Cardiovascular System 42.1

Question 1

Why do we not want carbon dioxide to build up within the organism?

Answer 1

We need oxygen to serve as a final electron acceptor within the process of electron transport chain which is associated with oxidative phosphorylation which generates a bunch of ATP

Question 2

Why is a feathery gill beneficial?

Answer 2

Helps increase the surface area, increasing opportunity for exchange to take place. if gills have less of these extensions we would expect a reduced capacity for effective exchange

Question 3

Diffusion

Answer 3

• only efficient over small distances because the time it takes to diffuse is proportional to the square of the distance
• passive movement that depends on concentration gradients
• random thermal motion

Question 4

what do animals that lack a circulatory system (cnidarian & flatworm) have instead?

Answer 4

Gastrovascular cavity which incorporates both digestion and distribution of substances throughout the body. An opening at one end connects the cavity to the surrounding water.

Question 5

Why do we want a gastrovascular cavity to be around 2 cells thick?

Answer 5

Nutrients only diffuse a short distance to reach the cells of the outer tissue layer

Question 6

Open circulatory system

Answer 6

• There is no distinction made between the circulatory fluid and the extracellular fluid which is called hemolymph
• Contraction of the heart pumps the hemolymph through the circulatory vessels into interconnected sinuses

Question 7

Open circulatory system

Answer 7

• There is no distinction made between the circulatory fluid and the extracellular fluid which is called hemolymph
• Contraction of the heart pumps the hemolymph through the circulatory vessels into interconnected sinuses. Within the sinuses, the hemolymph and body cells exchanges gases and other chemicals. Relaxation of the heart draws hemolymph back in through the pores, which have valves that close when the heart contracts. Body movements periodically squeeze the sinuses, helping circulate the hemolymph

Question 8

What are sinuses?

Answer 8

Spaces surrounding the organs

Question 9

How does the heart power circulation?

Answer 9

By using metabolic energy to elevate the circulatory fluid’s hydrostatic pressure. The fluid then flows through the vessels and back to the heart.

Question 10

What is hydrostatic pressure?

Answer 10

The pressure the fluid exerts on surrounding vessels

Question 11

What is the function of the circulatory system?

Answer 11

By transporting fluid throughout the body, the circulatory system functionally connects the aqueous environment of the body cells to the organs that exchange gases, absorbs nutrients and dispose of waste.

Question 12

How does each cell of an animal participate in exchange?

Answer 12

Natural selection has resulted in two basic adaptations:
1) Simple body plan that places many or all cells in direction contact with the environment. Each cell can thus exchange materials directly with the surrounding medium

2) Circulatory system, system moves fluid between each cell’s immediate surrounding and body tissues. As a result, exchange with the environment and exchange with body tissues both occur over very short distances

Question 13

How does gastrovascular cavity work?

Answer 13

Fluid bathes both the inner and outer tissue layers, facilitating exchange of gases and cellular waster. Only the cells lining the cavities have direct access to nutrients released by digestion.

Question 14

Why is a flat body beneficial?

Answer 14

Optimizes exchange by increasing surface area and minimizing diffusion distances

Question 15

Closed circulatory system

Answer 15

Blood is confined to vessels and is distinct from the interstitial fluids. One or more hearts pump blood in to large vessels that branch into smaller ones that infiltrate the tissues and organs. Chemical exchange occurs between the blood and interstitial fluid, as well as between the interstitial fluid and body cells.

Question 16

Why is open circulatory system advantageous?

Answer 16

The lower hydrostatic pressures allow them to use less energy than closed systems.

i.e spiders use the hydrostatic pressure of their open circulatory system to extend their legs

Question 17

Why is closed circulatory fluid beneficial?

Answer 17

Blood pressure high enough to enable effective delivery of oxygen and nutrients in larger and more active animals.

Question 18

Three main types of blood vessels?

Answer 18

Artieries, veins and capillaries.

Arteries carry blood from the heart to organs throughout the body. Within organs, arteries branch into arterioles. These small vessels convey blood to capillaries, microscopic vessels with very thin, porous walls. Networks of capillaries, capillary beds, infiltrate tissues, passing within a few cell diameters of every cell in the body. Across the thin walls of capillaries, dissolved gases and other chemicals are exchanged by diffusion between the blood and interstitial fluid around the tissue cells. At their “downstream” end, capillaries converge into venules, and venules converge into veins, the vessedls that carry blood back to the heart.

Question 19

How are arteries and veins distinguished?

Answer 19

By the direction in which they carry blood

Arteries carry blood away from the heart towards the capillaries (efferent). Arteries are the distribution system

Veins return blood toward the heart from capillaries (afferent) . Veins are the collection system

Exception: portal veins which carry blood between pairs of capillary beds

Question 20

Atria

Answer 20

The chambers receiving the blood entering the heart

Question 21

Ventricles

Answer 21

The chambers responsible for pumping blood out of the heart

Question 22

Single circulation

Answer 22

Have a heart with two chambers, an atrium and a ventricle. Blood entering the heart collects in the atrium before transfer to the ventricle. Contraction of the ventricle pumps blood to a capillary bed in the gills, where there is a net diffusion of oxygen into blood and carbon dioxide out of the blood. As blood leaves the gills, capillaries converge into a vessel that carries oxygen-rich blood to capillary beds throughout the body. Following gas exchange in the capillary beds, blood enters veins and returns to the heart.

Question 23

Double circulation in amphibians

Answer 23

The pumps for the two circuits are combined into a single organ, the heart. The heart has 3 chambers , 2 atria (left and right) and a single ventricle. The right side of the heart pumps oxygen poor blood to the capillary beds of the gas exchange tissues, receiving this deoxygenated blood from the systemic (pulmonary or pulmocutaneous circuit). The other circuit, systemic, begins with the left side of the heart pumping oxygenated rich blood from the gas exchange tissues to capillary beds in organs and tissues throughout the body. Following the exchange, the oxygen poor blood returns to the heart, completing the circuit.

Question 24

What is the benefit of having both pumps with a single heart?

Answer 24

Simplifies coordination of the pumping cycles and reduce the mixing of oxygen in the heart

Question 25

In single circulation what happens to blood after flowing through the capillary bed?

Answer 25

Blood pressure drops, limiting the rate of blood flow in the rest of animals body. As the animal swims, the contraction and relaxation of its muscles helps accelerate the pace of circulation.

Question 26

Pulmonary circuit

Answer 26

Gas exchange takes place in lungs for most verterbrates including reptiles and mammals.

Question 27

Pulmocutaneous circuit

Answer 27

gas exchange takes place in capillaries in both the lungs and skin for amphibians

Question 28

In double circulation, what happens to blood after flowing through capillary beds?

Answer 28

The heart repressurizes the blood after it passes through the capillary beds or lungs or skin, providing vigorous flow to other organs. So blood pressure is often higher in systemic than in the gas exchange circuit.

Question 29

Double circulation in birds and mammals

Answer 29

The heart has two atria and two completely divided ventricles. The left side of the heart receives and pumps only oxygen rich blood, while the right side receives and pumps only oxygen poor blood.

Question 30

Difference between amphibians/reptlies and birds/mammals for double circulation?

Answer 30

Birds and mammals cannot vary blood flow to the lungs without varying blood flow throughout the body in parallel

Question 31

How has natural selection shaped the double circulation of birds and mammals?

Answer 31

As endotherms, they use about 10X as much energy as equal-sized ectotherms. Their circulatory systems therefore need to deliver about 10X as much fuel and oxygen to their tissues and remove 10X as much carbon dioxide and other wastes

Question 32

What does an earthworm have?

Answer 32

has pseudohearts (auxiliary hearts) but they play a role in pumping the circulatory fluid within the organism

Question 33

How do we want blood to flow in the vessels?

Answer 33

unidirectional because we don’t want to create any back-flow in order to help increase efficiency of moving that circulatory fluid throughout our bodies

Question 34

Roles of blood vessels?

Answer 34

Transport, regulation of blood flow, secretion of chemicals, control of blood pressure.

Question 35

Different types of arteries? Dia

Answer 35

Elastic arteries - conducting, provide a major force of blood movement throughout the artery (i.e aorta or pulmoary trunk). Withstand a ton of pressure due to their proximity to the heart, they need to resist that level of pressure so we don’t have abrupt changes in blood flow

Muscular arteries - distributing exits to supply specific areas of the body (i.e femoral artery). More active in vasoconstriction which is going to change the amount of blood that can flow to different areas of the body.

Arterioles - resistance, really thin, help control blood flow to tissues and are the sites in which we feed into capillary beds.

Question 36

Capillary bed

Answer 36

Exchange vessels, site in which vessels with varying oxygen content will have an opportunity to merge with one another

Question 37

Venule

Answer 37

Drain the capillary bed

Question 38

Veins

Answer 38

ultimately return blood to heart. Veins have a more collapsed organization compared to arteries because they’re serving as reservoirs and they don’t need to withstand the same amount of pressure as arteries so we don’t need to worry about them bursting. Also have a larger lumen allowing for little resistance to blood flow.

Question 39

Amphibians have a single ventricle

Answer 39

meaning that the separation of the systemic circuit and pulmocutaneous circuit are incomplete. but the ventricle will pump blood to both the lungs and body. we dont have a means of separating the blood content completely within the ventricles.