Tissues: Epithelium

Question 1

epithelial tissue basic functions

Answer 1

covers body surfaces and lines hollow organs, body cavities, ducts; and forms glands

Question 2

connective tissue

Answer 2

protects, supports, and binds organs

-stores energy as fat and provides immunity

Question 3

muscular tissue

Answer 3

generates the physical forces needed to make body structures move and generate body heat

Question 4

nervous tissue

Answer 4

detect changes in body and responds by gnerating nerve impulses

Question 5

3 tissue layers

Answer 5

ectoderm (nervous), endoderm, and mesoderm (connective and muscle)

-epithelial is all of them

Question 6

tight junctions

Answer 6

web-like strands of transmembrane proteins

-in stomach, intestines, and urinary bladder

Question 7

desmosomes

Answer 7

• contain plaque and cadherins that extend into the intercellular space to attach adjacent cells
• plaque is connected by intermediate filaments that have keratin
• good in heart and skin

Question 8

hemidesmosomes

Answer 8

• look like half a desmosome
• anchor cells to basement membrane
• transmembrane glycoprotein: integrin
• integrin attaches to basement membrane’s intermediate filaments and protein, laminin

Question 9

gap junctions

Answer 9

connect neighboring cells with connexons (made of connexin)

allow ions, nutrients, waste, chemical and electrical signals to pass from cell to cell

Question 10

3 functions of epithelial tissue

Answer 10

• selective barrier
• secretory surfaces
• protective surfaces

Question 11

surfaces of epithelial cells

Answer 11

• apical (free surface)
• lateral surface (faces adjacent cells)
• basal surface (opposite to apical)

Question 12

Basement membrane (of epithelial tissues) structure

Answer 12

• thin double extracellular layer
• basal lamina = closer to and excreted by epithelial cells –> contains laminin, collagen, glycoproteins, and proteoglycans
• reticular layer = closer to and secreted by underlying connective tissue cells –> contains collagen

Question 13

different epithelial cell shapes and their functions

Answer 13

squamous = good for filtration or rapid diffusion
cuboidal = food for secretion/absorption
columnar = special secretion/absorption
transitional = bladder

Question 14

Where to find simple squamous epithelium? (both endothelium and mesothelium)

Answer 14

endothelium = heart, blood vessels, and lymph vessels

mesothelium = serous membranes

both derived from mesoderm

Question 15

where to find simple cuboidal epithelium?

Answer 15

thyroid glands and kidneys

Question 16

where to find nonciliated simple columnar epithelium

Answer 16

• linings of digestive, respiratory, reproductive, and urinary tracts
• also stomach lining
• have microvili and goblet cells

Question 17

where to find ciliated simple columnar epithelium

Answer 17

uterine tubes

Question 18

where to find pseudostratified columnar epithelium

Answer 18

ciliated: trachea

Question 19

stratified squamous spithelium

characteristics and where to find

Answer 19

• new cells pushed up to apical layer
• as cells move away from blood supply, they harden and die
• can be keratinized (superficial layer of skin)
• can be unkeratinized (mouth, esophagus, vigina)

Question 20

stratified cuboidal epithelium

Answer 20

-pretty rare

for protection of esophageal glands

Question 21

stratified columnar epithelium

Answer 21

• rare

- for protection and secretion in esophageal glands

Question 22

transitional epithelium

Answer 22

only in urinary system

Question 23

endocrine glands

Answer 23

• don’t have ducts
• secretions are hormones and theydiffuse into bloodstream
• their function is to maintain homeostasis

Question 24

exocrine glands

Answer 24

• secrete products into ducts that empty onsurface of epithelium
• skin surface or luman of hollow organ
• secretions include mucus, sweat, oil, earwax, saliva, and digestive enzymes

Question 25

Structural classification of exocrine glands

Answer 25

1. Ducts - “simple” if unbranched, “compound” if branched

2. Shape - tubular, acinar (round), or tubuloacinar

Question 26

Functional classification of exocrine glands

Answer 26

1. Merocrine = protein is synthesized in cell and carried out with vesicle (exocytosis)
2. Apocrine = secretions hang out at apical end of cell until that whole end is pinched off and secreted into duct
3. Holocrine = cell explodes, dies, disintigrates, and the whole thing is secreted