circulation 8 Flashcards
closed circulatory system
capillary connections, blood does not directly connect cells, higher bp=strong heart and higher cost
-small diameter caps create vascular resistance
open circulatory
sinuses between cells, no endothelial lining
- hemolymph directly contacts cells
- low resistance to flow in large dinuses, so lower opreating cost, but also slower circulation time due to less local control of flow
red pink and blue resp pigments that bind O2 in invertebrates
red: rbc hemoglobins in mollucs and annelids, or extra cell hemoglobins and chlorocruorin in bivalve molluscs and arthropods
pink blood cell hemerythrins (amino acids) seen in marine worms
blue hemocyanin, extracellular in arthropods and molluscs
ostial hearts in invertebrates
-single cardiac chamber
-pericardial sinus surrounding outisde heart is filled with hemolymph
-CNS stimulates heartbeat, therefore its neurogenic
-
ostial heart cycle
systole: cardiac muscle contract in unison, jejecting hemolymph into arteries and stretching suspensory ligaments
diastole: cardiac muscles relax, recoil of suspensory ligaments expands the heart chamber, drawing hemolymph from sinus via ostia into the heart
NOTE: some energy of contaction is stored in elactic suspensory ligaments to enable blood to be sucked into heart during relaxing
segmental arrangement
common for open circulatory systems, have multiple neurogenic hearts in large dorsal distribution vessels
insects
terrestrial insects have very high metabolic rate
- tracheal resp system moves O2 directly to tissues, while open circ moves nutrients, wastes, white cells and hormones
- multiple segmented hearts, NO RESP pigments
- sluggish flow rates and hydraulic function
- accessory pumps can pressurize wing and limb vessels; so body movements assist hemolymph flow
crustaceans
- aquatic+terrestrial, some capable of high metabolic rates
- open circ moves GASES (insects dont), nutrients, wastes, wbc, hormones
- most crustaceans are small, hav segmental ostial hearts, large sinus volumes, and resp pigments
- DECAPODS are larger, active, and have GILLS
- SINGLE ostial heart, arterial outflow sphincters for regional control
- hemocyanin, and smaller tissue sinuses
bivalve molluscs
sedentary filter feeders, low metabolic rates, some even live in hypoxic environ
-open cic, single ostial heart, some vessels
cephalopod molluscs
- have TRUE CAPILLARIES AND CLOSED CIRC
- CHAMBERED, MYOGENIC HEARTS
- paired branchial heart pumps deoxy blood to gills, systemic herat pumps oxygenated blood
- hemocyanin(blue) dissolved in blood
annelids
tubeworms, earthworms, and leeches have low metablolic rates, but can live in hypoxic environ
-tubeworms have open circ, chambered heart, vessels, hemolymph flow in sinuses, body wall movements via cilia
but earthworms have closed circ, five segmental contractile tubes, vessels, and connecting vessels
what animals have no circulatory system
sponges: due to using convection for digestion powerered by flagella, cell contractions, or cilia
