Lecture 5 - Epithelial Tissue

Question 1

Germ layers of epithelial tissue

Answer 1

All three layers. Ectoderm –> epidermis, endoderm –> lining of GI tract and respiratory tract, mesoderm –> endothelium, mesothelium

Question 2

Two types of epithelial tissue

Answer 2

Membranous epithelia, glandular epithelia

Question 3

Five functions

Answer 3

protection/containment, absorption, secretion, sensation, contractility

Question 4

apical vs. basal

Answer 4

apical –> uptake, secretion, protection; basal –> cell-substrate contact

Question 5

Simple Epithelial Tissue

Answer 5

Just one layer of cells

Question 6

Simple squamous tissue

Answer 6

Flat tissue; Found in lungs, blood vessels, cavities; serves as site of diffusion of fluids and gasses.

Question 7

Simple Cuboidal Epithelium

Answer 7

cube-ish cells, centrally located nucleus; Found in ducts of the kidney, thyroid glands, salivary glands; serves as site of excretion, secretion, absorption (good surface:volume ratio)

Question 8

Simple columnar epithelium

Answer 8

height>width, nucleus basal; found in intestine; good for absorption

Question 9

Simple columnar ciliated epithelium

Answer 9

Columnar with cilia; oviduct/respiratory tract; propel ovum over cell surface, towards uterus

Question 10

Pseudo-stratified columnar ciliated epithelium

Answer 10

Ciliated columnar cells w/ nuclei at different heights; Trachea; propel mucus and trapped particles

Question 11

Stratified epithelial tissue

Answer 11

2 or more layers; serves as protection

Question 12

Stratified squamous epithelium

Answer 12

many layers, top one squamous, lower ones more cuboidal; oral cavity, esophagus, cervix, vagina; serves to withstand chronic abrasion

Question 13

Stratified Squamous keratinized epithelium

Answer 13

like stratified squamous with surface layer of keratin (dark pink H&E); epithelial surface of the skin; also withstands chronic abrasion

Question 14

Stratified cuboidal epithelium

Answer 14

1-2 layers cuboidal cells; larger excretory ducts of exocrine glands (salivary glands); provide thicker lining

Question 15

transitional epithelium

Answer 15

many layers of cells, surface layer large, round pillow shaped; urinary tract; withstands toxicity and accommodates stretch

Question 16

types of glandular epithelia

Answer 16

1. Exocrine, stays connected to surface epithelia during development, when epithelial cells invade connective tissue
2. Endocrine, after epithelia cells invade connective tissue the duct cells break down and the gland is surrounded by connective tissue. Two types
   2a. Endocrine glands that secrete into capillaries
   2b. Follicular endocrine glands, secrete into interior lumen

Question 17

Types of exocrine glands

Answer 17

Merocrine –> No loss of membrane so glands not exposed to lumen (goblet cell)
apocrine –> secretory product in vesicles
Holocrine –> whole cell broken for discharge of products (sebaceous glands)

Question 18

Synthesis of mucigen

Answer 18

Protein component made in RER, carb. part attached in Golgi

Question 19

Goblet cell function

Answer 19

Upper GI –> protective coat
Lower GI –> lubrication
Respiratory –> prevent drying, humidifies air, act as a sticky surface to trap potential irritants