Chapter 23; The Circulatory System
Anatomy of Blood Vessels
•Closed system of tubes that carries ________
•________carry blood from heart to tissues
- ____________arteries; stretch to help blood to pass
- ____________arteries; help pump blood – vasoconstriction
- ________________; smaller divisions of arteries
•________________are thin enough to allow exchange
•____________merge to form veins that bring blood back to the heart
•Thicker walled than ________
•Move blood away from the ________
•May assist in the ____________process
•Layers; Tunica ________ (intima); Tunica ________; circular smooth muscle & elastic fibers; Tunica
•Largest-diameter arteries have lot of ____________fibers in tunica media
•Help propel ________onward despite ventricular relaxation (____________________________________)
•Medium-sized arteries with more ____________than elastic fibers in tunica media
•Capable of greater ____________________and ____________________to adjust rate of flow
–walls are relatively ________; called distributing arteries because they direct ________flow
•Small arteries delivering blood to ________________; tunica media containing few layers of muscle
•Metarterioles form branches into ____________________bed
–to bypass ____________________bed, precapillary sphincters close & blood flows out of bed in
•Microscopic vessels that connect arterioles to ________________
•Found near every cell in the body but more extensive in highly active tissue (muscles, liver, kidneys & brain)
–entire capillary bed fills with blood when tissue is ____________
–lacking in: ____________________________________________________________
•Function is exchange of ________________& ____________between blood and tissue fluid
•Structure is single layer of simple ________________epithelium and its basement membrane
•Small veins collecting blood from ____________________
•Tunica media contains only a few ____________muscle cells & scattered fibroblasts
–very porous endothelium allows for escape of many phagocytic ____________blood cells
•Venules that approach size of ________more closely resemble structure of vein
•Proportionally ____________________walls than same diameter artery
–tunica media less ________________
–lack external & internal elastic lamina
•Still adaptable to variations in ________________& ________________
•________________are thin folds of tunica interna designed to prevent backflow
•Venous sinus has no muscle at all; ________________sinus or dural venous sinuses
•Twisted, dilated superficial veins;caused by leaky venous ________
•congenital or mechanically stressed from prolonged ________________or ________________
–allow ________________and ________________of blood
•extra pressure forces ____________into surrounding tissues
•nearby tissue is inflamed and ________________
•Deeper veins not susceptible because of support of surrounding ________________
•Union of 2 or more _________supplying the same body region; blockage of only one pathway has no ____
•________________________________ of heart
•Alternate route of blood flow through an anastomosis is known as ________________________________
–can occur in veins and ________________as well
•____% of blood volume at rest is in systemic veins and venules; function as blood reservoir
•veins of skin & abdominal organs; blood is diverted from it in times of ________
•increased muscular activity produces ________________________
•hemorrhage causes ________________________to help maintain blood pressure
•____% of blood volume in arteries & arterioles
•Movement of materials in & out of a capillary; ____ ____ ____(most important method)
•substances move down ____________________gradient
•all plasma solutes except large ________________pass freely across
–blood brain barrier does not allow diffusion of water-soluble materials; ____________________
•passage of material across endothelium in tiny vesicles by ________________and ________________
–large, lipid-insoluble molecules such as insulin or maternal antibodies passing through
________________circulation to fetus
•Pressure exerted by blood on walls of a vessel
–caused by contraction of the ________________
–highest in ________________
•________ mm Hg during systole & ________during diastole
•If heart rate increases cardiac output, ________rises
•________________falls steadily in systemic circulation with distance from left ventricle
–____mm Hg entering the capillaries
–____ mm Hg entering the right atrium
•Water retention increases ________pressure
•Volume of ________flowing back to the
heart from the systemic veins
–depends on pressure difference from venules
(16 mm Hg) to right ____ ____ (0 mm Hg)
–tricuspid valve leaky and buildup of blood on
________side of circulation
•Skeletal muscle pump
–contraction of ________________&
presence of valves
–decreased thoracic ____________and increased abdominal
____________________during inhalation, moves blood into
thoracic veins and the right atrium
•____________or a sudden, temporary loss of consciousness
not due to ____________
–due to cerebral ________________or lack of blood flow to the
–________________________ = sudden emotional stress
–____________________syncope = pressure stress of
coughing, defecation, or urination
–________________________________syncope = antihypertensives, diuretics, vasodilators and tranquilizers
–______________________hypotension = decrease in BP upon standing
Shock and Homeostasis
•Shock is failure of cardiovascular system to deliver enough ________ and ________________
–inadequate ________________; ____________________________________________
–cells forced to switch to ________________respiration
–________________acid builds up
–cells and tissues become ________________& ________
Signs & Symptoms of Shock
•____________resting heart rate (sympathetic stimulation)
•________, rapid pulse due to reduced cardiac output & fast heart rate
•____________, cool skin due to cutaneous vasoconstriction
•________________-- sympathetic stimulation
•Altered ____________state due to cerebral ischemia
•Reduced ____________formation -- vasoconstriction to kidneys & increased aldosterone & antidiuretic
•____________-- loss of extracellular fluid
•____________-- buildup of lactic acid
•____________-- impaired circulation to GI tract
1. What vessels always carry blood away from the heart?
2. What type of artery stretches to allow blood to pass?
3. What type of artery helps pump blood through contraction and is capable of vasodialation?
4. What type of vessel is a smaller division of the arteries that supplies the capillaries with blood?
5. Where does all exchange of materials between the blood and the body cells occur?
6. What vessels always carry blood back toward the heart?
7. Arteries have thinner wall than a similarly sized vein; T/F
8. Which of the following is not a layer of the arteries;
9. In which layer of the arteries would you most likely find smooth muscle fibers?
10. Why is only smooth muscle found in blood vessels (and not the other two types of muscle tissue)?
11. The aorta is an example of what type of artery?
12. How do elastic arteries help move blood?
13. Muscular arteries are the largest in the body; the aorta is a good example; T/F
14. What term means a reduction in the diameter of a blood vessel, reducing flow?
15. What term means an increase in the diameter of a blood vessel, increasing flow?
16. What is another term for muscular arteries?
17. Why are muscular arteries called distributing arteries?\
18. What structures form branches that lead blood from arterioles to capillaries?
19. When a precapillary sphincter closes, what region does not receive much blood flow?
20. Capillaries are found in the highest concentrations near tissues that are;
21. Which of the following is an unimportant internal organ;
22. In what areas of the body are capillaries missing?
23. What are the main functions of capillaries?
24. Capillaries are composed of what two layers?
25. What process means that materials move through capillary walls from an area of high pressure to an area
of low pressure?
26. If you were an RBC leaving a capillary bed, into what type of vessel would you move next?
27. Why is the tunica media of venules very porous?
28. There is a clear difference, structurally, between large venules and small veins; T/F
29. Why do veins require thinner walls than those found in arteries?
30. Veins are capable of adapting to variations in blood volume and pressure; T/F
31. What are thin folds of the tunica interna of veins that are designed to prevent backflow of blood?
32. What are twisted, dilated superficial veins?
33. What are the main causes of varicose veins?
34. The extra pressure in varicose veins has what effect on the vessels and the surrounding tissues?
35. Why are deeper veins not susceptible to the development of varicose veins?
36. The union of 2 or more arteries supplying the same body region is known as;
37. What are the two non-superficial regions of the body in which there is a well known anastomosis?
38. The alternate route of blood flow through an anastomosis is known as;
39. Where is the majority of the body’s blood located when you are at rest?
40. What term means that the blood that is found in the venous system can be transferred to the arterial system
in an emergency?
41. What process occurs in the venous system when you loose a large amount of blood?
42. Plasma proteins cannot cross a membrane; T/F
43. What plasma proteins must cross the placental membrane?
44. The main cause of arterial blood pressure is;
45. The blood vessel that shows the highest average blood pressure is the;
46. What term means the blood pressure measured when the ventricles are contracting?
47. What term means the blood pressure measured when the ventricles are relaxing?
48. In what part of the circulatory system is blood pressure the lowest?
49. Be able to explain the following figure (for sure) on the next exam;
50. Be able to answer questions regarding the following figure;
51. What structures are found in veins that are not found in arteries?
52. How does respiration help move blood?
53. Fainting or sudden temporary loss of consciousness not due to trauma is;
54. Which type of syncope is due to sudden emotional distress?
55. Which type of syncope is due to high internal body pressure?
56. Which type of syncope is due to drugs?
57. When you are in a bathtub and suddenly stand up, you can become dizzy and even pass out. What is this
58. What is a failure of the cardiovascular system to deliver enough oxygen and nutrients to the body?
59. Which of the following is not one of the events that results from shock;
60. Which of the following is not a sign and symptom of shock;