Q11

What are the differences between hyperplasia and hypertrophy?
Prompt: What are the differences at a cellular level?

  • Hyperplasia
    • increase in number of cells in organ/tissue
    • usually resulting in increase in volume
    • occurs if cellular population capable of synthesising DNA thus permitting mitotic division.
  • Hypertrophy
    • increase in size of cells
    • causes increase in size of organs.
  • Hypertrophy and hyperplasia often co-exist.

Pass criteria:

  • 2 out of 3 to pass

Describe the different types of hyperplasia and give an example of each?

  • 1 Physiologic: Hormonal, Compensatory.
  • 2 Pathological
  • Hormonal stimulation excessive e.g. oestrogen and effect on uterus, benign prostatic hypertrophy caused by androgens
  • Growth factors e.g. proliferation of connective tissue cells and blood vessels in aiding wound repair

Q12

What is apoptosis?
Prompt: What are the features at a cellular level?

  • Pathway of cell death.
  • Induced by tightly regulated intracellular programme
  • Cells that are destined to die activate enzymes that degrade the cells’ own nuclear DNA and nuclear/cytoplasmic proteins.
  • The cell’s plasma membrane remains intact.
  • Apoptotic cell becomes target for phagocytosis.
  • Dead cell rapidly cleared before contents leak out so this does not elicit an inflammatory reaction in the host.
  • Cell shrinks

Pass criteria:

  • 3 out of 6 including bold

Describe the physiologic situations where apoptosis occurs?

  • Programmed destruction of cells during embryogenesis.
  • Hormone dependent involution in adult such as endometrial breakdown.
  • Cell deletion in proliferating cell populations e.g. intestinal crypt cells.
  • Death of host cells that have served their purpose e.g. neutrophils in acute inflammation.
  • Elimination of potentially harmful self-reactive lymphocytes.
  • Cell death induced by cytotoxic T cells.

Pass Criteria:

  • 2 out of 6

Q13

What are the phases involved in scar formation?
Prompt: One phase is fibroblast migration and proliferation. Can you name another phase?

  1. Fibroblast migration and proliferation
  2. Extracellular matrix (ECM) deposition
  3. Tissue remodelling

Pass criteria:

  • 2 out of 3

What are the local triggers of fibroblast migration and proliferation (at the site of an injury)?
Prompt: Can you name a growth factor / cytokine involved.

  1. Growth Factors- TGF-beta; PDGF; EGF; FGF;
  2. Cytokines – IL-1; TNF

Pass Criteria:

  • 2 to pass

What are the sources of these local triggers?
Prompt: Which blood cells or constituents are involved? Platelets are one example. Can you give another?

  1. Platelets
  2. Macrophages and other inflamm cells such as mast cells, eosinophils, lymphocyte
  3. Endothelium

Pass criteria:

  • 2 to pass

Q14

What are the differences between hyperplasia and hypertrophy?
Prompt: What are the differences at a cellular level?

  1. Hyperplasia
    • Increase in number of cells in organ/tissue
    • Usually resulting in increase in volume
    • occurs if cellular population capable of synthesising DNA thus permitting mitotic division.
  2. Hypertrophy
    • Increase in size of cells
    • Causes increase in size of organs.
  3. Hypertrophy and hyperplasia often co-exist.

Pass criteria: 2/3 to pass

Describe the different types of hyperplasia and give an example of each.

  • Physiologic:
    • Hormonal
    • Compensatory.
  • Pathological
    • Hormonal stimulation excessive e.g. oestrogen and effect on uterus, benign prostatic hypertrophy caused by androgens
    • Growth factors e.g. proliferation of connective tissue cells and blood vessels in aiding wound repair.

Pass criteria: Need basic classification to pass

 


Q15

What is atrophy?

  • Shrinkage in the size of the cell by loss of cell substance

Pass criteria:

  • Placental ischaemia PLUS 1 other point

What are the pathological types of atrophy?
Prompt: What are the causes?

  • Disuse
  • Denervation
  • Diminished blood supply
  • Inadequate nutrition
  • Loss of endocrine stimulation
  • Ageing
  • Pressure

Pass Criteria:

  • At least 4

Give some examples of atrophy?

  • Fracture disuse
  • Damage to nerves causing muscle atrophy
  • Breast/reproductive organs from oestrogen lack.

Pass criteria:

  • 2 to pass

Q16

What is hypertrophy?

  • Increase in the size of the cells, due to synthesis of more structural components, resulting in an increase in the size of the organ (no new cells, just larger cells)
  • Physiological or pathological in response to increased functional demand or specific hormonal stimulation
  • Can occur in both dividing and non-dividing cells

Pass criteria:

  • Bold to pass

What are the types of hypertrophy?

  • Physiological
  • Pathological

Pass Criteria:

  • Both to pass

Give examples of physiologic and pathologic hypertrophy?

  • Physiologic: Enlarged skeletal muscles in labourers (workload), Enlarged uterus in pregnancy (hormonal), Enlarged breasts in lactation
  • Pathological: Enlarged prostate in BPH, Enlarged heart in valve disease or chronic hypertension (workload)

Pass criteria:

  • 1 example of each

Q17

What is reperfusion injury?

  • Further injury to ischaemic tissue that occurs after restoration of blood flow

What are the proprosed mechanisms of reperfusion injury?

  • Oxygen free radicals
  • Mitochondrial permeability transition.
  • Inflammation: cytokine production and increased expression of adhesion molecules, recruitment polymorphs
  • Complement pathway activation

Pass Criteria:

  • 2 out of 4 to pass

Q18

What is apoptosis?

  • Programmed cell death

Under what conditions may apoptosis occur?

  • Physiological:  embryogenesis, hormone-dependent involution in adult, cell deletion, elimination of potentially harmful self-reactive lymphocytes, cell death induced by cytotoxic T cells
  • Pathological:  cell death secondary to radiation injury or cytotoxins, viral hepatitis, pathologic atrophy after duct obstruction in pancreas, parotid or kidney, cell death in tumours.

Pass Criteria:

  • Must be able to give at least one example of each group to pass

What happens at a cellular level?

  • Cell shrinkage
  • Chromatin condensation
  • Formation of cytoplasmic blabs and apoptotic bodies
  • Phagocytosis of apoptotic cells or cell bodies, usually by macrophages.

Q19

Describe the morphological changes seen in cells with reversible ischaemia?

Cellular swelling: failure to maintain ionic and fluid homeostasis; organelles become swollen;

  • Plasma membrane alterations
  • Mitochondrial changes
  • Distended segments of ER; ‘vacuolar’ degeneration.
  • Nuclear alterations.
  • Fatty change: lipid vacuoles in cytoplasm.

Pass criteria:

  • Bold PLUS 2 others

What metabolic changes occur in reversible ischaemia?

  • Depletion of ATP –> sodium pump reduction –> swelling,  Na into cells.  Increased. catabolites in cells –> increased. osmotic load –> swelling.
  • Anaerobic metabolism. –> lactic acidosis, decreased pH.
  • Detachment of ribosomes from ER –> decreased protein synthesis

Pass Criteria:

  • 2 out of 3 to pass

Q20

Describe the vascular response in acute inflammation.

  • Changes in vascular flow and caliber:-> transient constriction –> dilation –> heat and redness.
  • Increased vascular permeability: -> slowing of circulation, hemoconcentration –> stasis –> leucocyte margination, adherence to endothelium -> oedema

What are the mechanisms of increased vascular permeability in acute inflammation?

  • Vascular leakage
    • Endothelial contraction;
    • cytoskeletal reorganisation;
    • direct injury;
    • leucocyte injury;
    • increased. transcytosis

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