<< Chapter < Page Chapter >> Page >

Bile salts act as emulsifying agents, so they are also important for the absorption of digested lipids. While most constituents of bile are eliminated in feces, bile salts are reclaimed by the enterohepatic circulation    . Once bile salts reach the ileum, they are absorbed and returned to the liver in the hepatic portal blood. The hepatocytes then excrete the bile salts into newly formed bile. Thus, this precious resource is recycled.

Bilirubin , the main bile pigment, is a waste product produced when the spleen removes old or damaged red blood cells from the circulation. These breakdown products, including proteins, iron, and toxic bilirubin, are transported to the liver via the splenic vein of the hepatic portal system. In the liver, proteins and iron are recycled, whereas bilirubin is excreted in the bile. It accounts for the green color of bile. Bilirubin is eventually transformed by intestinal bacteria into stercobilin, a brown pigment that gives your stool its characteristic color! In some disease states, bile does not enter the intestine, resulting in white (‘acholic’) stool with a high fat content, since virtually no fats are broken down or absorbed.

Hepatocytes work non-stop, but bile production increases when fatty chyme enters the duodenum and stimulates the secretion of the gut hormone secretin. Between meals, bile is produced but conserved. The valve-like hepatopancreatic ampulla closes, allowing bile to divert to the gallbladder, where it is concentrated and stored until the next meal.

Watch this video to see the structure of the liver and how this structure supports the functions of the liver, including the processing of nutrients, toxins, and wastes. At rest, about 1500 mL of blood per minute flow through the liver. What percentage of this blood flow comes from the hepatic portal system?

The pancreas

The soft, oblong, glandular pancreas    lies transversely in the retroperitoneum behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen. It is a curious mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions ( [link] ).

Exocrine and endocrine pancreas

This figure shows the pancreas and its major parts. A magnified view of a small region of the pancreas shows the pancreatic islet cells, the acinar cells and the pancreatic duct.
The pancreas has a head, a body, and a tail. It delivers pancreatic juice to the duodenum through the pancreatic duct.

The exocrine part of the pancreas arises as little grape-like cell clusters, each called an acinus    (plural = acini), located at the terminal ends of pancreatic ducts. These acinar cells secrete enzyme-rich pancreatic juice    into tiny merging ducts that form two dominant ducts. The larger duct fuses with the common bile duct (carrying bile from the liver and gallbladder) just before entering the duodenum via a common opening (the hepatopancreatic ampulla). The smooth muscle sphincter of the hepatopancreatic ampulla controls the release of pancreatic juice and bile into the small intestine. The second and smaller pancreatic duct, the accessory duct    (duct of Santorini), runs from the pancreas directly into the duodenum, approximately 1 inch above the hepatopancreatic ampulla. When present, it is a persistent remnant of pancreatic development.

Questions & Answers

where can we find the short bones
Chidi Reply
Carpal bones are examples of short bones
Dara
what is blood supply
Chidi
during pregnancy which would more increase size the mothers abdominal or pelvic cavity?
Nurmalyn Reply
define the main directional terms of the body
cris Reply
during physical exercise respiratory rate increace two student are discussing the mechanisms involved. student A claim they are positive feedback and student B claim negative feedback do you agree with student A or B and why
cris
what is the physiology of circulation
Chidi
please I mean the physiology of criculation
Chidi
blood flow refers to the movement of blood through the vessels from arteries to the capillaries and then to the veins
Laraib
during pregnancy, which would more size the mother's abdominal or pelvic cavity? explain
cris Reply
list and define the three plane of devision of the body
cris
complete the following statements using correct directional terms for human being. 1. the navel is________to the nose 2. the heart is______to the breastbone(sternum) 3 the ankle is______to the knee 4 the ear is______to the eyes.
cris
1. superior 2. posterior 3. superior 4. lateral
Mnm
anterior fuerior
Chidi
name the system of the body and its function
cris Reply
11 system are human body 1.integumentary system 2. skeletal system 3. muscular system 4. nervous system 5. endocrine system 6. cardiovascular system 7. lymphatic system 8. respiratory system 9. digestive system 10. urinary system 11. reproductive system male and female.
Vineeta
during pregnancy, which would more size the mother's abdominal or pelvic cavity? explain
cris
how the body maintain hormeostasis in terms of bloodglucose level
cris Reply
It releases hormones from the pancreas insulin and glucagon
TONY
why human blood pressure high
amin Reply
fear, anxiety, sickness
Inemesit
why in mothers womb the foetus head is in anus direction?
Kick
As it seems the position downside n if we did such position thn soon we got vomiting then how foetus stay in downward position long time?
Kick
What is red blood cell
HANNAH Reply
A type of blood cell that is made in the bone marrow and found in the blood. Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It
Noor
red blood cell are the most numerous blood cells.they comprise about 99% of all blood cells red blood cells are non nucleated it has red colour due to present to hemoglobin.
Vineeta
Thanks for the answers
HANNAH
how will you promote quality of life in ptb patient using the 14 basic needs and 21 nursing problems?
rOx Reply
coronary circulation ?
Juri Reply
Coronary circulation is the circulation of blood in the blood vessels that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle, and cardiac veins drain away the blood once it has been deoxygenated. Because the rest of the body.
Riyaz
coronary circulation ,is flow of blood that supplies the heart tissue itself is the coronary circulation. the functional blood supply of the heart,is the shortest circulation in tha body.
Vineeta
what about the easy way to understand action potential
Bright
event of cardiac cycle
Juri Reply
hii
Chandan
whatisanatom
kaso Reply
anatomy is the scientific way of studying the body structure.
cynthia
the branch of science concerned with the bodily structure of humans, animals, and other living organisms, especially as revealed by dissection and the separation of parts.
Noor
what is means by LAPE and HAPE
Noor
what is respiratory rate
Chidi
guys i've question what occur when homeostasis balance mechanisms lost
cris Reply
Bladder is blank to the small intestine, what is the right directional term for that?
Julaika Reply
When peristaltic movement is correct.
Farid
what tissue that support body organ?
Sabrina Reply
the skeleton
veronica
Skeleton
GEBAH
skeleton
Juwita
skeleton
Farid
skeleton
Priya
skeleton
Emmanuel
skeleton
Noor
skeleton
BILAL
skeleton
hanuman

Get the best Anatomy & Physiology course in your pocket!





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