Discuss the role of endogenous pacemakers in the control of circadian rhythms [AO1 8 marks‚ AO2 16 marks] An endogenous pacemaker is an internal biological clock that controls the way in which many of our biological rhythms behave. Many of these rhythms run on a 24 hour basis‚ such as the sleep/wake cycle‚ bodily temperatures and some of our hormones. The main endogenous pacemaker in mammals is the suprachiasmatic nucleus (SCN)‚ which is located in the hypothalamus. It receives information
Premium Circadian rhythm Sleep Pineal gland
Essay ON PAcemaker A pacemaker (or artificial pacemaker‚ is a medical device that uses electrical impulses‚ delivered by electrodes contacting the heart muscles‚ to regulate the beating of the heart. The primary purpose of a pacemaker is to maintain an adequateheart rate‚ either because the heart’s native pacemaker is not fast enough‚ or there is a block in the heart’s electrical conduction system. Modern pacemakers are externally programmable and allow the cardiologist to select the optimum pacing
Premium
Do Endogenous or Exogenous Shocks Have the Greater Impact on Economic Output The UK is an open economy meaning that a high percentage of our national income and output comes from trading with the rest of the world; we are highly integrated within the global economy. Endogenous models explain cyclical fluctuations in terms of internal events or policies i.e. changes which lie within the economic system; For example: if the economy is already near full employment (at Yf)‚ with only a small output
Premium Supply and demand Economics Inflation
In the qualitative study‚ Cardiovascular Patients’ Experience of Living with Pacemaker: Qualitative Study‚ the objective was to look into the experiences of patients living with a pacemaker. In the introduction‚ the authors describe the reason of cardiovascular disease being one of the most common causes of disease associated mortality being that there is an increase in urbanization‚ industrialized lifestyle and decrease physical activity as well as socio-economic conditions. Coronary artery disease
Premium Myocardial infarction Medicine Atherosclerosis
CHAPTER 1 Basic principles of pacing Malcolm Kirk The aim of this chapter is to give sufficient background and information about cardiac pacemakers to allow interpretation of electrocardiograms (ECGs) and telemetry strips of normal pacemaker behavior. For more in-depth information‚ such as would be necessary for programming pacemakers‚ a standard pacing text should be consulted. Several of these are listed in the bibliography. Most italicized terms are defined in the glossary at the end of the chapter
Premium Heart Cardiology Blood
Implantation Although the pacemaker can be used by everyone‚ physicians who recommend permanent pacemaker implantation must consider “comorbidities‚ surgical risks‚ quality of life‚ and patient preference” (Bains 2017). Before we begin the surgical procedure‚ we need to understand the difference between the 4 types of pacemakers. External (transcutaneous) pacemakers are outside of the body‚ but the wires are attached to the skin. This type is used for emergencies because they are only temporary.
Premium
TYPES OF PACEMAKERS The classification of pacemakers into different types is based on the mode of application of the stimulating pulses to the heart. EXTERNAL PACEMAKERS: These are used when the heart block presents itself as an emergency and when it is expected to be present for a short time i.e during critical post operative periods and in patients during cardiac surgery‚ involving the valves or septum. * The pacemaker is placed outside the body. It may be in the form of wrist watch or in
Premium Heart Blood Cardiac electrophysiology
Living with a Pacemaker or Implantable Cardioverter Defibrillator (ICD) With advances in technology‚ pacemakers and ICDs generally last five to seven years or longer (depending on usage and the type of device) and‚ in most cases‚ allow a person to lead a normal life. In addition‚ advances in device circuitry and insulation have reduced the interference risk from machinery‚ such as microwaves‚ which‚ in the past‚ may have altered or otherwise affected these surgically implanted cardiac devices. Even
Premium Magnetic resonance imaging
Pacemaker The human heart is an essential organ of the human body. Its sole purpose is to supply the body with oxygen by pumping blood through a complex system of veins and arteries. However‚ it is often common for the human heart to suffer from various heart conditions‚ such as a heart block‚ slow heart beat‚ heart attack or heart failure. Such heart conditions can lead to weakness‚ fainting‚ shortness of breath‚ or even possibly death. These can usually be treated with medication but in cases
Premium Cardiology Magnetic resonance imaging Heart rate
Recall that in the Harrod-Domar‚ Kaldor-Robinson‚ Solow-Swan and the Cass-Koopmans growth models‚ we have maintained‚ either explicitly or implicitly‚ that technical change is "exogenous". In the Schumpeter version‚ this was not true: we had "swarms" of inventors arising under particular conditions. The Smithian and Ricardian models also had technical change arising from profit-squeezes or‚ in the particular case of Smith‚ arising because of previous technical conditions. Allyn A. Young (1928)
Premium Economic growth Endogenous growth theory Exogenous growth model