Comparative Circulatory System

The function of animal circulatory systems is mainly…

AND…

Transport of O2 to the cellsTransport of CO2 out of the body

Transport of nutrients

Two Different Circulatory Systems• Open Circulatory

System• Blood (hemolymph) is

pumped into open body cavity (hemocoel).

• Blood reenters heart through openings (ostia).

• Does not require much energy to operate, but can’t sustain high levels of activity.

• Closed Circulatory System

• Blood is contained within blood vessels:– Arteries move blood

away from the heart.– Veins move blood toward

the heart.• Energetically costly to

operate, but allows higher levels of activity.

Invertebrate Circulatory Systems

Most Invertebrates have an open circulatory system.

Fish Circulation• A fish heart

has two chambers, one atrium and one ventricle.

• “Single-loop circulation” results in lower blood pressure in the body capillaries

Heart pumps blood to the gills to be re-oxygenated (gill circulation) after which blood flows to rest of body and back to the heart in one circuit.

Amphibian and Reptile Circulation• Amphibian and Reptilian

heart is a “Double-loop circulatory system.”

• Advent of lungs resulted in two circulations:– Pulmonary circulation -

(Lungs)– Systematic circulation -

(Rest of body)• Maintains blood pressure in

body capillaries• Oxygen rich and oxygen

deficient blood mix in the ventricle.

Mammalian and Bird Circulation

• Mammals, birds, and crocodiles have four- chambered heart.– right and left atria– right and left ventricles

• The right and left ventricles are separated by a muscular wall called the septum

• This prevents oxygen rich and oxygen deficient blood from mixing

• Made up of two pumping systems/circuits.– Pulmonary circulation– Systemic circulation

Comparison of Vertebrate Hearts

• Functions:– Transports

gases, nutrients, hormones, and waste

– Regulate body temperature

– Fight infection• Major Organs:

– Heart– Blood vessels

The Human Circulatory System

Circulation through body– Heart pumps blood

• Pulmonary circulation (heart to lungs to heart)

• Systemic Circulation (heart to body to heart)

Circulation through heart• Vena Cava• Right atria• Right ventricle• Pulmonary artery• Lungs• Pulmonary vein• Left atria• Left ventricle• Aorta• Body

Unoxygenated blood enters the

atrium on the right side of the heart.

Unoxygenated blood comes in

from the top of the body through the

superior vena cava.

Unoxygenated blood comes in from the lower

body though the inferior vena cava.

While the unoxygenated blood is in the right atrium, the tricuspid

valve is closed to keep the blood from

flowing down to the

ventricle.

The atrium

contracts and the tricuspid

valve opens, forcing

the blood down into

the ventricle.

The tricuspid valve closes again so that blood cannot move back up into the atrium.

The ventricle contracts. This forces

the unoxygenated blood through the pulmonary valve and into the pulmonary

arteries.

The right pulmonary artery takes the

unoxygenated blood to the right lung.

The left pulmonary artery takes the

unoxygenated blood to the left lung.

THE PULMONARY ARTERIES ARE

THE ONLY ARTERIES THAT

CARRY UNOXYGENEATED

BLOOD.

Oxygenated blood from the

lungs enters the heart through the

left atrium.

The mitral valve is closed to keep the blood from going into the

ventricle.

Oxygenated blood from the right lung returns to the heart

through the right pulmonary vein.

Oxygenated blood from the left lung

returns to the heart through the left pulmonary vein.

THE PULMONARY VEINS ARE THE

ONLY VEINS THAT CARRY

OXYGENATED BLOOD.

The left atrium contracts. This forces

the oxygenated

blood through the mitral

valve into the left ventricle.

The mitral valve closes again. This keeps the

oxygenated blood from

moving back up into the

atrium.

Oxygenated blood is forced into the aorta to be carried to the rest of

the body.

Blood Vessels• Tissues

– connective– smooth

muscle– endothelium

(type of epithelial tissue)

• Arteries• Veins• Capillaries

Blood• Connective tissue• Fluid structure

(can flow to all parts of the body)

• Blood Cells– Red blood cells

• lack nuclei• transport oxygen

– White blood cells• contain nuclei• fight infection

– Platelets• plasma proteins and

cell fragments responsible for clotting

• Blood Plasma– 90% water– 10 %

• dissolved gases• salts• nutrients• enzymes• waste• plasma proteins

– transport fatty acids, hormones, vitamins

– fight infections– involved in blood

clotting