Abnormal Growth

Nota:

• Adaptation is the cellular response to prolonged stress:

1. Reversible
   1. Atrophy

      Nota:

      • Atrophy: Decreased size of cell
      1. Brain

         Nota:

         • Cell shrinkage may lead to cellular death. The neurones are replaced by glial support 
   2. Hyperplasia and Hypertrophy

      Nota:

      • Hyperplasia: Increased in number of cells Hypertrophy: Increased size of cells
      1. Cardiac Myocyte
      2. Pathological Hyperplasia

         Nota:

         • Examples include: Nodular prostatic hyperplasia Graves' Disease
      3. Nodular Prostatic Hyperplasia

         Nota:

         • Extremely common, 90% males increase in frequency and severity from 40 years old. Proliferation of both epithelial glands and stroma. Caused by excessive androgens DHT (dihydrotestosterone) Exacerbated by smooth muscle contraction (A1 adrenergic)
         1. Macroscopic

            Nota:

            • Nodular Enlargement of Glands (solid or cystic) Predominantly periurethral Urethra compressed-slitlike.
         2. Microscopic

            Nota:

            • proliferating glands and stroma Glands lined by tall columnar epithelial cells and flattened basal cells Papillary infolding.
         3. Clinical Features

            Nota:

            • Prostatism: Obstruction, difficulty starting, interruption of stream Irritable bladder: Urgency, frequency, nocturia Urinary retention, UTI and renal impairment Complication: Hydronephrosis
         4. Complications

            Nota:

            • Obstructive nephropathy, tissue damage, such as hydroureter, hydronephrosis and maybe pyonephrosis.
         5. Treatment

            Nota:

            • Drugs: Inhibit DHT formation Alpha adrenergic blockers. Surgery
   3. Metaplasia

      Nota:

      • Metaplasia: Replacement of cellular type
      1. Oesophagus

         Nota:

         • Acid reflux in the stomach  Gives chronic irritation, tissue stem cells change gene and protein expression, however may increase risk for neoplasia.
2. Irreversible
   1. Neoplasia
3. Capacity

   Nota:

   • Different cells have differing capacity to undergo proliferation Cell types: Continuously dividing cells: Tissue stem cells, surface epithelia, lining of ducts of excretory glands Quiescent Cells (stable tissue) G0 state... Can go to G1 to divide further Nondividing cells (permanent tissues): Neurons, skeletal muscle, cardiac muscles goes into hypertrophy and atrophy.

Nota:

• Acute inflammation: Vasodilation, increased vascular permeability, vascular congestion. Neutrophils, macrophages. Haemostasis: Coagulation cascade Chronic inflammation: Persistent injury, inflammation, macrophages, lymphocytes, plasma cells, Repair. Repair: Granulation tissue

Nota:

• More of irreversible injury and death

1. Decreased Growth

   Nota:

   • Physiological: Hormonal, decreased workload, age Pathological: Ischaemia, nutritional deficiency, withdrawal of hormonal support, denervation
2. Increased Growth

   Nota:

   • Physiological: Hormonal, physiological stressors Pathological: Cell injury secondary to disease which increase functional demand or results in hormonal imbalance.