1. CARDIOVASCULAR SYSTEM
Blood Vessels

2. GENERAL 3 Types of Blood Vessels: Typical Blood flow: Arteries Veins
Capillaries
Typical Blood flow:
Heart  Arteries  Arterioles  Capillaries  Venules  Veins  Heart

3. STRUCTURE OF BLOOD VESSELS
3 Tunics (Coats):
Tunica Intima (Interna)
Innermost, Thin
Endothelium (Simple Squamous E.T.) + C.T.
Tunica Media
Middle, Thickest

4. STRUCTURE OF BLOOD VESSELS continued
Smooth Muscle Fibers, Arranged Circularly
C.T. (Elastic & Collagen)
Tunica Externa (Adventitia)
Fibrous C.T. Sheath

5. The Vascular System Slide 11.24 Figure 11.8b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

6. ARTERIES Carry Blood Away From the Heart Under Highest Pressure
Thickest Walled (Tunica Media)
Arteries usually carry oxygenated blood
Pulmonary Arteries Carry O2 Poor Blood
Systemic Arteries Carry O2 Rich Blood

7. ARTERIES continued 2 Types of Arteries: Elastic
Largest (Aorta, Pulmonary Trunk)
Thickest Tunica Media with Increased Elastic Tissue
Can Stretch & Recoil (Elastic Rebound)
Reduces Pressure Differences Between Systole & Diastole

8. ARTERIES continued Muscular (Distribution)
Tunica Media: Smooth Muscle Fibers > Elastic Fibers
Can Change Diameter
Can Influence Blood Flow & Blood Pressure
Capable of Growth & Establishing Collateral Circ.
Contract when Injured

9. Tunics of Elastic and Muscular Arteries
Figure 11.8b
Slide 11.24
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10. ARTERIES continued Arterioles Smallest arteries
Deliver Blood to Capillaries
Regulate Capillary Blood Flow

11. VEINS Return Blood to the Heart Thinner-walled
Wider Lumen, Greater Diameter
Tend to be more Superficially Located

12. The Vascular System Slide 11.24 Figure 11.8b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

13. VEINS continued Under Lowest Pressure Valves
In Veins Carrying Blood Against Gravity
Venules
Smallest Veins
Receive Blood from Capillaries

14. The Anatomy of Veins Slide 11.24 Figure 11.8b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

15. VEINS continued Venous Return Assisted By: Muscular Compression
Skeletal Muscle Contractions
Aids Venous Return
Respiratory Pump
Pressure Drops in Thoracic Cavity During Inhalation, Pulling Blood into Venae Cavae

16. Movement of Blood Through Vessels
Arterial blood is pumped by the heart
Veins use the milking action of muscles to help move blood
Figure 11.9
Slide 11.27
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17. CAPILLARIES Thinnest Walls (tunica intima)
Site of Exchange via Diffusion
Some capillaries form Capillary Beds
Precapillary Sphincters (& smooth muscle in arterioles) regulate blood flow into capillaries

18. Figure 11.10
Slide 11.28b
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19. Hepatic Portal System
Carries Venous Blood From Capillaries in Digestive Organs to Capillaries in Liver
Contains Substances Absorbed from Digestive Tract (Nutrients, Wastes, Toxins)
Liver Stores, Converts, Detoxifies
Liver also Receives Arterial Blood from Hepatic Artery

20. Special Circuits: Hepatic Portal System
Figure 11.14
Slide 11.33
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21. FETAL CIRCULATION - General
Differs from Adult
“Non-functional” Lungs & Digestive Tract
Primary Functions Carried out by Mom’s Systems
Exchange Between Fetal Blood & Maternal Blood Occurs at Placenta

22. FETAL CIRCULATION – Fetal Vessels
Placental or Umbilical Vein
Returns O2 Rich Blood from Placenta to Fetus
Branches Below Liver; 1st Branch Joins Portal Vein
Ductus Venosus
Branch of Umbilical Vein (O2 Rich)
Bypasses Liver; Empties into Inferior Vena Cava

23. Special Circuits: Fetal Circulation
Figure 11.15
Slide 11.34
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24. FETAL CIRCULATION – Fetal Vessels continued
Foramen Ovale
Interatrial Opening
Bypasses Pulmonary Circ.
Ductus Arteriosus
Connects Pulmonary Trunk & Aorta

25. Special Circuits: Fetal Circulation
Figure 11.15
Slide 11.34
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

26. FETAL CIRCULATION – Fetal Vessels continued
Placental or Umbilical Arteries (2)
Branch off Internal Iliac Arteries
Carry Blood towards Placenta

27. Special Circuits: Fetal Circulation
Figure 11.15
Slide 11.34
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

28. FETAL CIRCULATION – Fate of Fetal Vessels
Umbilical Vein  Round Ligament of Liver
Ductus Venosus  Ligamentum Venosum
Foramen Ovale  Fossa Ovalis
Ductus Arteriosus  Ligamentum Arteriosum
Umbilical Arteries  Umbilical Ligaments

30. Coronary Circuit Part of Systemic circuit
Coronary Arteries are 1st vessels to branch from aorta (ascending aorta)
Supply myocardium of heart with oxygen
Drain into right atrium via coronary sinus