The Cardiovascular System: Vessels and Circulation

Textbook chapter: 15.

Resources:

Use these web resources to supplement your studies of lecture notes and objectives.

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Lecture Notes

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I. Vessels
The vessels of our circulatory system contain the blood in a closed system. Red blood cells do not leave vessel, platelets seal tears in vessels and white blood cells can migrate through vessel walls. Other water and dissolved substances leave primarily at capillaries, only.

General sequence of vessels is: artery, arteriole, capillary, venule and vein. Except for capillary, vessels have two or three layers in their walls.

A. General structure of arteries and veins -most complex vessels 1. Lumen

2. Tunica interna or intima (innermost)
simple squamous epithelial
maintains smooth surface to promote flow
(in capillaries provides an easy exchange site)

3. Tunica media (middle layer)
elastic fibers and smooth muscle
these tissues promote vasodilation and vasocontstriction, respectively

4. Tunica externa (adventitia)
mostly collagen fibers
protects blood supply from loss

B. Comparison of arteries and veins                            
                                Arteries                            Veins
     Lumen         small, open         large, collapsed  Tunica media     thick                     thin  Tunica externa     thin                     thick  Valves         no                         yes
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Compare and contrast the structure of arteries and veins.

C. Arteries 1. Three layered walls

2. Larger arteries, near heart, have lots of elastic in tunica media to promote rebound keeping blood pressure continuous despite cyclical variation in blood pressure

3. Arteries function to distribute blood via strong pressure developed by myocardial contractions.
 
 

D. Arterioles 1. Two layered walls (t. externa absent)

2. Arterioles are normally partly vasoconstricted. More ANS stimulation causes greater vasoconstriction. Less stimulation allows elastic rebound and vasodilation

3. Arterioles function to control blood flow by vasodilation & vasoconstriction
 
 

E. Capillaries 1. One-cell thick, walled vessels (simple squamous epithelium cell) with many spaces between cells (loose junctions). Diameter not much larger than red blood cells.

2. Usually a capillary next to nearly every cell in body (except epidermis, cornea and cartilage)

3. Primary function is to promote the exchange of water, transported materials & gases to cells or away from cells

F. Venules (small veins) and Veins 1. Weak blood flow due to skeletal muscular and respiratory pumping

2. Tend to be larger than arteries so most blood (~60%) is stored in veins and venules

3. Function to drain areas serviced by capillaries

Each organ typically has an artery entering , many arterioles, very abundant capillaries, many venules and one vein exiting.

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Helpful web link

Another helpful web link

II The Systemic Circulation:

NOTE: PAY SPECIAL ATTENTION TO "VESSEL TYPE" (That is, whether the vessel is an artery or vein) AND "VESSEL SIDE" (That is, right or left).
A correct answer would include the "VESSELSIDE VESSELNAME VESSELTYPE"...for instance, "Right Jugular Vein"

 

NOTE: You should be able to recognize all the assigned vessels AND the vessels that either supply or drain from those vessels.

A. Arteries:


1. Aorta - ascending aorta
aortic arch
descending aorta

2. Brachiocephalic Artery/Trunk
3. Left Common Carotid Artery
4. Left Subclavian Artery

(NOTE: 2-4 are direct branches off the aortic arch.)

5. Right Common Carotid Artery
6. Right Subclavian Artery

(NOTE: 5 & 6 branch off the Brachiocephalic Trunk.)

7. L/R Axillary Arteries - continuous with subclavians
8. L/R Brachial - continuous with axillaries
9. L/R Radial
10. L/R Ulnar
11. L/R Palmar Arches

(NOTE: 9 & 10 branch off the Brachials.)

12. Thoracic Aorta

(NOTE: 12 becomes 13 once it passes through the diaphragm

13. Abdominal Aorta
14. Left Gastric - supplies the stomach
15. Splenic - supplies the spleen
16. Hepatic Artery - supplies the liver
17. L/R Renal - supply the kidneys
18 . Inferior Mesenteric - supplies the intestine
19. L/R Common Iliac - branch off and directly
continuous with the Aorta
20. L/R Femoral - continuous with the External Iliac
21. L/R Popliteal - behind the knee
22. L/R Posterior Tibia
23. L/R Dorsalis Pedis


B. Arterial Supply to the Head and Brain:

1. L/R Common Carotid


C. Veins:

1. Superior Vena Cava
2. Inferior Vena Cava
3. L/R Brachiocephalic - join to form the S. Vena Cava
4. L/R Subclavian - lead into the Brachiocephalics
5. L/R Internal Jugular
6. L/R Vertebral

 



7 . L/R Axillary - drain into subclavians
8. L/R Brachial - drain into the axillaries
9 1. L/R Ulnar
10 L/R Radial


11. L/R Median Cubital - superficial, anterior to elbow
- where they usually draw venous blood samples


12. L/R Palmar Venous Arches
13. Hepatic Portal System - collects blood from the
spleen, stomach, and intestines, carrying
it to the liver for processing NOTE: THIS IS ONLY VEIN SUPPLYING BLOOD TO AN ORGAN (liver)
14. Hepatic - drains the liver, carrying blood to the
Inferior Vena Cava
15. L/R Renal - drain the kidneys into the IVC
16 . L/R Common Iliac - meet to form and drain into
the IVC

17 . L/R Femoral - drain into the external iliacs
- posterior to the femur
18 . L/R Great Saphenous - drains into the femorals
- superficial and medial to the femorals
-important for use as coronary artery bypass
19 . L/R Popliteal - drain into the femorals

20. L/R Posterior Tibial
21. L/R Dorsal Venous Arch - drain into the Great
Saphenous

Helpful web link

A web activity

Another web activity

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Professor Thomas M. Lancraft
Human Anatomy Courses
at St. Petersburg College
St. Petersburg/Gibbs Campus

10/2006