Circulatory system

parazoans and simple metazoans(flat worms) -exchange of 02 and nutrients with environment is achieved via moevemtn of water Nematodes-fluids within bgody cavity are used for circulation

no distraction between blood and the extracellular (interstitial) fluids of body tissues eg) arthropods, and mollusks except cephalopods)

Open blood is pumped through vessels into body cavity Hemolymmph transports nutrients and metabolic waste, but ton o2 and CO2 heart with ostia

open ssystem Hemolypm also transports o2 and co2. blood has oxygen-binding pigments, hemocyanin, not hemoglobin)

Transportation-all substances essential to cellular metabolism are transported by the circulatory system -red blood cells transport oxygen to tissues -blood carries absorbed products of digestion to cells in the body -metabolic wastes and excess water in the blood are filtered through the kidneys regulation-transports hormones participates in temp regulation protection-circulatory system protects against injury and foreign substances 1)blood clotting platelets adhere to the damaged area 2)immune defense-white blood cells

blood is enclosed within vessels that transport the blood away from and back to heart, transports nutrients metabolic waste, and o2/co2 eg) annelids, cephalopod mollusks,

single-looped circulation; low blood pressure heat-gills body, back to heart -in the transition to lungs some aortic arches of the kills were repurposed to deliver deoxygenated blood to paired air sacs associated with pharynx

-the evolution of lungs coincided with the evolution of double-looped circulation -blood is pumped via the pulmonary circuit from the heart to the lungs and back -blood is pumped via the systemic circuit from the heart to the tissues and back Mammals, birds, crocodiles-4 chambered heart so deox blood and ox blood don’t meat

reptiles amphibians- 3 chamber heart so deox and o blood meet(two atria and one ventricle)

Mammals, birds, crocodiles-4 chambered heart so deox blood and ox blood don’t meat

Left ventricle-thicker walls, high pressure Right ventricle pumps deox blood to the lungs at low pressure

veins return blood, arteries take blood way from heart 1)Right atrium receives venous blood 2)blood flows to right ventricle and is pumped to lungs 3)left atrium receives ox blood from lungs 4)blood flows to left ventricle and is pumped to organs in body(via aorta) - 2 cycle pump: atrial chambers pump simultaneously followed by ventricular chambers

arteries and arterioles -blood leaves the heart via arteries and then to arterioles -contain more elastic fibers than other blood vessels.. When they contract they reduce heat loss and limits blood flow to injured vessels Capillaries -upon leaving the arterial system blood then enters an elaborate network of capillaries o2 is released to cells and co2 and other waste products are picked up Venules and veins -blood flows from venues and veins back to heart, aided by contractions of skeletal muscle -low pressure, most of body blood is contained in veins, pooling of blood causes varicose veins (bed ridded)

arteries and arterioles When they contract they reduce heat loss and limits blood flow to injured vessels

Increases heat loss, more blood flow

Capillaries -upon leaving the arterial system blood then enters an elaborate network of capillaries o2 is released to cells and co2 and other waste products are picked up

Venules and veins -blood flows from venues and veins back to heart, aided by contractions of skeletal muscle -low pressure, most of body blood is contained in veins, pooling of blood causes varicose veins (bed ridded)

-the circulatory system is a closed system; however some water and solutes of blood plasma filter through capillaries and form interstitial fluid -the amount of fluid that flows out of capillaries is greater than what flows in. The remainder renters the lymphatic system(open system) -excess interstitial fluid drains into lymph capillaries, which eventually passes to lymph nodes (in neck) and drained back into veins

respiration involes the diffusion of gases across plasma membrane -diffusion is passive, driven by the difference in o2 and co2 concentrations across a membrane. -ficks law of diffusion

R= (DxAxDeltap)/d r=rate of diffusion D=diffusion constant A=surface area deltap=difference in concentration on either side of membrane d=width of membrane -R can be increased by increased A, deltap or lowering d

Undirectional- in mouth out gills

bidirectional or tidal in mouth, goes out the opposite way birds have one way airflow

-gills are specialized vascularized filamentous structures that project into water. their design increased surface area (A) and minimized membrane width (d) for efficient gas exchange -papulae and tube feet in echinoderms serve as gills -naked gills in nudibranch(type of gastropod -many marine annelids breathe through their skin -aquatic insect larvae have external gills that connect to their tracheal system, lost as an adult -gills are found in most encrustations, many mollusks and annelids, as well as larval salamanders and fish -numerous groups of fish have evolved accessory breathing organs to cope with low dissolved o in water

if fished used concurentis fish would have no diffusion as water and blood would be 50/50