...milligrams. A synapse is a space between two neurons in which neurotransmitters are released from the presynaptic neurons to exert an effect on the subsequent postsynaptic neuron.An action potential is generated in the pre-synaptic neuron by generating the influx of Na+ through the sodium channels and an efflux of the K+ ions via the Potassium channels.The action potential at the presynaptic terminal, triggers the influx of calcium into the terminal axon. The influx of calcium plays a functional role in the release of neurotransmitters from the presynaptic vesicles into the synaptic cleft. The experiment performed by Katz and Ricardo Melidi showed that presynaptic terminals that are treated with tetrodotoxin( binds sodium) are still capable of generating prolonged action potentials. The current was flowing through calcium channels instead of sodium. Another experiment by rodolfo llinas indicated presence of voltage gated calcium channels in presynaptic terminals. The experiment was carried out by using giant squid axon, confirmed the presence of voltage gated calcium channels in the presynaptic cell.Neurotransmitter releases right after calcium enters the specific voltage-dependent calcium channels,which basically means that calcium channels are involved in neurotransmission. Therefore, presynaptic action potentials results in influx of calcium (Katz and Miledi,1960). In a presynaptic neuron, Small sacs that are referred to as...
Words: 848 - Pages: 4
...stain, but the rest of the body's organs did not. This demonstrated that there was some kind of compartmentalization between the bloodstream and the cerebrospinal fluid. Although, it had not yet been observed. It was the neurophysiologist Lina Stern who came up with the concept of the blood-brain barrier in 1921. She had been puzzled by the fact that medicines and serums injected into the body did not reach the brain, and came to the conclusion that there must be a special filter to protect the organ; she called it the "hematoencephalic barrier." WHAT IS BLOOD BRAIN BARRIER? A semipermeable membrane seperating the blood from the cerebrospinal fluid, and constituting a barrier to the passage of cells , particles and large molecules. It is a protective network of blood vessels and cells that filters blood flowing to the brain. Blood Brain Barrier is a membrane that controls the passage of substances from the blood into the central nervous system.It is a physical barrier between the local blood vessels and most part of the central nervous system itself, and stops many substances from travelling across it. ANATOMY OF BLOOD-BRAIN BARRIER The BBB is semi-permeable; that is, it allows some materials to cross, but prevents others from crossing. In most parts of the body, the smallest blood vessels, called capillaries, are lined with...
Words: 2054 - Pages: 9
...dinosaur, as if she would do if she had encountered a smaller animal, her body simply ran for cover. For her body to react this way, there are many steps her body must go thru, starting with her eyes. There are certain neuronal pathways that transmit action potentials generated by light from the time light enters her eye until it reaches the area of the cerebrum where vision is perceived. After light passes through the lens, light going to her brain to hit the visual sensory receptor cells- photoreceptors at the proximal end to cause any sort of visual stimulus. Then photoreceptor neurons in the retina collect the light and send signals to a network of neurons that then generate electrical impulses that go to the brain through the optic nerve. The optic nerves leave her eye through the optic foramen to enter the cranial cavity and connect each other at the optic chiasm. At the optic chiasm, ganglion cell axons from the nasal retina cross and project to the opposite sides of her brain. Ganglion cell axons from the temporal retina pass through the optic nerves and project to her brain on the same side of her body without crossing. On its way to the occipital lobe, most of the optic tract axons terminate in the lateral geniculate nucleus of the thalamus, but some axons do not terminate in the thalamus but separate from the optic tract to...
Words: 926 - Pages: 4
...4 Neural Conduction and Synaptic Transmission How Neurons Send and Receive Signals 4.1 4.2 4.3 ISBN 0-558-78571-9 Resting Membrane Potential Generation and Conduction of Postsynaptic Potentials Integration of Postsynaptic Potentials and Generation of Action Potentials Conduction of Action Potentials 4.5 4.6 4.7 Synaptic Transmission: Chemical Transmission of Signals among Neurons Neurotransmitters Pharmacology of Synaptic Transmission and Behavior 4.4 Biopsychology, Eighth Edition, by John P.J. Pinel. Published by Allyn & Bacon. Copyright © 2011 by Pearson Education, Inc. 76 Chapter 4 ■ Neural Conduction and Synaptic Transmission hapter 3 introduced you to the anatomy of neurons. This chapter introduces you to their function—how neurons conduct and transmit electrochemical signals through your nervous system. It begins with a description of how signals are generated in resting neurons; then, it follows the signals as they are conducted through neurons and transmitted across synapses to other neurons. It concludes with a discussion of how drugs are used to study the relation between synaptic transmission and behavior. “The Lizard,” a case study of a patient with Parkinson’s disease, Roberto Garcia d’Orta, will help you appreciate why a knowledge of neural conduction and synaptic transmission is an integral part of biopsychology. C The Lizard, a Case of Parkinson’s Disease “I have become a lizard,” he began. “A great lizard frozen in a dark...
Words: 14184 - Pages: 57
...By the third day of development, the human egg or zygote it is now a small mass called the blastocyst. By 1-2 weeks the blastocyst’s inner cell mass separates into three layers. The Mesoderm is responsible for developing muscles, bones, blood, circulatory system, teeth, connective tissues and kidneys. The endoderm is responsible for the internal organs such as the stomach and intestine. And the ectoderm is responsible for things such as our skin, hair, sweat glands, salivary glands, brain, spinal cord, and PNS. By week 2 of development the ectoderm will also start to thicken and fold in on itself to form the neural groove and by 2-8 weeks it will come together and form the neural tube. The interior of the neural tube will become the five ventricles, the central canal of the spinal cord. The anterior part of the neural groove will become the forebrain, the midbrain and the hindbrain. The inner surface of the neural tube is lined with cells that will produce neurons through the process called neurogenesis. These cells in the neural tube divide and become the ventricular zone. As the nervous system grows the cells move to fill out the brain through cell migration. These cells go through cell differentiation which allows them to take the characteristics of the neurons that exist in that particular region. Once they do this they are able to make synaptic connection with other neurons in that region through synaptogenesis. Neurons fight for synaptic sites and a chemical the target site...
Words: 1361 - Pages: 6
...external environment and to co-ordinate the activities of different organs. Organisms need to respond to external stimuli, e.g. temperature, oxygen concentration and levels of sunlight. These may be over time, e.g. winter fur to summer fur, or quickly, e.g. changing size of pupils. Internal environments change too- the build up of carbon dioxide as a result of respiration changes the pH of the tissue fluid, and therefore inhibits enzyme activity. Multicellular organisms need to coordinate different organs, so this requires a good communication system which will: • Cover the whole body • Enable cells to communicate with each other • Enable specific communication • Enable rapid communication • Enable both short and long-term responses. State that cells need to communicate with each other by a process called cell signalling. State that neuronal and hormonal systems are examples of cell signalling. Define the terms negative feedback, positive feedback and homeostasis. Negative feedback- A process in which any change in a parameter brings about the reversal of that change so that the parameter is kept fairly constant. Positive feedback- A process in which any change in a parameter brings about an increase in that change Homeostasis- The maintenance of a constant internal environment despite external changes Explain the principles of homeostasis in terms of receptors, effectors and negative feedback. Any change is detected by receptors, the communication system transmits...
Words: 8191 - Pages: 33
...A connection between two neurons is referred to as a synapse. A connection between a neuron and a muscle whether it be skeletal, cardiac, or smooth is referred to as a neuromuscular junction. This is a special junction between an axon terminal and a muscle fiber however there is no direct contact between the axon and the muscle. The synapses between spinal motor neurons and skeletal muscle cells occur at specializations called end plates. The synaptic cleft is very narrow being roughly 50-100nm in width (Squire, 2008). All over the synaptic cleft are Figure 1: Outline of Neuromuscular Junction→displays the motor end plate which is the differentiated version of membrane of muscle fiber which has a number of junctional folds to increase its surface area numerous acetylcholine receptors which will utilize the chemical messenger released from the synaptic vesicle to open ion channels. The neurotransmitter released at the neuromuscular junction is acetylcholine which binds with the nicotinic cholinergic receptor at the post synaptic membrane. To completely understand the binding of the acetylcholine with the ACh receptors, the synaptic cleft can be viewed in terms of the “saturated disk” model (Adams, 2015). This model suggest the cleft be divided into subsections of where the acetylcholine travels to upon release from the synaptic vesicle. The diameter of the vesicle itself is labeled as the initial center of the numerous circles. This area is where the acetylcholine is initially...
Words: 1708 - Pages: 7
...Nervous System (CNS) -Brain -Spinal Cord 2. Peripheral Nervous System (PNS): Nerves a. Sensory (afferent) -somatic (general) -special senses -visceral b. Motor (efferent) -Somatic/Voluntary nervous system -Autonomic Nervous System (ANS) (1) Sympathetic Division (2) Parasympathetic Division II. Histology of Nervous Tissues A. Neurons (Mod 11.2) 1. Special Characteristics: -Excitable - large, complex cells with elongate extensions -extreme longevity, amitotic, high metabolism 2. Structures: 3 major parts: cell body, dendrites, axon -Cell Body (soma) -Nissl bodies (rough ER) stain easily….gray matter -neurofibrils for support -found in CNS in Nuclei, in PNS in Ganglia -Neuronal Processes -Dendrites (incoming signal) -single or multiple -short and branched -Axon (outgoing signal) only one -conducting component of neuron -also called nerve fibers (part of nerves/tracts) -rarely branches (collaterals and telodendria) -axonal terminals end in synapses -Synapses: where one neuron ends and “talks” to another cell -release neurotransmitters (like Ach) -synaptic cleft = space between membranes -3 types: Neuro-neuronal; Neuro-muscular; -Neuro-glandular B. Classification of Neurons (mod. 11.3) 1. By Structure a. Multipolar b. Bipolar c. Unipolar d. Anaxonic (function not understood) 2. By Function: a. Sensory/Afferent (bipolar or...
Words: 1667 - Pages: 7
...LECTURE 10-19 OBJECTIVES Lecture 10 1. Describe the functions of the various types of muscle * Skeletal- limb movement * Cardiac- heart movements * Smooth- movements of hollow organs 2. Describe the involvement of connective tissue in a skeletal muscle * Endomysium- surrounds and fills up spaces between individual muscle fibers * Perimysium- ensheaths muscle fascicles (bundles of muscle fibers) * Epimysium- ensheaths the whole muscle 3. Name the components of a skeletal muscle fiber and describe their function * Sarcoplasm- cytoplasm * Sarcolemma- plasma membrane * T-tubules- inward extensions of the sarcolemma * Mitochondria- provide ATP * Sarcoplasmic reticulum- endoplasmic reticulum * Myofibril- contains thick and thin filaments, myosin and actin 4. Sketch a myofibril 5. Describe the neuromuscular junction * Junction of a muscle fiber and axon of motor neuron it is attached to 6. Name the neurotransmitter used at the neuromuscular function * Acetylcholine 7. Draw a diagram showing how the thin and thick filaments are organized in the sarcomere and list the five steps involved in the contraction of a muscle fiber 8. Define what is meant by excitation-contraction coupling, and describe how it works * The coupling of nerve impulse with muscle contraction hinges around the release of calcium ions * 1, the action of acetylcholine cause a wave of electrical depolarization to spread...
Words: 11309 - Pages: 46
...different branching than starch. Found in animals Cellulose: beta glucose polymer. Plant cell walls Chitin: similar to cellulose with extra nitrogen containing group. Fungus cell wall and exoskeleton Lipids Triglyceride 3 fatty acids attached to glycerol. Phospholipid One fatty acid in triglyceride replaced with a R containing phosphate group Steroids 4 carbon rings. 3 cyclohexane and 1 cyclopentane Proteins Primary structure AA sequence Secondary 3D shape resulting from hydrogen bonding btwn amino and carboxyl group. Alpha helix and beta pleated sheets Tertiary Hydrogen bonding btwn R groups Ionic bonding btwn R groups Hydrophobic and hydrophilic effects Disulfide bonds btwn Cysteine Quaternary Multiple tertiary structures come together. H-bond, disulfide bond, hydrophilic/phobic interactions Nucleic acids Polymer of what? nucleotides Parts of DNA Nitrogen base, 5 carbon sugar, phosphate group Structure 1' attached to base, 5' attached to phosphate group, 3' attached to another nucleotide, antiparallel Base types & number of H-bonds A-G: Purine - two rings C-T: Pyrimidine - one ring C-G: 3 h-bonds A-T: 2 h-bonds RNA vs DNA 2' extra OH in RNA; Single stranded; U instead of T Chemical reactions in metabolic processes Breakdown/synthesis of products is called Catabolism/anabolism(synthesis) ************************************* CELLS ************************************* Structure and functions of cell Basic...
Words: 6665 - Pages: 27
...Biol 121 lecture introduction 23rd feb : Pass program Little groups * Learning notes topics discussions * Informal * opens Friday 27th feb 5.00 Studies: How the body works Anatomy Gross anatomy – internal structures Microscopic anatomy- study of cells, study of tissues (microscope) Physiology- cellular physiology – e.g. nerves and muscle fibres Integrative physiology- different tissues and organs, functions e.g. cardiovascular Levels of organisation e.g. tissues, organs, organ systems organism levels Go through link called echo – access lecture recordings My unit- weekly feedback quiz Biology and chemistry lessons Textbook folder mastering a&p Lecture d 3rd week on a Tuesday Labour day (Monday) good Friday Assessments In class tests (30%) Quiz a (10 %) quiz b (20%) Worksheet questions (30%) Final exam 40% See unit outline for due dates, methods, extensions Quiz a Week 3 (early feedback) 30 mins to complete Opens 3pm Tuesday 10th Closes 3am Thursday 12th Quiz b Week 7 semesters Week 3 up to lecture 16 (muscles) 60 mins marked out of 50 Worksheet questions (30%) due week 11 of sem Set of questions provided online in week 8 Week 1-10 Final exam Mix mcq and sa Material from whole semester Higher weighting of 11 &12 Feedback about progress: Quizzes weekly Review assessments EIP BIOL 121 TUTORIAL 1 CHEMISTRY: Reading: pages 53-61 notes * Science of structure that...
Words: 5008 - Pages: 21
...A2 Biology Unit 5 page 1 AQA A2 Biology Unit 5 Contents Specification Human Nervous system Nerve Cells The Nerve Impulse Synapses Receptors Muscle Animal Responses Control of Heart Rate The Hormone System Homeostasis Temperature Homeostasis Blood Glucose Homeostasis Control of Mammalian Oestrus Plant Responses The Genetic Code Protein Synthesis Gene Mutations Stem Cells Control of Gene Expression Biotechnology DNA sequencing Southern Blot In vivo cloning Genetically Modified Organisms Gene Therapy Genetic Screening and Counselling 2 4 6 0 14 17 24 28 30 33 34 38 42 44 48 50 54 57 63 66 71 76 80 85 89 92 Molecular Genetics These notes may be used freely by A level biology students and teachers, and they may be copied and edited. Please do not use these materials for commercial purposes. I would be interested to hear of any comments and corrections. Neil C Millar (nmillar@ntlworld.co.uk) Head of Biology, Heckmondwike Grammar School High Street, Heckmondwike, WF16 0AH Jan 2010 HGS Biology A-level notes NCM 8/09 A2 Biology Unit 5 page 2 Biology Unit 5 Specification Control Systems Organisms increase their chance of survival by responding to changes in their environment. The Nerve Impulse The structure of a myelinated motor neurone. The establishment of a resting potential in terms of differential membrane permeability, electrochemical gradients and the movement of sodium and potassium ions. Changes in membrane permeability lead to depolarisation and the...
Words: 26586 - Pages: 107
...Biology guide First assessment 2016 Biology guide First assessment 2016 Diploma Programme Biology guide Published February 2014 Published on behalf of the International Baccalaureate Organization, a not-for-profit educational foundation of 15 Route des Morillons, 1218 Le Grand-Saconnex, Geneva, Switzerland by the International Baccalaureate Organization (UK) Ltd Peterson House, Malthouse Avenue, Cardiff Gate Cardiff, Wales CF23 8GL United Kingdom Website: www.ibo.org © International Baccalaureate Organization 2014 The International Baccalaureate Organization (known as the IB) offers four high-quality and challenging educational programmes for a worldwide community of schools, aiming to create a better, more peaceful world. This publication is one of a range of materials produced to support these programmes. The IB may use a variety of sources in its work and checks information to verify accuracy and authenticity, particularly when using community-based knowledge sources such as Wikipedia. The IB respects the principles of intellectual property and makes strenuous efforts to identify and obtain permission before publication from rights holders of all copyright material used. The IB is grateful for permissions received for material used in this publication and will be pleased to correct any errors or omissions at the earliest opportunity. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted...
Words: 43724 - Pages: 175
...cartoons in this book do not intend disrespect for any particular patient population or racial or ethnic group but are solely presented as memory devices to assist in the learning of a complex and important medical subject. We welcome suggestions for future editions. 1) Write in a conversational style for rapid assimilation. 2) Include numerous figures serving as "visual memory tools" and summary charts at the end of each chapter. These can be used for "cram sessions" after the concepts have been studied in the text. 3) Concentrate more on clinical and infectious disease issues that are both interesting and vital to the actual practice of medicine. MARK GLADWIN, MD BILL TRATTLER, MD D CONTENTS Preface v PART 1 1 2 3 BACTERIAL TAXONOMY CELL STRUCTURES, VIRULENCE FACTORS, and TOXINS...
Words: 117402 - Pages: 470
