Accessory Organs

Question 1

What ligament separates the liver into two lobes?

Answer 1

Falciform ligament

Question 2

Purpose of hepatic ducts

Answer 2

Brings bile + bile salts from different liver lobes –> gallbladder

Question 3

What is the porta hepatis? What is apart of it?

Answer 3

Where a lot of structures comes via inferior surface of liver

• Hepatic artery
• Hepatic portal vein
• Common hepatic duct: brings bile salt from liver –> S.I. (during meals) or gallbladder (storage)

Question 4

Bile salts in-between meals

Answer 4

Travels from common hepatic duct –> gall bladder via cystic duct

Question 5

What is the hepatopancreatic ampulla?

Answer 5

Common bile duct converges with pancreatic duct here

Question 6

What is the Sphincter of Oddi?

Answer 6

• Duodenal papilla of the S.I.
• Goes to the duodenum
• Stays closed during meals

Question 7

Dual blood supply of the liver

Answer 7

• Receives O2 rich blood from abdominal aorta via celiac trunk
• Mixes with the deoxy blood returning from GI tract
• All blood is drained by hepatic vein –> IVC –> RA

Question 8

Cell types of the liver (x2)

Answer 8

Hepatocytes and Kupffer cells

Question 9

Which liver cell makes up most of the liver cells?

Answer 9

Hepatocytes

Question 10

Functions of hepatocytes

Answer 10

Synthesize proteins, store nutrients (glucose + lipids), detoxify drugs + metabolize Vit D

Question 11

Functions of Kupffer cells

Answer 11

• 80% of body’s macrophages
• Exist in dilated spaces between hepatocytes
• Phagocytosis of microbes, toxins, damaged WBCs & RBCs
• Found in hepatic sinusoids

Question 12

Hepatic sinusoids

Answer 12

• Formed by sinusoid capillaries (huge gaps + incomplete basement membrane)
• Allows proteins (albumin, clotting factors + complement proteins) made by hepatocytes to move through

Question 13

Hepatic triad

Answer 13

1. Bile duct
2. Venule from hepatic portal vein
3. Hepatic arteriole from hepatic a.

Question 14

Flow of blood and bile

Answer 14

The direction of bile flow is opposite to the blood

Question 15

Roles of the liver

Answer 15

• Process/store intestinal nutrients (amino acids, lipids + vitamins)
• Synthesis of serum proteins
• Process drugs & hormones
• Storage of iron & excretion of bilirubin
• Aids in digestion (bile)

Question 16

Why can’t the liver store glucose?

Answer 16

Water follows glucose so hepatocytes would burst

This is why it has to be stored as glycogen

Question 17

Role of glycogen

Answer 17

Liver stores glucose (monosaccharide) as glycogen (polysaccharide)

Breaks down into glucose during times of need (used by CNS)

Question 18

What happens when the sugar capacity is full?

Answer 18

Liver converts glucose into fatty acids or triglycerides

Goes to adipose

Question 19

Gluconeogenesis

Answer 19

Liver creates glucose from lactic acid (waste from anaerobic respiration), pyruvate & amino acids (broken down, use the C chains)

Can also be made from triglycerides (with glycerol backbone)

Question 20

Why can’t you use the glycogen in skeletal muscle?

Answer 20

Because its been phosphorylated so its trapped in skeletal muscle and can’t be used by other systems

Question 21

Processing of amino acids

Answer 21

Essential amino acids are used for protein synthesis (e.g. albumin)

The liver converts toxic ammonia to urea (water soluble; then excreted by kidneys)
- Ammonia is produced during the breakdown of amino acids in liver

Question 22

What are chylomicrons?

Answer 22

The way in which breakdown products of fatty acids are packaged by the intestinal absorptive cell –> lacteal –> circulation

Question 23

What are lipoproteins?

Answer 23

Lipids attached to proteins; makes them miscible in the watery matrix of blood

Question 24

Lipoproteins (x3)

Answer 24

1. VLDL: transports fats made by hepatocytes (liver) –> adipocytes
2. LDL: transports cholesterol to tissues
   
   • Excess of this accumulates under the endothelium in blood vessels
   • Most cholesterol is generated by liver (not just from diet)
3. HDL: returns excess cholesterol from tissues –> liver (puts it into bile salts)

NOTE: fibre can trap cholesterol + eliminate it (high fibre diet)

Question 25

Vitamin A

Answer 25

Converted to retinyl esters (vision, rods for night vision)

Question 26

Vitamin D

Answer 26

Used in bone metabolism - Active form of Vit D (calcitrol) tells kidney not to pee out calcium Can be synthesized (needs UV) - UV activates precursors in skin --> liver --> kidney (controlled by PTH)

Question 27

Vitamin E

Answer 27

Antioxidant ROS reacts with proteins + DNA which results in aging Vitamin E gets rid of ROS

Question 28

Vitamin K

Answer 28

Utilized by hepatocytes to form functional coagulation factors

Question 29

Synthesis of serum proteins

Answer 29

Liver synthesizes: albumin, coagulation factors, complement proteins and a & b globulins

Question 30

Role of albumin

Answer 30

Provides colloid osmotic pressure that allows for fluid that escaped the capillary bed to come back into vascular space (so we don't lose too much fluid to the tissues) Acts as a taxi for hormones/cations/bilirubins etc.

Question 31

Storage of iron

Answer 31

Liver stores iron via ferritin Iron is bound to transferrin for transport in circulation Heme from damaged RBCs return to the liver where iron is scavenged & the heme is discarded as bilirubin (bile) Accumulation of bilirubin in tissues = jaundice

Question 32

Functions of bile

Answer 32

- Lipid digestion - Cholesterol metabolism - Excretion of lipid soluble drugs

Question 33

Composition of bile

Answer 33

- Bile salts (for emulsification) - Cholesterol - Bilirubin - Electrolytes (sodium + chloride)

Question 34

Bile storage + recycling

Answer 34

Stored in the gall bladder until needed Recycled by the ileum (was dumped into duodenum to help w fat breakdown)

Question 35

How to reduce cholesterol

Answer 35

Lots of fibre! Reduces cholesterol + increased excretion of excess bile

Question 36

3 F's of developing gallstones

Answer 36

Female, 40 & fertile Estrogen = more cholesterol and less water

Question 37

Control of gallbladder function

Answer 37

Parasym input = very weak contractions during cephalic phase + tells liver to increase bile production When fat enters duodenum, CCK and secretin are released CCK gets gallbladder smooth muscle to contract + release bile Secretin increases production of bicarb-rich bile secretions by hepatocytes

Question 38

Exocrine functions; pancreas

Answer 38

Products of exocrine (juices/enzymes) enter the duodenum via hepatopancreatic ampulla 90% of pancreas

Question 39

Gall stones at Sphincter of Oddi

Answer 39

Leads to pancreatitis Pancreatic secretion backup: inflammatory enzymes can activate pancreatic enzymes --> autodigestion

Question 40

Endocrine functions; pancreas

Answer 40

Endocrine products enter the BS Occurs in Islets of Langerhans - Secrete hormones (insulin + glycogen) that go into BS and regulate glucose

Question 41

Regulation of pancreatic exocrine function

Answer 41

During cephalic phase, vagus n. activates pancreas to release bicarb-rich juice (weak activation) Chyme enters duodenum --> CCK and secretin release

Question 42

Pancreatic endocrine function (blood glucose homeostasis)

Answer 42

Glucagon is released from alpha cells of pancreatic islets Insulin is released from beta cells High blood sugar = increased insulin (tells tissues to store glucose) - Liver turns glucose --> glycogen Low blood sugar = increased glycogen - Glucagon talks to liver to convert glycogen --> glucose