Cell Pathology Flashcards
Why would a death need to be reported to the coroner?
Is the cause of death is: Unknown Not seen a doctor in >14 days Violent/ suspicious Accidental (even if years later) Due to neglect by others Due to industrial disease Due to abortion During operation Suicide (even if suspicious) During/ after police detention Poisoning
What are the reasons for conducting a hospital autopsy?
1) Audit major discrepancies between stated COD and actual COD
2) Monitoring effects of new treatments
3) Teaching
4) Research
What consent is needed for a hospital autopsy?
Consent of next of kin.
With consent, tissue can be taken and used from the body for research etc
What consent is needed for a coroner’s autopsy?
No consent needed (although families wishes considered)
Material can only be taken if coroner gives permission and it is needed to establish cause of death.
List 4 causes of sudden unexpected death in the community
1) Cardiovascular disease
2) Vascular system (e.g. ruptured aortic aneurism)
3) Central nervous system (e.g. Berry aneurism, intracerebral haemorrhage (stroke) or epilepsy)
4) Respiratory system (e.g. Pulmonary embolus, asthma, bleeding ulcers or pancreatitis)
5) Not natural (e.g. drugs, alcohol or trauma)
What is a contusion? What would cause one?
A bruise.
It is an extravasated collection of blood which has leaked from small arteries, venules and veins but not capillaries. Takes hours-days to form. May be patterned or deep. Caused by a blunt trauma injury.
Cannot age a bruise as can bruise after death
What is an abrasion? What mechanism of injury would cause an abrasion?
A graze/scratch.
Superficial blunt trauma confined to the epidermis (may extend to superficial dermis). can occur before or after death.
Due to tangential force (distal skin tag occurs) or vertical force (no tag)
e.g. friction burn, car radiator, flooring, whip, stamp
What is a laceration? What mechanism of injury would cause an abrasion?
Split to skin (caused by blunt force trauma over stretching the skin).
Deep (full thickness). Bleeds. Margins ragged and crushed/ bruised.
Common where skin can be compressed between force and bone (scalp, elbow, shin). Rare over soft fleshy areas (buttocks, breasts)
Flaying- tangentially applied force → horizontal laceration (difficult to identify the object causing it)
What are the causes of cell injury? (8)
1) Oxygen deprivation
2) Chemical agents
3) Infectious agents
4) Immunological reactions
5) Genetic defects
6) Nutritional imbalances
7) Physical agents
8) Ageing
What is lethal injury?
Causes cell death
What is sub-lethal injury?
Produces injury not amounting to cell death. It may be reversible or progress to cell death
What does cellular response to an injurious stimuli depend on? (3)
1) The type of injury
2) It’s duration
3) It’s severity
What four intracellular systems are particularly vulnerable to cell injury?
1) Cell membrane integrity
2) ATP generation
3) Protein synthesis
4) Integrity of the genetic apparatus
What is atrophy? Give an example
Shrinkage in the size of the cell (or organ) by the loss of cell substance
e.g. dementia
What is hypertrophy?
An increase in the size of cells and consequently an increase in the size of the organ.
It can by physiological or pathological. Caused either by increased functional demand or by specific hormone stimulation
What is hyperplasia?
An increase in the number of cells in an organ. Can be physiological or pathological.
Physiological hyperplasia can be either hormonal or compensatory
Pathological hyperplasia is usually due to excessive hormonal or growth factor stimulation
What is metaplasia?
The reversible replacement of one differentiated cell type with another differentiated cell type
What is dysplasia?
An abnormality of development; in pathology, alteration in size, shape and organisation of adult cells.
Precancerous cells which show the genetic and cytological features of malignancy but not invading the underlying tissue
What types of cell adaptation are reversible?
- Hypertrophy and hyperplasia
- Atrophy and involution
- Metaplasia
What types of cell adaptation are irreversible?
- Apoptosis
- Necrosis
What is apoptosis?
A process of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death
What is necrosis?
A form of cell injury which results in the premature death of cells in living tissue by autolysis
What is necroptosis?
A programmed execution of cell death. It is favoured in certain circumstances, such as aiding targeting of pathogens by the immune system
What is acute inflammation?
Transient and early response. Release of chemical mediators. Typical vascular and leucocyte response.
NOT the same as infection
What is chronic inflammation?
Inflammation of prolonged duration (weeks to years). usually due to persistence of injury-causing agent.
Active inflammation, tissue destruction and attempts at repair occur simultaneously
What is granulomatous inflammation?
A specialised form of chronic inflammation
What are the cardinal signs of inflammation?
1) Rubor (redness)
2) Calor (heat)
3) Tumor (swelling)
4) Dolor (pain)
5) Loss of function
What causes calor in inflammation?
Histamine-mediated vasodilation
What causes tumor in inflammation?
Oedema and histamine
What is histamine?
A vasoactive amine produced by mast cells.
Pre-formed and released cell degranulates. Degranulation triggered by cell surface IgE antibody interactions with antigen
Leads to vasodilation and increased vascular permeability
Dysregulation in allergy (Type 1 hypersensitivity)
What cells are predominant in acute phase inflammation?
Neutrophils
What are the three phases of an inflammatory response? Which cells are present in each phase?
Acute phase (neutrophils) Chronic phase (monocytes/ macrophages/ lymphocytes/ plasma cells) Resolution/ Repair (macrophages/ fibroblasts)
What causes chronic inflammation?
Persistent infection (HCV, TB) Prolonged exposure to toxic agent (uric acid) Autoimmunity Foreign body (splinter)
What is the basic pathology of granulomatous inflammation?
Cluster of macrophages
Involves specific immune reaction T cells
What are the causes of granulomatous inflammation?
Infection (TB, fungal)
Foreign material
reaction to tumours
Immune diseases (sarcoid, Crohn’s)
What are the benefits of an inflammatory response?
Removal of causative agent
Cessation of the inflammatory reaction
Healing of tissue damage to preserve integrity and function (resolution)
What are the negative local effects of inflammation?
Can cause excess local tissue damage and scarring
Secondary effects on nearby tissue (e.g. bronchoconstriction in asthma)
What are the negative systemic effects of inflammation?
Can evolve into systemic inflammatory reaction and secondary multi-organ failure (e.g. septic shock, amyloid)
What is wound healing?
Parenchymal cell regeneration and resolution
repair by connective tissue and scar tissue formation
What is resolution in terms of wound healing? When does it occur?
Tissue architecture returns to normal
Only occurs if:
- Tissue contains cells able to regenerate to replace lost cells (e.g. liver)
- Little structural damage is done- cells need a framework to build on (basement membrane e.g. lung in lobar pneumonia)
What is repair in terms of wound healing? What are the important components of repair?
If tissue loss is too great and cells are unable to regenerate normal tissue is replaced with scar tissue
Fibroblasts- produce collagen
Collagen- strong “scar” type collagen
Remodelling- reorientation of collagen fibres for maximal tensile strength
What general and local factors hinder repair?
General
- Poor nutrition (require protein for collagen production and energy for cell function)
- Vitamin deficiency (Vit C- needed by fibroblasts to make collagen. Vit A- required for epithelial regeneration)
- Mineral deficiency (e.g. zinc)
- Suppressed inflammation (e.g. by steroids, old age, diabetes)
Local
- Poor blood supply (e.g. ischaemic leg ulcers)
- Persistent foreign body (e.g. splinter)
- Movement (e.g. across a fracture site- need for a cast)
What complications can occur in wound healing?
- Keloid formation (excess collagen deposition)
- Contractures (fibrous scar tissue contracts as it matures. If scarring occurs across a joint it can cause poor joint mobility
- Impaired organ function (e.g. fibrous scars in the myocardium after a heart attack)