Study guide Lecture 31 Objectives Understand the difference between benign and malignant tumors Malignantis cancerous Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body Benign is not cancerous Benign tumors may grow larger but do not spread to other parts of the body Know the tissue types of cancers Main types Carcinoma epithelial cells 90 of all cancers Sarcoma cells of supporting tissue Lymphoma lymphocytes Leukemia blood cells explain why inhibitors of angionesis can be anticancer drugs A substance that inhibits the growth of new blood vessels Understand metastasis Invasion and penetration of surrounding tissue to reach blood vessel Travel to other parts of the body through bloodstream Reestablish new tumor at new location Describe the common factors that contribute to cancer Life style Cigarette smoking lung cancer Excessive drinking hepatoma Environmental factors Chemicals Carcinogens UV and ionizing radiation Oncogenic viruses and bacteria UV and ionizing radiation cause DNA damage Thymidine dimer formation melanoma Definition a virus that cause cancer human papillomavirus cervical cancer Radiation Oncogenic viruses Bacteria infection cancer Helicobacter pylori H pylori link to stomach and pancreatic Distinguish between proto oncogene and oncogenes Distinguish between oncogenes and tumor suppressor genes Oncogenes are cancer causing genes Proto oncogenes are the corresponding normal cellular genes that are responsible for normal cell growth and division Conversion of a proto oncogene to an oncogene can lead to abnormal stimulation of the cell cycle Tumor suppressor genes help prevent uncontrolled cell growth Mutations that decrease protein products of tumor suppressor genes may contribute to cancer onset Tumor suppressor proteins Repair damaged DNA Promote apoptosis programmed cell death Inhibit the cell signaling pathway that lead to cell division What is apoptosis and what is its relationship with cancer Apoptosis is cell suicide It is considered to be a result of a tumor suppressor Understand the multistep model of cancer development A tumor grow from a single cell Cancer cells invade neighboring tissues Cancer cells spread through lymph and blood vessels to other parts of the Cancer cells may survive and establish a new tumor in another part of the protein body body Terms and Concepts Carcinoma epithelial cells 90 of all cancers Sarcoma cells of supporting tissue Lymphoma lymphocytes Leukemia blood cells Angiogenesis growth of new blood vessels Metastasis Invasion and penetration of surrounding tissue to reach blood vessel Travel to other parts of the body through bloodstream Reestablish new tumor at new location Oncogenes are cancer causing genes Proto oncogenes are the corresponding normal cellular genes that are responsible for normal cell growth and division Tumor suppressor proteins Repair damaged DNA Promote apoptosis programmed cell death human papillomavirus cervical cancer Inhibit the cell signaling pathway that lead to cell division Helicobacter pylori H pylori link to stomach and pancreatic cancer Hyperactive Ras protein product of oncogene issues signals on its own P53 Transcription factor Apoptosis programmed cell death Cell transformation immortalize cells in culture Immortarlization Cancer cells can reproduce indefinitely in culture Study Guide Lectures 32 33 Objectives List and describe the major parts of a neuron and explain the function of each Most of a neuron s organelles are in the cell body Most neurons have dendrites highly branched extensions that receive signals The axon is typically a much longer extension that transmits signals to other from other neurons cells at synapses Many axons are covered with a myelin sheath Most neurons are nourished or insulated by supporting cells called glia Define a resting potential Resting potential membrane potential of neurons that are not transmitting signals the channel Distinguish between ligand gated ion channels and voltage gated ion channels Ligand gated ion channels open or close when a specific chemical binds to Voltage gated ion channels respond to a change in membrane potential Explain the role of voltage gated ion channels in an action potential describe the two main factors that underlie the repolarization phase of the action potential At resting potential 1 Most voltage gated sodium Na channels are closed most of the voltage gated potassium K channels are also closed When an action potential is generated 1 Voltage gated Na channels open first and Na flows into the cell 2 During the rising phase the threshold is crossed and the membrane potential increases 3 During the falling phase voltage gated Na channels become inactivated voltage gated K channels open and K flows out of the cell 4 5 During the undershoot membrane permeability to K is at first higher than at rest then voltage gated K channels close and resting potential is restored Define the refractory period and explain why an action potential is propagated in only a single direction over a neural pathway The refractory period is a result of a temporary inactivation of the Na During the refractory period after an action potential a second action potential cannot be initiated The action potential can only move AWAY from the initial site of channels depolarization Describe the structures of a chemical synapse and explain how they transmit an action potential from one cell to another The vast majority of synapses are chemical synapses In a chemical synapse a presynaptic neuron releases chemical neurotransmitters stored in the synaptic terminal into the synaptic cleft when an action potential reaches a terminal Explain how excitatory postsynaptic potentials EPSPs and inhibitory postsynaptic potentials IPSPs affect the postsynaptic membrane potential Define summation and distinguish between temporal and spatial summation Temporal summation two EPSPs produced in rapid succession add together Spatial summation EPSPs produced nearly simultaneously by different synapses on the same postsynaptic neuron add together List the main types of neurotransmitters Understand salutatory conduction of action potentials Action potentials are formed only at nodes of Ranvier gaps in the myelin sheath where voltage gated Na channels are found Action potentials in myelinated axons jump between the nodes of Ranvier in a process called saltatory conduction Terms and Concepts Neurons or nerve cells are responsible for
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