Session 5.2e - Lecture 1 - Epithelial Tissues and Glands Flashcards
Slides 65 - 78
Glands can be made up of a single cell or a collection of cell. What are the terms used to describe these compositions?
Unicellular
Multicellular
What is the simplest type of gland?
Unicellular (as opposed to multicellular).
Give an example of a unicellular gland.
A goblet cell
What type of gland is a goblet cell?
A unicellular exocrine gland.
Give an example of a unicellular exocrine gland.
Goblet cell
What is a goblet cell?
A unicellular exocrine gland that produces mucus. It is so-named bc it appears as a goblet under the microscope (has a long thin stem).
Fig. 65
Identify the mucus.
All the pink stuff would be filled with mucus
What organelles in the goblet cell are making mucus?
Golgi apparatus
Rough endoplasmic reticulum
Nucleus
etc. etc.
What do goblet cells sit on?
The basement membrane
What happens to the mucus in goblet cells?
It is secreted
Where is the mucus from goblet cells secreted?
Onto the respiratory or gut surface, often
Where are goblet cells found?
Respiratory tract:
- trachea, bronchi, and larger bronchioles
Intestinal tract:
- small and large intestines
Eye:
- conjunctiva in the upper eyelid
How do goblet cells appear under a microscope?
Pale and goblet shaped
Goblet cells are little ____
Little exocrine glands in their own right
Fig. 65
Caption this diagram, explaining about glands and goblet cells.
Glands can be UNICELLULAR or MULTICELLULAR. This diagram shows a goblet cell (a unicellular exocrine gland).
This type of unicellular gland is important for producing mucus in the respiratory and intestinal tracts.
Fig. 65
Label this diagram
- Microvilli
- Mucinogen granules
- Golgi apparatus
- rER
- rER
- basal lamina
Draw a diagram of a Goblet cell and its associated organelles.
See Fig. 65
- Microvilli
- Mucinogen granules
- Golgi apparatus
- rER
- rER
- basal lamina
Fig. 66
Caption and label this image.
G G
Unicellular goblet cells (G) in the epithelium of the upper respiratory tract.
Draw how goblet cells would appear on a histology slide, from the respiratory tract.
See Fig. 66
G G
Unicellular goblet cells (G) in the epithelium of the upper respiratory tract.
What type of epithelial cell do goblet cells derive from?
Simple columnar cells.
Fig. 66
Distinguish between the goblet cells and other simple columnar cells,
The other simple columnar cells have cilia and a different morphology and they’re not producing mucus
How do goblet cells differ from the other simple columnar cells around it?
The other simple columnar cells have cilia (1) and a different morphology (1) and they’re not producing mucus (1)
Fig. 67
Identify the goblet cells.
The ones looking like goblets/wine glasses.
Fig. 67
What is the function of a goblet cell here?
To secrete mucus onto the surface of an intestinal villus
What are intestinal villi?
Intestinal villi (singular: villus) are small, finger-like projections that extend into the lumen of the small intestine
Fig. 67
Other than the goblet cells, what other type of cell is present here?
Simple columnar cells which sit on a basement membrane
Fig. 67
What do the simple columnar cells have?
Microvilli (brush border)
Microvilli on the surface of epithelial cells form what?
A brush border
What is a brush border?
Microvilli on the surface of epithelial cells
Fig. 67
What is found amongst the simple cuboidal cells which have microvilli?
Goblet cells, which produce mucus
Fig. 67
Caption this image.
Unicellular goblet cells in the epithelium of an intestinal villus
(Note: - goblet cells look like a wine glass
- other simple cuboidal cells have microvilli, a brush border
- sits on a basement membrane (top?))
Draw the epithelium of an intestinal villus as seen under a histology slide.
See Fig. 67
Unicellular goblet cells in the epithelium of an intestinal villus
What is the function of goblet cells in the intestine?
Produce mucus that’s needed by the intestinal lumen contents.
What produces the mucus that’s needed by intestinal lumen contents?
Goblet cells
What are colonic crypts?
Crypts of Lieberkühn (intestinal glands)
Explain the relationship between goblet cells and crypts of Lieberkühn?
Goblets cells are one of the types of cells that make up these crypts. The goblet cells secrete mucus.
Fig. 68
Caption this image.
Goblet cells in tubular colonic crypts
(Goblet cells are the light coloured cells
Colonic crypts = crypts of Lieberkühn = intestinal gland, made up of (+ others) goblet cells.
This is further down the intestine than where the intestinal villus lay).
Draw an image of goblet cells in tubular colonic crypts, as seen on a histology slide.
See Fig. 68
Goblet cells in tubular colonic crypts
(Goblet cells are the light coloured cells
Colonic crypts = crypts of Lieberkühn = intestinal gland, made up of (+ others) goblet cells.
This is further down the intestine than where the intestinal villus lay).
What secretes mucus in the crypts of Lieberkühn?
Goblet cells (a ty[e of cell which make up the crypt) secrete mucus in the crypts of Lieberkühn
Why is it important to know what a gland is in histology?
Normally, for about the last 20 years the histology of glands would be covered comprehensively: salivary glands, the adrenal gland, the parathyroid glands etc., but now - once you’ve got the hang of the basics of histology you can read about any gland and understand it
Where does the pancreas sit?
Not far from the stomach, with its head tucked into the curve of the duodenum.
Where does the head of the pancreas lie?
Tucked into the curve of the duodenum
What lies tucked into the curve of the duodenum?
The head of the pancreas
What is the duodenum?
The first part of the small intestine (preceding the jejunum and the ileum). It is the shortest part of the small intestine, and connects the stomach to the jejunum.
What is the first part of the small intestine called?
The duodenum
What connects the stomach to the jejunum?
Duodenum
What does the duodenum connect in the alimentary tract?
Stomach and jejunum
What type of gland is the vast majority of the pancreas?
An exocrine gland
What do the exocrine cells of the pancreas produce?
Digestive enzymes, together with bicarbonate
What produces digestive enzymes in the pancreas?
Its exocrine cells (ductal cells and acinar cells)
80% ductal adenocarcinomas for pancreatic cancer
Where does the pancreas secrete its digestive enzymes into?
The duodenum
The duodenum receives digestive enzymes secreted by ____
The pancreas
What does the duodenum receive from the pancreas?
Digestive enzymes secreted by it
What secretes the bicarbonate from the pancreas?
Duct cells (exocrine glands)
What do duct cells secrete?
- Aqueous component (isotonic)
- Bicarbonate
What is the function of the bicarbonate produced by the pancreas?
To neutralise the acid (chyme) produced from the stomach.
What neutralises the acid produced by the stomach?
Bicarbonate
What is chyme?
Chyme is the semi-fluid mass of partly digested food that is expelled by the stomach, through the pyloric valve, into the duodenum (the beginning of the small intestine).
What is the semi-fluid mass of partly digested food expelled by the stomach known as?
Chyme
What pH is chyme?
Acidic (~2)
Where is chyme produced?
The stomach
Where does chyme from the stomach go?
To the duodenum
What are the endocrine cells in the pancreas?
Islets (literally, islands) of Langerhans
What types of cells are the islets of Langerhan?
Endocrine cells of the pancreas
Where are islets of Langerhans found?
Particularly in the tail and outermost area of the pancreas
Name 3 peptide hormones secreted by the islets of Langerhans.
- Glucagon
- Somatostatin
- Insulin
Where is glucagon produced?
Islets of Langerhans in the pancreas