Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Molecular BIO > 31. Stem Cells And Tissue Renewal > Flashcards

31. Stem Cells And Tissue Renewal Flashcards

1
Q

Are stem cells tissue specific?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are stem cells maintained throughout the life of an organism?

A
  1. Asymmetric division

2. Independent choice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can asymmetric division provide stem cells teh ability to maintain through out a lifetime?

A

2 cells are created. One has stem cell characteristics and the other has the ability to differentiate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can independent choice provide stem cells the ability to maintain existence throughout lifetime?

A

The division has 2 identical cells for but the outcome is influenced by the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is one drawback of teh asymmetric division theory of stem cell proliferation?

A

Unable to explain how stem cells rapidly increase their numbers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is the independent choice more highly supported as the theory for stem cell proliferation?

A

More flexible and more able to explain the rapid increase of stem cells. The environment can influence how many cells are able to differentiate or remain as stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are founder stem cells?

A

Cells in a tissue with a fixed number of founder stem cells that are programmed to undergo a set number of divisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What ultimately controls the size of a final structure?

A

The number of founder stem cells present in that tissue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a unique feature of the founder stem cells?

A
  1. They are established early in development.
  2. Have a set number in each tissue that will grow and divide for a finite amount of time until they reach/fulfill the size of their final structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why do stem cells retain BrdU label and when is this label taken into the cell??

A
  1. Retain due to slow division rate

2. Taken into the cell during S phase of cell cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the epidermis?

A
  1. Outer skin layer
  2. Water barrier
  3. Epithelial cells. Continuously repaired and renewed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the dermis?

A

2m layer of collagen, provides toughness to skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the hypodermis?

A

Fatty SubQ layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What provides teh skin with mechanical support?

A

Extracellular matrix secreted by the fibroblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What components of the skin remove waste products?

A

Blood vessels and endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which cells provide defense against microbes and pathogens?

A

Dendritic cells and macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What cells form the epidermis?

A

Stratified keratinocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the only dividing cells located in the epidermis?

A

The basal cell layer, which are attached to the basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the layers of cells from deep to superficial?

A
  1. Basal lamina
  2. Basal cell layer
  3. Prickle cell layer
  4. Granular cell layer
    5 keratinized squamous epithelium
20
Q

What are teh characteristic features of prickle cells?

A

Multiple desmosomes that attach tufts of keratin filaments

21
Q

What is characteristic of the granular cells?

A

Seal together to form the waterproof barrier

22
Q

What boundary do teh granular cells form?

A

Boundary between the inner metabolically active strata and the dead epidermis

23
Q

What is the outermost layer of epidermis?

A

Squame: flattened dead cells packed with keratin but no organelles

24
Q

What are the characteristics of stem cells?

A
  1. Not terminally differentiated
  2. Divide without limits
  3. Undergo slow division
  4. Provides one stem cell and one with ability to differentiate
25
How does the epidermis renew itself?
Basal cells divide to produce new basal cells, and other cells that will migrate superficially to replace the cells from inside out
26
How often are the epidermis cells replaced?
Once every month
27
What controls the rate/initiation of basal cell division and differentiation?
1. Contact with basal lamina via beta-integrins prevents the differentiation of the basal cells. 2. Reduced beta-integrin contact allows basal cells to divide and differentiate
28
Where does a hair follicle grow up from?
1. Dermal papilla
29
What is sebum?
1. Oily liquid secreted from the sebaceous gland
30
What is the specific integrin that prevents stem cell differentiation while in contact?
Beta-1 integrin subunit
31
Where do transit amplifying cells come from?
Basal layer and incorporate into higher layers
32
What cells have finite division but originate in the basal layer and migrate to higher levels?
1. Transit amplifying cells
33
What are transit amplifying cells used for?
To control growth
34
What are the factors that control the rate of epidermis renewal?
1. Rate of stem cell division 2. Rate of transit amplifying cells division 3. Migration rate from basal layer to differentiated state
35
What is the single most important signal for controlling epidermis renewal?
1. Contact with the basal lamina, via beta-1 integrin.
36
What happens if a signaling pathway is disrupted within the epidermis renewal system?
1. Increase chances of epidermal cancer development
37
What happens if the hedgehog pathway becomes overactive?
1. Cells continue to divide after leaving the basal layer. Overproduction of improper cells
38
What happens if sonic hedgehog is deficient to the epidermal layer?
1. Reduced function or presence of sebaceous glands
39
What happens when Wnt-signaling is overactive during epidermis renewal?
1. Extra hair follicle develop, can form tumors
40
What happens when Wnt-signaling is underproduced in the epidermal signaling pathways?
1. No hair follicle development
41
What happens if Notch signaling is too high in the epidermal renewal?
Stem cell population will be dramatically decreased
42
What happens if Notch is released in too low amounts?
Stem cell population is not inhibited and can overgrow=> tumor growth
43
What is the signaling molecule that promotes skin wound repair by forming a collagen rich scar?
1. TGF-beta
44
What is the role of TGF-beta in the epidermal renewal pathway?
Promotes skin wound repair.
45
What is the role of Wnt signaling pathway?
Controls the formation of hair follicles.
46
What is the role of sonic hedgehog in terms of epidermal renewal pathways?
1. Controlling the sebaceous gland formation.

Molecular BIO (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions