liver and pancreas Flashcards
what is the pancreas?
- “Dual purpose” gland- two parts, two functions (endocrine portion and exocrine portion)
what is the endocrine function of the pancreas?
hormonal
- islets of langerhans
- insulin (promotes glucose absorption from blood into liver, skeletal muscle and fat cells. This enables the conversion to glycogen - i.e. storage of glucose in this form)
- glucagon (opposite of insulin, results in the conversion of the stored glycogen into glucose for release into the bloodstream when levels are low)
- somatostatin inhibits insulin and glucagon secretions
what is the exocrine function of the pancreas?
(99% of pancreas is exocrine)
digestive
- digestive enzymes (help break down carbohydrates, proteins and fats)
- bicarbonate ions
what are the enzymes found in the pancreas and where are they from?
(from acinus)
- amylase
- lipase
- trypsin, chymotripsin
- nucleases
what is the function of bicarbonate in the pancreas and where is it from?
- from ducts
- neutralises gastric acid
what is the function of enzyme amylase?
breaks down starch into sugars
what is the function of enzyme lipase?
involved in the breakdown of fats into monoglyceride and fatty acids
what is the function of enzyme trypsin?
secreted in its inactive form of trypsinogen. The trypsin secreted breaks down or hydrolyses proteins. Chymotrypsin arises from the inactive chymotrypsinogen. Chymotrypsin, the active form, breaks down proteins and polypeptides.
what is the function of enzyme trypsin?
secreted in its inactive form of trypsinogen. The trypsin secreted breaks down or hydrolyses proteins. Chymotrypsin arises from the inactive chymotrypsinogen. Chymotrypsin, the active form, breaks down proteins and polypeptides.
what is the function of enzyme nucleases?
break down nucleotides
what are the 5 parts of the pancreas?
- head
- ucinate process
- neck
- body
- tail
describe the head of the pancreas
the widest part of the pancreas. It lies within the C-shaped curve created by the duodenum and is connected to it by connective tissue
describe the ucinate process of the pancreas
a projection arising from the lower part of the head and extending medially to lie beneath the body of the pancreas. It lies posterior to the superior mesenteric vessels
describe the neck of the pancreas
located between the head and the body of the pancreas. It overlies the superior mesenteric vessels which form a groove in its posterior aspect
describe the body of the pancreas
centrally located, crossing the midline of the human body to liebehind the stomach and to the left of the superior mesenteric vessels
describe the tail of the pancreas
the left end of the pancreas that lies within close proximity to the hilum of the spleen. It is contained within thesplenorenal ligamentwith the splenic vessels. This is the only part of the pancreas that isintraperitoneal
what are the duodenal papillae?
The major duodenal papilla serves as the common entrance for the bile and pancreatic ducts, whereas the minor duodenal papilla is the entrance for the accessory pancreatic ducts into the duodenum.
what makes up the islet of langerhans of the pancreas?
- alpha cells (15%) - glucagon
- beta cells (80%) - insulin
- delta cells - somatostatin
what are the clusters of cells in the exocrine pancreas called?
acini
what are acini connected by?
short intercalated discs
what links to intralobular ducts and what do they do?
acini link to intralobular ducts which ultimately drain to the pancreatic duct
what are centroacinar cells?
spindle shaped and are extensions of intercalated ducts into each pancreatic acinus. They typically secrete bicarbonate and mucin.
in what part of the pancreas does cystic fibrosis occur?
exocrine
describe cystic fibrosis
- an inherited autosomal recessive condition affecting the lungs
- Abnormal, thick secretions
- Damage to lungs, liver and pancreas
- Destruction of primarily exocrine pancreas
- reduced digestive function
- malabsorption
- steatorrhoea
- Can affect the salivary glands
what is nail clubbing?
- a deformity of the fingers and toe nails
- associated with a number of conditions of the heart and lungs
- loss of the angle of the nail bed of <165° angle between the nailbed and the fold
- increased convexity of the nail fold followed by thickening of the distal thumb.
describe pancreatic cancer
- Head of pancreas typically
- Loss of appetite orweight loss, without trying, feeling tired or lethargic, abdominal pain,
- Biliary obstruction –blocks bile and pancreas secretions
- Obstructive jaundice – yellowing of skin and sclera. It is a symptom rather than a disease in itself. It is a build up of bilirubin which is not excreted, and typically they have pale stools also (steatorrhoea)
- Metastasis – spread to other sites eg liver
what are the functions of the liver?
- Metabolism
- material absorbed from G.I.T. (detoxifies all)
- storage of glycogen
- release of glucose
(regulates blood glucose levels)
- Protein synthesis (including clotting factors and platelet regulations)
- Inactivation of hormones, drugs
- Excretion of waste
- Produces bile
what is the liver?
major organ, around 1.5kg, red-brown in colour
how does the liver act as an accessory organ for digestion?
produces bile, which goes on to be stored and concentrated in the gallbladder
describe the importance of the liver being involved in drug metsbolsim
It inactivates hormones and drugs, as well as insulin and many waste products and is heavily involved in drug metabolism, and sometimes this can be of detriment when the product of metabolism is more toxic than the initial compound e.g. paracetamol.
where is the liver located?
in the upper right-hand portion of the abdominal cavity, beneath the diaphragm, and on top of the stomach, right kidney, and intestines, and extends over to the left (specifically it lies in the right hypochondrium, extending to the epigastric region and then to the left hypochondrium)
what does the liver have the largest of in our body?
gland
what is the liver covered by?
lower ribs and costal cartilages
what is the falciform ligament?
embryological remnant of ventral mesentery – attaches intestines to the posterior abdominal wall
what is the round ligament?
remnant of the umbilical vein. Sometimes continuous with this is the ligamentum venosum, the fibrous remnant of the ductus venosus. The ducts venosus directs blood in foetal life
what is the dual supply to the liver?
the hepatic portal vein (deoxygenated, brings nutrients) from the gut, spleen and related organs (approximately 75%). The hepatic arteries account for 25% of that blood flow, and this artery provides the oxygenated blood for the liver. Blood from these two flow past hepatocytes in large capillaries called sinusoids which drain to the hepatic vein (inferior vena cava). Bile flows in the opposite direction.
what are liver cells called and what do they produce?
hepatocytes produce bile
what is the liver made up of that contain hepatocytes?
hexagonal hepatic lobules
what do bile salts/acids do?
help cholesterol metabolism and aid absorption of fat soluble vitamins (A, D, E, K)
what are bile salts?
lipid emulsifiers
what is bilirubin?
a breakdown product of red blood cell metabolism, and normally is excreted in faeces (which gives it’s brown colour), and urine its straw yellow colour
what is the function of the hepatic portal vein?
- carries blood from the gut (GIT), pancreas, spleen to the liver
- drains unpaired abdominal organs
- almost all material absorbed from the GIT enters the HPV, passes through the liver and is processed
why is the hepatic portal vein not a true vein?
it conducts blood to the capillaries of the liver not the heart
what veins form hepatic portal vein?
the superior mesenteric, inferior mesenteric vein and splenic veins
where does the hepatic portal vein receive blood from?
the inferior mesenteric vein, superior mesenteric vein and splenic vein (stomach and gall bladder)
what do sinodoid capillaries have compared to normal capillaries?
larger diameter, specialised lining endothelial cells which clear blood waste and Kupffer cells which are specialised macrophages
what are some conditions which can arise from the liver?
- Hepatomegaly
- Cirrhosis
- Viral hepatitis
- Obstructive jaundice
- Hepatic carcinoma
what is hepatomegaly?
enlarged liver and is a sign of underlying problems eg with the liver itself, or perhaps cardiac failure or cancer metastasis. it presents with abdominal pain, Fatigue, Nausea and vomiting, Jaundice. Many conditions cause this.
what is cirrhosis?
scarring or fibrosis of liver. Inflammation like hepatitis or chronic alcoholism
what is obstructive jaundice?
a SYMPTOM where normal drainage of bile from the liver to the small intestines is blocked
what is hepatic carcinoma?
most common primary liver cancer, and linked to chronic liver disease and cirrhosis. May need surgery, liver transplant or chemotherapy.
