Cellular adaptations of growth and differentiation (G) Flashcards
(135 cards)
1
Q
What are adaptation of cell growth and differentiation?
A
Changes in cell size, number, appearance or function in response to environmental conditions
2
Q
5 main types of cellular adaptations
A
Hyperplasia
Hypertrophy
Atropy
Metaplasia
Dysplasia
3
Q
Which (4) types of cellular adaptations are reversible?
A
Hyperplasia
Hypertrophy
Atrophy
Metaplasia
4
Q
Which type of cellular adaptations are mechanisms through which cells, tissue and organs adapt by increasing their size?
A
Hyperplasia
Hyerptrophy
5
Q
What is hyperplasia?
A
Increase in number of cells of an organ or tissue
Results in increase in the volume of tissue
6
Q
What is hypertrophy?
A
Increase in volume of cells in an organ and thus increase in size of an organ
7
Q
What do we need to know to be able to predict which mechanism can be used to increase size of organ?
A
Regeneration capacity of the cell
8
Q
3 types of cells
A
Labile
Stable cells
Permanent cells
9
Q
Which type of cell is hyperplasia typical of?
A
Labile
10
Q
Which type of cell do both hyperplasia and hypertrophy?
A
Stable (liver)
11
Q
Which type of cell is hypertrophy typical of?
A
Permanent cells
12
Q
2 types of hyperplasia
A
Physiological
Pathological
13
Q
2 types of physiological hyperplasia
A
Hormonal hyperplasia
Compensatory hyperplasia
14
Q
2 examples of hormonal hyperplasia
A
Proliferation of granular epithelium of the breast during puberty and pregnancy
Uterus during pregnancy
15
Q
3 examples of compensatory hyperplasia
A
Liver regeneration
Response to hypoxia and proliferation of medullary red blood cell precursors
Intestinal villi
16
Q
What cytokine is produced during hypoxia?
A
Erythropoietin
17
Q
Why is it not correct to call it regeneration (Of ex. liver)?
A
As it does not maintain original morphology
18
Q
What of the liver can regenerate?
A
Size/volume
19
Q
Are all cytokines growth factors?
A
Yes
20
Q
Are all growth factors cytokines?
A
NO
21
Q
What kind of hormones are growth factors?
A
Protein hormones
22
Q
What kind of hormones are not growth factors?
A
Amine and steroid hormones
23
Q
What is liver regeneration induced by?
A
Integrated action of growth factors and cytokines
24
Q
3 phases of liver regeneration
A
Trigger phase
Growth phase
Termination phase
25
What happens during the trigger phase of liver regeneration?
Kupffer cells produce cytokines (ex. IL-6) which act on hepatocytes and then make competent for the action of growth factors
26
What does the cytokines produced by kupffer cells during liver regeneration act on?
Hepatocytes
27
What happens during the growth phase of liver regneration?
Growth factors (ex HGF) act on competent hepatocytes and induce their proliferation initiation of the cell cycle which takes a few hours, it is preceded by induction of transcriptional factors (ex. AP-1, c-Myc, P53) followed by cyclin synthesis
28
What does growth factors act on during the growth phase of liver regeneration?
Competent hepatocytes
29
What happens during the termination phase of liver regneration?
Release of inhibitory signals (ex TGFbeta and activin) stops cell proliferation when the number of cells or the volume reaches the original size
30
When does the proliferation stop in liver regneration?
When inhibitory signals are released when the liver reaches the original size of number of cells
31
What are the 3 cytokines of liver regneration?
Tumours necrosis factor alpha (TNFalpha)
IL-6
IL-4
32
Which are the 2 growth factors of liver regneration?
TGFalpha
Hepatocyte Growth Factor (HGF)
33
What do the cytokines and growth factors of liver regneration do?
Induce cell proliferation
34
What does TGFalpha bind to?
Epidermal growth factor receptor (EGFR)
35
What does HGF bind to?
Met receptor
36
Different name for HGF
Scatter factor
37
What does the cytokines do in liver regneration?
Priming of the cell
38
What does growth factors do in liver regneration?
Progression to cell
39
What are the 2 types of growth factors?
Growth factors of proliferative competence
Growth factors of progression
40
What are the transcription factors involved in liver regeneration?
C-myc
AP-1
41
Is it always the same transcription factors that are involved in liver regeneration?
Yes
42
What is hyperplasia in the intestinal villi?
When there is an increase in the mucosal surface and in the height of the villus die to increased functional demand (ex. pregnancy and lactation or diabetes)
43
What is pathological hyperplasia?
When there is an excessive hormonal stimulation
44
What is endometrial hyperplasia?
When there is an imbalance between oestrogen and progesterone
Hyperplasia of the prostate is due to testosterone or androgenic stimulus
45
What are stem cells and the proliferative cells in contact with in hyperplasia of the epidermis?
Basal lamina
46
What separates the epidermis from the dermis?
Stem cells and proliferative cells being in contact with the basal lamina
47
What are keatinocytes?
Stratum corneum cells that have lost the nucleus and are completely differentiated
48
How long does passage from the basal layer to the stratum corneum take?
2-4 weeks
49
What can be a result of repeated mechanical stimulation?
Hyperplasia and thickening of stratum corneum
50
Which is the most important layer of skin and why?
Stratum basale, because cells that are able to divide are there
51
What is psoriasis?
Chronic inflamation
52
How many percent of the population does psoriasis affect?
1-2%
53
What kind of disease is psoriasis?
Autoimmune
54
What makes psoriasis an autoimmune disease?
Lymphocytes are activated by self molecules in basal lamina
Doesn't recognise self proteins
Is meditated by T cells
55
What factor can psoriasis be related to?
Stress
56
What can be found infiltrated in inflamed skin?
Leukocytes
57
How many times is activity of the basal layer increased by in psoriasis?
10 times
58
How long does the transition take in psoriasis?
4 days (the normal is 2-4 weeks)
59
Is the differentiation process complete in psoriasis?
No
60
How are the basal cells in the epidermis arranged in psoriasis?
Over several layers
61
What abnormal place can cells in mitosis be found in psoriasis?
Above the basal layer
62
Where can inflammation be found in psoriasis?
In the dermis
63
What is parakeratosis?
Defect cell proliferation where nuclei is located in the scales of stratum corneum
64
What happens when T lymphocytes enter in contact with the basal membrane in psoriasis?
They become activated and synthesise cytokines that affect proliferation and differentiation
65
Can hypertrophy be both physiological and pathological?
Yes
66
What 2 things is hypertrophy caused by?
Increased functional demand
Hormonal stimulation
67
2 examples of increased functional demand causing hypertrophy
Intense muscle work in skeletal muscle
Chronic hemodynamic overload int he heart (left ventricle)
68
2 examples of hormonal stimulation causing hypertrophy
Pregnant uterus
Breast during lactation
69
What is the increased volume in hypertrophy caused by?
Synthesis of a greater quantity of structual components (in particular proteins)
70
What is the increased volume in hypertrophy not caused by?
Swelling (influx of water)
71
Where does chronic hemodynamic overload happen?
Left ventricle
72
When does chronic hemodynamic overload happen?
During hypertension
73
What is chronic hemodynamic overload a response to?
Increased workload of the heart fibers
74
What increases during chronic hemodynamic overload?
Size of cells (not number)
75
What does chronic hemodynamic overload result in?
Thickened wall of the left ventricle
76
What is the increase in cell volume regulated by in cardiac hypertrophy?
Mechanical sensors
Vasoactive receptors (ex. alphaadrenergic hormones)
Growth factors (ex. IGF-1)
77
What are receptors at the cytoplasmic level used to induce the activation of in cardiac hypertrophy?
Transduction pathways of PI3K and mTok and receptors associated with G proteins
78
What does the activation of transduction pathways in cardiac hypertrophy result in the activation of?
GATA4 transcription factor, NFAT, MEF2 and expression of genes coding for muscle proteins
79
What does the activation of transduction pathways in cardiac hypertrophy result in the increase of?
Increased synthesis of contractile proteins with increased number of my filaments and increased capacity of the muscle
80
What is hypertrophy associated with the expression of?
Embryonic/fetal contractile proteins (ex beta isoform of the heavy myosin chain)
81
What kind of contraction does embryonic/fetal contractile proteins present?
Slower contraction allowing the organ to save energy
82
What does ANF stand for?
Aerial natviuretic factor
83
What does ANF induce?
The kidneys to release more water which reduces the volume of blood and the blood pressure valves
84
What is c-Myc?
Transcriptional factor
85
What does c-Myc bid to?
Promoter or enhances region of genes that codifies for proteins involved in transition G0 or G1 to S
86
What is c-Myc able to do in a cell?
Induce proliferation
87
Aside from proliferation, what is c-Myc important in?
Differentiation
Survival
Apoptosis
Metabolism
88
What kind of gene is p-53?
Oncosupressor gene
89
Does p-53 induce cell proliferation?
No
90
What does p-53 induce?
A block of cell proliferation
The synthesis of molecules that inhibit cyclin dependant kinases (ex. p-21)
91
When does hypotrophy of the intestinal villi take place?
When there is prolonged fasting
92
What can atrophy be a cause of?
Apoptosis
93
Different name for atrophy?
Hypotrophy
94
What is atrophy?
The reduction of size of an organ or tissue by reducing number or size of cells (loss of cell material)
95
What is atrophy caused by?
Decrease in protein synthesis and increase in protein degradation
96
When does physiological atrophy occur?
During embryonic and fetal development
97
7 causes of pathological atrophy
Reduction of workload
Inadequate nutrition
Loss of endocrine stimulation
Denervation
Ageing
Compression
Reduction of blood flow
98
What does ageing cause the atrophy of?
The frontal lobe
99
Clinical syndrome of pathological atrophy caused by inadequate nutrition
Cachexia
100
Is metaplasia reversible?
Yes
101
What is metaplasia?
Reversible alteration where a differentiated tissue of a certain type is replaced by on of a different type
102
What is metaplasia an adaptive response to?
Stress
Cell type which is sensitive to the adverse condition is replaced by a more resistant type of same histogenetic origin
103
In adults what kind of origin does the tissue which experiences metaplasia have?
Only:
Epithelial
Mesenchymal
104
3 different events of metaplasia
Cell A changes directly in cell B
Cell A is eliminated and its progenitors produce cell B
New cell type is the result of reprogramming of undifferentiated stem cells or mesenchymal cells
105
Is metaplasia a normal physiological process?
No
106
What kind of lesion is metaplasia considered to be?
Preneoplastic lesion
107
What can be the first step in cancer
Metaplasia
108
What happens if the stimulus that predisposes to metaplasia persists?
It can induce neoplastic transformation in the mesa tic epithelium
109
In epithelial metaplasia what is replaced by multilayered flat epithelium?
Cylindrical cell epithelia or transitional epithelia
110
What can epithelial metaplasia be a result of?
Smoking (both in trachea, bronchi and oral cavity)
Shortage of vitamin (especially vitamin A)
Calcus in gallbladder
111
Why can a shortage in vitamin A cause epithelial metaplasia?
It is important in the maintenance of epithelial diffeentiation
112
What is mesenchymal metaplasia?
Formation of cartilage, bone and adipose tissue in tissues not containing these elements
(replacing non-mesenchymal cells with mesenchymal cells)
113
What can bone metaplasia develop in muscle as a result of?
Trauma (traumatic ossifying myositis)
114
As a part of what sequence can bone metaplasia take place in ateriosclerotic arteries?
Clacification -> ossification
115
Where is metaplastic bone sometimes formed in paraplegic patients and why?
Around the joints
Unknown reason
116
What kind of scars is bone metaplasia especially observed in?
Those resulting from abdominal operations
117
What is dysplasia?
Disordered growth
Alteration of cell proliferation and differentiation
118
Where is dysplasia often observed ?
Scaly epithelia as a result of continuous insult
119
What makes dysplasia different from the other conditions?
It is irreversible
120
Is dysplasia reversible?
NO
121
What can dysplasia represent the initial stages of?
Cancer
122
What is dysplasia characterised by?
Loss of uniformity of individual cells
Loss of architectural orientation of cells
Remarkable polymorphism
Hyperchromatic nuclei
Mitosis is more frequent and localised at the superficial level
Differenting alterations
123
Does in situ carcinomas invade the connective tissue?
No
124
Where are in situ carcinomas localised?
Epithelium and basal membrane (is not destruct)
125
What does HPV stand for?
Human papilloma virus
126
What is HPV?
Dysplasia in the uterine cervix
127
What is the most important factor effecting the appearance of the uterus?
HPV
128
What are dysplasia and (more so) anaplasia characterised by?
Numerus morphologival and functional changes
129
What is pleiomorphism?
The presence of cells different in size and shape, large and hyper chromatic nuclei: nuclei contain a characteristic quantity of DNA higher than normal
130
What is frequent or abnormal mitosis a sign of?
Malignancy (abnormal mitosis is always a sign of this)
131
What is the presence of giant cells a sign of?
Malignancy
132
How is cell orientation in a tissue altered?
Anapaestic cells lose polarity, epithelial cells are polarised and thus cell orientation in the tissue is altered
133
What is controlled proliferative variations?
Control of cell multiplication is active and are reversibel processes
134
Is tumor growth reversible?
No
135
What is tumor growth?
Process that escape the control of growth
