• A neuron is a nerve cell specialized for conducting nerve signals over long distances • Dendrites receive impulses from the other neurons • The impulses are then passed on to the cell body which contains the nucleus • They are then transmitted to the axon, the axon terminal, and finally the synaptic knob • They also contain a neurolimma, which helps it repair itself if it’s injured • A white, fatty myelin sheath covers the axon, which is composed of Schwann cells • The spaces between each Schwann cells are called the Nodes of Ranvier, they allow the impulse to jump along the axon for faster transport
• There are 3 different kinds of neurons • Sensory neurons carry signals from sensory organs to the CNS • Motor neurons carry the signals from the CNS to the muscles • Signals travel through the CNS through interneuron’s
How do neurons produce electrical charges? Neurons produce electrical charges by altering the ion charge on either side of a neuron membrane. When a neuron is at rest, the Na+ ions are mostly found on the outside of the axon in the extracellular fluid. K+ ions are found on the inside in the intercellular fluid. The membrane is impermeable to Na+ so it stays on the outside. The membrane is slightly permeable to K+ ions so they can leak from the inside of the axon to the extracellular fluid. Therefore, there are slightly more positively charged ions on the outside of the cell than on the inside. Because of this, the resting membrane is polarized – the outside is more positive than the inside. -70mV • The voltage is always given from the perspective of the ICF • If the dendrite is stimulated strongly enough to reach threshold, and action potential/nerve impulse occurs • Once it is stimulated, the membrane becomes permeable to Na+ ions, causing them to rush into the ICF – the ICF becomes more positive on the inside than on the outside until it reaches an electrical potential of +30mV/+40mV – depolarized • In order for another impulse to be sent, it must go back to its normal state through repolarization. • The sodium channels close again and the positive ions are then actively transported back into the ECF • Once a particular point on the membrane has been depolarized, the impulse travels down the axon by conduction – an increase in sodium permeability causes increased permeability at an adjacent point • If the axon is covered in myelin, the Schwann cells prevent the entire axon from depolarizing – myelinated neurons are able to conduct impulses much faster than unmyelinated neurons • All action potentials reach a voltage of +30mV; anything that doesn’t reach threshold (-50mV) will fade out. This is called the all or nothing • More intense pain causes more impulses per second – instead of a larger action potential, there will be a greater frequency in depolarization
• An impulse will eventually reach a synapse – the space between the synaptic knob of a pre-synaptic neuron and the dendrite of a post synaptic neuron • Transmission is when an impulse is sent across a synapse – it begins when an axon potential arrives at the axon terminal • Calcium ions enter into the axon, stimulating the synaptic vesicles in the synaptic knob to release neurotransmitter molecules into the synapse • These diffuse across the synapse and bind with receptor sites on the postsynaptic dendrite, causing it to depolarize • All neurotransmitters are proteins produced by neurons – most common is acetylcholine • Hypersecretion of
…...…Isaiah Barnes Presents The Nervous System There are two main Parts of the nervous system Central nervous system • Made up of the brain and the spinal cord Peripheral nervous system • Made up of sensory neurons, clusters of neurons called ganglia, and nerves connecting them to each other and to the central nervous system. These regions are all interconnected by means of complex neural pathways. Central nervous system The Cerebellum Click icon to add picture The cerebellum is the part…
pleasure The Nervous System The body’s speedy, electrochemical ____________________________ system Central Nervous System (CNS) the ____________ and ______________ ______________ Peripheral Nervous System (PNS) the _______________ and ____________ ________________ that connect the central nervous system (CNS) to the rest of the body Nerves neural “cables” containing many ______________ part of the __________________ nervous system connect the _______________ nervous system with muscles…
Functions of the Nervous System: The nervous system’s functions include sensory input, integration, control of muscle and glands, homeostasis, and mental activities. For sensory input, the nervous system detects external and internal stimuli through sensory receptors. Some of the stimuli result in sensations we are aware of, such as vision, hearing, smell, touch, pain, body position, and temperature. Other stimuli, such as blood pH, blood gases, or blood pressure are processes at an unconscious…
Nervous system Moving, breathing, the ability to physically feel; one may wonder how. How are all these things, these simplified actions, possible? The answer that is giving is simplistic in nature and yet is so complex in actuality. The simplistic answer is the Nervous system. The Nervous system, however, is never simple: the organs, the location (while it may be simple in theory the things that could happen because of it are not), the amount of time dedicated to learning to help people with…
N E U R O The Nervous System Function Controls and integrates sensory, motor and autonomic functions Maintains internal homeostasis Enables connection and response to external environment Divisions of the Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS) The Brain Control Center of the nervous system About 1400 grams/3 lbs Protected by the skull 3 protective membranes (Meninges) Dura Mater – Outter Layer Arachnoid – Middle Layer Pia Mater – Inner Layer Epidural Space…
The organ systems that I choose to discuss were the female reproductive system and nervous system. For life to have an ongoing process there must be the process of creating new life. This process is called reproduction. Human beings reproduce in much the same way as other mammals. There is need for both male and female to be involved in the human reproductive process. On the other hand the nervous system is the most complex system in the body. This particular system is well needed for…
Chapters 2 and 3 Structure and Function of the Nervous System Chemical Signaling by Neurotransmitters and Hormones Neuron Structure Three main features of every neuron Dendrites Treelike projections from the soma that receive information from other cells Constantly modified and change shape rapidly in response to changes in synaptic transmission Soma Cell boy Contains the nucleus and other organelles that maintain metabolic function Axon Single tubular extension that conducts the electrical signal…
hormones, drugs etc Behaviour = actions, thoughts, feelings, memories and perceptions etc 1. Introduction to Biopsychology and the Nervous System Somatosensory cortex is an area of the brain that processes input from the various system in the in the body that are sensitive to touch – Pain and Temperature (detect pain, warmth and cold) The Nervous System responsible for coordinating all of the body’s activities controls maintenance of normal functions body’s ability to cope with…
The Nervous System is a complex and important part of body and your life function. The Nervous System consists of the brain and the spinal cord; and off of that there are the neurons. There are three types of neurons, and each have their own responsibilities. The neuron is a nerve cell, going off into its own class. There are two sections of the Nervous System, the Central Nervous System; and the Peripheral Nervous System. The Neuron is an impulse conductor, so it creates its own type of electricity…
Diseases and Disorders of the Nervous System The nervous system is responsible for the control of the body and communication among its parts. It consists of the brain, the spinal chord, sensory organs, and all of the nerves that connect these organs to the rest of the body. Brain + spinal chord = central nervous system (CNS) Where the information is evaluated and the decisions are made. Sensory nerves + sense organs = peripheral nervous system (PNS) Monitors conditions inside and out of the…