Circulation and Respiration

• Basic features– Distribute nutrients throughout body– Remove wastes from cellular activity– Exchange gases

• Advanced features– Defend against infection– Cell communication – hormones

Why is a circulatory system necessary?

• Rate of diffusion limits effective transfer of nutrients.

• Fluid carries nutrient and dissolved gases to cells.– Connects organs of exchange with the rest of the body– Organs of exchange in animals

• Nutrients – stomach, intestines

• Gases – gills or lungs

Simple Distribution in Radiates

• Fluid filled channels distribute nutrients

• Branching– Increases surface

area

– Allows rapid diffusion to all cells

Open and Closed Circulatory Systems

Open Closed

• Blood and interstitial fluid the same - Hemolymph

• Exchange occurs at sinus

• Separate blood and interstitial fluid

• Exchange occurs at blood vessels

What Are the Features of Our Circulatory System?

• Fluid

• Vessels – tubes to carry fluid

• Pump to move fluid

• Valves to keep fluid moving in one direction

• Blood cells

Vertebrate Circulatory Schemes

Mammalian Circulatory

System• Pulmonary Loop

• Systemic Loop

Valve Structure of the Heart

• One way valves keep blood flowing in one direction

Cardiac Cycle

Cardiac Muscle

• Each cell is electrically connected to the next

Control of Heart Rhythm

• Coordinated contraction keeps blood flowing in one direction

Blood Vessels

• Arteries– Blood moves by pressure from heart

• Veins– Blood moves by action of valves and skeletal

muscles

• Capillaries– Many small branches to increase surface area

Structure of Blood Vessels

Vein vs. Artery

• Thin flexible wall• One way valves• Moved by skeletal

muscles

• Thick more rigid wall• No one way valves• Moved by heart

Effects of Blood Vessel Branching

• As cross-sectional area increases blood velocity decreases

• As surface area increases blood pressure decreases

Veins

Blood Flow in Veins

Control of Blood Flow in

Capillaries

• Blood can be diverted prevented from entering capillary net

Movement of Fluid in and Out of Capillaries

Components of Blood

Blood

Blood Cells

Blood Clotting

Warfarin

Gas Exchange

Gas Exchange in Aquatic Invertebrates

Gill Structure in Fish

Countercurrent flow

• Maximizes oxygen uptake

• Greatest difference in Oxygen content comes into contact with water

The human respiratory tract

Alveoli Structure 1

Alveoli Structure 2

Negative Pressure Breathing

Oxygen Loading and Unloading

• Hemoglobin in red blood cells carries oxygen and carbon dioxide

Hemoglobin

• Found in red blood cells

• Multiple protein complex with iron molecule

• Each hemoglobin binds to 4 oxygen or carbon dioxide molecules

• In general:– High oxygen/low carbon dioxide – releases carbon

dioxide and binds to oxygen– Low oxygen/high carbon dioxide – releases oxygen and

binds to carbon dioxide

Oxygen Dissociation

• Oxygen dissociation is greater at lower pH

• Metabolically active tissues have lower pH

Carbon Dioxide Exchange

Effect of respiratory poisons

• Carbon monoxide and cyanide– Bind to hemoglobin more strongly than oxygen

or carbon dioxide and don’t release– Cells do not receive oxygen