epithelium

Question 1

Tissue

Answer 1

a group of cells that assemble to perform a common function

Question 2

What are the four basic tissues in the body?

Answer 2

1. Epithelium
2. Connective tissue
3. Nervous tissue
4. Muscle tissue

Question 3

Epithelium

-definition

Answer 3

Purely cellular

• a vascular layer or layers of cells covering all free surfaces of the body
• form glands of the body
• typicall one surface is free=face fluid or air
• other surface is attached to connective tissue

Question 4

General Characteristics of Epithelium

Answer 4

1. Highly Cellular
2. No direct blood supply (avascular)
3. Regeneration capacity
4. Cells exhibit polarity

Question 5

Apical Surface

• def
• function
• surface specialization

Answer 5

Free surface
-faces air or fluid

Function:
-absorption, recognition

Surface Specialization

• Cilia, microvilli, stereocilia
• clathrin coated vesicles
• Glycocalyx

Question 6

Basal surface

• def
• function
• surface specialization

Answer 6

Attached surface
-usually connected to connective tissue

Function:
-attachment, transport, absorption

Cell Specialization:

• hemidesmosomes
• Membrane folds

Question 7

Lateral Surface

• def
• function
• surface specialization

Answer 7

Attached to other epithelial cells

Function:
-attachment, communication

Surface Specialization:

• junctional complexes
• gap junctions
• Cell adhesion molecules (CAMs)

Question 8

Types of Epithelium

-def

Answer 8

Lining or membranous epithelium
-covers the surface of the body and lines organs

Glandular epithelium

• forms glands (exocrine and endocrine)
• specialized for secretion

Question 9

Functions of epithelia

Answer 9

1. Protection
2. Secretion
3. Excretion
4. Absorption
5. Filtration
6. Lubrication
7. Reproduction
8. Transport
9. Sensory Perception

Question 10

Histogenesis

Answer 10

epithelium is derived from all 3 germ layers

Question 11

Microdomain

Answer 11

Region of cell membrane that has a distinct structure ofr function

Question 12

What is the basement membrane composed of?

Answer 12

Basal Lamina

Reticular Lamina

Question 13

Basal Lamina

Answer 13

Produced by epithelia

Two Parts:

• Lamina lucida
• Lamina Densida

Glycosaminoglycans

Collagen type IV-does not form fibrils

Laminin-glycoprotein, connects basal lamina to epithelial cells

Question 14

Reticular Lamina

Answer 14

produced by connective tissue
-collagen III fibrils AKA reticular Collagen

Glycosaminoglycans (GAGs)

Functions;

1. support
2. Selective Filtration

Question 15

Where is simple squamous found?

Answer 15

• Bowmans Capsule in kidney

- lines alveoli of lungs

Question 16

Where are mesothelial cells found?

Answer 16

Mesothelium

• lines surface of body cavities
• Peritoneal, pleural, pericardial cavities

Question 17

Where are Endothelium found?

Answer 17

lines blood vessels and lymphatic vessels

Question 18

Where are Simple columnar cells found?

Answer 18

-Line the intestine

Question 19

Funciton of simple columnar cells

Answer 19

absorption and secretion

Question 20

Function of pseudo stratified columnar cells

Answer 20

absorption of material

Question 21

Pseudostratified columnar

Answer 21

Can be:

Ciliated with Goblet Cells

• lines respiratory passages
• function in moving surface material

w/Stereocilia

• lines part of the male reproductive tract
• Long microvilli NOT CILIA

Question 22

Stratified Squamous

-two types

Answer 22

1. Cornified (AKA keratinized)
   - contains filaggrin
2. Non-cornified (AKA nonkeratinized)
   - keratin intermediate filaments present BUT NOT CROSSLINKED

Question 23

Function of transitional epithelium

Answer 23

Accommodates stretch

-protects underlying tissue from hypertonic urine

Question 24

Mucous Membranes

Answer 24

AKA mucosa
Mucous Secretion
-rich in proteins O-glycosylated with anionic oligosaccharides=more viscous thicker

-lines gastrointestinal and respiratory tracts

Question 25

Function of mucous membranes

Answer 25

In GI Tract: -viscous fluid (mucus) protects against chemical irritation) In Respiratory Tract: -traps inhaled particles

Question 26

Goblet Cells

Answer 26

secrete mucus

Question 27

Exocrine vs Endocrine

Answer 27

ALL EXOCRINE and MOST Endocrine glands are made of epithelia cells 2 endocrine exceptions - Posterior Pituitary - Adrenal Medulla Exocrine -products are secreted into ducts Endocrine - ductless - produces hormones that are secreted into the bloodstream - wrapped in capillaries

Question 28

3 types of acini

Answer 28

1. Acini 2. Mucous 3. Mixed (both serous and mucous) - may or may not have serous demilune

Question 29

Types of secretion

Answer 29

``` Serous Secretion (watery) Mucous Secretion (mucoid) ```

Question 30

Serous Secretion | -general characteristics

Answer 30

Serous Acinus -Watery ``` Pyramidal shaped cells -cell boundaries indistinct -spherical nucleus -Apical Secretory granules-stain acidophilic with H & E Basophilic cytoplasm around the nucleus ``` Secretory product - proteinaceous - thin, watery, and contains enzymes

Question 31

Mucous Secretion

Answer 31

Mucous Acinus -mucoid Pyramidal shaped cells - cell boundary distinct - nucleus flattened an at base of cell Secretory product (mucinogen)--thick an may act as a lubricant - lost during preparation of the tissue=apical part of cell is clear with H&E - only slight basophilia around nucleus

Question 32

Mode of secretory product release

Answer 32

1. Merocrine (eccrine) 2. Aprocrine 3. Holocrine 4. Cytogenous

Question 33

Mode of Secretory product: Merocrine

Answer 33

ECCRINE - secretory granules fuse with cell membrane and contents ONLY are released - serous or mucous

Question 34

Mode of Secretory product: Apocrine

Answer 34

- secretion is released with plasma membrane enveloping the particle - part of the cytoplasm leaves the cell

Question 35

Mode of Secretory product: Holocrine

Answer 35

Whole cell dies and is secreted

Question 36

Mode of Secretory product: Cytogenous

Answer 36

Whole living cell is released

Question 37

Epithelia Cells

Answer 37

Cells with Epithelial characteristics but lack a free surface