Cardio System

• Arteries


  carry blood from heart to tissues
• Sequence of arteries


  Large-medium-small-arterioles-capillaries
• Capillaries


  microscopic vessels where substance exchanged between blood & tissues
• Veins


  convey blood from tissue back to heart, has valves to prevent backflow
• Venules


  collect blood from capillaries & drain to veins
• Basic Exchange mechanism in Capillaries

  • Diffusion
  • Transcytosis
• Diffusion


  most important method of capillary exchange, exchange process form oxygen, carbon dioxide, glucose, amino acids and hormones
• Transcytosis


  substances in the blood plasma become enclosed

  within tiny vesicles

  • Endocytosis: entrance of substances

  • Exocytosis: exit of substance
• Hemodynamics:factors affecting circulation


  • Blood flow
  • Cardiac output
  • Blood pressure
  • Resistance
  • Venus return
• Blood flow


  volume of blood flows thru tissue
• Cardiac output


  volume of blood circulates thru systemic blood vessels
• 2 factors influencing cardiac output:

  1. Blood pressure
  2. resistance between blood & vessel wall
• Blood pressure


  hydrostatic pressure exerted by blood on walls of blood vessels, generated by contraction of ventricles & highest in AORTA and large SYSTEMIC ARTERIES, resting adult the BP rises about 120 systole (contraction) and drops to 80 diastole (relaxation)
• Resistance


  opposition to blood flow principally, result of friction between blood & walls of blood vessels
• Resistance depends on:


  • average bv radius
  • blood viscosity
  • total length of bv
• Venus return 


  volume of blood flowing back to hearts from systemic veins, depends on pressure diff from venules to right ventricle
• Pulse


  travelling pressure wave created by alternate expansion & recoil of elastic arteries after each systole of left ventricle, Normal resting pulse: 70-80 bpm
• Tachycardia 


  rapid resting heart rate over 100 bpm
• Bradycardia


  slow resting heart under 60 bpm
• Superficial temporal artery

  Located in lateral to orbit of eye
• Facial artery


  Located in mandible on line with corners of mouth
• Common carotid artery


  Lateral to larynx
• Brachial artery


  Located in medial side of biceps brachii muscle
• Femoral artery


  Located in inferior to inguinal ligament
• Popliteal artery


  Located in posterior to knee
• Radial artery


  Located in Distal half of wrist
• Dorsalis pedis artery


  located in superior to instep of foot