1. Functions of a transport/circulatory system

2. Invertebrate circulationa. Diffusionb. Aided by gastrovascular cavity

c. Water vascular systemd. Open circulatory systeme. Closed circulatory system

3. Vertebrate circulationa. Fishesb. Amphibians

c. Reptilesd. Birdse. Mammals

1) Pathway of blood2) Cardiac cycle3) Maintenance of heartbeat4) Principles governing blood

circulation5) Lymphatic system6) Blood composition and

function7) Cardiovascular disease

Transports materials Nutrients from digested food Respiratory gases: CO2 and O2 Waste materials: toxins and nitrogenous wastes Antibodies Hormones Enzymes

Immune functions Maintains homeostasis

Blood pH Heat transport

Gastrovascular cavity in simple invertebrates

Cnidarians (e.g. Hydra) and flatworms (e.g. planarians)

No system requiredSingle opening: exchange

of materials with the environment

Central cavity for digestion and distribution of substances throughout the body

Body walls two cell layers thick materials undergo diffusion

Water vascular system in echinoderms

multi-purpose: locomotion, food and waste transport, respiration

movement of muscles pump water into canals

closed system of canals connecting tube feet

madreporite ring canal radial and lateral canal tube feet ampullae

Open circulatory system

Phylum Arthropoda, Phylum Mollusca (with one exception)

hemolymph heart(s) sinuses ostia

heart(s)diffusion from sinuses to

organsoften serve a support

purposedisadvantage: loss of

pressure in sinuses insects: well-developed

respiratory systems, O2 not transported through the blood

Closed circulatory system or cardiovascular system

cephalopods, annelids, vertebrates

presence of blood vessels advantages

1. rapid flow2. may direct blood to

specific tissues3. blood cells and large

molecules remain within vessels

4. can support higher levels of metabolic activity

HeartAtriumVentricle

Blood vesselsArteriesArteriolesCapillaries and

capillary bedsVenulesVeins

Blood

FISHESSingle-circulationFish heart

2-chamberedatrium and ventricle

African lungfish heart3-chambered

2 atriaLA: O2-rich bloodRA: O2-poor bloodspiral fold

partially divided ventricle

Amphibians

Pulmocutaneous and systemic circulation are partly separated

Amphibian heart1 ventricle2 atria:

LA: O2-rich bloodRA: O2-poor blood

advantage: oxygen-rich blood reaches the body’s organs faster

disadvantage: some mixing of O2-rich and poor blood occurs

Reptiles

Reptilian heart3-chambers

(crocodilians have 4)2 atria1 ventricle (2 in

crocodiles and alligators) partially divided,

decreases mixing

Birds and Mammals 4 chambered heart:

2 atria 2 ventricles

full separation of pulmonary and systemic circuits

Advantages1. no mixing of oxygenated and

deoxygenated blood2. gas exchange is maximized3. pulmonary and systemic circuits

operate at different pressures

Importance1. Endothermic high nutrient and O2

demands in tissues

2. Numerous vessels great deal of resistance, so requires high pressure

R side of heart:pulmonary circuit

L side of heart:systemic circuit

one way valves:atrioventricular

valvessemilunar valves

1. right atrium receives O2-poor blood from superior and inferior venae cavae

2. from right atrium into the right ventricle through the tricuspid valve

3. pumped into the pulmonary artery through the pulmonary semilunar valve to lungs

4. O2-rich blood from lungs is returned to the left atrium via the pulmonary veins

5. enters the left ventricle via the mitral or bicuspid valve

6. exits the left ventricle into the aorta via the aortic semilunar valve

7. circulated to body tissues