Tissues of the body Wk 4

Question 1

Define tissues vs organs

Answer 1

tissues - group of similar cells/cell products that perform specific roles in organs

organ - structure with discrete boundaries comprising two or more tissue types

Question 2

Describe cell junctions.

Answer 2

connections between two cells
- allow cells to communicate, resist mechanical stress (protiens) & control movement

Question 3

Describe four kinds of cell junctions

Answer 3

Tight junctions: linkages bwn cells by transmembrane cell-adhesion proteins

Desmosome: ’patch’ holding cells together (like a peg) e.g. proteins

hemidesmosomes: anchor basal region of cells to basement membrane - can’t easily peel from underlying tissues

Gap junctions - transmembrane proteins - ions, nutrients & other small solutes pass between cells

Question 4

why do primary tissues differ

Answer 4

respect to characteristics of surrounding extracellular material/matrix
-comprises fibrous proteins & clear gel (ground substance)
e.g. tissue fluid, extracellular fluid (ECF), interstitial fluid, or tissue gel

Question 5

Describe epithelial tissues structure alongside basement membrane, basal surface and apical surface

Answer 5

Sheets of closely adhering cells
-high rate of mitosis
-basement membrane: anchoring layer bwn epithelium & underlying connective tissue(nourishes)
-basal surface :surface of epithelial cell facing basement membrane
-apical surface: surface of epithelial cell facing away from basement membrane
-avascular (no vessels)

Question 6

Describe epithelial tissue function and location

Answer 6

-protect deeper tissues from injury & infection
-excrete wastes
-absorb chemicals
-selectively filter substances
-sense stimuli

-cover body surfaces & line body cavities
-upper surface exposed to enviro/internal space in body
-constitutes most glands

Question 8

Describe structure and location of connective tissue

Answer 8

-diverse, abundant w/fewer cells relative to matrix
.most cells not in direct contact with each other
-highly variable vascularity
.loose connective tissues have multiple blood vessels
.cartilage few/no blood vessels

Connecting tendons and ligaments

Question 9

Describe connective tissues functions

Answer 9

-connect organs: tendons & ligaments
-support: bones & cartilage
-physical protection: cranium, ribs, sternum
-immune protection: WBC’s attack foreign invaders
-movement: bones provide lever system
-storage: fat, calcium, phosphorus
-heat production - metabolism of brown fat in infants
-transport - blood