Cell Injury, Adaptations, and Death I and II

Question 1

what type of stimuli can cells/organs respond to?

Answer 1

physiologic stimuli/stress (response of cells to normal stimuli ex. hormones during pregnancy); pathologic stimuli/stress (cells modify structure or function to decrease or avoid injury or death)

Question 2

Proliferative capacities of tissues…what are the three groups of proliferative tissues?

Answer 2

• continuoulsy dividing cells (labile; hematopoietic cells, surface epithelia- ex. linings of upper airways, GI tract, skin)
• stable tissues (quiescent; liver, kidney pancreas, endothelia cells, fibroblasts, smooth muscle cells)
• permanent tissues (neurons and cardiac muscle cells)

Question 3

hypertrophy

Answer 3

increase in size of cells=increase of size of organ; increased amounts of proteins and organelles.
occurs in cells that have limited or no capacity to divide.

Question 4

what are some examples of physiologic/pathologic hypertrophy?

Answer 4

physiologic: increased functional demand or hormonal stimulation ex. skeletal muscle hypertrophy in weight lifting athlete and uterus in pregnancy
pathologic: ex. cardiac muscle hypertrophy seen in hypertension, aortic valve stenosis

Question 5

hyperplasia

Answer 5

increase in cell number; occurs in cells capable of division (labile and stable cells)

Question 6

what are some examples of physiologic/pathologic hyperplasia?

Answer 6

physiologic: ex. hormonal hyperplasia of female breast in puberty and in pregnancy; compensatory hyperplasia of liver after partial resection; connective tissue response with wound healing
pathologic: excessive stimulation by growth factors or hormones; ex. hormonal imbalance stimulates endometrial hyperplasia-reversible. cells respond to normal regulatory mechanisms. Clinical significance-increases risk for cancer; another example: benign prostatic hyperplasia (BPH)-different than endometrial hyperplasia in that it is not associated with increased risk of prostate cancer; another example: skin warts and mucosal lesions associated with viral infections (papilloma viruses)

Question 7

what is an example in which an organ/tissue can undergo hyperplasia and hypertrophy at the same time?

Answer 7

uterus during pregnancy!

Question 8

atrophy

Answer 8

decrease in size of a cell due to loss of cell substance.
if severe=decreased organ size
decreased protein synthesis and increased degradation
decreased function, but NOT cell death

Question 9

what are some examples of physiologic and pathologic atrophy?

Answer 9

physiologic: loss of hormonal stimulation; ex: endometrium at menopause
pathologic: decreased functional demand (ex. broken arm in cast); loss of innervation (ex. trauma to peripheral nerve); inadequate nutrition (ex. calorie or protein deficit)

Question 10

in which condition can you see both skeletal muscle hypertrophy and atrophy?

Answer 10

myopathy!

Question 11

Metaplasia

Answer 11

• when one adult cell type is replaced by another adult cell type (that is better able to handle the stress)
• adaptive process to chronic stress +/or persistent cell injury (ex. chronic smokers, chronic gastric acid reflux)
• cells are “reprogrammed”
• reversible
• may be associated with risk of cancer

Question 12

epithelial metaplasia

Answer 12

• ciliated columnar epithelium becomes squamous epithelium (ex. trachea/bronchi of smokers)
  
  • stimulus that causes metaplasia may predispose to development of malignant neoplasm *in this case squamous cell carcinoma of lung)
• squamous epithelium becomes gastric/intestinal type epithelium (ex. distal esophagus in those with reflux)
  
  • Barrett Esophagus: protects against reflux of stomach acid (predisposes to development of glandular carcinoma-adenocarcinoma)

Question 13

mesenchymal metaplasia

Answer 13

bone formation in soft tissue (muscle/connective tissue) at sites of injury

Question 14

what are some causes (etiologies) of cell injury?

Answer 14

• oxygen depravation (hypoxia; ischemia)
• physical agents (trauma, temperature extremes, radiation, etc.)
• chemical agents (chemicals-sodium, glucose-, poisons, asbestos, etc.)
• infectious agents (viruses, fungi, bacterial, parasites, etc.)
• immunologic reactions (autoimmune diseases, hypersensitivity)
• genetic derangements (point mutations, polymorphisms)
• nutritional imbalances (protein/calorie imbalance, vitamin and mineral deficiencies, etc.)
• aging (decrease ability to repair damage)

Question 15

what defines irreversible cell damage? and what are two types of irreversible cell death?

Answer 15

inability to reverese mitochondrial dysfunction (lack of oxidative phosphorylation and ATP generation); disturbances of membrane function

necrosis and apoptosis

Question 16

features of necrosis:
cell size?
nucleus?
plasma membrane?
cellular contents?
adjacent inflammation?
physiologic or pathologic role?

Answer 16

cell size=enlarged (swelling)
nucleus=pyknosis, karyorrhexis, karyolysis
plasma membrane=disrupted
cellular contents=enzymatic digestion: may leak out of cell
adjacent inflammation=frequent
physiologic or pathologic role=invariably pathologic

Question 17

features of apoptosis:
cell size?
nucleus?
plasma membrane?
cellular contents?
adjacent inflammation?
physiologic or pathologic role?

Answer 17

cell size=reduced (shrinkage)
nucleus=fragmentation into nucleosome-sized fragments
plasma membrane=intact: altered structure
cellular contents=intact: may be released in apoptotic bodies
adjacent inflammation=NO
physiologic or pathologic role=often physiologic: eliminating unwanted cells; may be pathologic

Question 18

morphology of reversible cell injury?

Answer 18

fatty change; cellular swelling-hydropic change or vacuolar degeneration

Question 19

what are some reasons as to why a fatty liver would develop?

Answer 19

accumulation due to any/all of the following (finish from pg 41/108)