Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histo, Anat & Physiol > Digestive System- Accessory Organs > Flashcards

Digestive System- Accessory Organs Flashcards

1
Q

Digestive System Accessory Organs

A
  • Pancreas
  • Liver
  • Gall bladder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The Pancreas

A
  • The pancreas is an elongated organ, light tan or pinkish in color, that lies in close proximity to the duodenum
  • Pancreatic duct connects with the duodenum
  • It is covered with a very thin connective tissue capsule which extends inward dividing the gland into lobules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Histology of the Pancreas

A
  • Partitions of connective tissue divide the interior of the pancreas into distinct lobes
  • Blood vessels of the pancreatic ducts are located within these connective tissue septum
  • In each lobule:
    – Ducts branch repeatedly->
    ending in pockets called pancreatic acini
  • Each acinus is lined with simple cuboidal epithelium
  • Pancreatic islets (endocrine tissues) are scattered among the acini
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The Pancreas- Exocrine

A
  • Secrete into ducts
  • Secretes “pancreatic juice”
  • Acinar cells; enzymatic secretions
  • Duct cells; aqueous NaHCO3 (sodium bicarbonate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The Pancreas- Endocrine

A
  • Release secretory products (hormones)-> blood
  • Glycaemic homeostasis
  • Islets of Langerhan
  • Insulin/glucagon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Exocrine Cells

A

Acinar cells
Duct cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Acinar cells

A
  • Produce small volume of primary
    secretion
  • Water, electrolytes, and digestive
    enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Duct cells

A
  • Produce bicarbonate-rich fluid
  • Large volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Endocrine- Pancreatic islets

A

Alpha cells
Beta cells
Delta cells
F cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Alpha cells

A

glucagon; glucagon raises blood glucose levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Beta cells

A

insulin; lowers blood glucose levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Delta cells

A

somatostatin; suppresses release of glucagon and insulin; slows rate of food absorption and enzyme secretion along digestive tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

F cells

A

pancreatic polypeptide; inhibits gallbladder contractions and regulates production of pancreatic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pancreatic Juice

A

composed of 2 secretory products critical to proper digestion:
– Digestive enzymes (secreted from Acinar cells)
– Bicarbonate (a base) (secreted from epithelial cells lining the ducts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Types of Digestive Enzymes

A

Proteases
Pancreatic Lipase
Amylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Proteases

A

Digestion of proteins is initiated by pepsin in the stomach, but the bulk of protein digestion is due to the pancreatic proteases.
2 major pancreatic proteases: Trypsin and Chymotrypsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pancreatic Lipase

A
  • Major form of dietary fat is triglyceride, or neutral lipid.
    – A triglyceride molecule cannot be directly absorbed across the intestinal mucosa.
    – It must first be digested into a 2-monoglyceride and two free fatty acids.
  • The enzyme that performs this is Pancreatic lipase, which is delivered into the lumen of the gut in pancreatic juice.
  • Bile salts are also needed –from liver
18
Q

Amylase

A
  • The major dietary carbohydrate is starch.
  • the enzyme that hydrolyses starch to maltose.
  • also present in saliva.
19
Q

Bicarbonate and Water

A
  • Epithelial cells in pancreatic ducts are the source of the bicarbonate and water secreted by the pancreas.
  • In pancreatic duct cells, the bicarbonate is secreted into the lumen of the duct and hence into pancreatic juice– buffering the duodenum and preventing damage from stomach acid
20
Q

The Liver

A
  • lies in the abdominal cavity, in contact with diaphragm
  • Its mass is divided into several lobes, the number and size of which vary among species – four lobes in humans
  • In most mammals, a greenish sac - the gallbladder - is seen attached to the liver
  • The common bile duct delivers bile from the liver and gallbladder into the duodenum
21
Q

Gross anatomy of the liver

A
  • Tough fibrous capsule
  • Covered by layer of visceral peritoneum
  • Right & left lobes
  • Further subdividing lobes
  • Anteriorly:
    – falciform ligament divides left/right lobes becoming round ligament/ligamentum teres
  • Posteriorly:
    – depression for inferior vena cava
  • Caudate & quadrate lobes also visible
22
Q

Liver Hepatocytes

A
  • Cuboidal epithelia
  • Two hepatocytes forming plates/cords
  • Bile canaliculus between hepatocytes
  • Sinusoids lined with fenestrated capillaries between plates
  • Basal surface has microvilli that project into sinusoids
  • Apical surface forms canaliculi
23
Q

Liver Hepatic lobules

A
  • Each lobe is divided into lobules
  • 100,000 liver lobules = functional units of liver
  • Adjacent lobules separated by interlobular septum (connective tissue)
  • Hepatocytes form irregular plates arranged in a hexagon shape
    – Plates are one cell thick
  • Within a lobule, sinusoids between adjacent plates empty into central vein.
    – Sinusoids contain Kupffer cells- phagocytic cells
    – Blood enters liver sinusoids from small branches of the hepatic portal vein (Venous blood) and hepatic artery (arterial blood)
24
Q

Histological Organisation of the Liver

A
  • Hepatic lobes consist of +100,000 lobules
  • Lobules are separated by connective tissue at the interlobular septum
  • Central vein
  • Hepatocytes radiate outwards (cords/plates)
  • Sinusoids spaces between plates lined with fenstrated capillaries
  • Bile canaliculi channels arising between hepatocytes
25
Q

Liver Portal area of the lobule

A
  • There are 6 portal areas in each lobule
  • Portal area contains:
    • branch of hepatic portal vein
    • branch of hepatic artery
    • small branch of bile duct
26
Q

Liver- Metabolic Regulation

A

– Metabolism – Carbohydrate, Fat & Protein
– Detoxification – toxins, ammonia, etc.
– Storage – Vitamins (B12), carbohydrates etc. e.g. glycogen

27
Q

Liver- Haematological Regulation

A

– Secretory – bile – Bile acids, salts & pigments
– Excretory – Bilirubin
– Synthesis – Albumin, coagulation factors

28
Q

Liver- Bile Functions

A

– Emulsification of lipids in duodenum
– Excretion of lipid soluble waste

29
Q

Liver- Non-digestive functions (hepatobiliary system)

A
  • Synthesis of plasma proteins
  • Synthesis of clotting factors
  • Synthesis of the inactive angiotensinogen (blood pressure)
  • Phagocytosis of damaged red blood cells
  • Breakdown of circulating hormones (insulin and epinephrine) and immunoglobulins (IgA etc)
  • Inactivation of lipid-soluble drugs
30
Q

Liver- Digestive & metabolic functions (hepatobiliary system)

A
  • Synthesis and secretion of bile
  • Storage of glycogen and lipid reserves
  • Maintaining normal blood glucose, amino acid and fatty acid concentrations within blood
  • Synthesis and release of cholesterol bound to transport proteins
  • Inactivation of toxins
  • Storage of iron
  • Storage of fat-soluble vitamins
31
Q

Liver- Vitamin & Mineral Storage

A
  • Fat soluble vitamins (A,D, E and K) absorbed from the blood and stored in the liver (Vit B 12 also stored but not fat soluble)
  • These reserves are called on when the diet contains inadequate amounts of those vitamins
  • Liver converts iron reserves to ferritin (essential for haemoglobin) and stores this protein-iron complex
32
Q

Liver- Removal of Waste products

A
  • Removal of ammonia from the body by synthesis of urea.
    – Ammonia is very toxic and if not rapidly and efficiently removed from the circulation, will result in central nervous system disease.
  • Other waste products, circulating toxins and drugs are also removed from the blood for inactivation, storage or excretion.
33
Q

Liver- Drug Inactivation

A
  • Liver removes and breaks down circulating drugs, limiting drug duration.
  • Rate at which liver removes drug is important.
  • If absorbed quickly, drug must be administered every few hours to keep plasma concentrations at therapeutic levels.
34
Q

Liver Hepatic Vascular system

A
  • The circulatory system of the liver is unlike that seen in any other organ:
    – The majority (75%) of the liver’s blood supply is venous blood
  • Roughly 75% of the blood entering the liver is from the portal vein.
    – All of the venous (waste) blood returning from the small and large intestine, stomach, pancreas and spleen enters this vein
  • The remaining 25% of the blood supply to the liver is arterial blood from the hepatic artery.
    – This provides the liver tissue with oxygen and nutrients
  • Converging at the hilus (porta hepatis)
  • Venous return via hepatic veins-inferior vena cava
  • The hepatic portal vein and hepatic artery empty together and mix as they enter sinusoids in the liver.
  • Sinusoids are vascular channels (leaky capillaries) lined with highly fenestrated or “holey” endothelial cells and surrounded by hepatocytes.
  • As blood flows through the sinusoids:
    – plasma is filtered into the space between endothelium and hepatocytes, providing a major fraction of the body’s lymph
    – Plasma proteins are secreted
    – Solutes are absorbed from the plasma
35
Q

Hepatic veins

A

carry blood AWAY from liver

36
Q

Hepatic Portal vein

A

carry blood TO liver

37
Q

The Biliary System

A
  • a series of channels and ducts that conveys bile - a secretory and excretory product of hepatocytes - from the liver into the lumen of the small intestine
  • Biliary canal is the space between the apical surfaces of the hepatocytes that form cords
  • Hepatocytes secrete bile into the canals, and those secretions flow parallel to the sinusoids,– but in the opposite direction that blood flows – towards the portal area.
    *Small bile ducts, join into larger and larger ducts, eventually forming the common bile duct, which dumps bile into the duodenum.
    *The gall bladder is another important structure in the biliary system.
    *This is a sac-like structure adhering to the liver.
    *During periods of time when bile is not flowing into the intestine, it is diverted into the gall bladder, where it is dehydrated and stored until needed.
38
Q

The Gallbladder

A
  • Hollow, pear-shaped organ
  • Stores, modifies, and concentrates bile
  • There are two important functions of bile:
    • Bile acids are critical for digestion and absorption of fats and fat soluble vitamins in the small intestine.
    • Many waste products are eliminated from the body by secretion into bile and subsequent elimination in faeces
39
Q

Liver disease

A
  • Any condition that severely damages the liver represents a serious threat to life
  • The liver can regenerate itself after injury, but liver function will not recover fully unless normal vascular patterns return
  • Conditions such as Cirrhosis and Hepatitis interfere with liver function
    – they cause structural changes to occur
40
Q

Alcoholic Fatty Liver

A

yellow appearance
Can be Reversible

41
Q

Cirrhosis

A

End stage liver disease
Irreversible

Histo, Anat & Physiol (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions