Glands Independent Learning Sep 26 Flashcards
How do glands form?
Cells from the surface epithelium will grow down into the underlying connective tissue.
If exocrine: the connecting cells will persist to form a duct and the deepest cells become secretory
If endocrine: the connecting cells disappear, but the deepest cells remain to secrete into the capillaries
What are glands
organs composed of individual or groups of cells specialized for the funciton of secretion
Within the gland structure, what is the epithelial component called? What is the connective tissue component called?
- stroma: connective tissue component that supports parenchyma
- parenchyma: epithelial component of the gland
What are 4 classification schemes for glands?
- Presence or abscence of Ducts
- Method of Product DIscharge by Cells
- The number of cells in the gland (unicellular or multicellular)
- Nature of the secretory product
What are the three modes of secretion (on the gland level, not the cellular)?
- exocrine glands
- endocrine glands
- mixed glands
Describe exocrine glands
They have ducts
THeir secretions pass onto an epithelial surface
Describe endocrine glands
These do NOT have ducts
Their secretions enter the blood or lymphatic system
Describe misxed glands. WHere are they found in the body?
They contain both exocrine and endocrine components
Pancreas and testes are exampes
What are the three methods of product discharge by cells?
- Merocrine (eccrine) gland
- Apocrine gland
- Holocrine gland
Describe a merocrine (eccrine) gland
The cell remains completely intact
the cell product is release via exocytosis throught he membrane
Describe secretion from an apocrine gland?
A portion of the cell is lost during the secretory process
Describe secretion from a holocrine gland.
An entire daughter cell becomes part of a secretory product
There are different natures of secretory products. What are they?
Serous
Mucous
Describe a serous gland
product a thin, watery secretion
the nucleis are rounded and are seen near the base of the cell
the cytolasm at the base of the cell is strongly basophili due to numerous free ribosomes and RER
The apical cytoplasm may be occupied by granular material
Describe a mucous gland
produce a viscous slippery secretion
the nuclei are flattened against the base of the cell in th esecretory uits
the cytoplasm at the base of the cell is NOT strongly basophilic
the apical cytoplasm tnds to look bubbly or foamy due tot he presence of amny mucous secretory vesicles or droplets
Describe a mized serous/mucous gland
It contains both mucous and serous secretory portions
the serous portion is frequently present in the form of demilune, which are crescent shapped groups of serous cells capping the mucous secreting units
What is a unicellular exocrine gland called?
Describe its overall structure
A goblet cell
The RER is located down neae the basal lamina, this is where protein syntehsis and the initial glycosylatin occurs
The secretion then travels up to the golgi complex where terminal glycosylation and sulfation happems
Near the top the glycoprotine grandules accumulate
At the apical surface the granules are exocytosed out of the cell onto the surface
The whole process takes about 1.5 hours
What are the two guildlines for classifying multicellular exocrine glands?
The extent of duct branching (does it branch or not/)
Shape of the secretory unit
If a duct doesn’t branch is it called a _____gland
If a durct does branch, it is called a _______gland,
a simple gland
a compound gland
WHat are the 3 possible shapes of the secretory unit in a multicellular exocrine gland?
- tubular
- alveolar
- tubuloalveolar
What does a tubular secretory unit look like?
WHat does an alveolar/acinar/saccular secretory unit look like?
What does a tubuloalveolar secretory unit look like?
Tubular just looks like a tube
Alveolar is more flaskline
a tubuloalveolar is a combinaiton of the two where some look like tubes and some look like flasks
Describe myoepithelial cells.
Where are they located?
What is their structure?
What is thier function?
Myoepithelial cells are star-shaped in structure with a central nucleus and long cytoplasmic processes
THey have filaments in the cytoplasm which may be contractile
THey are located between the basal lamina and the base of secretory cells
They help secretory processes by pressing on secretory cells (for example in sweat glands, mannary glands, and salivary glands
Is this a mucous or a serous gland?
This is a serous acini - the nuclei are in the center of the cell
Is this a mucous gland or a serous gland
This is a mucous acini (the nuclei are fflattened at the base)
THis picture is a mixed serous mucous gland. What is the dark portion along the left lower mucous acini?
that’s the demilune
What are the blue things?
goblet cells
