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HPsych-Chapter2:CvSy
| Question | Answer |
|---|---|
| Pumping Cycle Step 1 | blood from the body flows into the right atrium, then the right ventricle, to be pumped to the lungs |
| Pumping Cycle Step 2 | Blood from the lungs goes into the left atrium, then the left ventricle, to be pumped to the body |
| Systole | ventricles contract and pump blood out of the heart, atrioventricular valves (tricuspid and mitral) close to stop backflow into the atria; begins the cycle |
| Diastole | Aortic and pulmonary (semilunar) valves close and blood flows from the atria into the ventricles; resting phase |
| Effects of increased heart rate | cardiac cycle is completed in a shorter period of time; most of the speed up comes out of the diastolic period; chronically rapid heart rate reduces overall time for rest and decreases heart strength |
| blood pressure | systolic/ diastolic |
| fluid dynamics factors of blood pressure | cardiac output, blood volume, peripheral resistance, elasticity, viscosity |
| cardiac output | blood volume pumped per minute; more output= higher bp |
| blood volume | amount of blood in the system; greater volume= higher pressure needed to move it |
| peripheral resistance | difficulty of passing through blood vessels; more resistance= more pressure; as you go down the line, blood vessels get smaller and peripheral resistance increases |
| elasticity | ease of stretching the blood vessels; less elasticity= higher bp (usually systolic) |
| viscosity | blood thickness; thicker blood= more pressure |
| individual factors/circumstances affecting blood pressure | environmental temperature, activity, emotions |
| environmental temperature | higher temp --> skin vessels expand--> bp drops; lower temps have the opposite effect |
| activity | exercise increases pressure as does posture; standing decreases pressure in the veins to the heart due to gravity, bp falls |
| emotions | stress, anger, or anxiety activate the sympathetic nervous system and increase blood pressure |
| factors affecting hypertension (make it more likely) | obesity, old age, gender, race (blacks) HOWEVER, all are tied to obesity |
| blood composition | formed elements and plasma |
| formed elements | cells and cell-like structures making up 45% of the blood |
| red blood cells | contain hemoglobin, which carries oxygen; each cell lasts ~3 months |
| anemia | too few RBC's |
| erythrocytosis | too many RBC's |
| sickle-cell anemia | genetic abnormality of RBC's including hemoglobin; more common in blacks; may help malaria resistance |
| leukocytes | several types of white blood cells with protective functions like attacking bacteria |
| leukemia | malignancy where abnormal WBC's are overproduced and crowd out other blood cells |
| Leukopenia | insufficient WBC's, poor immunity |
| Leukocytosis | excess white cells, usually to fight infection |
| Platelets | involved in blood clotting |
| plasma | 90% water; about 55% of the blood; includes plasma proteins, nutrients from digestion, enzymes, hormones, waste products, etc. |
| atherosclerosis | accumulation of fatty plaque on artery walls |
| arteriosclerosis | resulting decrease in artery diameter and flexibility; this process starts pretty early in life (late teens?) |
| myocardial infarction | heart attack caused by obstruction of the heart's blood supply |
| angina pectoralis | brief interruption of the heart's blood supply; caused by narrow arteries; shows up during exercise; could be a sign of a heart attack in the future |
| aneurysm | bulge in weakened artery wall section which can rupture; frequently in the aorta |
| stroke | disruption of blood supply to the brain by thrombosis (blood clot) or vessel rupture; Problem: must determine the cause quickly (thrombosis can be treated with chemicals to break up the clot) |