Blood Vessels

Question 1

Layers of the blood vessel wall

Answer 1

• t. intima (endothelium): loose CT + simple squamous epi.
• t. media: smooth muscle (not cardiac), may have elastin
• t. externa (adventitia) : fibrous CT with elastin

Question 2

Arteries

Answer 2

• distinguishing features: relatively small diameters (compared to veins), thick t. media, abundant elastin
• function of arteries: carry blood away from the heart to H and B tissues (not always oxygenated)

Question 3

Veins vs. Arteries

Answer 3

• 1 systemic artery leaves the L ventricle vs. 3 systemic, major veins enter the R atrium
• Large and medium size arteries –> deep locations vs. “superficial veins” underneath the skin
• Several parallel veins take the place of a single larger vein (“venous plexuses”)

Question 4

Veins

Answer 4

• Distinguishing features: relatively large diameters, thin t. media, thick t. externa,
large veins have valves especially in legs
• Function of veins: carry blood from Head and Body tissues back to the heart (not always deoxygenated)
• At any moment at rest 50-70% of your blood is in your veins

Question 5

Capillaries

Answer 5

• structure: endothelium (t. intima) only (keeps CVS closed)
• function: exchange of substances with Head and Body tissues

Question 6

Regions of the aorta (3)

Answer 6

1. ascending: the 1st section, exits the LV
2. arch: bends to the left and posteriorly
3. descending: passes blood in an inferior direction
   – thoracic aorta: the descending aorta superior to the diaphragm
   – abdominal aorta: the descending aorta inferior to the diaphragm

Question 7

2 branches from the ascending aorta

Answer 7

• 1. Coronary arteries: supply the myocardium
• Rt. Coronary branches to the marginal artery and posterior interventricular artery
• Lt. Coronary branches to the anterior interventricular a. and circumflex a.

Question 8

Cardiac veins

Answer 8

• Drain capillaries of the myocardium
• Supports the myocardium of the heart (not endo- or pericardium.
• Endocardium uses the blood in the heart chambers
• Pericardial aa. arise from other sources

Question 9

What the aortic arch supplies

Answer 9

the head, neck, upper limbs, and anterior chest wall

Question 10

What the brachiocephalic branches to

Answer 10

rt. subclavian a. and rt. common carotid a.

Question 11

Lt. common carotid a.

Answer 11

Branches to internal and external carotid a.

Question 12

Lt subclavian a. passes under clavicle toward the left arm

Answer 12

Branches to:
• vertebral a.
• thyrocervical a.
• costocervical a.
• internal thoracic a.
• axillary a.

Question 13

Superior Vena Cavae

Answer 13

• superior: formed by 2 brachiocephalic veins and azygos system of veins
• brachiocephalic veins (2): formed by internal jugular and subclavian veins
• (external jugular veins empty into the subclavian veins)

Question 14

From the thoracic aorta

Answer 14

• posterior intercostals arise from the thoracic aorta
– anterior intercostals arise from the internal thoracic a. or costal cervical a
• bronchial, esophageal, and superior phrenic arteries

Question 15

From the abdominal aorta (abdominal region)

Answer 15

• inferior phrenic arteries
• celiac trunk; quickly branches to (3): hepatic, lt. gastric, splenic
• other gastric arteries: lt. gastroepiploic a. and rt gastric
• gonadal arteries either spermatic or ovarian a.
• inferior mesenteric artery other areas of the colon not supplied by the superior mesenteric a.
• lumbar arteries muscles and spinal cord of lumbar region

Question 16

Suprarenal arteries

Answer 16

Supply the adrenal (suprarenal) glands

Question 17

Superior mesenteric artery

Answer 17

Supplies small intestines, pancreas, appendix, and many portions of the colon

Question 18

Branches from the abdominal aorta (pelvic region)

Answer 18

• median sacral artery (middle sacral artery) supplies the sacrum and coccyx
• common iliac arteries branches into external and internal branches supplies to lower extremities

Question 19

Examples of major portal systems of the body

Answer 19

1. between the hypothalamus and pituitary
2. in the kidneys (renal portal system)
3. between the GI tract, spleen and the liver (hepatic portal system)

Question 20

Inferior vena cava receives blood from

Answer 20

• R and L hepatic veins
• R and L renal veins
• R suprarenal (L drains into the renal vein)
• R gonadal (L drains into the renal vein)
• lumbar veins
• common iliac veins

Question 21

Renal blood vessels (renal portal system)

Answer 21

• The renal a. branches extensively between renal pyramids, then small lobules leading to afferent arterioles
• Afferent arterioles lead directly to glomeruli

Question 22

Glomerular capillaries

Answer 22

• Emerge into efferent arterioles
• Efferent arterioles lead to a second network of capillaries known as
peritubular capillaries
– absorb fluids that have been modified by the nephron
• Both types of capillary beds return this fluid to the general circulation by remerging into “interlobular” veins

Question 23

Vasa recta

Answer 23

The portion of peritubular capillaries deepest in the medulla

Question 24

Vascular anastomoses

Answer 24

• Interconnections between blood vessels without capillaries
• 2 parallel arteries or veins (collaterols)
• arteriovenous

Question 25

Fetal Circulation

Answer 25

* the significance of fetal vs adult circulation is * the fetal vs adult source of oxygen * differences are the result of differences in the environment * all major blood vessels are in place by the 3rd month of development & flowing in the same direction

Question 26

2 major differences of fetal circulation

Answer 26

1. fetus supplies blood to placenta | 2. fetal respiratory organ is in the placenta and fetus does not breathe

Question 27

Umbilical vessels

Answer 27

* Paired U. arteries (arise from internal iliac a. in pelvis) carry deoxygenated blood from the fetus --> placenta * Unpaired U. vein carry oxygenated blood into the ductus venosus * Ductus venosus (shunt) -connected to an intricate network of veins in the fetal liver

Question 28

Shunts away from the pulmonary circuit

Answer 28

* foramen ovale- an opening between the atria to shunt blood from L-R; a valve * ductus arteriosus- a shunt between the pulmonary trunk and aorta (prevent overload on the immature lungs)

Question 29

Summary of fetal circulation

Answer 29

All returning blood to the fetus proceeds to hepatic veins, inferior vena cava and right atrium • Postnatal

Question 30

Umbilical vein --->

Answer 30

Ligamentum teres

Question 31

Ductus Venosus (shunt) -->

Answer 31

Ligamentum venosum

Question 32

U. arteries -->

Answer 32

Medial U. ligaments

Question 33

Foramen ovale & Ductus arteriosus -->

Answer 33

Constrict and close when newborn takes its 1st breath (3 months to completely close) • Become fossa ovalis and ligamentum arteriosum respectively