Epithelium Flashcards

1
Q

4 basic types of tissues

A

Epithelial

Connective

Muscle

Nervous

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2
Q

Location of Epithelium

A

Covers surfaces

Extends into all complex invaginations

Mostly cells

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3
Q

Parenchyma vs. Stroma

A

Parenchyma: Essential/Functional

Stroma: non-essential (connective tissue, blood vessels, ducts)

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4
Q

Functions of epithelium

A

Protection (chemical and mechanical)

Control of transport (absorption and secretion)

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5
Q

Epithelium Characteristics

A

Uninterrupted layer of cells

avascular (no vessels)

Polarized

Apical

Basal

*Basal layer undergoes mitosis

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6
Q

Where is the basement membrane? What is it also called?

A

Basement membrane (aka Basal Lamina )

Between epithelium and connective tissue

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7
Q

Basal cell layer of epithelium

A

Stem cells that reside closest to the basal lamina (undifferentiated)

Mitosis (renewal/turnover)

Progenitor cells (division)

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8
Q

Metaplasia

A

Adaptation of mature tissue to physical or chemical stress

Stem cells alteration

✰Can lead to cancer (neoplasia)

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9
Q

Paracellular vs. Transcellular transport

A

Paracellular - Between two cells

Transcellular - Through a singular cell

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10
Q

Junctions of epithelium

A

*Tight: Seal
- proteins: occludens, claudins, ZO proteins

*Adherens: Anchor
- proteins: actin filaments and cadherins.

*Desmosomes: anchor (velcro) mechanical stress
- proteins: Desmogleins, desmoplakin, plakoglobin

*Gap junctions: communication
- protein: Connexin.

*hemidesmosomes: anchor to basal lamina
- proteins: integrins/laminins
*blistering disorder

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11
Q

Classification: epithelial types

A

Simple (single layer) vs. Stratifies (multi-layered)

Cuboidal, columnar, squamous (low)

keratinized vs non-keratinized

Pseudostratifies columnar

Urothelium (kidneys, ureters, bladder, urethra)
-stratified
-Stretch and leak prevention

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12
Q

T/F: Mast cells are resident cells of connective tissue that contain many granules rich in histamine and heparin.

A

TRUE

mast cells are key players in the inflammatory response.

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13
Q

eosinophils are associated with… and …

A

eosinophils are associated with INFLAMMATORY RESPONSE and ASTHMA

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14
Q

fibroblasts secrete most of the ___

A

ECM

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15
Q

adipocytes store energy and regulate ____

A

metabolism

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16
Q

aquaporins

A

channels that allow water transport when they are inserted in the cell membranes

17
Q

tight junctions

A

control paracellular transport

18
Q

gap junctions

A

cell to cell communication

19
Q

which connective tissue component is located in the ECM but not in the ground substance?

A

Collagen bundles!

ECM: ground substance and collagen fibers

Ground substance: fills space with fibers (collagen fibers), water, organic molecules (GAGS), proteoglycans, and glycoproteins (fibronectin, laminin).

20
Q

what cell type produces hormones important for metabolism and stores energy?

A

adipocytes

adipocytes store energy in the form of lipid molecules

adipocytes have important endocrine and metabolic roles
- secreting hormones (adipokines- regulate energy balance)
- food intake and satiety
- inflammatory response
- metabolism of steroid hormones

21
Q

what cell is involved in adhesion to the basement membrane?

A

Integrins

Integrins are receptors

Fibrilin and laminin are ligands (bind with integrins)

22
Q

desmoplakin

A

component of desmosomes which mediate cell to cell attachment

23
Q

cadherins

A

component of adherens junctions which mediate cell to cell attachment

24
Q

fibrillin

A

component of elastic fibers

glycoprotein

secreted by fibroblasts

25
Q

occludens

A

proteins associated with tight junctions

26
Q

T/F: all epithelia will have some attachment to a basal lamina and express desmosomes

A

TRUE

27
Q

what structural feature of the epithelial cells contributes to selective permeability and surface specialization?

A

polarity

apical and basal surfaces

28
Q

macrophages defend against infection via ____

A

phagocytosis and presenting antigen to T cells

secrete cytokines and chemokines to recruit immune cells, promote inflammation, tissue repair/healing, clear dead cells/debris

28
Q

what characteristic of epithelia cells gives the protective function?

A

tight junctions between cells that create a continuous barrier

29
Q

junctions and their protein(s)

A

tight junctions: occludens, claudins, ZO proteins

adheren junctions: cadherins and actin filaments

desmosomes: desmogleins and desmoplakin

hemidesmosomes: integrins and laminins

gaps junctions: connexin

30
Q

how do molecules pass the epithelial membrane?

A
31
Q
A