Comprehensive Guide to Cardiovascular System Histology & Circulation Organization

1. CH 22: The Cardiovascular System:Vessels & Circulation Histological Organization of Blood Vessels Pulmonary & Systemic Circulation Circulatory Changes at Birth

2. 1 aorta & 1 pulmonary trunk 2.5 cm 10 bio capillaries (~ length 5,000 miles) ?

3. Histology of Blood Vessels • Tunica interna or intima (endothelium + c.t.) • Tunica media (muscle + c.t.) • Tunica externa or adventitia (thick layer of c.t.)

4. Arteriesvs. Veins

5. Distinguishing Arteries from Veins: • Artery walls thicker (more muscle and elastic fibers) • Additional: internal & external elastic membrane in histology slide: • Arterial walls contract; endothelium cannot contract: pleated appearance • Veins collapse Fig 2-1c Fig 2-1a

6. elastic arteries muscular arteries arterioles large vein medium-sized vein venules capillaries

7. Superior & inferior vena cavae and their tributaries Pulmonary trunk & aorta and their major branches

8. ~ 4 mm 2 - 9 mm External carotid, brachial & femoral arteries

9. ~ 10 -50 µm ~ 30 µm

10. Different Types of Capillaries: ~ 8 µm Choroid plexus, endocrine organs, kidneys (special case: sinusoids) Most body regions

11. Sinusoids • Resemble fenestrated capillaries, yet • irregular shapes • have longer pores • thinner (or no) basement membranes • Blood movement very slow • Location?

12. Capillary Bed = Capillary region serving a body area • BF controlled via arterioles • Precapillary sphincterat entrance to each capillary • Arteriovenous anastomosis

13. From Capillary Bed Blood Returns to Heart 3 exceptions!!! ?? • Hypophyseal portal system • Hepatic portal system • In kidney nephrons Fig 19-6 Fig 22-26

14. Uneven Distribution of Blood Total blood volume: ? 65 -70% in veins (= blood reservoir) Walls of veins easily stretch and recoil depending on volume changes 30-35% in heart, arteries and capillaries

15. Why are valves found in veins but not in arteries? Do all veins have valves?

16. someBlood Vessel Pathologies p 768 • Aneurysms • Problems with venous valve function • Loss of elasticity and resilience in c.t. throughout body due to ?? • Found where especially?

17. Atherosclerosis (= type of Arteriosclerosis) thickening and toughening of arterial walls Pathogenesis covered in Physiology

18. Gross Anatomy of Circulatory System Pulmonary & Systemic Circulations

20. Brachiocephalic artery 1 Left common carotid 2 Left subclavian 3 Aortic Arch

21. Circle of Willis = Cerebral Arterial Circle = Ring of vessels surrounding the pituitary gland (ring shaped anastomosis) Brain can receive blood from carotids or vertebrals (significance?) ic v

22. Abdominal aorta Common iliac External iliac Femoral Descending aorta • thoracic aorta • abdominal aorta

23. Circulation Changes at Birth • Fetus gains O2 from? • Umbilical arteries and vein • Two passage ways to bypass lung: • Foramen ovale • Ductus arteriosus

24. ? The End

26. back Circle of Willis

27. back Abdominal Aorta:

28. Fetal Circulation

29. Foramen ovale back