Chapter 4: Tissues

Question 1

Tissue

Answer 1

group of cells that have similar embryological origin and are specialized for a particular function

Question 2

Histology

Answer 2

study of tissues

Question 3

4 types of tissue

Answer 3

1. connective
2. epithelial
3. nervous
4. muscle

Question 4

cell junctions

Answer 4

points of physical contact btwn adjacent cells

Question 5

functions of cell junctions

Answer 5

• support
• sealing
• communication
• interaction

Question 6

Types of cell junctions

Answer 6

1. tight junctions
2. adherens junctions
3. desmoosomes
4. hemidesmosomes
5. gap junctions

Question 7

Tight junctions

function & location

Answer 7

• fluid tight seals
• found in stomach, intestines, bladder

Question 8

Adherens junction

function

Answer 8

• made of actin filaments + plaques of protein that anchor cells together or to ECF

Question 9

Desmosomes

aka anchoring junctions

Answer 9

• bond cytoskeletons of adjacent cells
• linked by transmembrane glycoproteins that extend across cell proteins to create strong bond

Question 10

hemidesmosomes

Answer 10

• integrin family of protein that connect cells to extracellular material (i.e. basement membrane)
• 1/2 of a desmosome

Question 11

gap junctions

Answer 11

• allow cells in tissue to communicate quick through connexins
• connexins=channels that flow ions from other cells cytoplasm
• i.e. heart tissue

Question 12

characteristics of epithelial tissue

Answer 12

• arranged in sheets that cover body (internal & external)
• closely packed
• many cell junctions
• apical (free) surface + basal surface (basement membrane)
• avascular (frequently replaced, mitotic)
• no nerve supply

Question 13

apical (free) surface

Answer 13

faces a lumin

Question 14

basal surface

Answer 14

• sits on basal lamina (top layer or basement membrane)
• NOT reticular lamina (below basement)

Question 15

functions of epithelial tissue

Answer 15

• protection
• absorption
• gas exchange
• secretion
• transpo
• lubrication
• repair

Question 16

how are epithelium covering and lining classified?

Answer 16

• cell arrangement
• cell shape

Question 17

types of cell arrangement

Answer 17

1. simple
2. stratified
3. pseudo-stratified

Question 18

Simple cells

Answer 18

• single layer
• sits on basement membrane

Question 19

stratified

Answer 19

multiple layers of cells

Question 20

pseudo-stratified

Answer 20

appears multi-layered but all sit on basement membrane

Question 21

types of cell shapes

Answer 21

• squamous
• cuboidal
• columnar
• transitional

Question 22

squamous cell

Answer 22

flat with central nucleus

Question 23

cuboidal

Answer 23

cube shape with single nucleus

Question 24

columnar cell

Answer 24

tall, long with nucleus twd bottom

Question 25

simple columnar epithelium descrption, function, types

Answer 25

* single layer of column shape cells * lines GI, respiratory tracts, glands * increase surfacearea for absorption, movement * goblet type: produces premucin * non-ciliated type: microvolli at apical border

Question 26

stratified epithelium

Answer 26

* stratified squamous epithelium * stratified cuboidal epithelium * stratified columnar epithelium * transitional epithelium

Question 27

stratified squamous epithelium descrition, function, location

Answer 27

* several layers, top=squamous * lines mouth, esophagus, vagina, anus * softens apical surface, protects, repels water/bacteria * keratinized type: skin, top layer has keratin * non-keratinized: no keratin

Question 28

stratified cuboidal epithelium description, function, location

Answer 28

* several layers, top=cuboidal * lines ducts of glands. surrounds developing egg cells and testes * protection