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Chapter 6

chapter 6

11 Pages

Health Studies
Course Code
Dan Silver

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Chapter 6 Aging of the Internal Organ SystemsBasic Anatomy and PhysiologyCARDIOVASCULAR SYSTEMCardiovascular systemmain transportation system Supplies tissues with fluids hormones oxygen and nutrients and removes waste products carbon dioxide and hydrogen ionsBloodcomplex fluid composed of water red and white blood cells platelets nutrients such as fat globules carbs and proteins Blood also carries electrolytes to help maintain the acidbase balance and a host of other chemicalsHeartlocated behind the chest wall somewhat to the left of the sternumbreastbone Its enclosed in a fibrous sac the pericardium The left and right side of the heart each have two upper chambers atriawhich have thin walls which collect the blood and two lower chambers ventricleswhich have thicker walls which pump blood to the lungs and bodyOxygenpoor blood is collected in the right atrium from the large veins of the body and flows to the right ventricleOxygenrich blood is sent through the pulmonary veins to the left atrium where it flows to the left ventricle and is pumped out through the aortaAorta large arteriessmaller arteries arterioles and capillaries which are one cell wideCapillarieswhere fluid nutrients electrolytes and hormones are exchangedVenules collect blood from the capillaries and move it into larger veins until it reaches the superior and inferior vena cavaIn a healthy heart oxypoor blood is never mixed with oxyrich bloodContraction of the heart muscle is called systole and relaxation diastoleTo help keep blood moving up to the heart and prevent it from pooling some veins have valves ex the saphenous found in the back of the legs Skeletal muscle movement puts pressure on the vein to keep the blood movingThe heart alters its rate of pumping depending on both external and internal demands Stimulation to decrease and increase the heart rate is under the direction of the autonomic nervous systemAgeRelated ChangesMost studies report a normal enlargement of the heart mass with age due to increase in size of the muscle cells or myocytesAn increase in the amount of fat tissue around the sinoatrial node which interferes with the conduction system and can cause a slow pulse called bradycardiaChanges in collagen in the middle layer of large arteries cause them to thicken widen stiffen and lengthen Over time the large size of these arteries require the heart to work harder eventually increasing blood pressureThe capillaries become narrower with age which impedes the normal flow of bloodOverall there is a decrease in cardiovascular responsiveness to exercise It takes longer for the heart rate and blood pressure to return to normal resting levelsDiseaseRelated ProcessesHypertension Optimal blood pressure for adults over 18 is 12080 or lower systolicdiastolic pressureSystolic hypertension increases throughout life diastolic levels off in later yearsHigh blood pressure affects all the major arteries of the body and the organs and tissues they serve Highly labile blood pressure refers to the rapid expansion and contraction of the arteriesboth conditions damage the collagen in the arterial walls making them stifferCauses of hypertensionObesity hormonal changes increased sensitivity to sodium changes in kidney functionArteriosclerosis and Atherosclerosis Arteriosclerosisthe thickening and loss of elasticity of arterial walls Stiffended arteries tend to be contracted which raise blood pressure High blood pressure is both the results from and cause of arteriosclerosis
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