Circulatory System

The circulatory system transports

Oxygen to all cells. Nutrients from the digestive system to all cells. Waste products from cells and returns them to the respiratory, digestive, and urinary systems for disposal. Hormones from where they are secreted to their target organs

The circulatory system is involved in

immune response and thermoregulation

Sponges and most cnidarians use \______ as their circulatory fluid

water

In invertebrates with a pseudocoelom, the \________ acts as the circulatory fluid

coelomic fluid

In an open system the \_______________ is circulated around the body

extracellular fluid

Circulatroy system of molluscs

There is a vessel from the heart that supplies the gills and one that supplies the rest of the body.

What is the circularoty fluid in insects?

Haemolymph

Lymph contains

Cancer cells, Damaged cells, Fats, Bacteria and viruses, White blood cells (lymphocytes)

Blood pressure in veins is significantly \________ than in arteries

lower

How is blood moved the great distances necessary in bipeds?

Venous pressure combined with muscles in the legs squeezing the veins, and the valves in veins.

Plasma

carries endocrine molecules, proteins, solutes, that includes nutrients, gasses, and wastes

Formed elements

Erythrocytes, thrombocytes, leukocytes

Capillaries

where gas, nutrient and waste exchange happens between the blood and the cells.

Blood slows right down when passing through capillaries because

of the small diameter of the vessels, which allows for more time for the exchange of materials

Continuous capillaries

complete basement membrane and continuous endothelium with intercellular clefts. Least amount of exchange. Found in muscle, skin, lungs and CNS

Fenestrated capillaries

complete basement membrane and continuous, fenestrated endothelium. Greater exchange. Found in endocrine glands, small intestine and kidneys.

Sinusoid capillaries

discontinuous basement membrane and discontinuous, fenestrated endothelium. Maximum exchange. Found in liver, spleen and bone marrow

The circulatory part of the lymphatic system consists of

lymphatic capillaries, vessels and ducts

Lymph ducts empty back into

the bloodstream at the junctions of the jugular and subclavian veins on each side of the body

How is lymph moved?

By movement of the body and in "lymph hearts" in amphibians, reptiles and some birds.

The most ancestral vertebrate circulation system is found in

Fish, they have a single circuit and a two chamber heart

In birds and mammals the sinus venosus evolved into

the sinoatrial node

In birds, mammals, and crocodilians the conus arteriosus becomes incorporated into

the ascending aorta and pulmonary trunk

What caused the need for a second pulmoary circuit?

The developments of lungs

Double circulation

One circuit goes to the lungs, where the blood is oxygenated. This oxygenated blood returns to the heart to be circulated to the body. Found in amphibians, reptiles, birds and mammals

The trend in evolution of the vertebrate heart is towards

increasing separation of oxygenated and deoxygenated blood

Amphibians have how many chambers in their heart?

three, with two atria and one ventricle. Oxygenated and deoxygenated blood don’t mix in the atria and ventricle is partly divided to reduce the mixing.

Why does fluid need to return from the lymphatic system back into the bloodstream?

To maintain normal blood pressure and volume and prevents fluid from building up in tissues

Edema

Fluid build up in the tissues (swelling)

Lymph nodes

Filter out all the waste from the lymph

The evolution of endothermy is thought to be related to

The increased efficiency of the heart of birds and mammals

What four types of tissues are found in arteries, veins, arterioles, and venules?

Endothelium, Elastic fibers (two layers in arteries), Smooth muscle (thicker in arteries), Connective tissue

Why are there two layers of elastic fibers in arteries?

Arteries are under much higher and need to be able to recoil and not burst each time a pulse of blood comes through.

What does the muscle layer in blood vessels allow for?

Vasoconstriction and vasodilation

Vasoconstriction

lowers blood flow through a particular artery, and

Vasodilation

Increase blood flow to a particular artery

How many hearts do Cephalopods have?

three, two branchial hearts send blood to the gills and a systemic heart that sends blood to the body

How many hearts do annelids have?

most have five hearts, blood flows away from the heart through ventral vessels and returns through dorsal vessels

What are the advantages of a closed circulatory system?

Higher pressure and more rapid blood flow. Blood flow can be targeted to individual organs. Blood flow to organs can be adjusted depending on the need of the body

How do lizards and snakes keep oxygenated and deoxygenated blood separate?

They have a septum that partly divides the oxygenated and deoxygenated blood in the ventricle.