INTRO TO THE NERVOUS SYSTEM Exercises 16 and 20 Nervous System Anatomy CNS Function CSF Flow Agenda Prelab Intro to the Nervous System CNS PNS Cell Types The Brain Brain Stem Diencephalon Cerebellum Cerebrum CSF Flow Preceptor Presentation Practicals Nervous System Organization Central Nervous System Brain and Spinal Cord and all the nuclei and tracts therein Peripheral Nervous System Ganglia and nerves outside of the CNS Other Nervous System Subdivisions Enteric Nervous System Neural plexi that help to regulate the GI Tract Works in concert with CNS CAN work completely independent of the CNS Autonomic Nervous System Parasympathetic rest and digest Sympathetic fight or flight Somatosensory Nervous System Sensory and motor neurons CNS Brain PNS Cranial nerves Spinal cord Spinal nerves Ganglia Nervous System Organiza4on Enteric plexi in small intestine Sensory receptors in skin a Cell Types Two Overarching Cell Types in the Nervous System Neurons Cells that send and receive action potentials that allow for integration of messages Neuroglia support cells for the neurons Essential to protection and possibly play role in disease Each type can be further divided into more specific types Neurons Three Subtypes of Neurons Unipolar One central neurite that exends that length of the neuron A dendritic tree at one end then an axon terminal at the other Cell body isnt between the two Uncommon in humans but present in the cerebellum and cochlear nuclei Bipolar Two main extensions Common in interneurons and special sensory neurons retina Multipolar Common type of neuron Single axon many dendrites that arise from soma Receive information from many different places Neurons Myelin Myelinated or Unmyelinated Myelin is a fatty tissue that surrounds some axons Oligodendrocytes or Schwann cells Insulate the axons Increases conduction velocity Further propagation of the A P Multiple Sclerosis Nodes of Ranvier Gaps in the myelin sheath Action potentials are recharged at these nodes High density of v gated Na channels Afferent vs Efferent Afferent Neuron Running from the periphery to the CNS Sensory Neurons Take info from periphery to the brain for integration Unipolar Efferent Neuron Running from the CNS to the periphery Motor Neurons also autonomic neurons Take info from the brain and cause an action in the periphery Multipolar S A M E Neurons Sensory Interneuron Motor Neuroglia Glial Cells Maintain the surrounding environment Form myelin Provide and maintain support 6 Types CNS Neuroglia Astrocytes Oligodendrocytes Microglia Ependymal Cells PNS Schwann Cells Satellite Cells Neuroglia Astrocytes Maintain the cellular environment keeps neurons in place and forms the blood brain barrier Oligodendrocytes Processes from the cell form the myelin sheath around axons Microglia Engulf invading microbes debris necrotic tissue Ependymal Cells Line the walls of the 4th ventricle chorid plexus and central canal Form circulate CSF Schwann Cells Entire cell forms the myelin sheath of PNS neurons Satellite Cells Corvers the sensory neuron cell bodies maintain environement Cells of pia mater CNS Protoplasmic astrocyte Oligodendrocyte Microglial cell Myelin sheath Neuron Oligodendrocyte Fibrous astrocytes Protoplasmic astrocyte Microglial cell Neurons Ependymal cell Ventricle PNS Node of Ranvier Schwann cell Myelin sheath Axon Schwann cell Unmyelinated axons Schwann cell Nucleus Cytoplasm Neurolemma PNS Myelin sheath Myelinated axon TE M 5000x Transverse section of myelinated axon BRAIN STRUCTURE AND FUNCTION Rostral vs Caudal New directional terms Rostral situated toward the front tip of the brain frontal lobe Caudal at or near the tail or posterior of body In humans it means toward the feet The Brain Complex Structure within the central nervous system Four Principle Regions Brain Stem Diencephalon Cerebellum Cerebrum Highly organized Distinct areas and structures with very specific functions NOTE Brain talks with different areas in order to integrate many different stimuli One area typically doesn t control everything but could be essential to that function sufficiency vs necessity Plasticity Brainstem Three Regions of the Brainstem Medulla Oblongata Houses nuclei and ganglia responsible for control of basal functions Heart Rate Blood Pressure Respiration Reflexes Parasympathetic nerves Pons Houses mainly respiratory control centers Breathing Rate and Depth of Breathing Midbrains Two man Sections Inferior Colliculi Part of Auditory system Controls startle reflex pitch and frequency processing spatial localization of sound Superior Colliculi Integrates visual cortex Help to activate eye movements Following and orienting visual stimuli The Brainstem Midbrain Superior colliculi Inferior colliculi Pons respiratory center Medulla respiratory cardiovascular reflex Cerebellum Means little brain Two hemispheres connected by the vermis Cerebellar Cortex Superficial grey matter Arbor Vitae Deep white matter Folia Cerebellar folds Controls Motor function and muscle control balance The Cerebellum Cerebellum Posture Balance Coordination Cerebellum Diencephalon Three Main Regions Thalamus Hypothalamus Epithalamus Thalamus This is the relay station per se in the brain Communicates motor and sensory information from cortical areas to lower areas as well to from the spinal cord Acts as a Filter Helps control Consciousness Emotions Learning Memory Intermediate Mass Connects 2 thalami Hypothalamus Controls autonomic processes of the body Metabolism hormone release body temperature feeding behavior thirst emotions ect Mammillary body Smell Taste reflexes Optic Chiasm Area where optic nerves come through cross Pituitary Gland Releases hormones when signaled to by the hypothalamus Infundibulum Connects pituitary to the hypothalamus Hypothalamus Epithalamus Pineal Gland The pineal gland is an endocrine gland in the brain Secretes melatonin Helps to modulate circadian rhythm Internal Clock The Diencephalon Epithalamus Thalamus Thalamus relay station filter Hypothalamus homeostasis Hormones emotions Pituitary gland Epithalamus endocrine Pineal gland Hypothalamus Cerebrum Two hemispheres Connected by the Corpus Collosum Divided into Lobes Frontal Temporal Parietal Occipital 3 Main Regions Cerebral Cortex White Matter Basal Ganglia Nuclei Seat of Intelligence White vs Grey Matter White Matter Comprised of myelinated axons Myelin being a fatty substance is the reason these axons appear white Grey Matter Unmyelinated axons White and Grey