<< Chapter < Page Chapter >> Page >

Hepatic portal system

The liver is a complex biochemical processing plant. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile; and disposes of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes (for example, materials produced by the spleen) travel to the liver for processing. They do so via the hepatic portal system    ( [link] ). Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver, the hepatic sinusoids. You saw the only other portal system with the hypothalamic-hypophyseal portal vessel in the endocrine chapter.

The hepatic portal system consists of the hepatic portal vein and the veins that drain into it. The hepatic portal vein itself is relatively short, beginning at the level of L2 with the confluence of the superior mesenteric and splenic veins. It also receives branches from the inferior mesenteric vein, plus the splenic veins and all their tributaries. The superior mesenteric vein receives blood from the small intestine, two-thirds of the large intestine, and the stomach. The inferior mesenteric vein drains the distal third of the large intestine, including the descending colon, the sigmoid colon, and the rectum. The splenic vein is formed from branches from the spleen, pancreas, and portions of the stomach, and the inferior mesenteric vein. After its formation, the hepatic portal vein also receives branches from the gastric veins of the stomach and cystic veins from the gall bladder. The hepatic portal vein delivers materials from these digestive and circulatory organs directly to the liver for processing.

Because of the hepatic portal system, the liver receives its blood supply from two different sources: from normal systemic circulation via the hepatic artery and from the hepatic portal vein. The liver processes the blood from the portal system to remove certain wastes and excess nutrients, which are stored for later use. This processed blood, as well as the systemic blood that came from the hepatic artery, exits the liver via the right, left, and middle hepatic veins, and flows into the inferior vena cava. Overall systemic blood composition remains relatively stable, since the liver is able to metabolize the absorbed digestive components.

Hepatic portal system

This diagram shows the veins in the digestive system.
The liver receives blood from the normal systemic circulation via the hepatic artery. It also receives and processes blood from other organs, delivered via the veins of the hepatic portal system. All blood exits the liver via the hepatic vein, which delivers the blood to the inferior vena cava. (Different colors are used to help distinguish among the different vessels in the system.)

Chapter review

The right ventricle pumps oxygen-depleted blood into the pulmonary trunk and right and left pulmonary arteries, which carry it to the right and left lungs for gas exchange. Oxygen-rich blood is transported by pulmonary veins to the left atrium. The left ventricle pumps this blood into the aorta. The main regions of the aorta are the ascending aorta, aortic arch, and descending aorta, which is further divided into the thoracic and abdominal aorta. The coronary arteries branch from the ascending aorta. After oxygenating tissues in the capillaries, systemic blood is returned to the right atrium from the venous system via the superior vena cava, which drains most of the veins superior to the diaphragm, the inferior vena cava, which drains most of the veins inferior to the diaphragm, and the coronary veins via the coronary sinus. The hepatic portal system carries blood to the liver for processing before it enters circulation. Review the figures provided in this section for circulation of blood through the blood vessels.

Questions & Answers

what is meant by control center?
Freeman Reply
what is anatomy
Ajibola Reply
is the study of the structure of the body and their relationship to each refers to the shapes iyo sizes
Khadar
what is a blastomere?
Toluba Reply
In biology, a blastomere is a type of cell produced by cleavage (cell division) of the zygote after fertilization and is an essential part of blastula formation.
Adnan
what is cell
Shivaani
Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. ... Cells have many parts, each with a different
Adnan
function
Adnan
cell is a membrane bound unit that contains the fundamentals molecules of life
Sushma
A1
Adnan
excellent
Adnan
movement,reproduction, excretion, respiration ,growth ,nutrition, response to external stimuli.
Sushma
good
Adnan
sister excellent
Adnan
questions pushy ja sukty hy kya
Maryam
jwab forun milta hy ya ak do din k bad
Maryam
Maryam Riaz sister what you say
Adnan
i want to say that k kush questions k answer mil sukty hy mjhy
Maryam
inshallah
Adnan
zaror mere behen
Adnan
question kari
Adnan
hn mil mil sakte h na esly
Ziya
Which muscle of the gluteal region originates from lumber spine? a. Gluteus medius b. Psoas major c. Iliacus d. Gluteus maximus
Maryam
sweet sister's
Adnan
question tu kari Inshallah Allah behtar kariga
Adnan
to mcqs kia to hy
Maryam
answer ni mila abhi
Maryam
wait sister
Adnan
what is the functional unit of kidneys
Khadar
nephron is the functional unit of kidney
Maryam
Maryam Riaz sister option. d. gluteus maximus
Adnan
thanks
Maryam
sorry Maryam Riaz sister
Adnan
option b. psoas major
Adnan
right answer this one
Adnan
nephron is the functional unit of kidney
Ihsan
I discussed with to my teachers
Adnan
d
Ihsan
d. is right option bro
Adnan
yes
Ihsan
what is cell
Shilpa
cell is the smallest unit of life
Maryam
ok
Shilpa
Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. ... Cells have many parts, each with a different
Adnan
function
Adnan
Maryam Riaz sister I m clear option d. also right thank you ihan bro
Adnan
type structure function origin insertion action of muscles
DAMINI Reply
oxygn amount in our body
Tg Reply
A normal level of oxygen is usually 95% or higher. Some people with chronic lung disease or sleep apnea can have normal levels around 90%. The “SpO2” reading on a pulse oximeter shows the percentage of oxygen in someone's blood
Adnan
What is the difference between cytoplasmic and endoplasmic
Ajibola Reply
The cytoplasm is 90℅ water and 10℅ of organic and inorganic compounds. The cytoplasm contains mitochondria. ... Lysosomes of Cytoplasm contains 50 different enzymes that digest proteins, lipids, and nucleic acids. The endoplasmic reticulum produces process and transport proteins, lipids for all the
Adnan
tarsal are cube shaped broad and long whiles metatarsal they are longer than they are wide
Priscilla Reply
articular cartilage serve as shock absorber and also reduces friction
Priscilla
articular cartilage serve as shock absorber and also reduces friction
Priscilla
when a bone joint with another bone
Priscilla
to know how you body function to know the relationship between the body parts to know specific functions of a certain body parts
romeo Reply
To know our body function we shd know chemical secretion of our glands, we can map all the function of our body and also relation ship between the body parts.
KUSUMA
that z it kusuma
kanaku
can you get fungi infection by seating on a public toilet?
Calls Reply
explain how blood acts as a connective tissue in the body
Rymz Reply
how does blood act as a connective tissue in the body
Rymz
what is anatomy
Victoriah Reply
fat deficiency in the body
Agbor Reply
Explain how body exercise regulates blood pressure
dranimva Reply
thank you
Thelma
what is cillia and flangella
Kalah Reply
what are the proceduers of condactive system ?
Salua Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?

Ask