Brainscape's Knowledge GenomeTM

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


See full index

COT pt. 2 > Lecture: Liver > Flashcards

Lecture: Liver Flashcards

1
Q

Liver: Gross Anatomy

A

The Liver is divided into lobes.

“The lobes of the liver are defined surgically by the pattern of blood inflow and the branching pattern of the blood outflow”

Each lobe is supplied by a major division of portal vein & hepatic artery.

Each lobe is drained by a major division of the hepatic vein.

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

Liver: Microanatomy

A

Portal triad contains the following:

Dumps into the central vein:
-Portal vein: 75% of blood inflow to liver, already gave up its O2 to the GI tract, this is the second capillary bed

-Hepatic artery: 25% systemic circulation that oxygenates the liver

Goes in the reverse direction:
-Bile ductule: goes out into the bille duct = exocrine outflow

-Lymphatic vessel: liver clears blood of toxin and those waste products that are produced go out with the lymph fluid

“Plates” of hepatocytes separate the inflow circulation from the outflow.

Sinus (sinusoid) capillaries are lined with LSEC and separated from
hepatocytes by the (CT) Space of Disse

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

Central vein

A

The beginning of the outflow of the liver. This is where the blood is exposed to the hepatocytes.

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

Bile canaliculi

A

Where the bile ductule gets its bile from. Small structures in between hepatocytes

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

Liver: Embryology

A

Liver, gall bladder, bile duct and
pancreas derive from endoderm
foregut.

The liver is positioned to receive
blood from the gut.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Liver: Blood Flow

A

The liver receives a systemic circulation via the hepatic artery (branches off the celiac artery).

The liver receives the majority of its blood from the digestive tract through a venous portal system.

Blood is returned through the hepatic veins, which drain to the inferior vena
cava.

Liver disease may result in portal hypertension, i.e. increased blood pressure in the portal vein. (hypertension because blood is backing up in portal vein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Portal Hypertension

A

Blood may try to route itself around the portal circulation if the pressure is too high

Portal hypertension may result in anastomoses at either end of the circulation:

 esophageal varices: normal circulation to portal vein may anastomose several places (diagram shows sites of venous drainage of esophagus)

 anorectal varices: internal hemorrhoidal veins (dilated venules in region of anal canal) normally drain to superior rectal vein -> portal vein, but abnormally to iliac vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Functions of the Liver

A
  1. bilirubin metabolism
  2. porphyrin met.
  3. bile acid met.
  4. amino acid & protein met.
  5. carbohydrate met.
  6. lipid & lipoprotein met.
  7. hormone met.
  8. vitamin met.
  9. trace elements
  10. detoxification
  11. ammonia detox.
  12. bicarbonate neutralization
  13. alcohol degradation
  14. reticuloendothelial system
  15. free radicals & antioxidants
  16. cellular transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The Reticuloendothelial System

A

The space of Disse drains into
portal triad lymphatics (through
the space of Mall).

Reticuloendothelial system - cells
following reticulated endothelia in
lymph nodes, spleen etc.

Mononuclear phagocyte system - macrophages (histiocytes and
resident tissue macrophages)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Space of Disse

A

space between the sinusoidal endothelium and the hepatocyte

Hard to see, tiny space

A lot of the work done by the hepatocyte takes place here. Hepatocytes can take thing up out of the space or put things in. CT compartment that is basal to the hepatocyte and endothelium

Wispy type 3 collagen

Drains into lymphatic

Space of Disse drains to lymphatics via space of Mall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LSEC

A

Liver Sinusoidal Endothelial Cell

LSEC …
- are sinusoid, lining sinus capillaries
- endocytose blood waste products. “Some things you don’t need hepatocytes for. These endothelial cells are acting like local macrophages for the blood”
- are self-replenishing
- coordinate liver immune cell population
- secrete hepatocyte growth factor and other cytokines to control liver growth
- are antigen-presenting cells (APCs)

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

gall bladder

A

OUTFLOW
stores and concentrates bile diverticulum of common bile duct dorsally directed output

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

portal vein

A

INFLOW
blood inflow from gut venous portal system dorsal input

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

hepatic artery

A

INFLOW
systemic (oxygenated) blood inflow dorsal input

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

hepatic vein

A

OUTFLOW
drains to inferior vena cava ventral output

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

lymphatics (deep)

A

OUTFLOW
drain to hilar hepatic nodes dorsal output

15
Q

bile ductule

A

delivers bile to duodenum exocrine duct

16
Q

3 ways that lymph can get out of the liver

A

1) Through portal triad: lymph drains (through space of Mall) via portal triad lymphatics to hilar nodes & cisterna chyli

2) lymph follows space around central vein & exits with hepatic vein

3) lymph drains to pericapsular regions & exits through capsule adventitial to diaphragm

Cancer metastases tend to follow the path of the lymphatics. This is one of the largest organs that has lymphatic drainage

17
Q

Hepatocyte

A

(this one is weird)

The “apical” surface of the hepatocyte faces the bile canaliculus. Bile is the exocrine product.

The “lateral” surface of the hepatocyte faces other hepatocytes, and is separated from the apical surface via tight junctions.

The “basal” surface faces the space of Disse and the sinus (sinusoidal) capillaries.

Hepatocyte microvilli extend from the basal surface into the space of Disse and from the apical surface into the bile canaliculus.

“The functional apical surface contains the bile canaliculi”

Hepatocytes are characterized by glycogen, lipid droplets, RER, free ribosomes and prominent SER, endocytotic vacuoles, numerous mitochondria and a euchromatic nucleus.

18
Q

Zonation of Hepatocytes

A

Hepatocytes differ in their particular
combinations of enzymes. Some enzymes are preferentially distributed around the central veins (zone 3, ‘pericentral’), others around the portal triads (zone 1, ‘periportal’), others inbetween (zone 2)

The ‘hepatic acinus’ was defined in an
attempt to emphasize these differences (zones 1,2,3) but in modern literature ‘periportal’ and ‘pericentral’ are more common terms.

Oxygen tension & metabolite concentrations in the blood also change dramatically with these zones.

Ex: Where would a hepatocyte that loves being near oxygen be? Near the portal triad
Where would a hepatocyte that is specialized to break down metabolites? Near the central vein

19
Q

Kupffer Cells

A

Look like they are in the sinus, but they have feet sticking into the sinus/space of Disse

Kupffer cells …
- are resident macrophages, seeded during fetal development
-phagocytose blood-borne pathogens
- break down RBCs - hemoglobin into bile pigment

20
Q

Kupffer cells and other immune cells also show __________

A

zonation

LSECs secrete cytokines that cause immune cells to localize preferentially to periportal locations

Zonation is dynamic & responds to pathogen load

21
Q

Hepatic Stellate Cells

A

also called perisinusoidal cells/Ito cells

Major functions:
-Vitamin A storage
-fibrosis during injury: fibers in liver will be in the CT space of the space of Disse. The more fibrosis there is, the harder it is for the hepatocytes to work by taking things up and out

No need to recognize these cells on a slide

hepatic stellate cells (HSCs also known as perisinusiodal cells, fat-storing cells, or Ito cells) which are important as the cells that produce the collagen in disease states that cause liver fibrosis

22
Q

canal of Hering

A

Hepatocyte stem cells reside in the canal of Hering, the connection of the bile ductules with the hepatocyte plates. “connection between bile canaliculi and bile ductule”

Similar in concept to the Space of Mall the connection between the space of Disse and lymphatic drainage

23
Q

Cholangiocytes

A

epithelial cells that line the bile ducts and are a key part of the liver

24
Q

Fibrosis and Cirrhosis

A

Normally, fibrillar collagens are
minimally present in the space of
Disse.

Insults to the liver produce fibrosis -
the appearance of collagens (III, I,
etc.) in the space of Disse.

Activation of hepatic stellate cells
initiates inflammation and wound
healing response. Fibrosis is reversible, but chronic fibrosis leads to cirrhosis, which is not.

steatosis - (intracellular) fatty
accumulation in hepatocytes - is also a prior characteristic of some disorders.

Factors that commonly lead to cirrhosis include:
-Hepatitis C virus
-Alcoholic liver disease
-non-alcoholic steatohepatitis (NASH)
-metabolic disorders
-drug toxicity

25
Q

ascites

A

abdominal distention due to peritoneal fluid accumulation

26
Q

fetor hepaticus

A

“liver stink” portal hypertension causes systemic shunting to the lungs. Thiols, normally removed by the liver, can be detected in expelled air.

27
Q

Clinical Liver Immunology

A

Antigens passing through the liver tend to evoke tolerance.

Liver transplants can thrive without immunosuppressant drugs.

Liver transplants are protective to other organ transplants.

Hepatitis (B, C) - viral diseases that take advantage of the liver’s unique immune system

28
Q

The liver produces the vast majority of circulating innate immunity proteins. What are they?

A

complement proteins
opsonins
bactericidal proteins

29
Q

Resident immune cell populations present in the liver

A

Kupffer cells - largest resident Mφ population in the body
resident APCs
resident NK-cells
resident T-cells
enriched NKT cells
enriched in γδT cells

30
Q

Glisson’s capsule

A

The liver is surrounded by connective tissue of Glisson’s capsule. The connective tissue also extends to the adventitial surfaces of the gall bladder (inferior) and diaphragm (superior). Both Glisson’s capsule and the serosal surface of the gall bladder are continuous with the serosa lining the peritoneal cavity.

31
Q

divide the stroma of the liver segments

A

The interlacing tubes of portal triads and central veins divide the stroma of the liver segments into lobules, which can be defined in different ways. A hepatic (or classic) lobule is the tissue centered around central veins. A portal lobule is the tissue centered around a portal triad. A hepatic acinus roughly corresponds to one incoming central artery and its drainage area to two central veins.

32
Q

Embryonic derivations of liver

A

The liver arises from embryonic endoderm as the hepatic diverticulum. The cystic diverticulum gives rise to gall bladder and pancreas.

COT pt. 2 (11 decks)

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