Cells in the Nervous System PDF

 All we are capable of doing like perceiving, thinking, learning, remembering, acting is made possible by the integrated activity of the cells of the nervous system. What body system is the brain part of? a. nervous system b. circulatory system...

 All we are capable of doing like perceiving, thinking, learning, remembering, acting is made possible by the integrated activity of the cells of the nervous system. What body system is the brain part of? a. nervous system b. circulatory system c. decimal system d. digestive system The brain creates connections, or pathways, between these microscopic cells: a. blood cells b. tiny cells c. brain tissues d. neurons How many nerve cells or neurons are there in the human brain? The brain stem is located at the base of the brain connecting to the spinal cord. Which of these functions does the brain stem control? a. feelings b. memory c. heart rate d. finger movement Which side of the body does the left side of the brain control? a. left b. right What is the name of the biggest part of your brain? a. brain stem b. cerebellum c. cerebrum d. frontal lobe What is the name of the area of the brain that controls memory? a. frontal lobe b. occipital lobe c. parietal lobe d. temporal lobe A typical adult brain weighs about how much? a. 3 pounds (1.4 kilograms) b. 3 ounces (85 grams) c. 22 pounds (10 kilograms) d. 6.6 pounds (3 kilograms) Your emotions are believed to come from the: a. cerebellum b. medulla oblongata c. amygdala d. heart Question 1: a. nervous system Question 2: d. neurons Question 3: c. heart rate Question 4: b. right Question 5: c. cerebrum Question 6: d. temporal lobe Question 7: a. 3 pounds (1.4 kilograms) Question 8: c. amygdala  Central Nervous System - Consists of the brain and the spinal cord - Communicates with the rest of the body through the nerves attached to the brain and the spinal cord  Peripheral Nervous System - Consists of the nerves and the most of the sensory organs Nerves are bundles of thousands of individual neurons all wrapped in a tough protective membrane Look like electrical cables under a microscope and these nerve fibers transmit messages through the nerve from a sense organ to the brain or from the brain to a muscle or gland Information in the form of light, sound, odors, tastes or contact with objects is gathered from the environment by specialized cells in the PNS called sensory neurons. Motor behaviors require contracting muscles which are controlled by motor neurons in the PNS INTERNEURONS - located between sensory neurons and motor neurons within the CNS LOCAL INTERNEURONS - form circuits with nearby neurons and analyze small pieces of information RELAY INTERNEURONS - connect circuits of local interneurons in one region of the brain with those in other regions. Through these connections, circuits of neurons throughout the brain perform functions essential to tasks such as perceiving, learning, remembering, deciding and controlling complex behaviors. What is a Neuron?  The basic information processing and information-transmitting unit of the nervous system. Structures of a Neuron data:image/png;base64,iVBORw0KG Parts of a Neuron  Cell body "Soma" contains the nucleus of the cell and involved the life processes of a cell  Dendrites functions like antennas to receive messages from other neurons. They receive messages that are transmitted across the synapse.  Synapse A small space between the terminal buttons of the sending cell (presynaptic cell) and a portion of the somatic or dendritic membrane of the other cell (postsynaptic cell)  Axon Long thin tube which carries information from the cell body to the terminal buttons. The basic message of the axon is called the action potential. Action potential (nerve impulse) is a brief electrical and chemical event that starts at the end of the axon near the cell body at a point called the axon hillock. Axoplasmic Transport Moves substances along "tracks" that run inside the length of the axon.  Proteins Proteins are responsible for nearly every task of cellular life, including cell shape and inner organization, product manufacture and waste cleanup, and routine maintenance.  Axoplasmic Transport Kinesin (Protein) These molecules of protein accomplished the transport of substances. In the cell body, kinesin molecules which resembles a pair of legs and feet attach to the item being transported down the axon. It walks down a microtubule carrying the cargo to its destination.  Axoplasmic Transport Adenosine Triphosphate (ATP) These molecules are produced by the mitochondria which supplied energy in the axo- plasmic transport process  Axoplasmic Transport Dynein (Protein) Carries substances from the terminal buttons to the soma.  Axoplasmic Transport Retrograde Axoplasmic Transport Transport is about half as fast as anterograde transport Anterograde Axoplasmic Transport Remarkably fast, moving contents at up to 500 millimeters (mm) per day  Myelin Sheath a fatty substance that provides insulation for the electrical message carried along the axon membrane appear as white matter in the brain and in the nerves bundles of myelinated exons are referred to as tracts  Terminal Buttons Little knobs at the end of the branches of a nueron and secrete neurotransmitters which either excites or inhibits the receiving cell. Open Forum  Other Cell Structures Cell Membrane - Defines the boundary of the neuron. It consists of a double layer lipid (fatlike) molecules. Embedded in the membrane are a variety of protein molecules that have special function.  Cytoskeleto n Framework of protein strands found in the interior of a neuron. It gives a neuron its shape like the bones of the skeletal system.  Microtubule s The thickest of the protein filaments arranged around a hollow core and provide structural support to the neuron. It forms the tracts for axoplasmic transport.  Cytoplasm A semi-liquid, jellylike substance that fills the space surrounded by the membrane including the soma. It contains small, specialized structures just as the human body contains specialized organs. Organelles or little organ is the generic term for these structures.  Nucleus Deep inside the cell, enclosed by the nuclear membrane and contains the chromosomes  Chromosomes Consist of long strands of deoxyribonucleic acid (DNA) , they contain the recipe for making proteins. Portions of the chromosomes are called Genes.  Genes Genes - Contain the individual recipes for individual proteins and responsible for initiating the process of protein synthesis in the cell. When they are active, the genes help produce another complex molecule called the MRNA (Messenger Ribonucleic Acid)  MRNA Copies the information stored by the gene MRNA leaves the nucleus witht the copied information and attaches to ribosomes in the soma.  Ribosomes Use the copied information from the MRNA to synthesize proteins for the cell. A ribosome is an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell. The ribosome reads the messenger RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins.  PROTEIN SYNTHESIS Protein synthesis is the process all cells use to make proteins, which are responsible for all cell structure and function.  Two-Step Process TRANSCRIPTION Information from the DNA is transcribed into a protable form which is the MRA 2. TRANSLATION The ribosomes use the information from the MRNA to create proteins from sequences of amino acids. Process: Protein Synthesis When a gene is active, a copy of the information is made onto a molecule of messenger RNA (TRANSCRIPTION), the MRNA leaves the nucleus and attaches to a ribosome where the protein is produced (TRANSLATION) Supporting Cells of the CNS Glia (Glial Cells) - surround neurons and hold them in place regulating their supply of nutrients and some of the chemicals they need to exchange messages with other neurons. Supporting Cells of the CNS Glia (Glial Cells) - Insulate neurons from one another so that neural messages do not get scrambled destroy and remove pathogens or dead neurons Supporting Cells of the CNS Glia (Glial Cells) - Insulate neurons from one another so that neural messages do not get scrambled destroy and remove pathogens or dead neurons involved in synaptic communication  3 Types of Glial Cells Astrocytes - provide physical support to neurons and clean up debris within the brain Oligodendrocytes - Provide support to axons and to produce the myelin sheath which insulates most axons from one another Microglia - smallest of the glial cells, serve as part of the immune system in the brain  Node of Ranvier Bare portion of an axon The myelinated axon resembles a string of elongated beads protecting the brain from invading microorganisms Primarily responsible for the inflammatory reaction in response to brain damage  Node of Ranvier Bare portion of an axon The myelinated axon resembles a string of elongated beads protecting the brain from invading microorganisms Primarily responsible for the inflammatory reaction in response to brain damage Node of Ranvier  Schwann Cells Provide myelin for only one axon and the entire schwann cell surrounds the axon. If damage occurs to a nerve, schwann cells help digets the dead and dying axons. Arrange themselves in a series of cylinders that act as guides for regrowth of the axons