How is the beating (heart rhythm) coordinated by the heart? What are the "pacemaker" cells and where in the heart are they located? Are they nerve cells or muscle cells? What are the other parts of the electrical conduction system in the heart?

answer

watching

117

views

For unlimited access to Homework Help, a Homework+ subscription is required.

You have 0 free answers left.
Get unlimited access to 3.8 million step-by-step answers.

Get unlimited access

Already have an account? Log in

Bunny GreenfelderLv2

9 May 2019

Unlock all answers

Get 1 free homework help answer.

Already have an account? Log in

Related questions

Need 150 word response to the below discussion post

The heart is the most important muscle in your body. The heart is just like a pump that moves the blood throughout the body. This action is what keeps us alive. We are typically taught about the danger of a heart attack, and what we must change in our lives to prevent it; but just like many people, I am at a high risk for heart disease because of family history as well as because of my firefighter career, as heart disease is the number one killer of firefighters (Fire Engineering, 2012). According to the American Heart Association, âboth the risk of heart disease and risk factors for heart disease are strongly linked to family historyâ (American Heart Association, 2016). However, even though your family history provided a picture or marker for possible issues, it is up to us to lower the risk by making changes in our lifestyles.

Heart attacks are caused by blockage that stops blood flow to the heart. A heart attack is when there is damage or death to the heart muscle tissue due to loss of blood supply and this does not necessarily result in an individual's death. A heart attack can show symptoms, such as radiating chest pain or discomfort, dizziness or nausea, sweating, anxiety, stomach pain and shortness of breath. Women have the same symptoms, but they do show some difference in that they describe the pain in their stomach and shoulder blades. In the field we treat heart attack by treating the symptoms; we use IV fluids, baby aspirin, as well as nitroglycerin.

There is another silent killer that most people do not hear much about or they think it is the same thing as a heart attack. As a medic, I deal with this life and death situation all the time, and it interesting to see how many people are not aware of the difference of a heart attack and a sudden cardiac arrest. Sudden cardiac arrest is the abrupt loss of heart function in a person who may or may not have diagnosed heart disease. This can happen at any time, its unexpected and occurs instantly, or seconds after symptoms occur. Cardiac arrest is caused when the heartâs electrical system malfunctions. This causes the heart to go into and irregular heart rhythm (ventricular fibrillation). When this happens, the hearts lower chambers suddenly start quivering and this stops the pump of blood in the heart. The only thing that can reverse cardiac arrest is early defibrillation and CPR. Most people think that a defibrillator can be used on heart attack patients, but this is not the case. The defibrillator is used to shock the heart and restore the normal heart rhythm, if the heart stops, then CPR has to be performed.

Unlike a heart attack, sudden cardiac arrest can happen to anyone, no matter how health or fit they are. According to the American Heart Association âcardiac arrest is a leading cause of death, nearly 360,000 out-of-hospital cardiac arrest occur annually in the United Statesâ (American Heart Association, 2016).

blackbeetle526

Developmental biologists did the following experiments to discover the role of endoderm in the specification of cardiogenic mesoderm.

Using early mouse embryos:
Experiment 1: Removed the anterior endoderm and cultured the embryo â no cardiogenic mesoderm and no heart muscle cells developed.

Experiment 2: Removed anterior endoderm and replaced it posterior endoderm from another embryo and cultured the embryo â no cardiogenic mesoderm and no heart muscle cells formed.

Experiment 3: Removed anterior endoderm and replaced it anterior endoderm from another embryo and cultured the embryo â cardiogenic mesoderm and heart muscle cells developed.

Interpret these data. What are the signals that come from the anterior endoderm? What is their role in specification of the cardiogenic mesoderm?

Under normal conditions, healthy heart cells (cardiac myocytes)prefer fatty acids as their fuel which ultimately results in energy being generated from oxidative phosphorylation through the electron transport chain. We will talk about how fatty acids are oxidatively metabolized in lecture 10. The condition ischemic cardiomyopathy is a result of narrowing of heart arteries which leads to decreased blood flow and a decrease in oxygen delivery to the muscle cells of the heart. In the ischemic heart, metabolism shifts from fatty acid oxidation to glucose metabolism via glycolysis to generate ATP and supply energy needs. a) Please explain why the ischemic heart shifts from energy generated by fatty acids to energy generated by glucose. b) In the ischemic heart, an increase in glycolysis is not associated with an increase in glycolytic enzyme expression. What is the general means by which the increase in glycolysis is mediated if it is not via an increase in enzyme expression? c) In ischemic cardiomyopathy, the decreased blood flow to the heart results in a decrease in blood glucose moving through hart arteries. Given that glycolysis is increased in the ischemic heart, discuss two potential ways that heart cells can acutely (in a rapid time period) increase glucose levels to supply the increased demand for glycolysis.