Veins from the Abdominal Viscera

Although veins usually carry the blood directly to the atria of the heart, those that drain the abdominal viscera are exceptions (fig. 15.57). They originate in the capillary networks of the stomach, intestines, pancreas, and spleen, and carry blood from these organs through a hepatic portal (por'tal) vein to the liver. There the blood enters capillarylike hepatic sinusoids (he-pat'ik si'nil-soids). This unique venous pathway is called the hepatic portal system (fig. 15.58).

The tributaries of the hepatic portal vein include the following vessels:

1. Right and left gastric veins from the stomach.

2. Superior mesenteric vein from the small intestine, ascending colon, and transverse colon.

3. Splenic vein from a convergence of several veins draining the spleen, the pancreas, and a portion of the stomach. Its largest tributary, the inferior mesenteric vein, brings blood upward from the descending colon, sigmoid colon, and rectum.

About 80% of the blood flowing to the liver in the hepatic portal system comes from the capillaries in the stomach and intestines and is oxygen-poor but rich in nutrients. As discussed in chapter 17 (pp. 709-710), the liver handles these nutrients in a variety of ways. It regulates blood glucose concentration by polymerizing excess glucose into glycogen for storage, or by breaking down glycogen into glucose when blood glucose concentration drops below normal.

External jugular v.

Subclavian v. Superior vena cava Axillary v.

Brachial v. Basilic v.

Azygos v.

Veins That Drain Thoracic Wall

Internal jugular v. Brachiocephalic v.

Cephalic v.

Superior hemiazygos v. Posterior intercostal v.

Inferior hemiazygos v.

Figure 15.56

Veins that drain the thoracic wall.

Liver-

Hepatic portal vein Gallbladder Pancreas

Superior-mesenteric vein

Small intestine Ascending colon

Internal jugular v. Brachiocephalic v.

Cephalic v.

Superior hemiazygos v. Posterior intercostal v.

Inferior hemiazygos v.

Spleen Stomach Pancreas Vein

Stomach

Left gastric vein Right gastric vein Spleen

Splenic vein

Inferior mesenteric vein

Descending colon

Stomach

Left gastric vein Right gastric vein Spleen

Splenic vein

Inferior mesenteric vein

Descending colon

Figure 15.57

Veins that drain the abdominal viscera.

• Head and upper limb capillaries

Superior — vena cava

Inferior — vena cava

Common -

iliac vein

• Head and upper limb capillaries

Superior — vena cava

Inferior — vena cava

Common -

iliac vein

Splenic Artery

Splenic artery

Mesenteric artery

(to intestine)

Renal afferent arterioles

Common iliac artery

Lower limb capillaries

Figure

In this schematic drawing of the circulatory system, note how the hepatic portal vein drains one set of the capillaries and leads to another set. A similar relationship exists in the kidneys.

Lower limb capillaries

Splenic artery

Mesenteric artery

(to intestine)

Renal afferent arterioles

Common iliac artery

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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  • Daniel Hoff
    What are the veins that drain abdominal viscera?
    3 years ago

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