Dr. Parsa - Cell Injury and cell death

Question 1

A normal cell is confined by a range of function and structural flexibility depending on:

Answer 1

1. the cell’s state of metabolism, differentiation, and specialization
2. the constraints of neighboring cell’s
3. the availability of metabolic substrates.

Question 2

Excess physiologic stress/pathologic stimuli beyond the cell’s threshold to maintain normal homeostasis results in ___ ___

Answer 2

cell injury. The injured cell can either adapt to a new steady state which would be reversible, or it could die if it can’t adapt it would undergo necrosis or apoptosis.

Question 3

Adaptations are ___functional and structural responses to more severe physiologic stresses and some pathologic stimuli, which new altered steady states are achieved, allowing the cell to survive and continue to function

Answer 3

reversible

Question 4

what are the adaptative responses of the cells:

Answer 4

1. atrophy: dec in size and function
2. hypertrophy: increase in size
3. hyperplasia: increase in number of cells.
4. metaplasia: change from one cell type to another

Question 5

Physiological atrophy is common during normal development. What are some examples of this?

Answer 5

1. notochord and thyroglossal duct during fetal dev.

2. uterus dec in size after parturition

Question 6

what is the pathologic cause of atrophy

Answer 6

1. disuse
2. loss of innervations
3. diminished blood supply
4. inadequate nutrition
5. loss of endocrine stimulation
6. aging
7. pressure

Question 7

what is the biomechanical mechanism of atrophy?

Answer 7

1. Decreased protein synthesis

2. Increased protein degradation

Question 8

What is the molecular pathogenesis of atrophy

Answer 8

1. ubiquitin proteasome pathway:
nutrient deficiency or disuse activates ubiquitin ligase which attach the small peptide ubiquitin to cellular proteins and target these proteins for degradation in proteasomes. 
2. increased autophagy:
starved cell eats its own components
3. reduction in size of organelle

Question 9

what is an ex of residual bodies

Answer 9

lipofuscin granule. look yellow/brown

Question 10

what happens if we see group atrophy

Answer 10

considered neurogenic atrophy

Question 11

describe hypertrophy. what is it due to?

Answer 11

increase in cell size, but no new cells! Due to increased functional demand or increased synthesis of structural proteins.

Question 12

what is physiologic hypertrophy stimulated by?

Answer 12

1. hormones; uterus and breasts in pregnancy

2. inc in workload (exercise): skeletal muscle hypertrophy

Question 13

what is pathologic hypertrophy

Answer 13

Inc. workload associated with changes in gene expression

Question 14

what is molecular pathogenesis of hypertrophy

Answer 14

1. Phosphoinositidide 3-kinase/Akt pathway

2. Signaling downstream of G protein coupled receptors

Question 15

Describe physiologic hypertrophy

Answer 15

1. mechanical sensors: triggers for physiologic hypertrophy

2. phosphoinositide 3 kinase/Akt pathway

Question 16

describe pathologic hypertrophy

Answer 16

G protein receptors:

1. growth factors: TGF, IGF-1
2. Vasoactive agents: adrenergic agonists, angiotensin II

Question 17

Describe physiological hypertrophy of cardiac muscle

Answer 17

sarcomeres are added in series to lengthen the cell, as on periphery to inc width of the cell

Question 18

describe pathological cardiac hypertrophy

Answer 18

1. can produce concentric hypertrophy in which the ventricular wall and septum thicken with a net dec. in ventricular chamber dimensions.
2. eccentric and dilatory cardiac growth; sarcomeres are added in series to ind. myocytes

Question 19

describe physiologic hyperplasia

Answer 19

1. hormonal: female breast during puberty and during pregnancy
2. compensatory: liver after partial hepatectomy

Question 20

describe pathologic hyperplasia

Answer 20

1. excessive hormonal stimulation; prostate, endometrium
2. effects of growth factors on target cells; repair: fibrovascular proliferation
3. viruses (HPV): epithelial/epidermal proliferative lesions.

Question 21

At the subcellular level, an organelle can undergoe ____ hyperplasia such as _____ hyperplasia in muscle hypertrophy

Answer 21

selective; mitochondrial

Question 22

Hypertrophy of the smooth ER is a ____response that inc. the amount of enzymes, _____available to detoxify the drugs.

Answer 22

adaptative; cytochrome P-450 oxidase

-overtime patients respond less to the drug bc of this adaptation

Question 23

Which type of hyperplasia is not precancerous

Answer 23

BPH (in prostate)

Question 24

what is the most common epithelial metaplasia

Answer 24

columnar to squamous

Question 25

in _____it is opposite and changes from squamous to columnar

Answer 25

esophagus

Question 26

what are the types of cell injury?

Answer 26

1. reversible

2. irreversible

Question 27

cell injury can occur due to the following cellular functions or components

Answer 27

1. Dec in ATP
2. Mitochondrial damage
3. Entry of Ca++
4. Inc of ROS
5. Membrane damage
6. Protein misfolding, DNA damage

Question 28

what are the sequence of events in cell injury

Answer 28

1. biochemical (functional

2. morphologic (structural)

Question 29

what are two features of reversible cell injury

Answer 29

1. cellular swelling

2. fatty change

Question 30

what are features of a irreversible cell injury

Answer 30

1. denaturation of intracellular proteins

2. enzymatic digestion of the lethally injured cell.

Question 31

what is mechanism of apoptosis

Answer 31

1. release of cytochrome c

2. Bcl family of proteins (20) regulate apoptosis