Chapter 4: Tissue Level of Organization

Question 1

A group of cells that usually have a common origin in an embryo and function together

Answer 1

Tissues

Question 2

Epithelial Tissues

Answer 2

covers body surfaces and lines hollow organs, body cavities and ducts and also forms glands

Allows the body to interact with both internal and external environment

Question 3

Connective tissue

Answer 3

Protects and supports the body and its organs

Various types of tissues bind organs together, store energy reserves as fat, and help provide the body with immunity to disease causing organisms

Question 4

Muscular Tissue

Answer 4

is composed of cells specialized for contraction and generation of forces

In the process, muscular tissue generates heat that warms the body

Question 5

Nervous Tissue

Answer 5

detects changes in a variety of conditions insides and outside of the body and responds by generating electrical signals called nerve action potentials that activate muscular contractions and glandular secretions

Question 6

Cell Junctions

Answer 6

Contact points between plasma membranes of tissue cells; 5 types

Question 7

The five types of cell junctions

Answer 7

1. Tight junctions
2. adherens junctions
3. desmosomes
4. hemidesmosomes
5. Gap junctions

Question 8

Tight junctions

Answer 8

• fuse togeher the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells
• web like strands of transmembrane proteins

eg. stomach or bladder cells are adhered with tight junctions to prevent leakage of contents into other tissues

Question 9

Adherens junctions

Answer 9

• contain plaque - a dense layer of proteins on the inside of the plasma membrane that attaches both to the membrane proteins and to microfilaments of the cytoskeleton
• it forms an adhesion belt
• transmembrane glycoproteins join the cells

Question 10

What are the transmembrane glycoproteins that join the cells in an adheren junction; they link together on the outside of the cell membranes o-o-o-o-o

Answer 10

Cadherins

Question 11

Adhesion belts

Answer 11

formed by adherens junctions in epithelial cells and encircle the cell.

help epithelial surfaces resist separation during various contractile activities

eg. digestive tract contractions

Question 12

Desmosomes

Answer 12

contain plaque and have transmembrane glycoproteins (cadherens) that extend into the intracellular space between adjacent cell membranes and attach cells to one another

however, the plaque of desmosomes does not attach to microfilaments, but rather intermediate filaments inside the cell

Found in skin and heart tissue cells

spot weld junctions

Question 13

Hemidesmosomes

Answer 13

Look like desmosomes but do not link adjacent cells; instead anchor cells to the basement membrane

transmembrane proteins in hemidesmosomes are integrins rather than cadherins

Question 14

When do integrins attach to in hemidesmosomes?

Answer 14

Intermediate filaments on the inside of the plasma membrane made of protein keratin

On the outside of the cell, they adhere to the protein laminin on the basement membrane

Question 15

Gap Junctions

Answer 15

Connect neighboring cells via membrane proteins called connexions that make connexons (tiny fluid filled tunnels)

Intercellular gap between them, not completely connected

Allows passage of ions, nutrients and wastes between avascular tissues cells like lens and cornea of the eye

Allows communications

Question 16

Epithelial Tissue (vs)

Many cells tightly packed with little or no extracellular matrix

No blood vessels

Usually forms surface layers and isn’t covered by another tissues (one expection is the blood vessel since blood is a tissue)

Answer 16

Connective Tissue

Large amount of extravellular material that separates cells that are usually widely scattered

Most have significant networks of blood vessels

Question 17

Why is epithelial tissue always found adjacent to connective tissue?

Answer 17

Because it lacks blood vessels and forms surfaces and the blood vessel rich connective tissues enables it to make exchanges with blood

Question 18

Describe epithelial tissue (epithelium)

Answer 18

cells arranged in a continuous sheet in either single or multiple layers

Question 19

Two general patterns of epithelial cells in the body

Answer 19

1. covering and lining various surfaces
2. forming the secreting portion of glands

Question 20

What is the function of epithelial tissues?

Answer 20

• protects, secretes, absorbs and excretes

Question 21

Apical Surface

Answer 21

(aka free surface) outermost / most superficial layer

faces the body surface, cavity, the lumen of an internal organ or tubular duct

may contain cilia or microvilli

Question 22

Lateral epithelial cell surfaces

Answer 22

Face adjacent cells on either side

may contain cell junctions (not hemidesmosome)

Question 23

Basal surface of epithelial cells

Answer 23

Opposite the apical surface - the deepest layer

Adhere to extracellular materials like the basement membrane

Contain hemidesmosomes

Question 24

Basement membrane

Answer 24

thin extracellular layer that consists of two layers

Question 25

two layers of basement membrane

Answer 25

1. basal lamina 2. Reticular lamina

Question 26

Basal lamina

Answer 26

the layer of the basement membrane that is closest to, and secreted by, the epithelial cells Contains laminin protein that adheres to the integrin in the hemidesmosome of the basal layer of the epithelial tissues

Question 27

Reticular Lamina

Answer 27

Closer to underlying connective tissues Contains proteins like collogen that is produced by connective tissue cells called fibroblasts

Question 28

Which tissue is avascular but has its own nerve supply?

Answer 28

epithelial tissue

Question 29

What process allows the exchange of substances between teh epithelial tissue and the connective tissue

Answer 29

diffusion

Question 30

Most important roles of epithelial tissues in the body

Answer 30

- protection, filtration, secretion, absorption, and excretion -also combine with nervous tissue to create sensory organs

Question 31

Two types of epithelial tissue

Answer 31

1. Covering and lining epithelium (surface epithelium) 2. Glandular epithelium

Question 32

Surface epithelium location/function

Answer 32

outer covering of the skin and some internal organs inner lining of blood vessels, ducts, body cavities interior lining of the respiratory, digestive, urinary, and reproductive systems

Question 33

Glandular epithelium

Answer 33

makes up the secreting portion of glands such as thyroid, adrenal, sweat and digestive glands

Question 34

Two characteristics used to classify cover and lining (surface) epithelium

Answer 34

1. Arrangement of cells in layers 2. Shape of the cells

Question 35

3 Types of Classifications for tissue based on arrangement of cells in layers

Answer 35

1. Simple epithelium 2. Pseudostratified epithelium 3. Stratisfied epithelium

Question 36

Simple Epithelium

Answer 36

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

Question 37

Pseudostratisfied Epithelium

Answer 37

Appears to have mulitple layers because cell nuclei lie at different levels and not all cells reach the apical surface It is a simple epithelium - it is a single layer of cells that rest on the basement membrane Cells that do not reach apical usually contain cilia or secrete mucous (goblet cells)

Question 38

Stratisfied Epithelium

Answer 38

Two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear (eg skin)

Question 39

4 cell shape classifications for epithelial tissues

Answer 39

1. Squamous cells (flat) 2. Cuboidal cells (cubes or hexagons) 3. Columnar Cells 4. Transitional Cells

Question 40

Describe squamous cells

Answer 40

Flat thin cells that allow rapid passage of substances through them

Question 41

Cuboidal cells

Answer 41

cubes or hexagon shape may have microvilli secrete or absorb

Question 42

Columnar Cells

Answer 42

Column structure Protect underlying tissues Apical surface may have cilia or microvilli Often specialized for secretion and absorption

Question 43

Transitional Cells

Answer 43

change shape from squamous to cuboidal and back seen in stretch organs like stomach and bladder

Question 44

I. Simple epithelium a. simple squamous epithelium - endothelium -mesothelium b. simple cuboidal epithelium c. simple columnar epithelium - nonciliated -ciliated d. Pseudostratisfied columnar epithelium - nonciliated -ciliated

Answer 44

II. Stratified epithelium a. stratified squamous epithelium ** - nonkeratinized - keratinized b. stratified cuboidal epithelium c. stratified columnar epithelium d. Transitional epithelium or urothelium

Question 45

The function of glandular epithelium?

Answer 45

secretion

Question 46

This structure consists of epithelium that secretes substances into ducts, onto a surface, or eventually into the blood in the absence of ducts Endocrine or exocrine

Answer 46

Glands

Question 47

Endocrine glands

Answer 47

secrete hormones interstitial fluid -> diffuse into blood stream No duct Systemic effects

Question 48

Exocrine Glands

Answer 48

Secrete products into ducts that empty onto a surface of a covering and lining epithelium Local effects only Sweat, mucous, etc

Question 49

Structural classifications of exocrine glands

Answer 49

Unicellular or multicellular

Question 50

Unicellular Exocrine Glands

Answer 50

Single celled glands eg goblet cells

Question 51

Multicellular Glands

Answer 51

most exocrine glands are multicellular many cells that form a distinctive microscopic structure or macroscopic organ Sweat (sudoriferous), oil (sebasceous), and salivary glands

Question 52

2 criteria for classifications of multicellular glands

Answer 52

1. Branched or unbranched ducts 2. the shape of the secretory portions of the gland

Question 53

An exocrine gland that does not branch

Answer 53

Simple gland

Question 54

An exocrine gland that branches

Answer 54

compound gland

Question 55

Glands with tubular secretory parts

Answer 55

Tubular glands

Question 56

Glands with rounded secretory parts (berry; alveolar)

Answer 56

Acinar Gland

Question 57

Glands that have both tubular and more rounded secretory parts

Answer 57

Tubuloacinar Glands

Question 58

Structure Classification Scheme for Multicellular Exocrine Glands I. Simple: 1. Simple Tubular 2. Simple branched tubular 3. Simple coiled tubular 4. Simple Acinar 5. Simple branched Acinar

Answer 58

II. Compound 1. Compound Tubular 2. Compoud acinar 3. Compound tubuloacinar

Question 59

Function Classifications of exocrine Glands

Answer 59

Merocrine GLands Apocrine Glands Holocrine

Question 60

Merocrine Glands

Answer 60

- released from the cell in secretory vessciles via exocystosis (eg. sailvary glands)

Question 61

Apocrine Glands

Answer 61

accumulate their secretory product at the apical surface of secreting cell, then that portion of the cell pinches off from the rest of the cell to release the substance by exocytosis (mammary glands)

Question 62

Holocrine Glands

Answer 62

Collect secretion in cytosol and then as the cell matures, it ruptures and becomes the secretions (sebasceous gland) Secretion contains a large amount of lipids from the cells membranes