Brainscape's Knowledge GenomeTM

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


See full index

Basic Principles Of Medicine 1-FTM 1 > Epithelial Glands > Flashcards

Epithelial Glands Flashcards

1
Q

Give the general characteristics of epithelium

A

Avascular

  • No blood vessels in epithelium
  • Oxygen & nutrients by diffusion from underlying connective tissue

Covers exterior body surfaces
-skin

Lines internal closed cavities
-endothelium of blood vessels of cardiovascular system

Lines body tubes

  • gastrointestinal tract
  • respiratory tract
  • genitourinary tracts

Forms secretory portion (parenchyma) & ducts of glands

Specialized cells function as receptors for special senses
-smell, taste, vision

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

What are the 3 principle characteristics of epithelium ?

A
  1. Cells are closely apposed & adhere to each other
    • Specialized cell to cell junctions
2.  Exhibit functional & morphological polarity
     3 surface domains
         1. Free surface/ apical domain 
         2. Lateral domain 
         3. Basal domain
  1. Basal surface attached to underlying basement membrane
    • cell to matrix junctions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the lateral specializations of cells ?

A

Lateral surface/domain

  1. Occluding junctions.
    • tight junction (zonula occludens)
  2. Anchoring junctions
    • Adhering junctions (zonula adherens)
    • Desmosomes (macula adherens)
  3. Communicating junctions
    • Gap junctions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe Zonula Occludens

A

Occluding junctions complex (cell to cell)

  • Zonular occludens = tight junctions
  • Localised sealing of the plasma membrane of adjacent cells
  • Network of anastomosing strands that completely surround the apical cell borders
  • Transmembrane proteins= Claudins & occludins
  • Interaction with action cytoskeleton via ZO-1
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the major proteins included in the zonula occludens junctions?

A
  1. Occluding
  2. Claudin
  3. JAM
  4. ZO-1
  5. ZO-2
  6. ZO-3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the associated protein partners and function of Occludin?

A

Occludin, ZO-1,ZO-2, ZO- 3, Vapp33, actin

Function: is present in most occluding junctions: maintains barrier between apical and lateral cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the associated protein partners and function of Claudin?

A

Claudin, ZO-1, JAM

forms backbone of zonula occludens strands: forms and regulates aqueous channels used for paracellular diffusion

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

What are the associated proteins and function of JAM?

A

JAM, ZO-1, Claudin

Function: present in endothelial cells; mediates interactions between endothelial cells and monocytes adhesions

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

What are the associated proteins and function of ZO-1?

A

Associated proteins: ZO-3,ZO-2, Occludin, Claudin, JAM, cingulin, actin, ZONAB, ASIP, AF-6

Function: important link in transduction of signals from all transmembrane protein; interacts with actin filaments, has tumor suppressor actin

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

What are the associated proteins and function of ZO-2?

A

ZO-1, Occludin, cingulin, 4.1R

Function: Required in the epidermal growth factor-receptor signaling mechanism

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

What are the associated proteins and function of ZO-3?

A

Associated proteins: ZO-1, Occludin, actin

Function: interacts with ZO-1, Occludin, and actin filaments of cell cytoskeleton

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

In detail, explain the function of zonula occludens

A

Zonula occludens separates the luminal space from the intracellular space and connective tissue compartment

Paracellular pathway: across the zonula occludens between two cells

Transcellular pathway: across the plasma membrane of the epithelial cell

Establishes functional domains in the plasma membrane

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

Explain detail the function of the zonula adherens

A

Anchoring Junctional Complex(Cell to Cell)
-Lateral adhesion between epithelial cells

-Continuous band or belt that surrounds the entire cell, found just beneath the tight junction

  • Transmembrane protein = E cadherin
    - calcium dependent
  • Helps to attach adjacent cells (15-20nm apart)
  • Interaction with actin cytoskeleton
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the functions of macula adherens in detail?

A

Anchoring junctional complex

-macula adherens= desmosome

  • lateral, localised, spot adhesion between epithelial cells about 30nm apart
    • Focal dense spots (macula)

-Found beneath the zonula adherens of cells

  • Transmembrane protein= desmocolin & desmoglein
    - Cadherin family, calcium dependent
  • Intracellular plaque=plakoglobins & desmoplakins
  • Interaction with intermediate filaments of cytoskeleton
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are gap junctions, where are they found?

A

Communicating junctional complex (cell to cell)

  • present in a variety of tissues
    • epithelium
    • smooth & cardiac muscle
    • nerve

-help coordinate activity of adjacent cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Differentiate between connexins and con exons for gap junctions

A

Connexin- Transmembrane protein subunits

Connexons -half channel formed by 6 connexins

Connexons align to form a communicating channel connecting the cytoplasm of adjacent cells

17
Q

Explain the lateral morphological specialization of lateral cell surface

A

Lateral interdigitations
-in foldings (plicae) of cytoplasmic processes of adjoining cells

-increased lateral cell surface area

  • common in cells engaged in fluid and electrolyte transport
    • Ex. Gall bladder, small intestine
    • Sodium ions are pumped out of cytoplasm by Na+/K+ -ATPases

-Fluid accumulates in the intracellular space until driven into underlying connective tissue

Tight junctions prevent fluid escape in apical direction

18
Q

Explain focal adhesion

A

Anchoring junctional complex

  • cell to extracellular matrix junctions
  • helps to anchor epithelial cells to basement membrane

Transmembrane proteins= integrins

  • Link between actin microfilaments of cytoskeleton and extracellular matrix
  • Important role during cell migration
19
Q

Explain the function of the hemidesmosomes

A

Anchoring junctional complex

  • cell to extracellular matrix junctions
  • helps to another epithelial cells to basement membrane
  • Half the component of a desmosome
  • Transmembrane proteins= integrins
  • Interaction with intermediate filaments of cytoskeleton
20
Q

What is Bollus pemphigod?

A

Disease characterized by blister formation at epithelium attachment to basement membrane

-Antibodies directed against BP320 & type XVII collagen

21
Q

Describe basal in folding s as a morphological modification

A
  • Significantly increase the surface area of the basal domain
  • Allow for more transport proteins and channels to be present
  • Well developed in cells performing active transport of molecules
    • kidney tubule
    • striated ducts of exocrine glands
  • Mitochondria arranged vertically in these folds
  • Light microscopy- “striated” appearance
22
Q

Explain the function of the basal membrane

A
  • Can be visualized with light microscope
  • Amorphus layer at basal surface of epithelia
  • Found between epithelial cells and underlying connective tissue
  • Especially thick in respiratory epithelium
    • H&E x450
23
Q

The basal lamina is called __________ in noneoithelial cells

A

External lamina

24
Q

How can the basal lamina be visualized?

A

By electron microscopy

25
Q

What is the function of the basal lamina?

A

Structural attachment site for overlying epithelial cells and underlying connective tissue (fibroreticulsr lamina)

26
Q

Describe the composition of the basal lamina

A

Composition :

  • lamins
  • type 4 collagen
  • proteoglycans & glycoproteins

2 layers

  1. Lamina lucida (rara)-considered an artifact
  2. Lamina densa- electron dense
27
Q

What is an exocrine gland?

A

Secrete onto a surface directly or through ducts that are connected to a surface

28
Q

What are the release mechanisms of exocrine glands?

A
  1. Merocrine- exocytosis of membrane bound vesicles(most common )
  2. Apocrine-product released at Apical surface surrounded by envelope of plasma membrane
    • Bleb
    • Ex. Lactating mammary gland
  3. Holocrine
    -programmed cell death releases secretory product & cell debris
    Ex: sebaceous glands of skin
29
Q

What is an endocrine gland?

A

Secrete products (hormone) into the connective tissue & then enter the bloodstream

  • paracrine=nearby cells
  • autocrine= same cells
30
Q

Explain the classifications of exocrine glands

A

Unicellular glands
1 single cell
-Ex goblet cells
-mucus secreting cells

Multicellular glands
-numerous cells

Sub classification

  1. Shape of secretory cells
    • tubular-tube
    • alveolar(acinar)= flask
    • tubuloalveolar= tube ends in a dilation
  2. Presence or absence of branching duct
    • simple= unbranched duct
    • compound = branched duct
31
Q

What are the classsifications based on type of secretion produced by exocrine gland ?

A
  1. Serous
  2. Mucous
  3. Mixes
32
Q

What are serous exocrine glands?

A

Watery
-poor or nongoycosylated protein secretion

  • Nuclei within cells are typically rounded or oval
  • Apical cytoplasm filled with zymogen granules is stained with eosin
  • Perinuclearcytoplasm is basophilic due to extensive rER
  • Ex. exocrine pancreas & parotid salivary glands
33
Q

What are mucous exocrine glands?

A
  • viscous/slimy
    • extensive glycisylation
  • Nuclei within cells are flattened & compressed to the base of the cell
  • PAS positive due to anionic oligosaccharides
  • Mucinogen granules
    • store mucus
    • water soluble oligosaccharide is poorly preserved
    • Appear empty in H & E staining
34
Q

Describe mixed exocrine glands, give an example

A

Contains both mucus and serous secretory components

-Ex. Submandibular & sublingual salivary glands

Submandibular gland
-serous> mucus

Compound tubuloacinar gland
Sublingual gland
-mucus>serous

Basic Principles Of Medicine 1-FTM 1 (39 decks)

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