Circulatory system

Circulatory system - Animal Circulation An Essential...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Animal Circulation: An Essential Delivery & Removal System A circulatory system is: Pump(s) Vessels Fluid (blood) Three options for a system: None Simple, or open system Closed Small & Thin Animals Have None Limiting distance for diffusion is about 0.5 mm. Open systems: blood meets tissues directly The fluid surrounding tissues and organs is circulated by a tubular pump (usually located on dorsal side of animal) Thus hemolymph (blood) comes in direct contact with tissues for exchange Blood-filled body cavity is called a hemocoel Closed systems In a closed system the blood does not come into direct contact with tissues: it is contained within specialized tubes (vessels) which run throughout the body Exchange occurs within specialized, smaller and thin-walled vessels (capillaries) Advantages of Closed System Higher rate of blood flow Higher flow = greater delivery rates By changing resistance in smaller vessels, flow of blood to specific organs can be controlled Cells and large molecules (usually proteins) important in transporting nutrients & hormones are kept within the vessels How big can a heart get? Blue whales, largest animal ever to live on our planet Heart is about the size of a VW Beetle Aorta is large enough in diameter for you to crawl through Powerful enough to pump 10 tons of blood per minute…for a lifetime Vertebrate Circulatory Systems Some definitions: Flow to/from lungs = pulmonary circuit Flow to/from rest of body = systemic circuit Vessels carrying blood away from heart are arteries ; towards the heart, veins Capillaries are tiny, thin-walled vessels connecting arterioles to venules But, before we get too impressed… Recall an average size maple tree transports about 200 liters (approx 50 gal) of water per hour from roots to leaves via xylem Right now, your heart is pushing out about 60 ml blood per contraction, at about 60 bpm, or roughly 54 gal per hour In other words, your circulatory system is achieving the same result as an average maple tree Fishes have simple circulatory systems Do you see a possible drawback to this system? Some fishes have lungs! Lungs evolved from non-gill structures (a swim bladder or similar organ from out- pocketing of esophagus); note direct return of blood to heart from lung (beginnings of pulmonary circuit) Lungfish are members of an ancient lineage of freshwater fish (fossils are known from the Devonian) and closely related to the group that gave rise to land vertebrates.gave rise to land vertebrates....
View Full Document

Page1 / 45

Circulatory system - Animal Circulation An Essential...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online