Test 1 (topic 1 - Tissues & ECM)

Question 1

What are the 4 types of tissues?

Answer 1

nervous tissue, muscle tissue, epithelial tissue, connective tissue

Question 2

Nervous tissue

Answer 2

Contains specialized cells which rapidly transmit electrical impulses

Question 3

Muscle tissue

Answer 3

Long cells which are specialized for contraction and relaxation

Question 4

Epithelial tissue

Answer 4

Layer(s) of closely packed cels forming coverings on internal and external surfaces

Question 5

Connective tissue

Answer 5

In most cases, a loose arrangement of cells embedded within a support medium

Question 6

Fxns of epithelial tissue (3)

Answer 6

1 - covering, lining, protecting exposed surfaces
2 - absorption (in gut)
3 - secretion

Question 7

Notable characteristics of epithelium (6)

Answer 7

1 - cells are tightly packed together with little/no space in between
2 - tissue always has a ‘free surface’
3 - tissue is usually anchored to an underlying layer of connective tissue via a ‘basement membrane’
4 - tissue has no direct blood supply
5 - cells in lower layers are usually mitotic
6 - 2 types: membranous and glandular

Question 8

basement membrane =

Answer 8

basal lamina (produced by the epithelial cells) + reticular lamina (produced by the connective tissue cells)

Question 9

basal lamina =

Answer 9

lamina lucida + lamina densa

Question 10

fxns of connective tissue (2)

Answer 10

1 - provides support, structure and protection

2 - binds strxs together

Question 11

notable characteristics of connective tissue

Answer 11

1 - composed of cells and supporting ‘extracellular matrix’
2 - cells are usually spaced far apart, not in direct contact ich each other
3 - usually, is well vascularized

Question 12

extracellular matrix (ECM)

Answer 12

Predominantly associated with connective tissue but not exclusive to it

Question 13

ECM is composed of:

Answer 13

Fibers and ground substance

Question 14

Name the different kinds of fibers in ECM

Answer 14

collagen fibers; reticular fibers; elastic fibers

Question 15

collagen fibers

Answer 15

long fibers formed of the protein collagen

Question 16

3 categories of collagen fibers

Answer 16

fibrillar collagens; netowork-forming collagens; linking/anchoring collagens

Question 17

fibrillar collagens:

Answer 17

long “thick” strands which are often visible with a light microscope; the most abundant is formed of type I collagen, type II and III collagens also are placed in this category (think of them like ropes)

Question 18

network-forming collagens:

Answer 18

an interlaced network of ultra-thin strands formed exclusively of type IV collagen; a major structural component of the lamina densa component of the basal lamina (form wheel like strx)

Question 19

linking/anchoring collagens:

Answer 19

short strands which connect fibrillar collagens to each other and to other components within the extracellular matrix; e.g., type VII collagen, which anchors the reticular lamina to the basal lamina

Question 20

reticular fibers:

Answer 20

very thin fibers formed predominantly of type III collagen

Question 21

reticular fibers also: (3 additional things)

Answer 21

1 - form a flexible scaffolding within organs like the liver, spleen, lymph nodes, and red bone marrow
2 - main component of the reticular lamina of the basement membrane
3 - may be found scattered throughout the ground substance of loose connective tissue; is the predominant fiber type in reticular connective tissue

Question 22

elastic fibers:

Answer 22

thin fibers formed primarily of the protein elastin

Question 23

elastic fibers are the main type of ____________

Answer 23

main type of elastic connective tissue and elastic cartilage, but also found in loose connective tissue as well

Question 24

what is vitamin C needed for?

Answer 24

Proper collagen formation; deficit leads to scurvy

Question 25

ground substance

Answer 25

transparent mixture of macromolecules; widely varying in consistency

Question 26

components of ground substance:

Answer 26

glycosaminoglycans (GAGs)
proteoglycans
glycoproteins

Question 27

glycoasiminoglycans (GAGs):

Answer 27

long linear polysaccharides, all highly hydrophilic, highly viscous, and poly anion ich (therefore, capable of binding a large # of cations [primarily sodium])

Question 28

GAG subtypes:

Answer 28

hyaluronic acid

Other GAGs, smaller and rich in sulfate “sulfated glycosaminoglycans”

Question 29

Hyaluronic acid:

Answer 29

largest and most ubiquitous glycosaminoglycan

Question 30

other GAGs, smaller and rich in sulfate “sulfated glycoasaminoglycans”

Answer 30

Smaller and rich in sulfate[= “sulfated glycosaminogycans”], bond covalently to proteins to form proteoglycans; predominant examples are dermatan sulfate, chondroitin sulfate, keratin sulfate, and heparin sulfate

Question 31

proteoglycans:

Answer 31

large protein molecules consisting of numerous sulfated glycosaminoglycans bonded covalently to a large, rod-like core protein; e.g., aggrecan (down in cartilage) and syndecan (protein in cell)

Question 32

glycoproteins:

Answer 32

large globular proteins covalently bonded to branched monosaccharide chains; e.g., fibronectin and laminin

Question 33

Fxns of ECM (5 fxns, first 1)

Answer 33

1 - ground substance holds and supports fibers and cells

a) linkages btwn cell-surface protein molecules (integrity) and the GAGS &/or glycoproteins anchor the cell in place or guide it on its migration/movement through the ground substance
b) GAGs and glycoproteins in turn bind to the fibers, anchoring them and connecting them to the cells and to each other
c) laminins bind the underside of epithelial cells to the fibers making up the Saal lamina (found within the lamina lucida)

Question 34

Fxns of ECM (5 fxns, 2-3)

Answer 34

2 - hydrophilic nature of GAGs allows for the absorption of a significant amount of water; this in turn, allows the tissues to resist compression and tension, protecting the cells and other strxs embedded within it (shock absorber
3 - viscous gel-like nature of ground substance acts to physically impede movement of invasive agents (bacteria)
a) viscous and slippery nature of hyaluronic acid makes it an excellent lubricant in joints

Question 35

Fxns of ECM (5 fxns, 4-5)

Answer 35

4 - ground substance passes nutrients from the blood supply to the cells and passes waste material from the cells to the blood supply, via diffusion through the water bound to the GAGs
5 - facilitates and regulates communication btwn cells found within the ECM; some proteoglycans within the ECM bind and sequester signaling proteins (fibroblast growth factor)

Question 36

Interstitial/extracellular fluid (tissue fluid):

Answer 36

fluid within connective tissue that is not bound up by the large molecules of the ground substance

Question 37

Interstitial/extracellular fluid predominantly derived from:

Answer 37

blood plasma, via diffusion and filtration; therefore, similar to plasma in its chemical make-up (ions), except for blood proteins
a) much lower concentration of blood proteins because most proteins are too large to cross the vessel wall

Question 38

Interstitial/extracellular fluid normally exists:

Answer 38

in very small quantities