9/4b Integument Histology Flashcards

1
Q

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

A

YES

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

Epithelial tissue

A

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

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3
Q

What are the main functions of epithelial tissue?

A

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

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4
Q

Main characteristics of epithelial tissue?

A

Cell-Cell Junctions
Functional Polarity
Connected to a basement membrane

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5
Q

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

A

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

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6
Q

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

A

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

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7
Q

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

A

Desmosomes
Hemi-desmosomes
Zonula Adherens

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8
Q

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

A

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)

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9
Q

Desmosomes

A

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
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10
Q

Hemi-desmosomes

A

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
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11
Q

Basement membrane of epithelial adhering cell

A

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

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12
Q

difference between basal lamina and basement membrane of a cell?

A

NONE

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13
Q

Integrins

A

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

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14
Q

Zonula Adherens

A

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
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15
Q

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

A
  • 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
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16
Q

lumen

A

center

17
Q

apical

A

at the top

18
Q

How is epithelium classified?

A
  • Number of layers

- Shape

19
Q

What are the differnt layers of epithelium

A

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

20
Q

What are the different shapes of epithelium

A

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

21
Q

Main function of stratified squamous??***

A

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

22
Q

Functions of integument

A

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

23
Q

Structure of integument

A

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

24
Q

Structure of the epidermis of integument

A

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
25
Q

Epidermis

A

4-5 layers
highly keratinized
major cell type - keratinocyte

26
Q

Keratinocyte

A

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

27
Q

Stratum basal (B)/germinativum

A
  • 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)
28
Q

stratum spinosum

A
  • 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
29
Q

langerhans cells

A
  • 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
30
Q

Stratum granulosum

A
  • 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
31
Q

Stratum lucidum

A
  • clear layer (4th from the bottom)
  • transition zone from having nuclei to no nuclei
  • only seen in thick skin
32
Q

stratum corneum

A

shedding skin (top most layer)

33
Q

Layers of the dermis

A

Papillary layer

Reticular layer

34
Q

Papillary layer*****

A
  • 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
35
Q

Reticular layer

A
  • 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
36
Q

hypodermis

A
Fat cells (primarily)
Blood vessels
Glands
pacinican corpuscle
nerves
37
Q

purpose of fat cells in the hypodermis

A

regulate body temp

start spanning the reticular layer of the dermis too

38
Q

what does the pacinian corpuscle do?

A

it is a sensory corpuscle and detects deep pressure and vibration

39
Q

Integument nerve supply

A
  • 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