Compare and contrast cardiac and smooth muscle. In cardiac muscle‚ each heartbeat is triggered by the hearts own pacemaker cells‚ which initiate electrical discharge and when this reaches the contractile muscle cells (the cardiomyocytes)‚ they create an action potential which increases the concentration of calcium ions into the cell. Calcium ions play a key role in activating what is known as the contractile machinery – the actin and myosin filaments. The cardiac action potential‚ unlike other forms
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physiologist‚ Wilhelm Pfeffer. Ten years prior‚ Moritz Traube prepared the first recorded synthetic membrane that was made from a precipitated film of copper ferrocyanide. It was not until almost two hundred years later that the process of osmosis was revisited and extensively reviewed by researchers from the University of California at Los Angeles. In 1959‚ Sidney Loeb and Srinivasa Sourirajan developed a membrane made from cellulose acetate‚ which removed at least ninety percent of salts from the water
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Exercise 1: Cell Transport Mechanisms and Permeability: Activity 1: Simulating Dialysis (Simple Diffusion) Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. The driving force for diffusion is You correctly answered: b. the kinetic energy of the molecules in motion. 2. In diffusion‚ molecules move You correctly answered: a. from high concentration to low concentration. 3. Which of the following dialysis membranes has the largest pore size? You correctly
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Introduction Neurons (also known as neurons‚ nerve cells and nerve fibers) are electrically excitable and the most important cells in the nervous system that functions to process and transmit information. Neurons have a large number of extensions called dendrites. They often look likes branches or spikes extending out from the cell body. It is primarily the surfaces of the dendrites that receive chemical messages from other neurons. One extension is different from all the others‚ and is called
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Living Units 3 P ART A Copyright © 2006 Pearson Education‚ Inc.‚ publishing as Benjamin Cummings But First… Let’s clean up… Hydrophobic Hydrophilic Copyright © 2006 Pearson Education‚ Inc.‚ publishing as Benjamin Cummings Plasma Membrane Separates intracellular fluids from extracellular fluids Plays a dynamic role in cellular activity Just like the doors‚ windows‚ and walls of a house Copyright © 2006 Pearson Education‚ Inc.‚ publishing as Benjamin Cummings 1 Fluid
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Investigation: A factor that affects the movement of water in and out of cells. Osmosis: movement of water from a region of high water potential to a region of low water potential through a partially permeable membrane. High water potential = lots of free water molecules‚ low solute concentration Low water potential = very few free water molecules‚ high solute concentration Factors That Affect the Movement of Water in and out of Cells * Solute concentration * If one solution
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REVIEW SHEET EXERCISE 1 Cell Transport Mechanisms and Permeability 1. Match each of the definitions in Column A with the appropriate term in Column B. |Column A |Column B | |__E__ term used to describe a solution that has a lower |a. diffusion | |concentration of solutes compared to another solution |b. facilitated diffusion
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Non-cardiogenic shock is caused by a circulatory collapse in the body that is not due to problems originating in the heart. Shock is commonly caused by hypo-perfusion though the blood vessels due to lack of blood in the vessels causing low blood pressure and rapid heartbeat. Besides cardiogenic shock‚ there are three other types that cause shock for non-cardiogenic reasons‚ obstructive shock‚ disruptive shock‚ and hypovolemic shock. Obstructive shock results from an obstruction that prevents blood
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Results The objectives of this experiment were to investigate diffusion of molecules across a membrane and the factors that affect the rate of diffusion. The hemolysis time of sheep erythrocytes was measured for each of eight different nonelectrolyte solutions by eleven groups in BI 108 Section D2. These eight nonelectrolytes were urea‚ thiourea‚ methanol‚ ethanol‚ propanol‚ ethylene glycol‚ diethylene glycol‚ and triethylene glycol‚ and the mean hemolysis times can be seen below in Figure 1. The
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acetylcholine and diffuse across the neuromuscular cleft. The transmitter molecules fill receptor sites in the membrane of the muscle and increase the membrane permeability to sodium. The sodium then diffuses into the membrane and the membrane potential becomes less negative. If the threshold potential is reached‚ an action potential occurs and a nerve impulse moves along the muscle cell membrane and the muscle will contract. While skeletal muscles will only contract by neurons‚ smooth and cardiac muscles
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