bsci202 lab practical 1

• where is the heart located?

  mediastinum area of your lungs
• how big is your heart?

  size of 2 fists together
• what are arteries?

  carry blood away from the heart (Thicker)
• what are veins?

  carry blood to the heart (thinner)
• what are the 4 chambers of the heart?

  two atria (atrium)

  two ventricles
• what do the atria do?

  receive blood from the pulmonary vein and vena cavae

  • left atrium receives oxygenated blood from lungs
  • right atrium receives deoxygenated blood returning from other parts of the body
• what do the ventricles do?

  receive blood from atria and pumps blood into aorta and pulmonary artery

  • right ventricle pumps deoxygenated blood to lungs
  • left ventricle receives oxygenated blood
• what are the pressure areas of the heart?

  atria: superior and low pressure areas

  ventricles: inferior and high pressure areas
• what is the tissue AROUND the heart?

  pericardium: double-walled sac; acts as lubrication to reduce friction between heart and surrounding structures
• what are the two layers of the pericardium?

  • fibrous pericardium: outer wall
  • serous pericardium: inner wall (double layered)
  • parietal pericardium: outer layer lining the fibrous pericardium
  • visceral pericardium: inner layer which forms the outer most layer of the heart (epicardium)
• what are the 3 layers of the heart wall?

  outermost to innermost: epicardium, myocardium, endocardium
• epicardium: the visceral pericardium
• myocardium: made of cardiac muscle

  • striated, intercalated discs, under involuntary control
  • supports cardiac muscle fibers and heart valves
• endocardium: composed of simple squamous epithelium
• what are the two circulatory systems of the heart?

  systemic and pulmonary circulation
• systemic circulation: carries blood to all tissues for nourishment, then transports oxygenated blood back to the heart

  • left ventricle --> aorta --> other arteries --> arterioles --> capillaries (within tissues) --> venules --> veins --> venae cavae --> right atrium
• pulmonary circulation: carries deoxygenated blood to the lungs for gas exchange, then brings oxygenated blood back to the heart

  • right ventricle --> pulmonary trunk --> pulmonary arteries --> capillaries within lungs --> left atrium
• why do the atria in the heart have thin walls?

  they are just receiving the blood under low pressure; they push the blood down into the relaxed ventricles
• why do the ventricles in the heart have thick walls?

  they push the blood back out of the heart with every contraction
• why does the left ventricle have thicker walls than the right ventricle?

  it is pumping the blood to tissues all over the body, rather than just the lungs
• what is the path of blood?

  left ventricle --> aorta --> other arteries --> arterioles --> capillaries (within tissues) --> ventricles --> veins --> vanae cavae --> right atrium --> right ventricle --> pulmonary trunk --> pulmonary arteries --> capillaries (within lungs) --> left atrium
• what are the steps of intrinsic conduction? (first 2)

  1. pacemaker cells generate their own action potentials
  2. impulses starts at the SA node
  3. sets depolarization rate (this is the pacemaker) and the impulse leaps across synapse-like connections between cells called gap junctions
  4. stimulus reaches atria causing atrial contraction to the AV node
• what are the steps of intrinsic conduction? (last 2)

  3. impulse is delayed at the AV node

  1. allows for atrial contraction to be completed before ventricular depolarization begins
  2. prevents premature closure of the AV valves

  4. electrical conduction through the ventricles requires

  1. bundle of his (AV bundle located in interventricular septum)
  2. bundle branches (in interventricular septum)
  3. subendocardial conducting network (purkinje fibers): in the muscles of ventricular walls (denser in left ventricle)
• what is the role of the nervous system in heart conduction?

  the sympathetic NS accelerates heart rate and the parasympathetic NS decelerates heart rate
• what is the p wave?

  depolarization of the atria, immediately prior to atrial contraction
• what is the QRS complex?

  depolarization of ventricles, immediately prior to ventricular contraction

  • atrial repolarization occurs during ventricular contraction
• what is the t wave?

  repolarization of ventricles
• what is the PR interval?

  signal travels from SA node to AV node

  • if <0.2 seconds, could be a partial heart block
• what is the QRS complex?

  ventricular depolarization and atrial repolarization

  • prolonged interval may indicate partial blockage of right or left bundle branch
• what is the QT interval?

  from ventricular depolarization through repolarization

  • faster heart rate: shorter interval
  • prolonged interval: greater risk of arrhythmias
• what is a junctional rhythm?

  • p wave is absent
  • SA node is not acting like a pacemaker, leading to the AV node pacing through the heart
• what is a second degree heart block?

  • not all p waves are followed by QRS complex
  • indicates damage to AV node
• what is ventricular fibrillation?

  • impulses generated in the atria do not pace ventricular contractions
  • uncoordinated contractions of the myocardium
• neutrophil:

  
• monocyte:

  
• basophil:

  
• lymphocyte:

  
• eosinophil:

  
• red bone marrow:

  
• white blood cells: