histology

Question 1

types of tissues

Answer 1

epithelial, connective, muscular, nervous

Question 2

cell junctions

Answer 2

how cells are held together to form tissues:
- tight
- adherens
- desmosomes
- hemidesmosomes
- gap

Question 3

tight junction

Answer 3

weblike (strands of transmembrane proteins fused together). Inhibits passage of substances between cells and prevents contents of organs from getting out.

Question 4

where are tight junctions found

Answer 4

stomach, intestines, urinary bladder

Question 5

adherens junctions

Answer 5

• dense layer of intracellular proteins attach to membrane proteins and microfilaments of the cytoskeleton
• forms adhesion belts that CONTAIN PLAQUE
• helps epithelial surfaces resist separation during contractile activities.

Question 6

desmosomes

Answer 6

• like buttons
• helps with stability of cell and tissue
• prevent separation under tension and contraction

Question 7

where do we find desmosomes

Answer 7

outermost layer of skin (epidermis), cardiac muscle

Question 8

hemidesmosomes

Answer 8

• like desmosomes but do not link adjacent cells
• anchor cells to basement membrane

Question 9

gap junctions

Answer 9

• plasma membrane of cells are not fused together, but have an intercellular gap
• has connexons
• allows for diffusion ions and small molecules to pass between cells
• allows for cells to communicate with each other - rapid spread of nerve/muscle impulses

Question 10

where do you find gap junctions

Answer 10

nervous system, smooth muscles of heart, GI tract, uterus

Question 11

which junction does not allow for cellular leakage

Answer 11

tight

Question 12

which junction attaches the cell to the basement membrane

Answer 12

hemidesmosomes

Question 13

which junction has connexons

Answer 13

gap

Question 14

which junction connects to the microfilaments of the cytoskeleton

Answer 14

adherens

Question 15

what is epithelial tissue

Answer 15

• cells arranged in continuous sheets - either a single layer or multi-layered
• cells are closely packed together and held by junctions
• has its own nervous supply but no blood supply (avascular)

Question 16

structural features of epithelial tissue

Answer 16

• apical (free) surface - top layer, has cilia or microvilli
• lateral surfaces have junctions
• basal surface - bottom/deepest layer. connects to basement membrane with hemidesmosomes

Question 17

basement membrane

Answer 17

• extracellular layer that has 2 parts - 1) basal lamina (secreted by epithelium) 2) reticular lamina (closer to underlying connective tissue)

Question 18

function of basement membrane

Answer 18

anchors epithelium to underlying connective tissue

Question 19

how can we classify epithelial tissue structurally

Answer 19

• layers - simple, pseudostratified, stratified
• shape - squamous, cuboidal, columnar, transitional

Question 20

functions of epithelial tissue

Answer 20

• protects
• secretes (mucus, hormones, enzymes)
• absorbs (GI tract)
• excretes (urinary tract)
• filtration (kidneys)
• special sense organs (combines with nervous tissue)

Question 21

where do we find epithelial tissue

Answer 21

• covering/lining surfaces. outer covering of skin and lining hollow organs
• forms the secreting portion of glands (thyroid, sweat, adrenal, digestive)

Question 22

what is a single layer of epithelial tissue called

Answer 22

simple

Question 23

how do we refer to multiple layer of epithelial tissue

Answer 23

stratified

Question 24

which portion of the basement membrane is secreted by the epithelium

Answer 24

basal lamina

Question 25

what are the 2 types of epithelium

Answer 25

glandular (glands) and surface (outer layer of skin and hollow organs)