Epithelial Tissues and Glands Flashcards
1
Q
Epithelial Tissue
A
Epithelium
Covers body surfaces and lines ducts, hollow organs (tubes in GI, respir., urogenital), and closed body cavities (peritoneal)
- Covering/Lining Epithelium
- Glandular Epithelium
*NO EC Matrix
2
Q
Connective Tissue
A
Abundant amount of EC Matrix
3
Q
Muscular Tissue
A
Generate force to make body move using stored ATP
4
Q
Nervous Tissue
A
Detects changes and stimuli along and outside body then reacts by generating nerve impulses (Action Potential)
Key to maintaining homeostasis
5
Q
Glandular epithelium
A
glands are formed by epithelium both in the duct and secretory portions
6
Q
What are the 6 functions of epithelial tissue/epithelium?
A
- Secretion (glands, epithelium in GI)
- Absorption (GI tract and SI, absorb material across epithelial lining)
- Filtration (blood-move things into or out of blood)
- Excretion (tube away from body)
- Transport (exo/pinocytosis; materials along surface via cilia, such as respiratory tract)
- Protection (mechanical, chemical, or bacterial; ex. transitional epithelium of urinary system)
SAFE TP
7
Q
Which characteristics define epithelial tissue?
A
- Cellularity (well packed, lots of cells, little to no EC matrix)
- Specialized Contacts (cells well packed together, adhesion molecules bind them forming specialized cell junctions)
- Polarity
- free or apical surface/pole/domain
- lateral surface/domain
- basal surface/pole/domain - Supported by Connective Tissue - lamina propria, basal membrane
- Avascular, but Innervated (relies on connective tissue underneath)
- Regeneration (easily damaged in outer surface of skin, lining of GI/respiratory; rapid cell division repairs quickly)
8
Q
Epithelial tissue is avascular and contains few nerve fibers, True or False?
A
FALSE
Epithelium is avascular but INNERVATED
-epithelial tissue is supported structurally and functionally by the underlying CONNECTIVE tissue, but is innervated with lots of nerve fibers (needed to pick up info about environment)
9
Q
Describe the lamina propria
A
connective tissue that is part of a mucous membrane, supports epithelial tissue
10
Q
What is the apical domain/pole/surface?
A
the area of the cell facing the lumen of closed body cavity, often has cilia or other specializations (microvilli)
-toward free surface/external environment or lumen of tube/cavity
11
Q
What is the purpose of microvilli vs cilia as associated with epithelial tissue polarity?
A
microvilli on the apical domain of epithelium help to increase the surface area
cilia move stuff across surface
12
Q
What is the lateral domain?
A
toward cell right next to it, this is where a lot of specialized contacts occur (cellular junctions holding them together)
13
Q
Describe the basal domain/surface
A
Where epithelium rests/lies on connective tissue
between connective tissue and epithelium is the basal membrane
-contains hemidesmosome and focal adhesion junctions
14
Q
Morphology is used to define the subclasses of epithelium, True or False?
A
TRUE
cell number and cell height/shape variation are used to define the subclasses
_# cells___ _height/shape__ epithelium*
(3 part name or its incorrect)*
15
Q
Number of cell layers are defined by which 3 classifications?
A
1) Simple
2) Stratified
3) Pseudostratified
16
Q
Cell height/shape is classified via which 3 variations?
A
1) Squamous
2) Cuboidal
3) Columnar
17
Q
Sometimes another name can be added based on any specializations at the apical surface of the cell (ex. ciliated) or at the apical surface of the tissue (ex. keratinized). This name would go in front of the 3 name tissue classification, True or False?
A
TRUE
18
Q
In simple epithelium, there is only one layer of cells, and therefore all cells are on the basement membrane, True or False?
A
TRUE
19
Q
Describe stratified epithelium
A
2+ layers of cells, only the bottom layer is on the basement membrane
20
Q
Squamous
A
very flat, cytoplasm flat and then perk up for nucleus then flatten again, nucleus bulges toward free surface, WIDTH > HEIGHT
cells very flattened near top if stratified
21
Q
Cuboidal
A
As tall as they are wide (width=height)
nucleus circular center
22
Q
Columnar
A
Taller than they are wide
Height> Width
elongated nucleus usually
23
Q
Is ciliated or nonciliated simple columnar epithelium more common in the body?
A
NONCILIATED
GI tract, gallbladder
24
Q
With stratified squamous epithelium, what question should you immediately ask?
A
find out if keratinized or nonkeratinized:
- at surface, dead, slough off for protection (nuclei gone, bag of keratin basically)
- keratinized only in skin
esophagus and vagina: nonkeratinized stratified squamous
25
transitional epithelium is also known as _____
Urothelium
26
Urothelium
(transitional epithelium)
associated with urinary system lining a lot of passageways associated with it, minor kelacis of kidney down to urethra, ureters, urethra, renal pelvis, etc
-known as transitional cause it will CHANGE SHAPE on you, when passageway is empty (like bladder), you can see multiple layers of cells and cells at surface have puffy appearance (called umbrella cells bc of it, sometimes have 2 nuclei as well)
as bladder stretches, surface cells become FLAT, ie transitioning
columnar should be flat across surface
when distended: squamous at surface
-kidney to urethra
27
Pseudostratified columnar epithelium is mostly _______
need to say if ciliated and non ciliated form
mostly in CILIATED form we’ll see it (typically respiratory tract)
Ciliated: trachea, upper respiratory tract
(propulsion of mucous)
Nonciliated: male’s sperm carrying-ducts, epididymis, ducts of larger glands
28
Simple columnar epithelium is mostly _______
NONCILIATED
| just simple columnar, don't need to say ciliated or non ciliated
29
Describe the structure and function of Simple Squamous Epithelium. Where is it found in the body?
ENDOTHELIUM, MESOTHELIUM
Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm (the simplest of the epithelia) great for tissue diffusion, secretion, absorption, transfer
Function:
- allows passage of materials by diffusion and filtration in sites where protection is NOT important
- secretes lubricating substances in serosae
Location:
-kidney glomeruli (Bowmans capsule) , air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae)
30
In the closed cavities of body like pleural, peritoneal, and pericardial cavities, the epithelium lining them is _______, but you call it mesothelium
simple squamous epithelium (in body cavity= mesothelium)
associated w/ a serous membrane (part of closed body cavity)
Ex: 3 cavities; peritoneum, pericardial, pleural
31
Endothelium is also known as
Simple Squamous Epithelium lining all blood vessels and the heart, as well as lymphatic vessels
-formed by embryonic mesoderm
32
Simple Cuboidal Epithelium
Single layer of cubelike cells with large, spherical central nuclei
Function: secretion and absorption (not very thick)
Located in:
- Kidney tubules
- ducts (pancreas) and secretory (thyroid) portions of small glands
- ovary surface
- anterior surface of capsule of lens of eye
- found exiting glomerulus
33
Simple Columnar Epithelium
Single layer of tall cells with round to oval nuclei; some cells have cilia
- layer may contain goblet cells (mucus-secreting unicellular glands)
- nuclei at basal surface, usually more stretched out nucleus but still by basal side
Function:
- absorption
- secretion of mucus, enzymes and other substances
- ciliated type: propels mucus or reproductive cells
Location:
1. Nonciliated (Majority in body):
- lining most of digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands
2. Ciliated:
- lining small bronchi
- uterine tubes
- some regions of uterus
- some paranasal sinuses
- central canal of spinal cord
- ventricles of brain
34
Describe the difference between ciliated and nonciliated simple columnar epithelium
The majority of simple columnar epithelium is nonciliated in the body
nonciliated:
- have much shorter MICROVILLI that don't move (are immotile)
- contains goblet cells (exocrine gland)
- stomach down to anus (GI tract), ducts of many glands, gallbladder
- secretion of mucous and absorption
ciliated:
- taller than wide, elongated nucleus
- respiratory tract, uterine tube, spinal cord, uterus, paranasal sinuses
- move mucus and secretion cells by cilliary action
- small bronchi, uterine tubes
35
Stratified Squamous Epithelium
Thick membrane composed of several cell layers
- Basal cells are cuboidal or columnar and metabolically ACTIVE (mitosis: produce the cells of the more superficial/surface layers)
- APICAL/Surface cells are flattened (squamous):
* Keratinized: when surface cells are full of keratin and DEAD; no nuclei (epidermis, outer surface thick skin)
* Nonkeratinized: still active, contain nuclei (vagina, esophagus)
Function: protection
*Look at APICAL SIDE aka FREE SURFACE of tissue
surface cells: stratified, squamous -> immediately think PROTECTION (multiple layers protecting underlying) -> immediately determine if KERATINIZED or not
36
How common is stratified cuboidal epithelium? Where is it located?
RARE in human body, shows up in ducts or transitions between tissues
Two or more layers of cells in which apical layer cells are cube-shaped; protection and limited secretion and absorption
Location:
- ducts of adult sweat glands
- esophageal glands
- part of male urethra
37
Describe stratified columnar epithelium as well as its function and location
several layers of irregularly shaped cells, ONLY APICAL layer has columnar cells (at surface they are taller than they are wide)
Location:
- lining part of urethra
- large excretory ducts of some glands (esophageal glands)
- small areas in anal mucous membrane
- part of the conjunctiva of eye
Function: protection and secretion
RARE
38
Pseudostratified columnar epithelium
actually SIMPLE: SINGLE layer of cells of differing heights (but all touching basement membrane), some don't reach free/apical surface
- nuclei seen at different levels
- may contain goblet cells (exocrine, mucous) and bear cilia
Function: secretion, particularly mucus
-propulsion of mucus by ciliary action
Location:
- nonciliated: male's sperm-carrying ducts (epididymis to vas deferens) and ducts of large glands
- ciliated: lines trachea, most of upper respiratory tract
39
Goblet cells
exocrine gland
nucleus near base, release mucigen to mix with water and make mucous
- pseudostratified columnar epithelium
- also in simple columnar epithelium
* Pseudo is simple too technically
40
Transitional epithelium (urothelium) resembles which two epithelial types? Where is it found and what is its function?
Both stratified squamous and stratified cuboidal epithelia; nice and puffy, sometimes more than one nucleus associated
Basal cells: cuboidal or columnar
Surface/Apical cells: dome shaped (umbrella) or squamous like (depends on degree of organ stretch)
Function: stretches readily and permits DISTENSION of URINARY organ by contained urine
Location: Lines ureters, bladder, and part of urethra
41
In transitional cells, the apical layer cells are _____ when stretched and _____ when relaxed
stretched: squamous
relaxed: cuboidal
* like stretching a cube of jello vs letting it sit still
42
The basement membrane is composed of which two parts?
The basal lamina (made by epithelial cells) and the reticular lamina (made by connective tissue-think reticular fibers)
43
Microvilli
Cytoplasmic extensions/processes with core of ACTIN filaments, do NOT move
Average height: 1µm
Average width: 0.08µm
Creating striated border (intestinal epithelium) or brush border (kidney tubule cells)
Function: increase surface area
44
Stereocilia
(stereovilli) – microvilli of unusual length
Considered long microvilli
only found a few places such as epididymis, proximal part of ductus deferens, sensory cells of the inner ear
Function: increase surface area, facilitate absorption
45
Cilia
MOTILE cytoplasmic processes
Produce movement; rapid back-and-forth
Length: 5-10µm
Diameter: 0.2µm (Longer and wider than microvillus)
Contains an axoneme (i.e. microtubules in 9+2 arrangement)
The microtubules insert into basal bodies
46
What is an axoneme and where is it located?
9+2 arrangement of microtubules found in cilia
2 central pair of microtubules surrounded by 9 microtubule doublets
47
Terminal bars appear different in light microscopy and EM, how?
In light microscopy, we see terminal bars at the apicolateral margin of the cells. With EM, the terminal bar has been shown to be a junctional complex.
48
Intercellular Junctions are located on the _____ domain, what are the three components?
Lateral domain
1) Zonula Occludens or Tight Junctions
2) Zonula Adherens
3) Macula Adherens or Desmosomes
49
Zonula Occludens aka Tight Junctions
type of occluding junction (creating different domains, impermeable)
Location: found closest to apical surface (keeps things out of cells from coming in between the cells)
```
transmembrane proteins (occludins and claudins) fuse outer surfaces of adjacent membranes together sealing off the intercellular space
-DIFFERENT STRUCTURES OF APICAL AND LATERAL SIDES
```
forms a continuous band (zonula) around the cell which is impermeable, thus it limits the movement of substances between luminal space and tissue compartments via the intercellular space
diffusion barrier between cells
gives the “barrier” characteristic to epithelial tissue; for items to get across now they must be actively transported via the specialized membrane proteins of epithelial cells
also prevents integral membrane proteins movement between domains
provide only limited resistance to mechanical stresses
50
Tight Junctions provide ____ resistant to mechanical stress
LIMITED resistance only
they can be ripped apart fairly easily
51
For items to get across epithelial tissue, they must be able to get through the barrier created by tight junctions. How does this occur?
items must be ACTIVELY transported via specialized MEMBRANE PROTEINS of epithelial cells
52
Zonula Adherens
type of anchoring junction
provide MECHANICAL stability by linking cytoskeleton of one cell to the cytoskeleton of the next; great for resisting separation
forms a continuous band around the cell
microfilaments (actin) of the first cell attach to a plaque on the inside of its plasma membrane; this plaque is attached to transmembrane protein (cadherin) which crosses the plasma membrane of the first cell and attaches to the cadherin of an adjacent cell; this second cell’s cadherin crosses its plasma membrane where it attaches to a plaque just on the inside of the plasma membrane; this plaque is attached to the microfilaments (actin) of the second cell; thus connecting cytoskeleton of one cell to the next.
53
Describe how Zonula Adherens connect the cytoskeleton of one cell to the next (include microfilaments, actin, plaque, cadherin, and plasma membrane in your description)
microfilaments (ACTIN) of the first cell attach to a plaque on the inside of its plasma membrane; this plaque is attached to transmembrane protein (cadherin) which crosses the plasma membrane of the first cell and attaches to the cadherin of an adjacent cell; this second cell’s cadherin crosses its plasma membrane where it attaches to a plaque just on the inside of the plasma membrane; this plaque is attached to the microfilaments (actin) of the second cell; thus connecting cytoskeleton of one cell to the next.
54
Macula Adherens (Desmosomes)
a type of anchoring junction
provide MECHANICAL stability by linking cytoskeleton of one cell to the cytoskeleton of the next; great for resisting separation
forms spot welds; not continuous around cell; localized
INTERMEDIATE filaments of the first cell attach to a plaque on the inside of its plasma membrane; this plaque is attached to transmembrane protein (cadherin) which crosses the plasma membrane of the first cell and attaches to the cadherin of an adjacent cell; this second cell’s cadherin crosses its plasma membrane where it attaches to a plaque just on the inside of the plasma membrane; this plaque is attached to the intermediate filaments of the second cell; thus connecting cytoskeleton of one cell to the next.
55
How does the formation of desmosomes differ from that of zona adherens?
They are the same except in zona adherens the filaments are MICROFILAMENTS while in Desmosomes they are INTERMEDIATE filaments
56
Gap Junctions are what kind of junctions? What kind of protein creates the connexon?
Communicating junctions: allows communication between cells; this is especially important in tissues were the activity of the cells need to be coordinated (so they can act as one unit)
Transmembrane proteins are in the form of a protein tunnel called a connexon that can exchange nutrients or waste products
57
In gap junctions, how are ions and small molecules exchanged?
the connexon of one cell lines up with the connexon of the next cell allowing the cells to exchange ions and small molecules; these items can diffuse from the cytosol of one cell to the cytosol of the next.
allows communication between cells; this is especially important in tissues were the activity of the cells need to be coordinated.
58
basal lamina vs basement membrane
the basal lamina (from epithelium) is one of two parts of the basement membrane; BM connects epithelium and underlying connective tissue, and contains type I and type III collagen fibers
59
Where is reticular lamina located?
the deeper portion of the basement membrane, it is located below or deep to the basal lamina and superior to the connective tissue
60
Where is the thickest basement membrane in the human body?
Trachea
| *can see it in H and E stain, usually use PAS stain
61
What are the two components of the basal lamina?
1. Lamina Lucida (clear layer, DOESNT actually exist) in body darker line/layer is BM, should be right against it
2. Lamina Densa
- in light microscopy if you see the distinguishable layer, you call it basement membrane (light micro)
- in EM: basal lamina (EM)
62
Which junctions exist in the basal domain?
cell-to-extracellular junctions
filtration system- cross basal lamina
needs to know which way is up
BL/BM can assist cells via signaling to tell which way to go, act as scaffolding for future generation
-need to make sure cells stay attached
1. Focal Adhesion
2. hemidesmosome
63
What is Focal Adhesion?
a type of anchoring junction
- looks somewhat similar to a zonula adherens junction, but it doesn’t link adjacent cells (attach actin to BM, anchor microfilament to BL)
- links the cell to the basal lamina; specifically it anchors microfilaments (actin) of the cytoskeleton of a cell to the basal lamina
- actin filaments are attached to extracellular matrix glycoproteins (ex. laminin and fibronectin) in the basal lamina via INTEGRINS (the transmembrane protein used here)
Functional role in signal detection and transmitting signals from the extracellular environment into the interior of the cell; MECHANOSENSITIVITY
to alter adhesion and migration and differentiation and growth can be impacted
deepest cells undergo cellular mitosis, need signaling to speed up
64
Integrins are _____
the transmembrane proteins used in focal adhesion (cell to extracellular junction) that attach actin filaments to EC Matrix glycoproteins (like laminin or fibronectin) in the basal lamina
-mechanosensitivity (signal detection and transmitting signals)
65
Hemidesmosome
a type of anchoring junction
-looks somewhat similar to a desmosome, but it does NOT link adjacent cells
links the cell to the BASAL LAMINA; specifically it anchors INTERMEDIATE filaments of the cytoskeleton (to plaque and then) into the basal lamina
-keeps epithelium from disconnecting underlying tissue
intermediate filaments are attached to laminin and type IV collagen in the basal lamina via integrins (the transmembrane protein used here)
Location: found in epithelia subject to abrasion and mechanical shearing forces; useful for keeping the epithelium from separating from the underlying connective tissue
function: help cells from getting ripped off
66
What are the two main categories of epithelium?
1. Covering or Lining Epithelium
| 2. Glandular Epithelium
67
Glandular Epithelium
formed by cells that create a duct and secretory portion
- via proliferation of cells and their downgrowth into the subjacent connective tissue
- initially stored in secretory granules (whatever is going to be secreted)
68
Glands can be classified by _____
connection to surface (where they secrete their secretion)
69
How do endocrine glands differ from exocrine glands?
Endocrine glands are ductless glands, and secrete hormones into interstitial fluid (En In) (THYROID)
Exocrine glands secrete their products onto a SURFACE directly or via an epithelial DUCT
-sweat and salivary glands (sweat exits)
70
Describe the various classifications of hormones secreted by the endocrine gland
1. Circulatory Hormones
2. Paracrine Hormones: do not get picked up by cardiovascular, only impact NEIGHBORING CELLS
3. Autocrine Hormones:
71
How do we classify exocrine glands?
1. Cellularity
2. Structure and Morphology (Shape)
3. Type of Secretion- What is secreted? Protein?
4. Mode/Mechanism of Secretion- How does it get out?
72
When considering cellularity in terms of exocrine gland classification, there are two types, which are ____ and ____
1. Unicellular Exocrine Glands (one cell) : Surface
2. Multicellular Exocrine Glands (more than one cell)
- consists of a cluster of cells : Some cells on surface, some tied to DUCT or secretory
73
What is the role of Goblet Cells within the Intestinal Epithelium? Where else are these cells found?
produce and secrete mucin; also located in respiratory tract
apical portion: mucin mixes with water to produce mucus
- only a cell that does this (unicellular)
- cells appear empty
74
Describe the breakdown of exocrine glands based on morphology or structure
A. Structure of Duct
1. Simple – unbranched
2. Compound – two or more branches (DO NOT SECRETE, ONLY LEAD to SURFACE)
B. Structure of Secretory Units*
1. Tubular – tube shaped; either short or long and coiled (all secretory units look like test tubes, very narrow)
2. Alveolar or Acinar – round or globular (almost like a grape)
3. Tubuloalveolar and Tubuloacinar – combination (some like test tubes some like rounded grape in same gland tho)
*Note: These secretory units can be branched or unbranched; they also may be coiled.
75
How are simple ducts different from compound ducts?
simple ducts are unbranched
| compound ducts have 2+ branches
76
Describe the 3 types of secretory units of exocrine glands
1. Tubular – tube shaped; either short or long and coiled (all secretory units look like test tubes, very narrow)
- intestinal (simple), gastric/stomach glands (branched)
- Brunner's gland of small intestine (compound)
2. Alveolar or Acinar – round or globular (almost like a grape)
- no important examples of simple in humans
- sebaceous (oil) glands (simple branched)
- mammary glands (compound)
3. Tubuloalveolar and Tubuloacinar – combination (some like test tubes some like rounded grape in same gland tho)
- salivary glands (compound)
These secretory units can be branched or unbranched; they also may be coiled.
77
What are the two parts that make up the exocrine gland?
Duct
| Secretory unit
78
When classifying exocrine glands by the TYPE of secretion, what are the three categories?
A. Mucous Glands
B. Serous Glands
C. Mixed
79
List and describe the two MAJOR types of secretory cells associated with glands
1. Serous cells
- Polarized, protein-secreting cells
- Typically produce digestive enzymes and other proteins
- Pyramidal in shape – broad base on basal lamina and narrow apical surface facing lumen
- Contain secretory granules called zymogen granules – spherical in shape; found in apical cytoplasm
- Basophilic cytoplasm due to RER and free ribosomes
- Nuclei are rounded
2. Mucous cells
- Produce hydrophilic glycoprotein mucins
- Cuboidal or columnar in shape
- Flattened nuclei at base of cells
- Contain secretory granules called mucinogen granules – found in apical cytoplasm; PAS positive
80
What is a zymogen granule and where is it located?
secretory granules in serous cells (major secretory cell type associated with glands) that are spherical in shape and found in the apical cytoplasm
81
Cytoplasm of serous cells is basophilic due to _____ and ______
Rough ER and free ribosomes
82
Myoepithelial Cells
Other associated cells with types of secretory cells (with glands)
Location: Found within the basal lamina of secretory units and the initial part of duct system
Function: Can contract; accelerates secretion of the product
-Also prevent distention of area when lumen fills
83
_____ is the basic unit of a salivary gland, and is composed of the _____ and ______
salivon
composed of the acinus and ALL related ducts
84
The acinus is a ____ sac composed of secretory cells and is the secretory portion. _#_ secretory acini are found in salivary glands.
```
BLIND
3 secretory acini are found in salivary glands:
1. Serous Acini
2. Mucous Acini
3. Mixed Acini
```
85
Describe the 3 types of acini found in salivary glands
1. Serous Acini – serous cells only; generally spherical shaped
2. Mucous Acini – mucous cells only; generally tubular shaped
3. Mixed Acini – contain both serous and mucous cells; in traditional fixation methods it appears the mucous acini have a cap of serous cells; these caps are called serous demilunes; found in the sublingual and submandibular glands.
86
serous demilunes
with Mixed Acini in traditional fixation methods it appears the mucous acini have a cap of serous cells, these are the "caps"
found in sublingual and submandibular glands
87
Exocrine glands can be classified based on the mode of secretion, which breaks down into what 3 categories?
1. Merocrine Glands
2. Holocrine Glands
3. Apocrine Glands
88
Describe the differences between merocrine, holocrine, and apocrine glands
Merocrine glands secrete a secretory vesicle (from the golgi complex) which then release the secretion
Holocrine glands secrete the mature cell that dies to become the secretory product (cell fragment) after cell division has replaced a lost cell
Apocrine glands pinch off a portion of the cell that becomes the secretion,
-mammary glands
89
Where are terminal bars
lateral apical domains
90
Serous cells
- Polarized, protein-secreting cells
- Typically produce digestive enzymes and other proteins
- Pyramidal in shape – broad base on basal lamina and narrow apical surface facing lumen
- Contain secretory granules called zymogen granules – spherical in shape; found in apical cytoplasm
- Basophilic cytoplasm due to RER and free ribosomes
- Nuclei are rounded
91
Mucous cells
- Produce hydrophilic glycoprotein mucins
- Cuboidal or columnar in shape
- Flattened nuclei at base of cells
- Contain secretory granules called mucinogen granules – found in apical cytoplasm; PAS positive
92
salivon
basic unit of a salivary gland
| -acinus and all related ducts
93
acinus
BLIND sac composed of secretory cells and is the secretory portion
3 secretory acini are found in salivary glands:
1. Serous Acini
2. Mucous Acini
3. Mixed Acini
94
serous acini
Serous cells only (proteins), generally spherical
serous : spherical
95
mucous acini
mucous cells only, tubular in shape
think "mucous: macaroni" (more tubular)
96
mixed acini
-produce proteins and mucous
contain serous and mucous cells
in traditional fixation:
- mucous acini have cap of serous cells (serous demilunes)
- found in sublingual and submandibular gland
97
serous demilunes
the serous cap of mucous acini in mixed acini that appears with traditional fixation
-conventional fixation causes the protein/serous cells to bulge out while the mucigen granules swell up pushing the serous portion out to create a crescent
- found in sublingual and submandibular gland
- not actually occurring in human body, just a result of fixation process
-rapid freezing allows you to see how they are in body (next to each other)
98
Merocrine glands
exocrine
secrete a secretory vesicle (from the golgi complex) which then release the secretion
-EXOCYTOSIS
-most what you see in body
99
Holocrine glands
exocrine
sebaceous (OIL) glands
secrete the mature cell that dies via apoptosis to become the secretory product (cell fragment, with cytoplasm and plasma membrane as well) after cell division has replaced a lost cell
-deepest cells undergoing mitosis replacing cells that are dying and breaking off
100
Apocrine glands
exocrine
pinch off a portion of the cell that becomes the secretion, aka the apical portion (plasma membrane, cytoplasm, and secretory product = secretion)
-mammary glands (IF apocrine secretion - highly debated - it would be in mammary glands)
-cell repairs itself and repeats
101
sebaceous glands are _____ glands, with a ____ mode of secretion that secrete _____
EXOCRINE
holocrine
oil (sebum)
102
Why is it debated that mammary glands are apocrine glands?
- lipid production that is often thought of as apocrine secretion is released with NO cytoplasm
- just plasma membrane with secretory product
103
merocrine : _____ as apocrine : ______
A. exocytosis, apoptosis
B. apoptosis, exocytosis
C. mammary glands, salivary glands
D. cytoplasm and plasma membrane lost, no part of gland is lost or damaged
A. exocytosis, apoptosis
