Circulatory System

Transport systems in animals

Overview1. Functions of a transp

ort/circulatory system

2. Cellular transport3. Invertebrate

circulationa. Gastrovascular cavityb. Water vascular systemc. Open circulatory syste

md. Closed circulatory syste

m

4. Vertebrate circulationa. Fishesb. Amphibians

c. Reptilesd. Birdse. Mammals

Functions of the circulatory system 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

Transport at the cellular level Cell membrane

Passive transport (diffusion, facilitated diffusion, osmosis) high concentration of solutes to low

concentration of solutes no need to expend energy

Active transport spending energy moving materials from low

concentration to high concentration of solutes

Transport of large molecules endocytosis vesicles

exocytosis Cyclosis (cytoplasmic

streaming) occurs in eukaryotes, e.g. Paramecium

facilitated by microfilaments requires energy

Transport at the cellular level (con’t) Endoplasmic reticulum

manufacturing and transport facility

proteins produced in rough ER are packaged in vesicles

Golgi apparatus modification and storage

facility receiving end and

shipping end Vacuole

large membrane bound sacs

usually stores undigested nutrients

Gastrovascular cavity in simple invertebrates No system is

required Single opening:

exchange of materials with the environment

Central cavity for digestion and distribution of substances throughout the body

Body walls are two cell layers thick materials undergo diffusion

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

How are materials transported in multicellular organisms?

How are materials transported in multicellular organisms?Water vascular

system in echinoderms

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

closed system of canals connecting tube feet

madreporite ring canal radial and lateral canal tube feet ampullae

How are materials transported in multicellular organisms?Open circulatory system Phylum Arthropoda,

Phylum Mollusca (with one exception)

hemolymph (colorless) heart(s) sinuses

ostia heart(s) diffusion from sinuses

to organs insects: well-

developed respiratory systems, O2 not transported through the blood

How are materials transported in multicellular organisms?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

General plan of the cardiovascular system Heart

Atrium Ventricle

Blood vessels Arteries Arterioles Capillaries and

capillary beds Venules Veins

Blood

Different adaptations of the cardiovascular systems in vertebrates: fishes Single-circulation Fish heart

2 chambered hearts atrium and ventricle vessel

African lungfish heart 3-chambered

2 atria left side of atrium

receives oxygenated blood (to tissues)

right side receives deoxygenated blood (to lung or gills)

spiral fold partially divided

ventricle

Different adaptations of the cardiovascular systems in vertebrates: amphibians Pulmocutaneous and

systemic circulation are partly separated

Amphibian heart 1 ventricle pumps

blood to lungs, skin, and tissues

2 atria: rt. atrium receives

deoxygenated blood lt. atrium receives

oxygenated blood advantage: oxygen-

rich blood reaches the body’s organs faster

some mixing of O2-rich and poor blood occurs

Different adaptations of the cardiovascular systems in vertebrates: reptiles Reptilian heart

3-chambers (except for crocodilians with 4) 2 atria 1 ventricle (2 ventricles

in crocodiles and alligators) partially divided,

decreases mixing

may stop sending blood to lungs when not breathing

Different adaptations of the cardiovascular systems in vertebrates: birds and mammals 4 chambered heart:

2 atria 2 ventricles

full separation of pulmonary and systemic circuits

Advantages1. no mixing of oxygenated and

deoxygenated blood

2. gas exchange is maximized

3. separation allows for pulmonary and systemic circuits to operate at different pressures

Importance1. Endothermic high nutrient and

O2 demands in tissues

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

Blood flow in mammals R side of heart:

pulmonary circuit L side of heart:

systemic circuit one way valves:

atrioventricular valves semilunar valves

Blood flow in mammals1. 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