Test Three Histology

Front 1

Small Intestine Overview

Back 1

* Functions:
- terminal food digestion
- nutrient absorption (90% of nutrient absorption occurs here)
- endocrine secretion

* Three Regions:
- duodenum (first, shortest, widest part)
- jejunum
- ileum (connects ultimately to the large intestine)

* Plicae- folds in walls of intestine to increase surface area. Most abundant in jejunum. Some are permanent, some aren't.

Front 2

Mucous Membrane- Plicae circulare

Back 2

* Plicae circulares (circular folds):
- permanent folds
- mucosa + submucosa

Front 3

Mucous Membrane- Intestinal villi

Back 3

* Intestinal Villi:
- epithelium + lamina (in center of it)
- transitional shape

The intestinal villi extend into the lumen for absorption

Front 4

Mucous Membrane- Intestinal glands

Back 4

aka Crypts of Lieberkuhn (or intestinal crypts)

- there to increase surface area
- goblet cells associated
- paneth cells at bottom

Front 5

Cells of Intestinal Mucosal Membrane

Back 5

* Enterocytes (function is absorption)

* Goblet (mucin-secreting gland; increase toward ileum)

* Paneth (bacterial defense)

* Enteroendocrine (produce paracrine and endocrine hormones)

* M Cells (cover enlarged lymphatic nodules (Peyer's Patch))
- they absorb pathogens and present them to lymphocytes

Front 6

Enterocytes- Brush Boarders

Back 6

- increases surface area
- most numerous type of cell in small intestine
- they are absorptive cells specialized for the transport of substances from the lumen of the intestine to the circulatory system

Front 7

Goblet Cells

Back 7

produce mucus; most numerous in ileum

Front 8

Paneth and Enteroendocrine Cells

Back 8

- paneth = at the base of crypts; involved in bacterial defense.

- enteroendocrine cells in the small intestine produce nearly all of the same peptide hormones as they do in the stomach (CCK, secretin, GIP, motilin, etc)

Front 9

Regional Differences between duodenum, jejunum and ileum

Back 9

- duodenum- short, broad villi; fewest goblet cells

- jejunum- increase in number of goblet cells; leaf shaped

- ileum- finger-like projections; most goblet cells are associated with here

Front 10

Large Intestine

Back 10

*Functions
- reabsorption of electrolytes and water
-elimination of undigested food and waste

*Anatomy:

1. Cecum
- vermiform appendix

2. Colon
- ascending, transverse, descending, sigmoid

3. Rectum

* Ileal-cecal valve connects the large and small intestine

Front 11

Haustra

Back 11

"pockets" or pouches that allow large intestine to expand

Front 12

Taeinia coli

Back 12

muscular bands that run the length of colon (help with expansion)
- the outer longitudinal layer of the muscularis externa exhibits three thickened, equally spaced bands known as teniae coli.

Front 13

Large Intestine- Mucous

Back 13

*Intestinal Glands:
- simple columnar
- goblet and absorptive cells
- no paneth

* Lamina Propria:
- lymphocytes
- large GALT
- no lymphatic vessels

Front 14

Rectum and Anal Canal

Back 14

* Rectum:
- transverse rectal folds
- glands with numerous goblet cells

* Anal Canal (the most distal portion of the alimentary canal):
- anal columns (upper part of canal)
- stratified squamous (lower)

*Muscularis becomes modified into Internal Sphincter.
*This canal has prominent longitudinal folds

Front 15

Rectum-Anal Junction

Back 15

*Anal Canal:
- submucosa dense irregular and vascularized

*Circumanal- gland that secretes pheromones (in animals)

*Vasculature associated with lamina propria in this area (hemorrhoids)

Front 16

Accessory Digestive Organs

Back 16

- Appendix
- Pancreas
- Liver
- Gallbladder

Front 17

Appendix

Back 17

- a fingerlike projection off the cecum
- it is a small blind sac and prone to become infected
- lymphatic nodules associated

Front 18

Pancreas

Back 18

- has a head, body and tail
- it is both an exocrine and an endocrine organ (exocrine= synthesizes and secretes enzymes into duodenum; endocrine= synthesizes and secretes insulin and glucagon into blood)
- has a capsule of CT
- has septa extending into liver

Front 19

Ducts Associated with Pancreas

Back 19

* Pancreatic Duct (Wirsung)- dumps into common bile duct which eventually goes into duodenum

* Accessory Duct (Santorini)- dumps into duodenum also

Front 20

Pancreas Microanatomy

Back 20

*CT divides into lobes
- blood and tributaries

*Pancreatic Acini- dark areas (the exocrine function is here)

*Pancreatic Islets (aka Islets of Langerhans)- endocrine function here

Front 21

Pancreas Exocrine Function

Back 21

*Acini:
- release product into tubule
- acini cells produce pancreatic juices (H2O, ions and also produce enzymes- this creates an alkaline buffer)
In acini:
- serous, pyramidal
- zymogen granules

*Intercalated duct- inside acini
- centroacinar cells- produce pancreatic juices along with the acini cells

*Intralobular duct

*Interlobular duct

*Main pancreatic duct

Front 22

Pancreas Endocrine Function

Back 22

*Isle of Langerhans (types of cells):
1. A (glucagon)
2. B (insulin)
3. D (somatostatin)

*interact with capillaries within the tissue (there are no ducts)

Front 23

Acute Hemoragic Pancreatitis

Back 23

- pancreas begins to digest itself
- alcohol contributes to this

Front 24

Cystic Fibrosis

Back 24

- defective cilia, affects a number of systems. Pancreatic duct gets backed up and creates a thick mucous.

Front 25

Liver

Back 25

- biggest internal organ in the body

*Bilobed organ:
- Falciform ligament- separates the two lobes

*Capsule (Glisson's)- has CT covering it

*Lobules:
- Portal triads associated

Front 26

Liver detoxifies blood and reabsorbs nutrients coming from...

Back 26

1. portal vein (from spleen, pancreas, intestines)
2. hepatic vein (from inferior vena cava)
3. hepatic artery (from large arteries)

Front 27

Liver- Blood supply

Back 27

- blood flows in through tetrad into central vein and it goes out
- bile ducts also present
- there is a central vein running through the center of the lobule
- the lobule is a hexagonal unit
- lobules aren't as prominent in humans as in other animals

Front 28

Liver Lobule

Back 28

- blood flows through sinusoids
- tissue of lobules = hepatocytes (responsible for cleaning up blood)

Front 29

Kupffer Cells

Back 29

basically macrophages in liver lobule
- they belong to the mononuclear phagocytic system

Front 30

Hepatocyte

Back 30

- radial, singular plate
- bili canaliculi
- exocrine and endocrine

Front 31

Gall Bladder

Back 31

-stores excess bile that is being produced (connected to duct into small intestine)

- Embryonic rudiment
- Blind sac
- Cystic duct

Front 32

Gall Bladder microanatomy

Back 32

*Mucosal folds
*Apical microvilli
*No:
- Muscularis mucosa
- Submucosa
*Smooth Muscle
*Adventitia

Front 33

Liver Diseases

Back 33

*Hepatitis- breakdown of liver; associated with a virus

*Cirrhosis- hepatocytes are breaking down/dying and being replaced with fibrous tissue (this disrupts the whole system). Excess alcohol can cause this.

*Liver Cancer- can get it from hepatocytes becoming cancerous or getting it from another organ.