1. Circulation System DITTO
December 14, 2011
Aim: Circulatory System in Animals
Warm-up:
What happens to your heart
rate when you exercise?
HW:
Circulation System DITTO

2. Feeding Energy Needs Why do we need a circulatory system? supplies in
fuel (sugars)
digestive system
oxygen
respiratory system
waste out
CO2
need to pick up & deliver the supplies & wastes around the body
circulatory system

3. Simple organisms
When your body is only 2-cell layers thick, you can get supplies in and waste out just through diffusion
all cells within easy reach of fluid
Jellyfish
Hydra

4. Complex organisms Circulatory system made up of 3 parts organ
heart
tissues & cells
blood vessels
arteries
veins
capillaries
blood
red blood cells
plasma

5. Circulatory systems All animals have: muscular pump = tubes = heart
circulatory fluid =
heart
Blood vessels
blood

6. Human Heart 4-Chambered heart atria (atrium) ventricles thin wall
collection chamber
receive blood
ventricles
thick wall pump
pump blood out
left atrium
right atrium
right ventricle
left ventricle

7. Evolution of circulatory system
Not everyone has a 4-chambered heart
fish
amphibian
reptiles
birds & mammals
2 chamber
3 chamber
3 chamber
4 chamber
A powerful four–chambered heart was an essential adaptation in support of the endothermic way of life characteristic of mammals and birds. Endotherms use about ten times as much energy as equal–sized ectotherms; therefore, their circulatory systems need to deliver about ten times as much fuel and O2 to their tissues (and remove ten times as much CO2 and other wastes). This large traffic of substances is made possible by separate and independent systemic and pulmonary circulations and by large, powerful hearts that pump the necessary volume of blood. Mammals and birds descended from different reptilian ancestors, and their four–chambered hearts evolved independently—an example of convergent evolution.
Why is it an advantage to get big?
Herbivore: can eat more with bigger gut.
lowers predation
(but will push predators to get bigger as well, although no one east elephant s.) V A A A A A A A V V V V V

8. Lub-dub, lub-dub 4 valves in the heart Heart sounds Heart murmur
flaps of connective tissue
prevent backflow
Heart sounds
closing of valves
Makes “Lub” and “Dub” sound
Heart murmur
leaking valve causes hissing sound
blood squirts backward through valve SL AV AV

9. Electrical signals heart pumping controlled by electrical impulses
stimulates ventricles to contract from bottom to top, driving blood into arteries
allows atria to empty completely before ventricles contract
heart pumping controlled by electrical impulses
signal also transmitted to skin = EKG

10. Cardiac Cycle How is this reflected in blood pressure measurements?
ventricles fill
How is this reflected in blood pressure measurements?
Systolic
________
Dystolic
The cardiac cycle. For an adult human at rest with a pulse of about 75 beats per minute, one complete cardiac cycle takes about 0.8 second.
During a relaxation phase (atria and ventricles in diastole), blood returning from the large veins flows into the atria and ventricles.
A brief period of atrial systole then forces all remaining blood out of the atria into the ventricles.
During the remainder of the cycle, ventricular systole pumps blood into the large arteries. Note that 7/8 of the time—all but 0.1 second of the cardiac cycle—the atria are relaxed and are filling with blood returning via the veins.
chambers fill
pump (peak pressure)
_________________
fill (minimum pressure)
120
________ 80
ventricles pump

11. Measurement of blood pressure
if systolic > 150 or
if diastolic > 90
hypertension = (high blood pressure)