Card Set Information
BIOL 1215-17 Circulation
Circulation and Gas Exchange:
Unicellular organisms exchange directly with environment.
Multicellular organisms cannot exchange directly with environment
Complex animals have internal transport systems that circulate fluid.
Simple animals with two cell body walls enclose a gastrovascular cavity.
This functions as digestion and distribution.
Open and Closed Circulatory Systems:
Present with complex animals.
List Three Basic Components of Both Circulatory Systems:
Circulatory Fluid [blood(
Set of Tubes (blood vessels)
Muscular Pump (the heart)
Open Circulatory System:
Blood bathes the organs directly
Arthropods and Molluscs.
Hemolymph = Blood + Internal Fluid.
Closed Circulatory System:
Blood is confined to vessels and distinct from interstitial fluid.
Closed systems are more efficient at transporting circulatory fluids.
Vertebrate Circulatory System:
Vertebrates have a closed circulatory system.
Three Main Blood Vessel Types:
Branch into arterioles and carry blood to capillaries.
Network of capillaries called
Site of chemical exchange.
Venules converge into veins.
Return blood from capillaries to heart.
Contain two or more chambers.
Blood enters through an atrium.
Pumped out through a ventricle.
Blood leaving heart passes two capillary beds before returning.
Bony fishes, Rays, and Sharks.
Amphibian, reptiles, and mammals have double circulation.
-poor and O
-rich blood pump seperately from right and left sides of heart.
Higher blood pressure in organs relative to Single Circulation.
Oxygen-rich blood delivers oxygen through systemic circuit.
Oxygen-Poor Blood Flow in Double Circulation:
circuit to get oxygen from lungs. (Most)
circuit to get oxygen from lungs and skin. (Amphibian)
Benefit of Double Circulation:
Can counteract gravity
: two atria and one ventricle.
Ventricle pumps blood into forked artery
Ventricle output is split to pulmocutaneous circuit and systemic circuit.
Blood flow to lungs is nearly shut off underwater.
Reptile (excluding Birds) Heart:
: two atria and one ventricle.
In crocodilians a septum divides the ventricle.
Reptiles have a pulmonary circuit (lungs) and a systemic circuit.
Mammal and Bird Heart:
with two atria and two ventricles.
pumps and receives only
receives and pumps only
Supplies oxygen for respiration and disposes carbon dioxide.
Gas diffuses down pressure gradients in lungs and organs by
Pressure exerted by a particular gas in a mixture of gases.
A gas diffuses from region of high to low partial pressure.
In the lungs and tissues O
Animals use air or water as source of respiratory medium.
There is less O
available in water than in air.
from water needs
Large, moist respiratory surfaces are needed for gas exchange.
Gas exchange takes place by diffusion.
Respiratory surfaces can include skin, gills, tracheae, and lungs.
Gills in Aquatic Animals:
Outfoldings of body creating large surface area for gas exchange.
Moves respiratory medium over respiratory surface.
Moving through water or moving water over gills for ventilation.
countercurrent exchange system
Countercurrent Exchange System:
Blood flows in opposite direction to water passing over the gills.
Blood is less saturated with O
Tracheal System in Insects:
Consists of tiny branching tubes that penetrate the body.
Tracheal tubes supply O
directly to body cells.
Respiratory and circulatory systems are separate.
Larger insects must ventilate their tracheal system to meet O
Infolding of body surface.
Circulatory system transports gases between lungs and rest of body.
Size and complexity of lungs correlate with metabolic rate.
Mammalian Respiratory System:
System of branching ducts conveys air to lungs.
Exhaled air passes over vocal cords to create sounds.
coat the surface of the alveoli.
Pathway of Inhaled Air:
Nostrils > Pharynx > Larynx > Trachea > Bronchi > Bronchioles > Alveoli
Ventilating the lungs is breathing.
Alternate inhalation and exhalation of air.
How an Amphibian Breathes:
An amphibian ventilates lungs by
Forces air down the trachea.
How a Mammal Breathes:
Mammals ventilate their lungs by
Which pulls air into the lungs.
Lung volume increases as rib muscles and diaphragm contract.
is volume air inhaled with each breath.
The maximum tidal volume is the
After exhalation residual volume of air remains in lungs.
How a Bird Breathes:
Eight or nine air sacs function as bellows keeping air flow.
Air passes through lungs in one direction.
Every exhalation completely renews air in lungs.
Metabolic demands require blood to transport large quantities of O
Blood Arriving in Lungs:
Low partial pressure of O
High partial pressure of CO
Relative to air in the alveoli.
diffuses into blood.
diffuses into air.
Partial pressure diffuses O
into interstitial and CO
Proteins that transport oxygen.
Greatly increases amount of oxygen that blood can carry.
Arthropods and molluscs have
with copper as oxygen-binding component.
Most vertebrates and some invertebrates use hemoglobin within
Can carry four molecules of O
Small change in partial pressure of oxygen means large changes in O
produced in respiration lowers blood pH and hemoglobin affinity for O
Hemoglobin helps transport CO
and assists in buffering.
from respiring cells diffuse into blood and transport into either blood plasma, bound to hemoglobin, or bicarbonate ions (HCO
Deep-diving air breathers stockpile O
and deplete it slowly.
Weddell seals have high blood to body volume ratio.
Also store oxygen in muscles via myoglobin proteins.