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Healing and Repair - Pathology (view source)
Revision as of 16:32, 25 July 2011
, 16:32, 25 July 2011no edit summary
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==Introduction==
==Introduction==
* There are several factors on which the ability to heal and repair depends:
* There are several factors on which the ability to heal and repair depends:
*# '''Species'''
*# '''Species'''
==Repair==
==Repair==
* Repair occurs through one of two mechanisms:
* Repair occurs through one of two mechanisms:
** '''Regeneration'''
** '''Regeneration'''
===Regeneration===
===Regeneration===
* In mammals, only epithelial and connective tissues regenerate extensively.
* In mammals, only epithelial and connective tissues regenerate extensively.
* The ability of tissue to regenerate depends upon whether the tissue is
* The ability of tissue to regenerate depends upon whether the tissue is
====Labile Tissues====
====Labile Tissues====
* Labile tissues constantly replenish their cells throughout life.
* Labile tissues constantly replenish their cells throughout life.
** For example skin and mucous epithelia normally desquamate their outer layer of cells during life, maintaining their overall composition by division of their basal layers.
** For example skin and mucous epithelia normally desquamate their outer layer of cells during life, maintaining their overall composition by division of their basal layers.
====Stable Tissues====
====Stable Tissues====
* Stable tissues have a limited ability to replace themselves.
* Stable tissues have a limited ability to replace themselves.
* They retain the ability to
* They retain the ability to
====Permanent====
====Permanent====
* Permanent tissues have poor or no regenerative capacity.
* Permanent tissues have poor or no regenerative capacity.
* This group includes tissues in which the cells are highly specialised and generally have only one function, for example:
* This group includes tissues in which the cells are highly specialised and generally have only one function, for example:
===Replacement===
===Replacement===
* Replacement is essentially endothelial and fibrous tissue proliferation to replace severely damaged tissue.
* Replacement is essentially endothelial and fibrous tissue proliferation to replace severely damaged tissue.
** This classical dual replacement gives rise to granulation tissue.
** This classical dual replacement gives rise to granulation tissue.
==Repair in the Skin==
==[[Skin Repair|Repair in the Skin]]==
==[[Fractures|Repair in the Bones]]==
==Repair in the Respiratory Tract==
==Repair in the Respiratory Tract==
* Severe damage to the alveolar wall results in fibrous tissue organisation of the entire alveolus.
* Severe damage to the alveolar wall results in fibrous tissue organisation of the entire alveolus.
* The appearance of inflammation in the respiratory tract varies with the route of entry of the agent.
* The appearance of inflammation in the respiratory tract varies with the route of entry of the agent.
===Airborne Agents===
===Airborne Agents===
* Infectious droplets tend to deposit in the anterior ventral portions of the lobes.
* Infectious droplets tend to deposit in the anterior ventral portions of the lobes.
** I.e. in the apical, cardiac and anterior portions of the diaphragmatic lobes.
** I.e. in the apical, cardiac and anterior portions of the diaphragmatic lobes.
* Airborne agents produce '''bronchopneumonia'''.
* Airborne agents produce [[Bronchopneumonia|'''bronchopneumonia''']].
** So-called because the inflammation is initiated and centred upon the airways.
** So-called because the inflammation is initiated and centred upon the airways.
* The usual appearance of bronchopneumonia in ruminants and the pig is as the name suggests.
* The usual appearance of bronchopneumonia in ruminants and the pig is as the name suggests.
*** Air trapped distal to the blockage is gradually absorbed into the bloodstream.
*** Air trapped distal to the blockage is gradually absorbed into the bloodstream.
**** This causes increased pressure on the injured wall, dilating it further.
**** This causes increased pressure on the injured wall, dilating it further.
*** This is a progressive process and results in irreversible dilatation of the airway lumen and is called '''bronchiectasis'''.
*** This is a progressive process and results in irreversible dilatation of the airway lumen and is called [[Bronchiectasis|'''bronchiectasis''']].
* Bronchopneumonia in the dog and cat often tends to be more diffusely spread.
* Bronchopneumonia in the dog and cat often tends to be more diffusely spread.
** These species have a poorly-developed interlobular septum and collateral ventilation between alveoli from different respiratory units.
** These species have a poorly-developed interlobular septum and collateral ventilation between alveoli from different respiratory units.
===Blood-borne Agents===
===Blood-borne Agents===
* Blood-bourne agents tend to have a patchy distribution throughout the lung.
* Blood-bourne agents tend to have a patchy distribution throughout the lung.
* Cause '''interstitial pneumonia'''.
* Cause [[Interstitial Pneumonia|'''interstitial pneumonia''']].
====Circulating Toxins====
====Circulating Toxins====
* For example, [[Acute Bovine Pulmonary Emphysema and Oedema|"Fog Fever"]] in adult cattle.
* For example, "Fog Fever" in adult cattle.
** Interstitial emphysema.
** Interstitial emphysema.
** 3-methyl indole is selectively toxic to Type 1 alveolar epithelium.
** 3-methyl indole is selectively toxic to Type 1 alveolar epithelium.
====Micro-organisms====
====Micro-organisms====
* A predominantly mononuclear reaction in the alveolar wall can be caused by:
* A predominantly mononuclear reaction in the alveolar wall can be caused by:
** Viruses
** Viruses
*** E.g. [[Salmonella|''Salmonella'']]
*** E.g. [[Salmonella|''Salmonella'']]
** Protozoa
** Protozoa
*** E.g. [[Toxoplasma]]
*** E.g. ''[[Toxoplasma gondii]]''
====Parasites====
====Parasites====
* Lungworms (''Dictyocaulus vivipara'') tend to affect the dorsocaudal areas of the diaphragmatic lobes in their invasion stage as larvae in the blood.
* Lungworms (''Dictyocaulus vivipara'') tend to affect the dorsocaudal areas of the diaphragmatic lobes in their invasion stage as larvae in the blood.
* Later adult stages irritate the airways and also release larvae which are inhaled deeper into the lung.
* Later adult stages irritate the airways and also release larvae which are inhaled deeper into the lung.
===Traumatic Implantation===
===Traumatic Implantation===
* Traumatic implantation is fairly rare.
* Traumatic implantation is fairly rare.
* Initially causes a pleural inflammation, with some extension to the adjacent lung tissue.
* Initially causes a pleural inflammation, with some extension to the adjacent lung tissue.
** Stake wounds in horses.
** Stake wounds in horses.
*** Usually fatal and cause extensive purulent, smelly inflammation.
*** Usually fatal and cause extensive purulent, smelly inflammation.
** Purulent pleuritis in dogs and cats due to [[:Category:Nocardia||''Nocardia'']] from a distant wound.
** Purulent pleuritis in dogs and cats due to ''[[:Category:Nocardia species]]'' from a distant wound.
*** Not uncommon in cats.
*** Not uncommon in cats.
*** May take some time to develop fully after the initial wound or cause has healed.
*** May take some time to develop fully after the initial wound or cause has healed.
==Repair in the Alimentary Tract==
==Repair in the Alimentary Tract==
===The Gut===
===The Gut===
* The gut is quite prone to infections.
* The gut is quite prone to infections.
** These are generally kept at bay by the profuse gut associated lymphoid tissue and the continuous movement of ingesta.
** These are generally kept at bay by the profuse gut associated lymphoid tissue and the continuous movement of ingesta.
*** There is a reduced water absorption compounded by loss of electrolytes - '''malabsorption'''.
*** There is a reduced water absorption compounded by loss of electrolytes - '''malabsorption'''.
**** Results in diarrhoea and progressive loss of weight.
**** Results in diarrhoea and progressive loss of weight.
**** E.g. in [[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's Disease]].
**** E.g. in [[Johne's Disease|Johne's Disease]].
===The Liver===
===The Liver===
* The [[Liver - Anatomy & Physiology|liver]] retains limited powers to regenerate and has considerable functional reserve.
* The [[Liver - Anatomy & Physiology|liver]] retains limited powers to regenerate and has considerable functional reserve.
* Acute inflammation is often due to viruses and bacteria.
* Acute inflammation is often due to viruses and bacteria.
** E.g. Infectious Canine Hepatitis and [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Salmonellosis|Salmonellosis]] in young livestock.
** E.g. Infectious Canine Hepatitis and [[Salmonellosis|Salmonellosis]] in young livestock.
** The [[Liver - Anatomy & Physiology|liver]] is swollen and may display hyperaemia.
** The [[Liver - Anatomy & Physiology|liver]] is swollen and may display hyperaemia.
** Small pinpoint foci of necrosis may be seen through the surface.
** Small pinpoint foci of necrosis may be seen through the surface.
===The [[Pancreas - Anatomy & Physiology|Pancreas]]===
===The [[Pancreas - Anatomy & Physiology|Pancreas]]===
* The [[Pancreas - Anatomy & Physiology|pancreas]] suffers both acute and chronic disease.
* The [[Pancreas - Anatomy & Physiology|pancreas]] suffers both acute and chronic disease.
* The acute form called acute pancreatic necrosis is the important type in dogs.
* The acute form called acute pancreatic necrosis is the important type in dogs.
==Repair in the Urinary Tract==
==Repair in the Urinary Tract==
* The kidney has a great functional reserve.
* The kidney has a great functional reserve.
** Only 30% of the tissue is required to function properly.
** Only 30% of the tissue is required to function properly.
===Glomerulonephritis===
===Glomerulonephritis===
* Glomerulonephritis and glomerular deposition of amyloid may cause loss of substantial quantities of protein into the urine.
* Glomerulonephritis and glomerular deposition of amyloid may cause loss of substantial quantities of protein into the urine.
* Oedema develops in the body, generally first in the back legs, then the ventral subcutis, and perhaps in the abdominal cavity.
* Oedema develops in the body, generally first in the back legs, then the ventral subcutis, and perhaps in the abdominal cavity.
===Pyelonephritis===
===Pyelonephritis===
* Important in the cow and sow.
* Important in the cow and sow.
** It tends to be quite acute in the sow, and chronic in the cow.
** It tends to be quite acute in the sow, and chronic in the cow.
* Arises from infection ascending the urinary tract.
* Arises from infection ascending the urinary tract.
* There is progressive loss of tissue.
* There is progressive loss of tissue.
** Starts with necrosis in the pelvic area, then the inflammation spreads up into the cortex. *P oor prognosis even with therapy.
** Starts with necrosis in the pelvic area, then the inflammation spreads up into the cortex.
*Poor prognosis even with therapy.
===Cystitis===
===Cystitis===
* Bladder inflammation.
* Bladder inflammation.
* Common in females.
* Common in females.
==Repair in the Genital Tract==
==Repair in the Genital Tract==
===Female===
===Female===
* '''Inflammation of the uterus''' in livestock can take place at two periods:
* '''Inflammation of the uterus''' in livestock can take place at two periods:
*# At service.
*# At service.
**# Chronic mastitis.
**# Chronic mastitis.
**#* Results in progressive destruction of the glandular tissue and replacement by fibrous tissue.
**#* Results in progressive destruction of the glandular tissue and replacement by fibrous tissue.
**#* E.g. [[Streptococcal mastitis - bovine|''Streptococcus agalactiae'']].
**#* E.g. [[Streptococcal Mastitis - Cattle|''Streptococcus agalactiae'']].
** Some organisms such as [[Staphylococcus aureus|''Staphylococcus aureus'']] can cause gangrenous, acute and chronic mastitis.
** Some organisms such as [[Staphylococcus aureus|''Staphylococcus aureus'']] can cause gangrenous, acute and chronic mastitis.
===Male===
===Male===
* '''Prostatitis'''
* '''Prostatitis'''
** Inflammation of the prostate.
** Inflammation of the prostate.
==Repair in the Central Nervous System==
==Repair in the Central Nervous System==
* '''Encephalitis'''
* '''Encephalitis'''
** Inflammation of neural tissue of the brain.
** Inflammation of neural tissue of the brain.
** Inflammation of the meninges.
** Inflammation of the meninges.
** Purulent meningitis follows haematogenous spread of infection from umbilical infections and certain septicaemias.
** Purulent meningitis follows haematogenous spread of infection from umbilical infections and certain septicaemias.
[[Category:Inflammation|B]]
[[Category:General Pathology]]