[PHY LEC- LE 1] 05 - Synapse.pdf

PHYSIOLOGY LECTURE | TRANS 5 LE Synapse...

PHYSIOLOGY LECTURE | TRANS 5 LE Synapse CAROLINA C. JEREZ, MD | 08/14/2023 01 OUTLINE I. Synapse V. Neurotransmitters A. Types of Synapse A. Classical Neurotransmitters II. Synaptic Transmission B. Neuromodulators A. Steps in Synaptic VI. Receptors Transmission (Chemical) A. Ionotropic B. How to end a Synaptic B. Metabotropic Transmission VII. Clinical Correlation C. Synaptic Potentials A. Botulism III. Presynaptic Modulation B. Tetanus A. Presynaptic C. Shellfish Poisoning Inhibition/Modulation D. Myasthenia Gravis IV. Neuromuscular Junction E. Lambert-Eaton Syndrome A. How Neuromuscular VIII. Review Questions blocking drugs work IX. References ❗️ Must know 💬 Lecturer 📖 Book 📋 Previous Trans Figure 1. Diagram of an Electrical Synapse [Guyton and Hall 14th Ed, p. 573 (2020)] SUMMARY OF ABBREVIATIONS SNARE Snap Receptors (Soluble N-ethylmaleimide sensitive factor attachment protein 2. CHEMICAL SYNAPSE receptor; (Madrigal et al., 2019); NCBI 2018) There is a distinct distance between presynaptic and postsynaptic EPSP Excitatory Postsynaptic Potential (📖 Berne and Levy, 7th Ed, 2017) neurons IPSP Inhibitory Postsynaptic Potential (📖 Berne and Levy, 7th Ed, 2017) Presynaptic neurons Gamma-aminobutyric acid (📖 Berne and Levy, 7th Ed, 2017) → Have vesicles containing chemical messengers GABA Neuropeptide Y (📖 Berne and Levy, 7th Ed, 2017) → Have Ca++ channels which are needed for the vesicles to be NPY released to the synaptic cleft Melanin-concentrating hormone (📖 Berne and Levy, 7th Ed, 2017) Postsynaptic neurons MCH Proopiomelanocortin (📖 Berne and Levy, 7th Ed, 2017) → Have receptors for the different chemical messengers POMC → These receptors must have the same configuration as the LEARNING OBJECTIVES vesicles ✔ Define synapse Takes a longer time for effective response to occur because of: ✔ Differentiate the types of synapses → Distinct distance between presynaptic and postsynaptic ✔ Differentiate neurotransmission and neuromodulation neurons ✔ Enumerate the different neurotransmitters → The time it takes for the chemical messengers to be released and to bind with the specific receptor sites in the postsynaptic I. SYNAPSE neurons point-to-point manner ( ) 📖 Synapse is a specialized junction where two neurons interact in a It is the junction point from one neuron to the next ( ) 📖 Mode of transmission is Unidirectional → The presynaptic and postsynaptic neurons have different structures since there are specific chemical messengers and It determines the directions that nervous signals will spread receptor sites through the nervous system body ( )📖 Located mostly on the neuronal dendrites, but also on the cell Neurons receive signals through synapses Neurons are able to communicate between each other or with 💬 target organs such as a gland or a muscle and produce secretions and contractions respectively ( ) A. TYPES OF SYNAPSE 1. ELECTRICAL SYNAPSE Have pores that are closed when inactivated and are opened when activated → Once stimulated, they open to allow passage of different ions from the presynaptic neuron to the postsynaptic neuron Distance of 2-4 nm (close proximity) between presynaptic and postsynaptic neurons hence, faster communication Made up of connexons (allow small molecules to pass selectively,