Mammalian Tissue Structure

Question 1

What is histology?

Answer 1

The study of microscopy structure of cells and tissue, allowing correlations between cellular structures + function to be examined

Question 2

What are tissues?

Answer 2

Collections of cells arranged in specific fashion

Question 3

What is histopathology?

Answer 3

Branch of histology that focuses on identification + study of disease

Question 4

How is histology of tissue analysed?

Answer 4

Tissues dehydrated + embedded in wax
Thin sections of tissue cut from “wax-block”
Mounted on microscope slides
Dyes added

Question 5

Why must the tissues be dehydrated + embedded in wax?

Answer 5

Tissue has to be “fixed” in formalin to prevent degradation

+ conserve structural attributes

Question 6

Why is the tissue cut into thin slices?

Answer 6

To allow light to transverse through tissue

Question 7

Why is dye added to the tissue?

Answer 7

To highlight specific features as tissue has little inherent contrast

Question 8

What dyes are used?

Answer 8

Haematoxylin

Eosin

Question 9

What does haematoxylin dye do?

Answer 9

Used for basophilia

Turns DNA/RNA blue/purple

Question 10

What does eosin dye do?

Answer 10

Used for basophilia

Turns proteins within + outside cell pink

Question 11

What are adipose tissue?

Answer 11

All same cells

Question 12

What are compound tissues?

Answer 12

Mix of cells with different functions

Question 13

What are the two types of cell barriers?

Answer 13

Epithelium

Endothelium

Question 14

What are the 4 categories of tissues?

Answer 14

Connective
Muscular
Nervous
Epithelium

Question 15

What are the 3 primitive (germ cell) layers?

Answer 15

Mesoderm
Ectoderm
Endoderm

Question 16

What primitive layer is connective tissue developed from?

Answer 16

Mesoderm

Question 17

What primitive layer is muscular tissue developed from?

Answer 17

Mesoderm

Question 18

What primitive layer is nervous tissue developed from?

Answer 18

Ectoderm

Question 19

What primitive layer is epithelium developed from?

Answer 19

All 3

Question 20

What is epithelia?

Answer 20

Tissues that serve as protective layers +/or secretory components of body organs + systems

Question 21

What is the structure of epithelia?

Answer 21

Formed into tightly cohesive cellular sheets

Cover/line body surfaces

Question 22

What does epithelia have a high capacity for?

Answer 22

Regeneration

eg. wound healing

Question 23

What is epithelia’s structure related to function?

Answer 23

Structure vital for the passage of O2, digested food + secretions through epithelia

Question 24

What are epithelia’s attributes?

Answer 24

Limited intracellular space
Mitotic capability
Basement membrane 
Single or multiple layers of cells
Free apical surfaces

Question 25

Why does epithelia have limited intracellular space?

Answer 25

Specialised junctions hold cells close together | Effective barrier + blocks infiltration of fluids between cells

Question 26

Why does epithelia have single or multiple layers of cells?

Answer 26

``` Thin = diffusion important Thick = protection from abrasion ```

Question 27

Why does epithelia have free apical surfaces?

Answer 27

During development or maturity of cell

Question 28

Why does epithelia have basement membrane?

Answer 28

Attachment of epithelium to underlying connective tissue

Question 29

Why does epithelia have mitotic capability?

Answer 29

Enables repair + regeneration

Question 30

What are the 3 types of epithelium layers?

Answer 30

Simple Pseudostratified Stratified

Question 31

What are the 4 types of cell shape?

Answer 31

Squamous Cuboidal Columnar Transitional

Question 32

What is simple?

Answer 32

One cell thick

Question 33

What is stratified?

Answer 33

Many cells BUT only bottom layer in contact with basement membrane

Question 34

What is pseudostratified?

Answer 34

Appear more than one cell thick BUT rest on basement membrane

Question 35

What is squamous shape?

Answer 35

Flattened

Question 36

What is columnar shape?

Answer 36

Taller than wide | Columns

Question 37

What is cuboidal shape?

Answer 37

Cubes

Question 38

What is transitional shape?

Answer 38

Change shape

Question 39

Where is an example of simple squamous?

Answer 39

Alveoli

Question 40

Where is an example of simple cuboidal?

Answer 40

Kidney tubule

Question 41

Where is an example of simple columnar?

Answer 41

Small intestine

Question 42

Where is an example of transitional?

Answer 42

Urinary tract

Question 43

Where is an example of stratified squamous?

Answer 43

Oesophagus

Question 44

Where is an example of keratinised stratified squamous?

Answer 44

Only found in skin

Question 45

Where is an example of stratified columnar?

Answer 45

Salivary gland duct | Urethra

Question 46

Where is an example of stratified cuboidal?

Answer 46

Sweat glands

Question 47

Where is an example of pseudostratified?

Answer 47

Trachea | Nasal mucosa

Question 48

What are the different types epithelial surface modifications?

Answer 48

Basal surface Apical surface Lateral surface

Question 49

What is basal surface?

Answer 49

Basement membrane = basal lamina | Selectively permeable

Question 50

What is apical surface?

Answer 50

``` Microvilli = finger-like extensions of plasma membrane Cilia = whip-like, motile extensions ```

Question 51

What is the function of microvilli?

Answer 51

Increase SA

Question 52

What is the function of cilia?

Answer 52

Move mucus over epithelial surface, in one direction

Question 53

Where is microvilli found?

Answer 53

Small intestine

Question 54

Where is cilia found?

Answer 54

Trachea | Respiratory bronchus

Question 55

What is lateral surface?

Answer 55

Adhesion junctions = adhesive spors (desmosomes) Tight junctions = apical plasma membrane of adjacent cells fuse Gap junctions = spot-like junctions allowing small molecule passage

Question 56

What is glandular epithelium?

Answer 56

Epithelial cells clustered together to perform secretory or excretory function Secrete hormones, milk, enzymes, sweat, mucus + oil

Question 57

What is exocrine glandular?

Answer 57

Pour products into ducts that open into lumen of organ or on to skin

Question 58

What is endocrine glandular?

Answer 58

Have no duct system, secrete into empty tissue space then bloodstream

Question 59

What is the morphological classification of exocrine?

Answer 59

``` Simple = single tube Compound = branched duct system Secretory = tubular, acinar/alveolar + saccular ```

Question 60

What are the 3 secretory mechanisms?

Answer 60

Merocrine Holocrine Apocrine

Question 61

What is merocrine mechanism?

Answer 61

eg. salivary gland From cells without damage to plasma membrane MOST glands secrete this way

Question 62

What is holocrine mechanism?

Answer 62

eg. sebaceous gland Cellular debris part of secretion (sebum) Involves cell death

Question 63

What is apocrine mechanism?

Answer 63

eg. mammary gland | Apical end pinched off

Question 64

What are the 4 types of epithelial membranes?

Answer 64

Mucous Serous Cutaneous Synovial

Question 65

Describe serous membrane

Answer 65

Lines closed body cavities Secrete watery fluid Simple squamous

Question 66

Describe structure of serous membrane

Answer 66

Rest on thin layer of connective tissue Parietal layer attaches to body wall around organ Visceral layer attaches to organ themselves

Question 67

Describe mucous membrane

Answer 67

Line cavities open to outside

Question 68

Describe cutaneous membrane

Answer 68

Skin Keratinised squamous epithelium Waterproof

Question 69

Describe synovial membrane

Answer 69

Line cavities of free moving joints Incomplete Contain connective tissue