balance of parasympathetic and sympathetic influence on the SA node. 1 action potential = 1 electrical impulse Parasympathetic: Slows HR Sympathetic: Speeds HR Parasympathetic Regulation of HR At rest‚ parasympathetic nerves will release Acetylcholine (Ach) Ach will bind to receptors on the SA node. Slow down the closure of Potassium channels‚ more potassium will flow out causing hyperpolarisation Since resting potential is farther‚ takes longer to reach threshold potential‚ therefore slower
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A-LEVEL BIOLOGY LAB REPORT NAME: NURUL AYUNI BT SABRI GROUP: 11SC4 TITLE: THE EFFECT OF CAFFEINE ON HEART RATE LECTURER : MDM ZAKIAH BINTI ZAKARIA TITLE The effect of caffeine on heart rate OBJECTIVE To determine the effect of caffeine on heart rate of daphnia INTRODUCTION Caffeine‚ medically known as trimethylzanthine. Its chemical formula is C8H10N4O2. When in pure form‚ caffeine is a white crystalline powder that taste very bitter. 1The most common way
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Chapter 15 Signal Transduction 1) Endocrine‚ paracrine ‚ autocrine signaling‚ and cell-cell contact (Fig. 15-2). Endocrine signaling is long distance signaling. An example would be pancreatic cells secreting insulin. Paracrine signaling is for close proximity. An example would be a nerve cell releasing neurotransmitters. In autocrine signaling the cell that produces the ligand also contains the receptor for that ligand. This is how cancer cells work. In signaling by plasma membrane attached
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The drugs that are on the market for the disease boost the action of a brain chemical called acetylcholine. These drugs typically improve the patient’s symptoms to where they were six months earlier. However‚ they do not work for all patients‚ and even when they do work‚ the symptoms eventually become so severe that a six-month improvement does not
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|Cells in the islets of Langerhans that release glucagon in response to low blood glucose levels. | |Acetylcholine |A neurotransmitter (transmitter substance) found in cholinergic synapses. | |Acetylcholinesterase |An enzyme in the synaptic cleft that breaks down the transmitter substance acetylcholine. | |Actin |A protein found in muscle cells. It is the main
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form of dementia that gradually gets worse over time. It affects its victim’s memory‚ thinking‚ and behavior. AchE is an enzyme that has been known to accelerate the formation of abnormal protein clumps in the brain and also breaks down acetylcholine. Acetylcholine is a chemical in the brain that has been linked to memory and learning. The substance THC‚ which is located in marijuana‚ is able to disrupt the abnormal clumping of malformed proteins. The approved drugs for Alzheimer’s‚ donepezil and
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LABORATORY REPORT Activity 2: Twitch Contractions and Summation Name: Trisha Mora Instructor: Professor Vais Date: 7/15/14 PREDICTIONS Effect of Muscle Fiber Length on Contraction 1. As muscle fiber length increases: Contraction Force Increases. Effect of Stimulation Frequency on Contraction 2. As the frequency of stimulation increases‚ the force of contraction: Increases. MATERIALS AND METHODS Measurement of Threshold Stimulus 1. Dependent Variable is the contraction force 2. Independent
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channel that is always open would be classified as a/an non-gated channel. 4. Would sodium ions move into or out of the neuron through these channels? Into 5. Voltage-gated potassium channels open at what voltage? -130 mV 6. Acetylcholine (ACh) and GABA are neurotransmitters that open chemically-gated channels. What ions pass into the cell when these channels are activated? a. ACh: Sodium (Na+) ions b. GABA: Chlorine (Cl-) ions 7. Ion channels are regionally located
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the storage and release of the substance‚ its interaction with a receptor in the membrane‚ and the removal of the transmitter form the synaptic cleft. The nervous system makes use of two types of neurotransmitters: small-molecule transmitters (acetylcholine‚ amines and A.A) and neuroactive transmitters(peptides) 2. Neurons have developed a sophisticated ability to regulate the synthesis‚ storage‚ release‚ and degradation (or removal) of neurotransmitters to achieve the desired levels of transmitter
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Extracerebral vessels‚ located at the base and surface of the brain‚ are innervated by perivascular nerves originating from the superior cervical ganglion‚ responsible for the sympathetic innervation‚ the sphenopalatine and otic ganglia‚ mainly supplying parasympathetic nerves‚ as well as the trigeminal ganglion [59]. This extrinsic innervation is lost‚ when perforating arteries enter the brain. These parenchymal arterioles have unique properties compared to the microvasculature found in other organs;
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