Lecture 12: Epithelial Tissue

Question 1

Epithelial Tissue Characteristics

Answer 1

• cellularity, polarity, attachment, avascular, innervation, regeneration
• rests on basement membrane
• physical protection, permeability ,secretion, sensation

Question 2

Epithelial Polarity

Answer 2

1. Apical Surface - face lumen/surface
2. Basal Surface - on basement membrane, anchors to CT
3. Lateral Surface - attaches to adjacent cells

Question 3

Tight/Occluding Junction

Answer 3

• impermeable, allows cell to act as BARRIER (belt-like)

- increasing junctions = decreasing permeablity

Question 4

Gap/Communication Junction

Answer 4

• fluid-filled channels connection cells

- mediates communication (CONNEXIN)

Question 5

Anchoring Junctions (3 types)

Answer 5

1. Adherens - lateral adhesion (actin); belt-like
2. Desmosome - lateral adhesion (intermediate filaments), spot-like; involve cadherins
3. Hemidesmosomes - basal adhesion (intermediate filaments), spot-like; involve integrins

Question 6

H. pylori and Tight Junctions

Answer 6

• bacteria bind tight junctions, increasing permeability
• loss of tissue fluid into intestinal lumen

gastric ulcers in stomach

Question 7

Pemphigus vulgaris and Desmosomes

Answer 7

• abnormal desmosome function = dec. cell-to-cell adhesion

blisters of oral mucosa

Question 8

Microvilli characteristics and Celiacs disease

Answer 8

• contain actin core
• nutrient absorption, inc. surface area by 20-30x

Celiacs = loss of microvilli on absorptive cells in small intestine

Question 9

Sterocilla characteristics

Answer 9

• microvilli of unusual length; long and less mobile
• actin core

restricted location = epididymis and hair cells of inner ear

Question 10

Cilia characteristics and 3 types (motile, primary, nodal)

Answer 10

• long, highly motile, internal microtubule arrays (longer than microvilli)

Motile: beat in wave-like fashion (keep airway clean)
Primary: immotile, chemo/osmo/mechanoreceptors
Nodal: embryonic –> left/right axis determination

Question 11

Simple Squamous (Location and Function)

Answer 11

Location: alveoli, loop of Henle, ducts

1. endothelium: line blood/lymphatic vessels
2. mesothelium: line serous membranes

Function: exchange, barrier, lubrication

Question 12

Simple Cuboidal (Location and Function)

Answer 12

Location: Kidneys, ovary covering, terminal bronchioles

Function: absorption, barrier, secretion

Question 13

Simple Columnar (Location and Function)

Answer 13

Location: auditory tubes, uterus, oviducts, stomach, gallbladder, SI/LI

Function: absorption, secretion

Question 14

Pseudostratified Columnar Ciliated (Location and Function)

Answer 14

Location: nasal cavity, pharynx, bronchi

Function: absorption, secretion, movement of debris

Question 15

Urothelium (Location and Function)

Answer 15

Location: urinary bladder, ureters, urethra

Function: barrier, distensible

Question 16

Nonkeratinized Stratified Squamous (Location and Function)

Answer 16

Location: oral cavity, pharynx, esophagus, anus, vagina, urethra, cornea

Function: barrier, protection

Question 17

Keratinized Stratified Squamous (Location and Function)

Answer 17

Location: epidermis of skin

Function: barrier, protection

Question 18

Stratified Cuboidal (Location and Function)

Answer 18

Location: sweat glands/ducts, ovarian follicles, salivary gland ducts

Function: barrier, passageway

Question 19

Mucous vs Serous membranes

Answer 19

Mucous: secretes mucus. lines body cavity and tubular organs

Serous: smooth, transparent, two-layered membrane (fluid derived from serum)

Question 20

Unicellular Glands (and Goblet Cells)

Answer 20

• simplest in structure

Goblet: mucous secreting cell lining intestines and respiratory tract

Question 21

What is parenchyma and stroma?

Answer 21

parenchyma: functional tissue of an organ, does not include CT or other supporting tissue
stroma: connective tissue that separate gland into lobules

Question 22

Which acini (mucous or acini) is more prominent in:

1. parotid gland?
2. sublingual gland?
3. submandibular gland?

Answer 22

1. serous acini
2. mucous acini
3. mucous and serous acini

Question 23

Merocrine, Holocrine, and Apocrine glands

Answer 23

Merocrine: membrane-bound vesicles (salivary gland)

Holocrine: apoptosis, secretion and cell debris (sweat)

Apocrine: release apical portion of cell in plasma membrane (mammary glands)

Question 24

Simple vs Compound glands and tubular vs acinar

Answer 24

Simple (unbranched ducts)
Compound (2+ branches) –> can have tubular and acinar for tubuloacinar

Tubular (straight tube)
Acinar (saclike structure)