Chapter 42 Circulation And Gas Exchange

Front 1

1. Circulatory system link exchange surfaces with cells throughout the body

Back 1

- diffusion time is proportional to the square of the distance and is efficient over small distances
-in small or thin animals cells can exchange materials directly with the surrounding medium while others use fluid-filled circulatory system

Front 2

2. How does gastrovascular cavity work for animals without circulatory system?

Back 2

- functions in both digestion and distribution of substances throughout the body
-body wall that encloses the grastrovascular cavity in only two cells thick

Front 3

3. What is the benefit of having a circulatory system?

Back 3

- minimizes the diffusion distance in animals with many cell layers

Front 4

4. What are the general properties of a circulatory system?

Back 4

- A circulatory system has
*circulatory fluid
*set of interconnecting vessels
*muscular pump the heart
- circulatory system connects the fluid that surrounds cells with the organs that exchange gases, absorb nutrients and dispose wastes

Front 5

5. What is open circulatory system?

Back 5

- blood bathes the organs directly
- no distinction between blood and interstitial fluid, and this general body fluid is called a hemolyph

Front 6

6. Explain closed circulatory system.

Back 6

- blood is confined to vessels and is distinct from the interstitial fluid
- closed systems are most efficient at transporting circulatory fluids to tissue and cells
-annelids, cepholopods, and vertebrates have closed circulatory system

Front 7

7. Organization of Vertebrate Circulatory systems

Back 7

-have cardiovascular system
-three main types of blood vessels are arteries, veins, and capillaries
-blood flow is one way in these vessels

Front 8

8. How blood vessels work?

Back 8

- arteries branch into arterioles and carry blood away from the heart to capillaries
- networks of capillaries called capillary beds are the sites of chemical exchange between the blood and interstitial fluid
-venules converge into veins and return blood from capillaries to the heart

Front 9

9. How blood enter and exit the heart?

Back 9

- blood enters through an atrium and is pumped out through a ventricle

Front 10

10. Describe single circulation and double circulation>

Back 10

a. bony fishes, rays and shark have a single circulation, in which, blood leaving the heart passes through two capillary beds before returning to

b. amphibian, reptiles and mammals have double circulation, in which oxygen-poor and oxygen-rich blood are pumped separately from the right and life sides of the heart

Front 11

11. Pulmonary circuit

Back 11

-oxygen-poor blood flows through the pulmonary circuit to pick up oxygen through the lungs

Front 12

12. Pulmocutaneous circuit

Back 12

-amphibians has this

Front 13

13. Systemic circuit

Back 13

- oxygen-rich blood delivers oxygen through the systemic circuit

Front 14

14. Mammalian circulation

Back 14

- blood begins flow with the right ventricle pumping blood to the lungs
- in the lungs, the blood loads O2 and unloads CO2
-oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped through the aorta to the body tissues by the left ventricle
- aorta provides blood to the heart through the coronary arteries
- blood returns to the heart through the superior vena cava and inferior vena cava
- superior vena cava and inferior vena cava flow into the right atrium

Front 15

15. What is cardiac cycle?

Back 15

- heart contracts and relaxes in a rhythmic cycle called cardiac cycle

Front 16

16. Define systole.

Back 16

- contraction or pumping phase

Front 17

17. Define diastole

Back 17

- relaxation or filling phase

Front 18

18. Heart rate

Back 18

- also called pulse is the number of beats per minute

Front 19

19. Stroke volume

Back 19

- amount of blood pumped in a single contraction

Front 20

20. Cardiac outpu

Back 20

- volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume

Front 21

21. What prevents backflow of blood in the heart?

Back 21

- valves
- atrioventricular valves separate each atrium and ventricle
-semilunar valves control blood flow to the aorta and the pulmonary artery

Front 22

22. What causes the "lub-dup" sound of a heart beat?

Back 22

- lub-dup sound of a heart beat is caused by the recoil of blood against the AV valves (lub) then against the semilunar (dup) valves

Front 23

23. Heart murmur

Back 23

-backflow of blood through a defective valve

Front 24

24. Explain the process of maintaining the Heart's Rhythmic Beat.

Back 24

- some cardiac muscle cells are self-excitable meaning they contract without any signal from the nervous system
- sinoatrial (SA) node or pacemaker, sets the rate and timing at which cardiac muscle cells contract
- impulses that travel during the cardiac cycle can be recorded as an ECG
-impulses from the SA node travel to the AV node
-at the AV node, the impulses are delayed and then travel to the Purkinjie fibers that make the ventricles contract

Front 25

25. How is pacemaker regulated?

Back 25

-regulated by two portions of the nervous system; the sympathetic and parasympathetic
- sympathetic speeds up the pacemaker
-parasympathetic slows the pacemaker
-also regulated by hormones and temperature

Front 26

26. Blood vessel structure and function.

Back 26

a. vessel's cavity is called the central lumen and the epithelial layer that lines the blood vessels is called the enodthelium
b. endothelium is smooth and minimizes resitance

Front 27

27. Capillaries

Back 27

- have thin walls, the endothelium plus its basal lamina, to facilitate the exchange of materials

Front 28

28. Arteries and Veins

Back 28

-arteries and veins have an endothelium, smooth muscle, and connective tissue
-arteries have thicker walls than veins to accomodate the high pressure of blood pumped from the heart
-in the thinner-walled veins, blood flows back to the heart as a result of muscle action

Front 29

29. Blood flow velocity

Back 29

- physical laws governing movement of fluids through pipes affect blood flow and blood pressure
- velocity is slowest in capillary due to high resistance and large total cross-sectional area
-blood flow in capillaries is slow for exchange of materials

Front 30

30. Blood pressure

Back 30

- blood flows from areas of higher pressure to areas of lower pressure
- blood pressure is the pressure that blood exerts against the wall of a vessel
- in rigid vessels blood pressure is maintained; less rigid vessels deforms and the blood pressure is lost

Front 31

31. Systolic pressure

Back 31

- pressure in the arteries during ventricular systole; it is the highest pressure in arteries

Front 32

32. Diastolic pressure

Back 32

- pressure in the arteries during diastole; lower than systolic pressure

Front 33

33. Pulse

Back 33

- rhythmic bulging of artery walls with each heartbeat

Front 34

34. Regulation of blood pressure

Back 34

- blood pressure is determined by cardiac output and peripheral resistance due to constriction of arterioles
-vasoconstriction is the contraction of smooth muscle in arteriole walls; it increases blood pressure and vasodilation is the relaxation of smooth muscles in the arterioles; it causes blood pressure to fall
-vasoconstriction and vasodilation help maintain adequate blood flow as the body's demands change
-nitric oxide is a major inducer of vasodilation
-peptide endothelin is an important inducer of vasoconstriction

Front 35

35. Blood pressure and Gravity

Back 35

- measured for an artery in the arm at the same height as the heart
- blood pressure for a healthy 20 year old at rest is 120 mmHg/70mmHg

Front 36

36. What are the two mechanism regulating distribution of blood in capillary beds?

Back 36

- contraction of the smooth muscle layer in the wall of an arteriole constricts the vessel
-precapillary sphincters control flow of blood between arterioles and venules

Front 37

37. How blood flow regulated?

Back 37

- nerve impulses, hormones, and other chemicals

Front 38

38. Capillary function

Back 38

- exchange of substances between the blood and interstitial fluid takes place across the thin endothelial walls of the capillaries
-difference between the blood pressure and osmotic pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end
-most blood proteins and all blood cells are too large to pass through the endothelium

Front 39

39. Lymphatic system

Back 39

-returns fluid that leaks out from the capillary beds
-fluid, called lymph, reenter the circulation directly at the venous end of the capillary bed and indirectly through the lymphatic system
-lymphatic system drains into veins

Front 40

40. Lymph nodes

Back 40

- organs that filter lymph and play an important role in the body's defense
-edema is swelling caused by the disruptions in the flow of lymph

Front 41

41. Blood composition and function

Back 41

- consists of several kinds of cells suspended in a liquid matrix called plasma
-cellular elements occupy about 45% of the volume of blood

Front 42

42. Plasma

Back 42

- 90% water
- solutes of inorganic salts in the form of dissolved ions called electrolytes
-plasma protein influencing pH, osmotic pressure, and viscosity
-plasma proteins function in lipid transport, immunity and blood clotting

Front 43

43. Cellular Elements

Back 43

- RBCs and WBCs
- Platelets involved in clotting

Front 44

44. Erythrocytes

Back 44

- RBCs
- contain hemoglobin, iron-containing protein that transports O2
- lack nuclei and mitochondria

Front 45

45. Leukocytes

Back 45

- WBCs
- defense of phagocytizing bacteria and debris or by producing antibodies

Front 46

46. Blood clotting

Back 46

- is the formation of a solid clot from liquid blood
- cascade of complex reactions converts inactive fibrinogen to fibrin, forming a clot
- blood clot formed within a blood vessel is called a thrombus

Front 47

47. Stem cells and the replacement of cellular elements

Back 47

- cellular elements of blood wear out and are being replaced constantly
- erythrocytes, leukocytes and platelets all develop from a common source of stem cells in the red marrow of bones, especially ribs, vertebrae, sternum and pelvis
-hormone erythropoietin stimulates erythrocyte production when O2 delivery is low