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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) |