Circulation and Gas Exchange Flashcards
What is a circulatory system?
moving fluids reducing functional diffusion distance that products must transverse
What is a circulatory system, and where is it usually found?
related to size, complexity, and lifestyle
usually internal, extracellular, aqueous medium
What do sponges and cnidarians do to circulate?
environmental water
What can be used to transport material?
body cavity
What do bastocoelomates use to circulate, and what kind of animals are they?
blastocoelomates uses body cavity fluid
small/ long and thin (rotifers)
What does circualtion limit animals to?
small size or shapes when there are no special chambers or vessels for fluids to diffuse material
What is a closed circulatory system?
blood stays in distinct vessels and may line chambers
How do closed circulatory systems exchange, and what is required at exchange sites?
exchange occurs in special systems like capillary beds
site must offer minimal diffusion resistance
What are closed circulatory systems common in?
well-developed or spacious coeloms
How do blood and coelomic fluid differ in function>
blood- transport nutrient and gas
coelom- accumulate metabolic waste for nephridia/ hydrostatic skeleton
What do closed circulatory systems rely on?
relies on body movement/coelomic pressure to move blood, or muscles/ hearts/ contractile vessels/ pulsatile organs
What is an open circulatory system?
heart, vessels, chambers, and sinuses where hemolymph empties from vessels into body cavity and bathes organs
What is a hemocoel (2), and what groups have it?
body cavity with a reduced coelom/ loss of peritoneal lining
can act as a hydrostatic skeleton/ movement
arthropods and non-cephalopod molluscs
3 types of structural emchanisms to pump blood
contractile vessels (annelids)
ostiate hearts (arthropods)
chambered hearts (molluscs and vertebrates)
What is intrinsic pumping structure, and an example?
originating from muscles of the structure itself
myogenic heart of mulluscs and vertebrates
What is extrinsic pumping structure, and an example?
originating from motor nerves outside the structure
neurogenic hearts of arthropods and vessels of annelids
Where does gas exchange occur in invertebrates that lack such structures?
occurs integumentary/cutaneous/ body surface
What are restrictions to organisms without specialized gas exchange structures
tiny or soft-bodied
restricted to moist or aquatic habitat
What are gills?
thin-walled, external organs well supplied with blood or body fluids
highly folded or digitated to increase diffusive surface area
What other non-gas exchange function can gills do?
can be used for sensory input and feeding in some
What is a con of gills?
must be protected from osmotic stress (estuaries)
What is hindgut irrigation?
use of gut lining for gas exchange and pumps water in and out of a hindgut (sea cucumbers)
What are book lungs, and what groups have it?
blind inpocketings with highly folder inner linings
arachnids, insects, and centipedes/millipedes
What is a tracheae?
branched, anastomosed invaginations of the outer body wall
What does trachea allow?
allows diffusion of oxygen from air to the tissues (no blood)
What does atmospheric pressure prevent in the trachea?
prevents fluids from being drawn too close to the body surface due to evaporation
What are spiracles?
special muscles to ventilate tracheae in large insects to pump air
What is a pseudotracheae, and what group has it?
invaginated gas exchange structures on some of their abdominal appendages
terrestrial isopod crustaceans
What are pneumostomes, and group?
gas exchange structure that opens to the outside via a pore, derived from the mantle cavity
land snails and slugs
What are respiratory pigments, and wheere are they found?
special molecules with metal ions that can reversibly bind and transport oxygen
occurs in solution, but some may uccyr within cells
What do respiratory pigments do in different oxygen concentrations? (3)
loads during high oxygen concentration and unloads in low oxygen concentrations
loads/binds at sight of oxygen exchange
unloads/releases at cells and tissues
What factors influence O2 carrying capacity of respiratory pigments?
temperature, CO2 concentration, and other factors
Four respiratory pigments
hemoglobin, hemocyanins, chlorocruorins, and hemoerthrins
Where does oxygen go first in cephalized groups?
head
What group are respiratory pigments rare in, and why?
insects
use tracheal system, not blood, to carry oxygen
How does oxygen vary in water?
turbulence, depth, temperature, salinity
What is hemoglobin (3)?
most common
some transport only, others stores
reddish
Where is hemoglobin found, and what groups have them?
annelids, crustaceans, insects, molluscs, and echinoderms + protists, fungi, and plants
carried in coelomic cells or dissolved in blood
What are hemerythrins (2), and its evolution?
violet to pink when oxygenated
functions for storage
long and complex evolution- may have other roles
What groups have hemerythrins?
annelids, brachiopods
WHat is chlorocruorins, and what group has it?
green to red
functions well in high environmental levels of oxygen
annelids
What are hemocyanins, and where (3) is it found?
hemolymph of molluscs and arthropods
copper instead of iron (blue)
release oxygen easily and provides space to tissue at high concentrations
in solutions, not cells
How does the body store CO2? (2)
body fluids have high CO2 concentrations to form carbonic acid in water
then turns into bicarbonate, adjusting pH due to changing carbon dioxide levels
