cardiovascular system

• cardiovascular system- regulates blood supply and generates blood pressure
• heart - > size of a fist and weighs less than 1 lb.

  > between lungs in thoracic cavity
• The heart is at the center, but oriented to the left
• Pericardium - Double-layered sac that anchors and protects heart ( heart coveriing )
• Fibrous Pericardium – elastic dense irregular connective tissue that prevents the over- stretching of the heart ( 2 layers of pericardium)
• Serous Pericardium – thinner, more delicate membrane that forms double layers around the heart ( 2 layers of pericardium)
• Visceral Pericardium – inner layer on the heart’s surface
• Parietal Pericardium – outer layer of membrane that surrounds the heart’s cavity
• Pericardial Cavity - Space around the heart that lies between layers.
• Pericarditis – inflammation of pericardium
• Epicardium ( heart layers )

  • external layer, on the heart’s surface (outside)
  • Also known as the visceral layer of serous pericardium
• Myocardium ( heart layers )

  • Thick, middle layer composed of cardiac muscle
  • Gives heart its special pumping ability
• Endocardium ( heart layers )

  • Inner thin layer of connective tissue
  • Lines chambers, covers valves
• cardiac muscle - 1 centrally located nucleus

  • branching cells
• 4 CHAMBERS:

  1. Right Atrium two superior

  2. Left Atrium chambers

  3. Right Ventricle two inferior

  4. Left Ventricle chambers
• ATRIA

   upper portion, holding chambers

   small, thin-walled
• Interventricular septum – separates right and left ventricles
• VALVES - structures than ensure 1-way blood flow
• Atrioventricular Valves (AV)

  • between atria and ventricles
• Semilunar Valves

  • Pulmonary Valve – base of pulmonary trunk •

  Aortic Valve – base of aorta

  • Chordae tendineae – attached to AV
• What happens when Bicuspid Valve is open?

  • Blood flows from LA into LV
  • Aortic semilunar valve is closed
  • Tension on chordae tendineae is low
• What happens when Bicuspid Valve is closed?

  • Blood flows from LV into aorta
  • Aortic semilunar valve is open
  • Tension on chordae tendineae is high
• I. Pulmonary Circuit ( circuits of heart )

  > right side of the heart

  > carries blood from heart to lungs
• II. Systemic Circuit ( circuit of heart )

  > left side of the heart

  > blood is O2 rich, CO2 poor
• Right Atrium – receives blood from:

  • Superior vena cava – drains blood above diaphragm

  • Inferior vena cava – drains blood below diaphragm
• Coronary sinus – drains blood from myocardium
• Right Ventricle – has thin walls because it only pumps blood to the lungs
• • Pulmonary trunk – splits into right and left pulmonary arteries
• Pulmonary arteries – carry blood away from heart to lungs
• Left Atrium – 4 openings (pulmonary veins) that receive blood from lungs
• Left Ventricle – opens into aorta – thicker, contracts more forcefully than right ventricle to get to the body
• Aorta – carries blood from the Left ventricle to the body
• Coronary Arteries

  • Supply blood to heart wall
  • Originate from base of aorta (above aortic semilunar valve)
• Left coronary artery – has 3 branches – supply blood to anterior heart wall and left ventricle
• Right coronary artery – originates on right side of aorta – supply blood to right ventricle
• Pacemaker Potential – changes in membrane channels’ permeability that are responsible for producing action potentials
• conduction system - > contraction of atria and ventricles by cardiac muscle

  cells
• electrocardiogram

  • record of electrical events in heart
  • diagnoses cardiac abnormalities
• cardiac cycle - Heart is 2 side by side pumps: right and left

  • repetitive pumping action which includes contraction and relaxation
• ➢ ATRIA: primers for pumps