2 Cell injury I test PDF

HOMEOSTASIS 1445 – Dentistry – Path310 (STEADY STATE)...

HOMEOSTASIS 1445 – Dentistry – Path310 (STEADY STATE) Cellular Responses to Stress ‫حالة مستقرة‬ Types of cell injury: GENERAL PATHOLOGY LECTURE 2 Cell Injury -1 ⚫ Within certain limits [mild] injury is ⚫ Homeostasis: The cells are ACTIVE participants in their reversible…… and cells return to normal. environment [surroundings, ECF etc.] is any self-regulating Department of Pathology, extracemarani process by which BUT, Severe or persistent stress results in me Colleges of Medicine / Dentistry, ⚫ Taibah University, Constantly adjusting their structure and function biological systems tend to maintain stability while irreversible injury and death of the affected Al Madinah Al Munawarrah. to the changing demands and stresses, cells. adjusting to conditions that permement both from inside and outside. are optimal for survival. ⚫ irrigularmembrane swelling organelis ii d amaged compelete cell lie 2 i s Causes of Cell Injury i.eorenisorgane i 1 ceermemnt.su 1. Oxygen deprivation (Hypoxia / Ischaemia) detotheca 2. Physical (Trauma, burns, frost, radiations) 3. Chemical Agents and Drugs (Glucose, O2, poisons, Alcohol) 4. Infectious Agents (Viruses to tapeworms) 3 5. Immunologic Reactions {External / internal (Autoimmune)} 6. Genetic Derangements (Down syndrome, Sickle cell anaemia) 7. Nutritional Imbalances (Marasmus to obesity /atherosclerosis) 8. sina.in Aging: (Diminished ability of cells to respond to stress) I.EE II FACTORS: week what do cellwill Reversible v/s Irreversible injury ADAPTATION ⚫ Nature of stress [physical, chemical, radiation] Reversible functional and structural responses to: ⚫ Degree of stress [mild, moderate, severe] Northalhaert 1. Severe physiologic stresses. AND several other variables….. 2. Some pathologic stimuli. ▪ Cellular metabolism [Brain & heart v/s soft tissue] a This is a NEW, but altered steady state, so that ▪ Blood supply [Face v/s feet; Young v/s Old] the cell can survive and continue to function ▪ Nutritional status [Rich European v/s poor African] stressed heart  Physiologic hypertrophy of the uterus Adaptation Types 1: Hypertrophy during pregnancy ⚫ An increase in the size of cells, leading to an fiIigiuinf Atrophy, Hyperplasia, Hypertrophy, Metaplasia. increase in the size of the organ. niss.EaF.in 2agicd ⚫ The hypertrophied organ has NO NEW CELLS, just larger cells (due to the synthesis of more structural components) wire.no i.mi.y ⚫ BUT some cells capable of dividing …may increase in size and number also. site maybePnumber hyperplasiaJonypertrophy 2: Hyperplasia 2A: Physiological Hyperplasia ⚫ Increase in the number of cells which results in a) Hormonal hyperplasia (e.g. Breast – Puberty & Pregnancy) increase in the size of the organ… in Hyperplasia and hypertrophy are different, BUT frequently they occur together, and they may be b) És IT a) Compensatory hyperplasia (e.g. Organ Donation Left Normal heart caused by the same external stimulus. Center Hypertrophied heart Right Hypertrophied and dilated heart [HEART FAILURE] For Example: in Pregnant Uterus both occur, but hypertrophy is more pronounced. www.ewanmiayia THE 2B: Pathological Hyperplasia Endometrial hyperplasia 3: Atrophy ⚫ Excesses of hormones or growth factors ⚫ Decrease in cell size and number, leading to acting on target cells. reduced size of an organ or tissue ⚫ Endometrial hyperplasia is an example of ⚫ Physiologic – Thyroglossal duct abnormal hormone-induced hyperplasia. Uterus (post-partum) me – ⚫ Pathological ⚫ Pathologic hyperplasia may lead to cancers. – disuse, denervation, ischaemic, malnutrition wants.ua I Normal UP normal  BRONCHIAL MUCOSA Oesophageal 4: Metaplasia REVERSIBLE INJURY ing Mucosa I ⚫ Metaplasia is a reversible change in which one Normal Many types, but TWO are most important..... differentiated cell type (epithelial or mesenchymal) is replaced by another cell type. ima 1. Cellular Swelling: Barrett’s 1. Columnar epithelium to Squamous epithelium: occurs in habitual Oesophagus [ we will study at cellular and organ levels ] cigarette smokers. Metaplasia 2. Squamous epithelium to Columnar epithelium in patient with gastro- 2. Fatty change: [Next lecture]. oesophageal acid reflux [GERD=gastro-esophageal reflux disease] 3. Soft tissue to Bone formation s.ie awxaiw Cellular Swelling -1 Cellular Swelling Cellular Swelling ⚫ Cell swelling is an early change that occurs in most types of MICROSCOPY [Kidney] Gross examination [at organ level]: acute cell injury 1. Eosinophilia is Normal kidney tubules PATHOGENESIS: Due to decreased energy [ATP] → Fluid w.it ⚫ and ion balance is not maintained [Sodium pump failure] → 2. Membrane blebbing The organ [for example: Liver] is….. Cellular swelling 3. Loss of cilia ⚫ Enlarged is ⚫ Also called……… 4. Degrading of tubules ⚫ Pale 1. Hydropic change [but basement ⚫ Firm 2. Hydropic degeneration memberane intact] ⚫ Heavy 3. Vacuolar degeneration 5. Nuclei intact, slightly 4. Cellular edema narrow [pyknotic] re.sn