Integration of Physiological Systems
General Principle
What determines flow?
General considerations
Reading: Randall chapter 12
Why an animal would need a circulatory system-----
Functions of circulatory system
Basic design --Pump -- Tubes
PUMPS--TUBES
peristaltic contractions -----open circulatory system
chambered heart ----closed circulatory system
Open circulatory system ---Closed circulatory system
animal examples
Characteristics of system
minimal peripheral resistance
high peripheral resistance
fluid bathes cells
continuos flow of blood
minimal redistribution of flow
regulated distribution of flow and velocity
slow return of blood to heart
rapid return of blood to heart
presence of lymphatic system
Consequences/advantages of each type of circulatory system
Pumps
Peristaltic pumps - contractions of smooth muscle in artery wall
earthworm--associated with closed circulatory system
Accessory hearts--lateral hearts in worms, also found at base of wing, legs, antennae of arthropods
Tubular hearts - contractile portion of dorsal aorta with ostia for filling
arthropods--associated with open system,
alary muscles, skeletal muscle that assists in expanding the tube
Chambered hearts--vertebrates
Fish- four chambers in series--one circuit system
Shunts
Amphibians-three chambers-functionally divided ventricle-shared circuits 1
Reptile--three chambers-functionally divided ventricle-shared circuits
Advantage of a three chamber system
Birds,Mammals-four chambers--two circuits,
High pressure systemic system, lower pressure pulmonary system
Mass of heart as function of body mass ---- heart rate as function
of body mass
Cardiac Output (CO or Q)