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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