Tissue Level of Organization

Question 1

what are Tissues?

Answer 1

• a group of cells with common embryonic origin that function together to carry out a specific function

Includes hard (bone), semisolid (fat - stores triglycerides) & liquid (blood, CSF, Lymph)

Question 2

List the types of tissues

Answer 2

• Epithelial
• Connective (5 classifications)
• Muscular
• Nervous

Question 3

Epithelial tissue

Answer 3

covers body surfaces, lines hollow organs, cavities ducts & forms glands

(5 classifications)

Question 4

What type of tissue connects, supports & binds organs?

Answer 4

Connective tissue

Question 5

What tissue generates physical force needed to move the body and generate body heat?

Answer 5

Muscular tissue

Question 6

What tissue type detects changes in the body & responds by generating nerve impulses?

Answer 6

Nervous tissue

Question 7

All tissue types form from which 3 things?

(Germ layers)

Answer 7

• Endoderm (GI tract, internal organs)
• Mesoderm
• Ectoderm

Epithelial tissues develop from all 3 germ layers

Question 8

all connective and muscle tissue derive from the what?

Answer 8

mesoderm

Question 9

the ectoderm creates what tissues?

Answer 9

Nervous tissue and skin

Question 10

What is a biopsy?

Answer 10

A sample of living tissue taken:
-looking for cancer
-infections
-inflammatory processes
-connective tissue disorders

Question 11

What are the 5 most common types of cell junctions?

Answer 11

1. Tight junctions (linkers)
2. Adherens junctions
3. Desmosomes
4. Hemidesmosomes
5. Gap junctions

Question 12

What type of junctions are common in epithelial tissues of the stomach, bladder, urinary & intestines?

Answer 12

Tight junctions
* prevent passage of substances between cells from leaking into surrouding tissues
* Transmembrane proteins fuse cells together (linkers)

Question 13

Adherens Junction

Answer 13

• dense layer of proteins called plaque form adhesion belts that encircle the cell (found 1 in epithelial cells)
• resists separation of cells during contractile activities
• cadherins are transmembrane proteins that insert into the plaque
• located inside the cell & attach to both membrane proteins and microfilaments of the cytoskeleton

Question 14

What are desmosomes?

Answer 14

• Contain plaque and
  cadherins that extend into
  the intercellular space to
  attach adjacent cells
• the plaque attaches to intermediate filaments that contain the protein keratin
• prevents epidermal cells from separating under tension & cardiac muscle cells from pulling apart during contraction

cell junction

Question 15

Hemidesmosomes

cell junction

Answer 15

• Connects epithelial tissue to underlying tissue (fascia)
• anchors CELLS to BASEMENT membrane (NOT cells adjacent to cells)
• contains transmembrane glycoprotein integrin
• Integrins attach to intermediat filaments and the protein lamilin present in the basement membrane

resembles half a desmosome

Question 16

what is a gap junction?

cell junctions

Answer 16

• a tiny, fluid filled tunnel between cells (called a connexon)
• cells are separeted by intracellular gap
• ions, nutrients, wastes, chemical & electrical signals travel through connexons

seen primarily in nerve & muscle (cardiac) cells

Question 17

What tissues consist of cells arranged in continuous sheets, from single to multiple layers?

Answer 17

Epithelial tissues
- functioning in covering & lining the body
- has a free surface to outside of body or hollow inside

Question 18

What are the 3 major functions of epithelial tissues?

Answer 18

1. Selective barrier - regulates what comes in and out of the body
2. Secretory surfaces - release products onto the surface
3. Protective surfaces against the environment

Question 19

What are the 3 general features of epithelial cells

and describe each

Answer 19

Apical (free surface) - the edge of the cell facing the body surface, cavity, lumen or duct
Lateral surface - faces adjacent cells
Basal surface - attached to the basment membrane

Question 20

what are basal & reticular lamina?

Answer 20

thin double layer that serves as the point of attachment between epithelial cells & underlying tissue

basal: attached to epithelial cells, contains lamilin, collagen, glycoproteins & proteoglycans (glue that holds fascia together)

reticular: attached to connective tissues, contains collagen

BASEMENT MEMBRANES

Question 21

how is epithelial tissue used in the body?

Answer 21

Outer covering
- skin
Inner linings
-blood vessels, ducts
- respiratory, digestive, urinary & reproductive
Glandular epithelium
- secreting portion of glands

Question 22

Epithelial tissue is avascular, what does that mean?

Answer 22

it does not have its own blood supply
- has its own nerve
- has a high rate of cell division for regeneration and repair

Question 23

what tissue regenerates and what tissue repairs?

Answer 23

skeletal muscle repairs with fibrous tissue

smooth cardiac muscle regenerates via mitotic cell division

Question 24

how is epithelial tissue classified?

Answer 24

by cell shape (simple, pseudostratified & stratified)
and
arrangement of layers (squamous - flat, cuboidal and columnar)

Question 25

what is simple epithelium?

Answer 25

a single layer of cells that function in diffusion, osmosis, filtration, secretion & absorption

Question 26

what is psudostratfied epithelium?

Answer 26

cells that appear to have multiple layers because the nucleus are at different levels, but is only one layer *all cells do not reach the apical surface*

Question 27

what is stratified epithelium

Answer 27

two or more layers of cells that protect the underlying tissues in areas of wear & tear

Question 28

What is the name of the shape of thin cells, arranged like floor tiles, that allow for rapid passage of substances called? ## Footnote Epithelial

Answer 28

Squamous cells

Question 29

which epithelial cells apear as tall as they are wide? And what are their functions?

Answer 29

cuboidal cells that may have cillia they function in secretions or absorption

Question 30

what is the name for the shape of epithelial cells that are taller than they are wide? | what are their functions? ## Footnote what other structures might they have?

Answer 30

columnar | secretion and absorption ## Footnote may have microvilli