl stains • Gray and white matter stains • Tract tracing (HRP, lipophilic dyes ect.) HRP tract tracing : Retrograde labelling using HRP. HRP is injected into a part of the brain and is retrogradely transported back to the cell body. The tissue is processed to create an electron - dense labelling product one can visualize with a microscope. Thus, only the cells that have projected axons into the injection site are labelled with HRP. Intracellular dye injection: Following an intracellular recording session, HRP is injected into the cell through the recording electrode. This allows the anatomical visualization of the speci fic neuron from which the recordings were made. Anterograde tracing techniques : Radioactive amino acids are injected into the retina and are transported trans-synaptically to the primary visual cortex. The tissue is processed using autoradiography and sh ows the alternating ocular dominance columns indicating the projections from the right and left eyes. The brain begins as a tube that bends and whose walls expand to form the major neural regions. The neuropore is the fluid filled core of the tube that gives rise to the ventricular system. The choroid plexus produces CSF which cushions and protects the brain. CSF circulates from the ventricular system into the subarachnoid space. CSF is “recycled” back into the venous system. Hydrocephalus: Blockage of CSF produces enlarged ventricular spaces that may enlarge the developing skull. Treatment involves shunting CSF into the abdominal cavity. Meninges • Protect brain and spinal cord • Support for vessels • Contains CSF • Suspend brain – reduce weight • Contain venous sinuses for drainage of cerebral blood • Source of tumors and headache Meninges = dura mater, arachnoid mater, pia mater The dura contain the venous sinuses that drain the cerebral veins – eventually into the internal jugular vein The layers of dura spli t to form the superior sagittal sinus, one of the major veins draining the brain Meningioma: tumors shift major brain structures Infectious Meningitis • Common features include headache, lethargy, photophobia, fever, nuchal rigidity • May be bacterial or vir al (no specific treatment) • LP to confirm diagnosis Blood supply to the brain – 2 anatomical systems Anterior system of arteries = Internal carotid system • Ophthalmic artery • Anterior cerebral artery • Middle cerebral artery Posterior system of arteries = Vertebral system • Basilar artery • Cerebellar aa • Posterior cerebral artery Cerebral arteries communicated through circle of Willis. The 3 major cerebral arteries: 1. Anterior cerebral 2. Middle cerebral 3. Posterior cerebral Causes of vascular compromise: • Aneurysm • Ischemic area (plaque in artery) • Arteriovenous malformation Herniation of the brain: the brain squeezes into areas that it normally doesn’t reside and crushes adjacent structures leading to functional loss or death When space occupying lesions (blood, tumors) causes the brain to shift (herniates), it often crushes adjacent structures. Spinal cord anatomy (general themes) 1. White matter tracts are on the outside, gray matter on the inside 2. Dorsal horns are sensory, ventral horns are motor in function 3. Dorsal columns carry touch and proprioceptive information 4. Lateral funiculus carries descending motor commands from the cortex 5. Ventrolateral funiculus carries pain and thermal information to higher centers 6. Medial funiculus is associated with posture and balance 7. Ends at L1-2 in adults 8. Composed of 10 lamina (layers) based on cell types and connections The spinal cord is made up of 5 different levels that connect to 31 pairs of spinal nerves. • Cervical cord • Thoracic cord • Lumbar cord • Sacral cord Major connections of the spinal cord: the cerebellum and basal ganglia indirectly influence the spinal cord through higher motor centers Dorsal root – sensory Ventral root – motor Cauda equina = nerve roots below the end of the cord; “the horses tail” The spinal cord contains major ascending (sensory) and descending (motor) tracts. Somatotopy is the point-for-point correspondence of an area of the body to a specific point on the central nervous system. The cervical spinal cord is large and transitions into the medulla. Levels of spinal cord: • Cervicomedullary junction • Cervical cord • Thoracic cord • Lumbar cord • Sacral cord Corticospinal tract: controls movement of contralateral limbs Vestibulospinal tracts: controls positioning of head and neck/balance via longitudinal back muscles The inner ear influences position and balance via descending tracts to the spinal cord. Posterior column-medial lemniscal pathway: vibration, proprioception, fine touch • Crosses in the caudal medulla Anterolateral pathway: pain, temperature, crude touch • Crosses in the cervical spinal cord Brainstem • Cranial nerve nuclei and related structures • Long tracts - Lesions produce sensory and motor deficits • Cerebellar circuits - Lesions produce ataxia • Reticular formation and related structures - Lesions produce impaired consciousness and autonomic loss Brainstem = medulla, pons, midbrain The medulla is thought to give you primordial feelings of the body. The nuclei in the brainstem have a stereotypic o rganization. General functions of the medulla: • Contains long sensory and motor tracts • Contains cranial nerve nuclei related to; – Respiratory and cardiovascular function, gut motility – Vestibular function (eye movements, equilibrium and posture) – Tongue movements – Sensory inputs from the head – Sensory inputs related to taste • Cerebellar inputs • Reticular formation – autonomic control • Raphe nuclei – 5HT (serotonin) inputs to spinal cord for pain modulation • Lesions are often fatal (cardio/resp failure) Raphe nuclei: highest source of serotonin in the brain Cochlear = hearing Semicircular canals = balance, eye movements Lesions of semicircular canals/cochlear lead to ▯ vertigo, tinnitus, dizziness, deafness Parallel pathways contain both sensory and motor i nformation. The motor (descending) and sensory (ascending) pathways run parallel to each other throughout the brainstem. A cross section through the caudal medulla. This is the closed part of the brainstem that shows a number of transitions from spinal cord to medulla. Note the large black areas which are tracts (bundles of axons) and the gray areas which are mostly neurons (nuclei). This is the open part of the medulla in the vicinity of the olive. The core gray matter areas at this level is referred to as the reticular formation. Note the cranial nerves associated with this section. Functions of the reticular formation in the brainstem: • Mesencephalic reticular formation - Alertness, attention, levels of consciousness • Pontine reticular form ation - Conjugate gaze, respiratory & heart rhythm , blood pressure • Medullary reticular formation - Cardiovascular and respiratory control, pain modulation The core nuclei of the brainstem are referred to as the reticular formation. They make up the so- called reptilian brain. Function of the pons: • Sensory input from face (V) • Controls chewing muscles (V) • Muscles of facial expression (VII) • Hearing and balance pathways (VIII) • Movement control (via cerebellum) • Long sensory and motor tracts Functions of the cerebellum: • Planning and control of precise dextrous movements of the extremities • Timing of muscle activation and duration of contraction • Motor learning of novel movements • Influence of extensor mm. for posture and balance The cerebellum is 3-layered cortex. Vermis = spinocerebellum • Coordinates movements • Muscle tone • Posture/Balance • Precision of movement • Motor planning Hemisphere of cerebellum = motor learning Cerebellar lesions = ataxia = uncoordinated movements Examples of the functional deficits in patients with cerebellar disease: • Past pointing = “intention” tremor • Dysdiadockinesia • Fetal alcohol syndrome Functions of the midbrain: • Eye movements = CN III and IV • Levels of consciousness = RF • Pain modulation = PAG • Motor control = substantia nigra • Long motor tracts = cerebral peduncles • Long sensory tracts Functions of the diencephalon: • Synaptic relay for motor and sensory systems (thalamus) • Hormonal and autonomic control (hypothalamus) • Limbic control (learning and memory) • Auditory and visual relays • Circadian rhythms (pineal) Thalamus and hypothalamus make up the majority of the diencephalon. Medial Hypothalamic Nuclei: • Regulating hormone release • Circadian rhythms • Body temperature • Heat loss/production • Feeding • Cardiovascular function • Food and water intake • Control ANS Functions of the telencephalon: • Frontal lobe = motor, cognition, memory • Temporal lobe = language, hearing, limbic • Occipital lobe = visual • Parietal lobe = association, spatial, sensory Basal ganglia: lesions produ ce hypokinetic disorders (Parkinson’s) or hyperkinetic disorders (Huntington’s) depending on location Initiation of movement depends on basal ganglia. Gerstmann’s Syndrome: • Agraphia • Acalculia • Right-left disorientation • Finger agnosia • Lesion of dominant inferior parietal lobule (angular gyrus) • May also involve visual field deficits General functions of the prefrontal cortex: • Working memory • Forming predictions about the future • Personality • Learning new material • Selective attention and arousal levels • Decision making • Planning 3 Domains of Frontal Lobe Function: • Restraint – inhibition of inappropriate behaviors • Initiative – motivation to pursue production activities • Order – correctly performing sequence of tasks
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'