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Circulatory system and the blood

Explore the circulatory system's role in delivering oxygen and nutrients, pathway of blood flow, heart structure, blood pressure, and common disorders like heart attacks and hypertension.

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Circulatory system and the blood

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  1. Circulatory system and the blood Chapters 5 and 6

  2. Circulatory system • PREVENTS CELLS FROM SUFFOCATING • BRINGS CELLS OXYGEN AND NUTRIENTS • Also called the cardiovascular system

  3. PATHWAYS HEART- PUMPS BLOOD ARTERIES- CARRY BLOOD AWAY FROM THE HEART VEINS- CARRY BLOOD TOWARD THE HEART CAPILLARIES- TINY VESSELS THAT REACH SINGLE CELLS- THE SITE WHERE EXCHANGE OCCURS

  4. ARTERIES WALL- have 3 LAYERS • INNER- simple squamous epithelium + connective tissue= endothelium • Middle- smooth muscle • Outer- loose and fibrous connective tissue Arterioles- tiny arteries

  5. Capillaries • Nourish individual cells • can be closed when muscles in precapillary sphincter are contracted • an arteriovenous shunt is a vessel allows the blood to bypass the capillaries and move on to a venule while the precapillary sphincter is closed

  6. Veins • Venules- tiny veins that drain capillary beds • 3 layers, but less muscle and connective tissue • Have one way valves to prevent blood from staying in the legs • Vein walls can expand- 70% of all the blood is in the veins

  7. Heart • Cone shaped, fist sized Myocardium- the cardiac muscle Pericardium- the thick sac around the heart Septum- the internal wall that separates the right and left halves • Upper 2 chambers- atria • Lower 2- ventricles

  8. Valves • Chordae tendineae- strings that prevent one way valves from opening backwards • Atrioventricular valves- separate upper and lower chambers Right- tricuspid Left- bicuspid or mitral • Semilumar valves- downstream of ventricles pulmonary- right aortic- left

  9. Major vessels • Right half source of blood- from superior and inferior vena cavae • Right blood output- to Pulmonary arteries • Left blood input- from pulmonary veins • Left output- to Aorta

  10. HEART RIGHT SIDE- PUMPS OXYGEN POOR BLOOD FROM BODY (VENA CAVA) TO LUNGS (PULMONARY ARTERY) LEFT SIDE- PUMPS OXYGEN RICH BLOOD FROM LUNGS (PULMONARY VEIN) TO THE REST OF THE BODY (AORTA) • The Left side works harder

  11. Cardiac cycle Systole- period of muscle contraction Diastole- resting period • Lub dub- sound of heart valves slamming shut • Murmur- caused by leaky valves SA node- the heart’s pacemaker- located on the right atrium, creates the electrical impulse AV node- below right atrium- electrical impulse passes through on its way to Perkinje fibers- conducts the impulses to the muscle cells that cause contraction of ventricles

  12. Control of heart rate 1 Medulla oblongata- nerve impulses from brain stem 2. Endocrine hormones from adrenal glands- epinephrine and nor epinephrine Defibrillation- an electrical shock to reestablish ventricular rhythm given to persons with heart problems

  13. HEART ATTACK • BLOCKAGE OF A CORONARY ARTERY which supplies the heart muscle with oxygen and nutrients • PART TO HEART MUSCLE SUFFOCATES • IF ENOUGH MUSCLE TISSUE STOPS WORKING THEN THE HEART CAN’T PUMP BLOOD (massive heart attack)

  14. Other Problems/Treatments Aneurysm- ballooning of weakened artery, can burst and cause massive internal bleeding Treatments for clogged vessels • Nitroglycerine- dilates blood vessels • Clot dissolving drugs- to treat heart attack • Angioplasty- balloon inflated inside a partially clogged artery to expand it

  15. BLOOD PRESSURE • THE FORCE THAT BLOOD EXERTS AGAINST THE WALLS OF OUR BLOOD VESSELS • CONTRACTION OF VENTRICLES= HIGH PRESSURE- SYSTOLE • PRESSURE DROPS MOMENTARILY- when the heart relaxes- DIASTOLE

  16. BLOOD PRESSURE SYSTOLE/DIASTOLE • MEASURED WITH A STETHOSCOPE AND PRESSURIZED CUFF • CUFF CUTS OFF BLOOD AT A HIGH ENOUGH PRESSURE • SYSTOLIC- 110-140 = NORMAL • BELOW 100- LOW HYPERTENSION- 140/90 or greater

  17. Other Problems Hypertension= High blood pressure Atheriosclerosis- cholesterol under endothelium of arteries • Blood clots may form on the irregular artery walls Thrombus- attached clot- embolus- free clot which is moving through the vessels Stroke- burst or blockage of brain arteriole

  18. Veins • Weak one way valves- causes swelled veins (spider veins and varicose veins- usually in the legs/feet) Hemorrhoids- swelled veins of rectum Phlebitis- inflammation of veins

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