Ch. 3 - Epithelial Tissue

Question 1

Epithelial Tissue General Characteristics

Answer 1

1. cover all body surfaces 2. cellularity 3. polarity 4. attachment 5. avascularity 6. regeneration

Question 2

covers all body surfaces (epithelial tissue)

Answer 2

covers inside and outside of body (skin vs blood vessels) -makes up our glands

Question 3

polarity (epithelial tissue)

Answer 3

apical side- exposed to top (microvilli/cilia)
basal side - attached surface
*organelles unevenly distributed and the 2 surfaces differ in function

Question 4

basal lamina (epithelial tissue)

Answer 4

point of attachment made up of lamina lucida and reticular lamina (collagen fibers)

Question 5

cellularity (epithelial tissue)

Answer 5

tightly packed cells bound by tight junctions (not a lot of space between cells. This makes good barriers (skin) *lines digestive/urinary tracts

Question 6

avascularity (epithelial tissue)

Answer 6

lacks blood vessels (tissue can’t be thick because relies on diffusion of nutrients from other tissues)

Question 7

Functions of Epithelial Tissue

Answer 7

1. physical protection - protects underlying tissues from abrasion/bacteria
2. controls permeability (what crosses through the tissue)
3. Detects environmental changes
4. secretions (from glands)

Question 8

Apical side (epithelial tissue)

Answer 8

exposed surface

• microvilli - extensions of cell membrane that increase surface area
• cilia - propel/move materials over the surface of the tissue (important in respiratory track)

Question 9

Simple Squamous

Answer 9

(floor tiles) -single layer of thin flat cells
-substances can pass easily through
functions: absorption/diffusion, controls vessel permeability, reduces friction
-easily damaged
-thin centered nuclei
(lines heart, blood vessels, alveoli, and kidneys)

Question 10

Simple Cuboidal

Answer 10

-single layer of cube-shaped cells
location: glands, ducts, portions of kidneys, thyroid gland
function: limited protection, secretion, absorption
centered spherical nuclei

Question 11

Simple Columnar

Answer 11

• single layer of elongated cells
• nuclei near bottom membrane
• lines uterus and organs of digestive tract
  location: lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys
  functions: protection, secretion, absorption
• goblet cells found in this tissue (secrete mucous)

Question 12

Pseudostratified Columnar

Answer 12

• single layer of multiple cells (all cells attached to basal lamina)
• appears layered but is not
• goblet cells (mucous producing)
  location: lining of nasal cavity, trachea, and bronchi, portions of male reproductive tract
• have cilia on apical surface

Question 13

Stratified Squamous

Answer 13

• many layers
• cellular reproduction occurs in deeper layers where the apical surface is flattened (skin)
• forms outer layer of skin (keratin)
  keratin: protein that makes skin tough/waterproof/impermeable to micro organisms
  function: provides physical protection against abrasion, pathogens, and chemical attack
  location: surface of skin, oral cavity, throat, esophagus, rectum, anus, vagina

Question 14

Stratified Cuboidal

Answer 14

lines ducts of sweat glands and mammary glands (protection secretion absorption)
-many layers of cuboidal epithelium

Question 15

Stratified Columnar

Answer 15

in small areas of pharynx, salivary gland ducts, mammary glands, urethra, and large excretory ducts

Question 16

mucous cells

Answer 16

thick secretion

location: digestive tract and respiratory tubes

Question 17

serous glands

Answer 17

secrete watery solution that usually contains enzymes, such as salivary amylase in saliva

Question 18

apocrine gland

Answer 18

shed small amounts of cytoplasm with secretion (mammary glands)
-apical portion of cell grows vesicles and sheds the part of the cytoplasm that holds the vesicles (regrowth and shedding continually occur) ex. mammary/sweat

Question 19

merocrine secretion

Answer 19

secretory vesicles release packaged proteins or products of the sell through exocytosis (passing through cell membrane) ex. salivary, pancreatic glands

Question 20

holocrine secretion

Answer 20

ex. sebaceous glands (attached to hair follicles and secrete a waxy oily substance) *associated with acne
- entire cell becomes packed with secretory products then bursts apart during secretion near the apical portion
- cells lower in the epithelium divide and reproduce to continue this holocrine secretion process ex. sebatious glands

Question 21

mesothelium

Answer 21

simple squamous layer that lines the outside of body cavities