Presentation on theme: "Nervous Tissue and Brain"— Presentation transcript:
1 Nervous Tissue and Brain Ch. 10 Nervous system:Nervous Tissue and Brain
2 Function of Relays messages (motor) Monitors changes in body systems (sensory)Responds to stimuli (sensory)Maintain homeostasis (sensory)Integrative – information is brought to CNS info is put together
3 Central Nervous system Includes brain and spinal cordControl center, coordinate body activities
4 Peripheral Nervous sys. Nerves that carry messages to and from the central nervous system
5 Cells of the Nervous System Neuroganglia – glial cells, nerve glueSupports, protect and nourish the neurons
6 2. Neurons Parts of : Cell body Dendrites – receive impulse Axon – carries impulse awayMyelin sheath- white fatty materialSchwann cells (pns)Neurilemma (outdside the sheath)Nodes of Ranvier
7 Types of NeuronsSensory neurons (afferent) – carries impulse to brain and spinal cord.
8 Types of NeuronsMotor neurons (efferent) – away from brain and spinal cord.
9 Types of NeuronsInterneurons or association neurons – relay impulses from sensory to motor neurons.
10 White matter vs Gray Matter White because of myelinGray matterCell bodies, interneurons, nonmyelinated fibersNuclei – clusters of cells in CNSGanglia – cell cluster in PNS
11 The Nerve Impulse Action potential – steps in the nerve impulse 3 stages of : polarization, depolarization, repolarization
12 Step 1: Polarization Resting state of a neuron Sodium/possium pump – sodium ions out of cells and potassium ions into cells
13 Polarization continued Inside of the cell is – chargedOutside of cell is + chargedDue to sodium-potassium pump2 K+ ions go in as 3 Ca++ go out
14 Step 2: Depolarization Due to stimulation Inside of the neuron becomes + charged.Na+ rushes into the cell
25 Protection Bone Meninges – 3 layers of connective tissue Cerebrospinal fluid –Blood brain barrier – cells associated with blood vessels that supply the brain with blood.
26 Aging BrainEnlargement of the ventricular system: the volume of the ventriclesWidening of sulci (the grooves) on the surface of the brain.Reduced brain weight and brain volume: loss of neurons.Neurological disorders: Alzheimer's disease, Parkinson's disease and stroke are more common in the elderly.