ASG1 A – Anatomy and Physiology
1. Describe the function of the heart, cardiac cycle and circulatory system
Function of the heart
The heart is a muscular organ that pumps and circulates blood throughout the body via a transport system of arteries and veins and capillaries. As the blood circulates throughout the body it supplies oxygen and nutrients to the tissues as well as removing carbon dioxide and harmful waste products (Tucker, 2015).
The structure of arteries
Arteries have thick muscular walls and a small lumen passage. According to L. Tucker they are constructed with three layers:
• A fibrous outer layer
• A middle layer of muscle and elastic tissue
• A lining made of squamous epithelial tissue
The epithelial lining has a
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The walls of veins are far thinner and the lumen passage much larger. The walls are not muscular and blood is pushed through the vessels by the action of skeletal muscles. Veins carry deoxygenated blood (dark red) to the heart, except for the pulmonary veins which carry oxygenated blood. Blood pressure is very low in the veins, so there are valves in the endothelial layer which prevent the back flow of blood (Tucker, 2015).
The structure of capillaries
Capillaries are the smallest blood vessels in the body. The walls are only one cell thick and porous, which allows the passage of oxygen to body tissues and collection of waste products, mainly carbon dioxide and urea. They also deliver nutrients (e.g. sodium and potassium) and hormones to body tissues. The blood is brick red in colour because it has oxygen and carbon dioxide. I understand this from reading L. Tucker’s book.
The cardiac cycle
The cardiac cycle is the sequence of events that occur when the heart beats. According to L. Tucker, the following occurs during the cardiac
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High blood pressure (hypertension) is defined as having a systolic reading equal to, or more than 140mmHg and a diastolic reading equal to, or more 90mmHg. Hypertension can be caused by stress, medication (steroids), obesity, diet, alcohol, smoking and hereditary factors. The renal system works with the circulation system to remove waste products and fluid from the body. Blood pressure rises if the volume of blood increases, due to fluid retention in the body or from disease of the kidneys. The effects of hypertension include angina, heart attack, heart failure, stroke, kidney failure and peripheral arterial disease (poor circulation in the
The liver has a portal vein as well as a hepatic vein. It also has unique exchange blood vessels similar to capillaries, called “sinusoids.” How do these unique structures determine the function of the organ? • The livers main function is to filter and process the blood it receives. The portal vein and hepatic vein then deliver the nutrient rich blood to the capillaries (sinusoids).
Arteries deliver oxygenated blood to the capillaries, where the exchange of oxygen and carbon dioxide takes place. An artery's muscle helps it expand and contract in rhythm with the heart beating to keep blood moving through the system. Capillaries connect veins and arteries to exchange oxygen and carbon dioxide. Thin and weak, capillaries are only as thick as one epithelial cell. Blood passes through capillaries one cell at a time, single file.
There are three main types of blood vessels that help blood flow through your heart. They are Arteries - They carry oxygen rich blood away from the heart to all of your body tissues. Which get smaller and smaller the farther they get away from the heart. Capillaries - Which Are small thin blood vessels that connect the arteries and the veins together.
With Audrey’s condition, blood pressure should be controlled and monitored as well as her cholesterol levels and heart rate to prevent stroke (John V Amerena, 2013) Digoxin and Warfarin medication will be given as per doctors order. 2. Hypertension means that the blood is pumping with more force than normal through the arteries, which are the vessels that carry blood from the heart to the rest of the body (Better Health Channel,
The cardiac cycle is the coordination of the filling and exhausting of blood by electrical signals that cause the heart muscles to contract and unwind. The contraction of the heart is directed by a nerve drive that goes from the SA node to AV node to AV group to Purkinje fibers to the myocardium. Amid the cardiac cycle, the heart contracts by means of systole, pushing blood out of the heart, and unwinds through diastole, filling the heart with blood. Cardiomyocytes, or cardiac cells, are striated and are in charge of the pumping of the heart; they are the main muscle cells with intercalated plates. The heart's inner pacemaker controls and times the thumping of the heart by means of electrical signals.
The heart pumps the blood while the blood vessels deliver blood to all body parts. 6.1 Personal context The cardiovascular system ceases to perform its roles when some factors like diseases are involved. The diseases affecting this system is referred to as cardiovascular diseases or heart diseases. These heart diseases are among the major diseases with high rate of mortality and morbidity rate.
All of the organs in the body maintain homeostasis. The circulatory system consisting of the heart and vessels is of vital importance. The heart pumps blood and other nutrients through the vessels to all of the other organs in the body. The heart, vessels, lungs all work together to maintain homeostasis. With out the circulatory system, no other organ could survive.
This prevents backflow of blood into the atria. The closure of these valves produces the familiar sound of the heartbeat. They last for about 0.1 s. 2. Ventricular systole. The ventricular muscle contracts and expels the blood into the circulatory system.
The heart is a vital organ, which pumps blood around the body which allows all of the cells and organs in the body to receive oxygen and nutrients that they require to function. It is a part of the cardiovascular system which also includes the blood vessels and veins. Within the heart, there are four chambers – two atria and two ventricles- and between each chamber there is a valve which blood flows through as it leaves the chamber. Valves have the physiological role of preventing blood flowing backwards through the heart. Unidirectional flow is critical and allows the heart to function in the most efficient way possible (Moore, 2014).
A homeostatic mechanism that helps regulate blood pressure is found in blood vessels, also known as arteries. Pressure-sensitive receptors in the walls of arteries sense changes and signal the control center. If the blood pressure is above the set point, the brain sends signals to the heart, telling it to contract more slowly and with less force. By sending out less blood, the pressure goes down.
The heart is located at the center of the chest, and is surrounded by the ribcage and protected by the breastbone. The heart’s main function is to keep blood continually circulating throughout the body. Arteries are the vessels that supply the body with oxygen rich blood; on the contrary the vessels that return blood to the heart are called veins. Like any other muscle in the body, the heart depends on a steady supply of oxygen rich blood. The arteries that carry this blood supply to the heart muscle are called coronary arteries.
Most often the blood pressure is tested by a healthcare worker using a gauge, sensor, or a stethoscope and they measure the systolic pressure (blood pressure when the heart beats) and the diastolic pressure (blood pressure between heartbeats). The reading is systolic over diastolic, for example, 120/80. The heartbeat
When the blood pressure is high, the heart has to work more to get the blood through your arteries. These then take a beating from having the blood pressured into them, and the danger of a stroke, heart attack, or even kidney troubles then become that much of a greater risk. High blood pressure is a serious disease because it has the heart working much harder. If the heart has to work harder for extended periods, it will become large. If the heart is slightly enlarged, it can and should still work alright, but if it becomes greatly enlarged it won't work alright.
The objective of this experiment is check how heart chambers, vessels and valves of the heart help the heart to achieve its function of pumping blood all over the body. In addition, this experiment would help us understand the double circulation of blood and reasons why it is vital for mammalian organisms. Due to the complexity of mammalian organisms, the exchanges of substances such as oxygen, nutrients and hormones cannot rely on diffusion itself (Kent, 2013). The transportation
1. Introduction Every human being have different levels of blood pressure in their body. Blood pressure is