9/4b Integument Histology

Question 1

All of the cells in the body are classified into 4 different tissue types?

Answer 1

YES

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

Question 2

Epithelial tissue

Answer 2

serves as the external layer of the body or the layer lining something (layer that lines all blood vessels). MOST Superficial layer
Avascular

Question 3

What are the main functions of epithelial tissue?

Answer 3

Protection - from UV rays
Transport - across cell membranes
Secretion/Excretion - secretes inactive form of vitamin D and excretes salt from sweat glands
Absorption - epithelium lines various segments of intestines

Question 4

Main characteristics of epithelial tissue?

Answer 4

Cell-Cell Junctions
Functional Polarity
Connected to a basement membrane

Question 5

What are the different kinds of cell-cell junctions in epithelial tissue?

Answer 5

Tight/occluding junctions
Adhering/anchoring junctions (not restricted to epithelial)
Communicating (gap)

Question 6

What is a tight/occluding cell-cell junction in epithelial tissue?

Answer 6

lateral border and just superficial to the cell surface. Prevent anything from entering the cell.
Ex: Blood Brain Barrier in the brain. Only certain things are allowed to get through the cells and nothing is between the cells

Question 7

What are the different kinds of adhering/anchoring cell-cell junctions in epithelial tissue?

Answer 7

Desmosomes
Hemi-desmosomes
Zonula Adherens

Question 8

What is a communicating (gap) cell-cell junction in epithelial tissue?

Answer 8

low resistance junction, connection of proteins that form a channel and allows for easy passage from one cell to an adjacent cell (not only epithelial)

Question 9

Desmosomes

Answer 9

Adhering/anchoring cell-cell junction of epithelial tissue

• Spot weld, like a dot of glue
• Connected with intermediate filaments (have the ability to resist tensile stress)
• Connected to intermediate filaments via cadherins
• Aid in structural integrity of the cell
• Communicate with external environment

Question 10

Hemi-desmosomes

Answer 10

Adhering/anchoring cell-cell junction of epithelial tissue

• half interacts with the cell
• other half interacts with the basement membrane
• connected with proteins called integrins to basement membrane/basal lamina

Question 11

Basement membrane of epithelial adhering cell

Answer 11

special layer of ECM that anchors the epithelium to whatever is underneath it

Question 12

difference between basal lamina and basement membrane of a cell?

Answer 12

NONE

Question 13

Integrins

Answer 13

proteins that connect the cytoskeleton and the ECM (extracellular matrix)

Question 14

Zonula Adherens

Answer 14

Adhering/anchoring cell-cell junction of epithelial tissue

• Follows the perimeter of the cell wall, often called belt adhesion.
• sticks the cell wall to an adjacent cell wall
• helps increase structural integrity
• helps communicate with the external environment

Question 15

what is the significance of the functional polarity characteristic of epithelial tissue?

Answer 15

• it defines the top and bottom of all epithelial cells
• allows things to go through the epithelial tissue in a distinct pathway
• apical surface faces the lumen

Question 16

lumen

Answer 16

center

Question 17

apical

Answer 17

at the top

Question 18

How is epithelium classified?

Answer 18

• Number of layers

- Shape

Question 19

What are the differnt layers of epithelium

Answer 19

Simple - 1 cell layer, squamous cuboidal columnar
Pseudostratified - 1 cell layer, not all cells reach the surface, all cells touch the bottom and adhere to basement membrane, columnar
Stratified - 2 or more layers, squamous cuboidal columnar, High Keratin and Moderate Keratin

Question 20

What are the different shapes of epithelium

Answer 20

squamous - fat in the middle and thin on the outside
cuboidal - all sides are the same size
columnar - rectangular, long sides
transitional - only seen in the bladder, not a focus

Question 21

Main function of stratified squamous??***

Answer 21

either highly keratinized or moderately keratinized and it helps anywhere where there is a lot of wear and tear.
Ex - vocal cords, trachea, and any place where there is a lot of mechanical stress

Question 22

Functions of integument

Answer 22

Protection - barrier and immune
Homeostasis - body temp and water loss
Sensation - sends sensory info to CNS
Metabolic Function - secretes precursor to vitamin D and excretes salt from sweat

Question 23

Structure of integument

Answer 23

Epidermis (5 layers) - top
Dermis (2 layers) - middle
Hypodermis - base

Question 24

Structure of the epidermis of integument

Answer 24

4-5 layers

1. B - stratum basal (B)/germanativum (bottom most layer)
2. S - stratum spinosum
3. GR - stratum granulosum
4. L - stratum lucidum
5. C - stratum coreum

Question 25

Epidermis

Answer 25

4-5 layers highly keratinized major cell type - keratinocyte

Question 26

Keratinocyte

Answer 26

starts as a stem cell at the base of the epidermis and migrates over around a month to the top most layer at the cell surface

Question 27

Stratum basal (B)/germinativum

Answer 27

- bottom-most layer - faces the dermis - 1 cell layer thick - made of stem cells (precursor for keratinocytes), melanocytes (produce skin pigment), and merkel cells (sensory receptors that are tactile)

Question 28

stratum spinosum

Answer 28

- prickle cells/pieces of Velcro (second from the bottom) - Spot welds used as junctions because skin has constant abrasion - creates stability - desmosome are the connecting welds - langerhans cells - detect antigens in epidermis and migrate out

Question 29

langerhans cells

Answer 29

- part of the stratum spinosum(second from the bottom layer of the epidermis) - detect antigens that enter the epidermis - produced in bone marrow - take foreign substance and migrate out of epidermis

Question 30

Stratum granulosum

Answer 30

- small dots that produce lamellar bodies (3rd from the bottom) - produce and accumulate keratin in the granules of the keratinocytes - loose nuclei - extrude a waxy-like substance from the cells that aids in water-proofing and hydration - connected by tight junctions

Question 31

Stratum lucidum

Answer 31

- clear layer (4th from the bottom) - transition zone from having nuclei to no nuclei - only seen in thick skin

Question 32

stratum corneum

Answer 32

shedding skin (top most layer)

Question 33

Layers of the dermis

Answer 33

Papillary layer | Reticular layer

Question 34

Papillary layer*****

Answer 34

- layer of the dermis - dermal papillae increase mechanical stability holding the epidermis to the dermal layer - Meissner's corpuscle - (compact fluorescent bulb), tactile sensory organ***** - Role of fibroblast - WOUND HEALING

Question 35

Reticular layer

Answer 35

- layer of the dermis - has lymphatic vessels, hair follicles and sebaceous glands (epidermal derivatives) - when langerhans (in stratum spinosum) ID foreign bodies, they send to the reticular layer of the dermis

Question 36

hypodermis

Answer 36

``` Fat cells (primarily) Blood vessels Glands pacinican corpuscle nerves ```

Question 37

purpose of fat cells in the hypodermis

Answer 37

regulate body temp | start spanning the reticular layer of the dermis too

Question 38

what does the pacinian corpuscle do?

Answer 38

it is a sensory corpuscle and detects deep pressure and vibration

Question 39

Integument nerve supply

Answer 39

- free nerve endings: in E layer, respond to pain and temperature, don't have CT around them - merkel's cells: tactile in nature, E layer - meissner's corpuscle: papillary dermis, tactile in nature - pacinian corpuscle: hypodermis, deep pressure and vibration - ruffini's corpuscle: dermis, sensitive to stretch