Autumn.wmf (12088 bytes)Introduction to Organismal Biology (BIOL221) - Dr. S.G. Saupe; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321;;

Animals Transport (Circulatory) Systems

I.  Functions

II.  Types

A. No specialized system  

B.  Open System

C.  Closed System

III.  Cardiovascular systems

A.  General Vertebrate

1.  Heart

  • atrium � receive blood from veins  
  • ventricles � pump blood into arteries
  • valves - separate chambers

2.  Vessels  

  • arteries branch to arterioles  
  • arterioles capillaries  
  • capillaries site of chemical exchange between interstitial fluid and blood  
  • capillaries  venules
  • venules veins
  • veins heart

B.  Fish

C.  Amphibians (& most reptiles)

D.  Birds & Mammals

E.  Evolutionary Trend Summary

1.  increase in # chambers
2.  single
 double circuits
2.  full separation of atria and ventricles

  • reduces mixing of oxygenated and deoxygenated blood
  • increased exchange of blood gases
  • venous and arterial system can operate at different pressures

IV.  Mammalian heart

A.  General

B.  Cardiac Cycle � one complete heart beat

 V.  Control

A.  Heart cells

B.  Sinoatrial node (SA) or Pacemaker

  1. maintains rhythms  
  2. located wall of atrium (junction of rt atrium & superior vena cava)  
  3. electrical impulse (like nerve)  
  4. spreads quickly � cardiac cells connected � intercalary disks  
  5. sets tempo � slowed by parasympathetic NS (noradrenaline);  sympathetic NS -speeds up  

C.  Atrioventricular Node (AV)

D.  EKG � electrical activity pattern

VI.  Vessels & Flow

A.  Parts

B.  Flow & Size  

C.  Pressure  

VII.  Blood Flow

A.  Veins

B.  Capillary Beds

C.  Capillary Exchange

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Last updated: February 11, 2009        � Copyright by SG Saupe