Chapter 9.2- The Heart

• atria


  thin-walled chambers at the top of the heart, which recieve blood
• ventricles


  thick-walled chambers at the bottom of the heart, which pump out blood
• septum

  structure that separated the left and right sides of the heart, keeping oxygenated blood separate from deoxygenated blood
• pulmonary veins


  veins that carry oxygenated blood from the lungs to the left atrium of the heart
• venae cavae


  large veins that bring deoxy blood to the right atrium
• aorta


  largest artery in the body, which recieves oxy blood from the left ventricle and delivers it to the body organs
• pulmonary artery

  artery carrying deoxy blood from the right ventricle to the lungs
• atrioventricular valve


  valve between an atrium and ventricle in the heart, which allows blood to flow from atrium to the ventricle but not in the opposite direction
• semilunar valve


  valves close to the entracnes to the aorta and pulmonary artery, which prevent backflow of blood from the arteries to the ventricles
• differences in muscle wall thickness


  - atria just recieve blood, but the ventricles PUMP them

  - hence, the ventricles have a thicker, muscular wall than the atria

  - left ventricle is especially thick since it pumps blood to the rest of the body, while the right ventricle pumps it to the lungs, which is relatively close to the heart
• coronary arteries


  vessels that deliver oxygenated blood to the heart muscles
• coronary heart disease


  desease caused by blockage of the coronary arteries
• causes of coronary heart disease


  - smoking: nicotine damages circulatory system; narrows and stiffens blood vessels

  - blood cholestrol levels: diets rich in LDL(low density lipids) causes CHD to develop

  - age: CHD risk increases with age

  - stress: unmanageable/long-term stress leads to development of CHD

  - high BP: caused by heavy amounts of stress and can lead to CHD

  - gender: more common in males, maybe due to sex-linked genes
• How exactly do the arteries get blocked?


  - cholestrol deposits can narrow the lumen of the artery, increasing BP and stiffening the artery

  - blood clots an form as a result, and if one breaks away, it can get stuck in a smaller blood vessel, so blood will not be able to get through
• preventing CHD


  - quit smoking

  - diet based on saturated fatty foods should be controlled; substitute animal fats with plant-based oils, etc.

  - have a diet based on fish and veggie oils

  - exercise regularly
• Treating CHD


  - statins: help lower BP and chances of blood clot forming

  coronary bypass operation: blocked/severely damaged coronary artery is replaced by another length of blood vessel taken from other parts of the body

  - angioplasty: a baloon is inserted in the damaged coronary artery and inflated w/ h20; pushes the artery open

  -heart transplant operation: in the rarest and worst cases of CHD, heart transplants may need to happen; if it is successful, then patients will need to take immunosuppresents for life
• Heartbeat:

  - avg. heart rate: 60-75 bpm

  - can measure by recording pulse rate wherever there is an artery fairly near to the surface of the skin; eg, wrist

  - use an ECG to record activity of the heart
• pulse rate


  number of times an artery expands and recoils in 1 min
• ECG


  graph showing electrical activity of heart plotted against time
• how does the heart beat


  through contraction and relaxation of the heart