Cellular Adaptations and Accumulations

Question 1

What are physiologic adaptations?

Answer 1

Responses of cells to normal stimulation by hormones or endogenous chemical mediators

Question 2

What are pathological adaptations?

Answer 2

Can share same underlying mechanisms as physiologic adaptations; allows cells to modulate their environment and escape injury

Question 3

True or false: pathological changes to cells can share the same underlying mechanisms as physiologic changes

Answer 3

True

Question 4

What are the four adaptations that cells can undergo?

Answer 4

Hypertrophy
Hyperplasia
Atrophy
Metaplasia

Question 5

What is hypertrophy?

Answer 5

Increase in cell size, not number

Question 6

What is hyperplasia? Metaplasia?

Answer 6

Hyperplasia = Increase in number of cells

Metaplasia = Change in cell type

Question 7

What is atrophy?

Answer 7

Decrease in cell size

Question 8

What is the underlying MOA of hypertrophy?

Answer 8

Increase in structural proteins and organelles

Question 9

True or false: hypertrophy can coexist with hyperplasia

Answer 9

True

Question 10

Is hypertrophy pathologic or physiologic?

Answer 10

Either

Question 11

How does hypertrophy signalled? (2)

Answer 11

via hormones or increased functional demand

Question 12

In the pregnant uterus, which cellular adaptation(s) occur? How is this signalled?

Answer 12

Hypertrophy and hyperplasia via hormonal stimulation

Question 13

When can pathologic cardiac enlargement occur? (3)

Answer 13

HTN
Aortic valve disease
MI

Question 14

What happens to non-necrotic cardiomyocytes following MI?

Answer 14

Enlargement of the surrounding the myocytes

Question 15

What major adaptation (of the four) occurs in a necrotic heart?

Answer 15

Hypertrophy (CANNOT undergo hyperplasia)

Question 16

What happens to the nucleus during hypertrophy of a cell? Cytoplasm?

Answer 16

Increases in size

Question 17

Why is a thicker ventricle problematic?

Answer 17

Increased resistance to coronary blood flow

Question 18

Why do cardiac muscle cell nuclei/cytoplasm increase in hypertrophy (boxcar nuclei)?

Answer 18

Kicking out more proteins

Question 19

Boxcar nuclei = ?

Answer 19

Increased nuclei size in hypertrophic myocytes

Question 20

Hypertrophy is the result of what?

Answer 20

increased production of cellular proteins

Question 21

What are the three types of signals involved in causing hypertrophy?

Answer 21

1. Mechanical signals (stretch)
2. Vasoactive agents (alpha adrenergic)
3. Growth factors (TGF-beta)

Question 22

What is the limit to hypertrophy of the heart?

Answer 22

When enlargement of muscle can no longer compensate for increased burden

Question 23

What is the mechanical signal for increased myocardial hypertrophy?

Answer 23

Increased stretch

Question 24

What are the vasoactive agents signaling heart hypertrophy?

Answer 24

Alpha adrenergic agonists, like angiotensin

Question 25

What are the growth factors that signal myocyte hypertrophy?

Answer 25

TGF-beta

Question 26

How is myocyte hypertrophy effected? (3)

Answer 26

1. Synthesis of contractile proteins 2. Production of growth factors 3. Induction of embryonic genes to increase performance

Question 27

True or false: hypertrophied cells have increased DNA content

Answer 27

True-- need more proteins per cell

Question 28

What is the requirement of the cells of tissues that can undergo hyperplasia?

Answer 28

Must be capable of replication

Question 29

What are the two physiologic forms of hyperplasia?

Answer 29

Hormonal hyperplasia (breast enlargement) Compensatory hyperplasia (e.g. liver regrowth)

Question 30

What is compensatory hyperplasia?

Answer 30

Increased tissue mass after damage or resection (think liver)

Question 31

Pathologic hyperplasia usually results from what?

Answer 31

excessive hormones or growth factors acting on target cells

Question 32

What is endometrial hyperplasia?

Answer 32

Hyperplasia d/t estrogen/progesterone imbalance

Question 33

What is benign prostate hyperplasia (BPH) caused by?

Answer 33

Increased mitotic activity d/t increased androgens

Question 34

True or false: pathologic hyperplastic processes remain controlled (except for CA)

Answer 34

True

Question 35

What happens histologically in BPH?

Answer 35

Increased infolding d/t hyperplasia (nodular hyperplasia)

Question 36

What are the histological changes in Grave's disease to the thyroid?

Answer 36

Cells pile up on themselves

Question 37

What is Grave's disease?

Answer 37

Autoimmune disease where the abs act like signals to produce more TSH

Question 38

Hyperplasia is the result of what?

Answer 38

Increased growth factor leading to increased output of new cells from stem cells

Question 39

What the MOA of atrophy (2)?

Answer 39

Decrease in organelles/proteins Increased protein degradation via ubiquitin

Question 40

What are the signals of atrophy? (6)

Answer 40

``` Decreased workload Loss of innervation Decreased blood supply Inadequate nutrition Low endocrine Pressure ``` (BP, WINE)

Question 41

How does pressure relate to atrophy?

Answer 41

Tissue compression leads to atrophy

Question 42

What is senile atrophy?

Answer 42

Decreased blood supply to tissues, leading to atrophy

Question 43

What is the initial atrophy response?

Answer 43

Decrease in cell size and organelles to reduce the metabolic needs of the cell to extent that they can survive

Question 44

Atrophy immediately results in dead cells (true or false)?

Answer 44

False--just smaller

Question 45

What is lipofuscin?

Answer 45

Bound residual cell debris from destruction of plasmalemma

Question 46

What is autophagy? What process is it seen in?

Answer 46

Self=eating by starved cells to survive Occurs in atrophy

Question 47

What are the two cellular accumulations in atrophy?

Answer 47

Autophagic vacuoles and lipofuscin

Question 48

How does aortic atherosclerosis result in kidney atrophy?

Answer 48

Decrease in blood supply to kidney

Question 49

True or false: metaplasia is reversible

Answer 49

True

Question 50

What is metaplasia?

Answer 50

reversible changes in which one differentiated cell types is replaced by another cell type that is better adapted to conditions

Question 51

What is the effect of smoking on bronchi? What can this lead to?

Answer 51

Columnar cells turn to stratified squamous cells May lead to CA

Question 52

Barrett's esophagus?

Answer 52

Changes of lower esophagus d/t changing from squamous epithelium to columnar with goblet cells

Question 53

What is muscular dystrophy the result of?

Answer 53

Dystrophin gene messed up

Question 54

What is CT metaplasia?

Answer 54

Formation of cartilage, bone, or adipose tissue in tissue that does not usually contain these elements

Question 55

What is CT metaplasia the result of?

Answer 55

May be the result of tissue injury, rather than metaplasia

Question 56

What type of CT metaplasia occurs in intramuscular hemorrhage?

Answer 56

Bone formation in muscle after intramuscular hemorrhage

Question 57

What is the cellular mechanism underlying metaplasia? What are the three types of signals?

Answer 57

Result of reprogramming of stem cells that exist in normal tissues via cytokines, growth factors, ECM components

Question 58

What is dysplasia?

Answer 58

Disordered growth

Question 59

What disease process is dysplasia seen in? What cell type usually?

Answer 59

Precancerous in squamous epithelial cells (usually)

Question 60

What are the histological changes is dysplasia? (2)

Answer 60

Disorderly arrangement of cells Enlargement of nuclei, irregular borders, and hyperchromasia of individual cell nuclei

Question 61

Intracellular accumulations are due to what?

Answer 61

Metabolic derangements

Question 62

Pathological calcification are due to what?

Answer 62

Calcium deposition at site of cell death

Question 63

In chronic cardiac overload, what genes are turned on?

Answer 63

genes expressed normally only in the neonatal heart are reactivated, and contractile proteins can switch to fetal isoforms, which contract more slowly

Question 64

When does cell injury occur? Is cell injury reversible?

Answer 64

when limits of adaptive response to stimulus are exceeded. Can be reversible or irreversible

Question 65

What are the three stages of progressive impairment that occur during cellular injury?

Answer 65

Adaptation, reversible injury, and cell death

Question 66

What happens to myocytes when the limit of enlarged muscle mass is reached? (2)

Answer 66

Lysis and loss of myofibrillar contractile elements or myocyte death

Question 67

Atrophy will continue until what point?

Answer 67

Until a new equilibrium is achieved so all cell can survive

Question 68

How are proteins degraded in atrophy?

Answer 68

Poly ubiquitination and proteasomal destruction