UNIVERSITY OF NAIROBI
COLLEGE OF AGRICULTURE AND VETERINARY SCIENCES
DEPARTMENT OF VETERINARY PATHOLOGY AND
MICROBIOLOGY
SYSTEMIC PATHOLGY: THE ALIMENTARY SYSTEM (class
Notes)
By: DR KARANJA D.N. (PhD, MSc, BVM)
Introduction: The digestive system consists
of a long muscular tube that begins at the
lips and ends at the anus, and certain large
glands (salivary glands, liver, gall bladder
and pancreas) that empty their secretion into
the tube. The latter develop from the same
epithelial lining.
2. MOUTH and PHARYNX/ ORAL
CAVITY
(i) Post mortem changes
These include (i) dryness of exposed parts of
mucus membranes, (ii) contamination by
stomach contents vomited during agonal
period or discharged post mortem, (iii)
impression of teeth on tongue as a result of
rigor mortis affecting the jaws and (iv)
maggots from eggs deposited in open mouth
VPMP- UoN – Dr Karanja Digestive System Notes 1
,whose stage of development may be an
indicator to time of death.
(ii) Malformations
Development of normal face and oral cavity
depends on a large number of embryonic
processes, hence abnormalities are common.
These include:
Cleft lip, jaw and /or palate. Commonly
involve lips in small animals. Cleft lip (hare
lip, chelloschisis) results from disturbances of
jaw and face during embryonic development.
Cleft of the lower lip is rare and occurs in
midline while cleft of upper lip occurs usually
at the junction of the pre-maxilla and
maxilla. Cleft palate (palatoschisis) is
occasionally seen in newborns of all species.
Previously, this malformation was thought to
be hereditary, but more recently, it has been
associated with toxic agents, use of steroids
or viral infections during pregnancy. Cleft lip,
jaw and/ or palate
(cheilognathopalatoschisis) in man is
bilateral with communication between oral
cavity and nasal cavity. Cleft palate and
VPMP- UoN – Dr Karanja Digestive System Notes 2
,arthrogyposis, both hereditary, frequently
occur together in Charolis calves.
Face- aprosopia (absence), ateloprosopis
(defective)
Lips – acheilia (absence), microcheilia
(defective).
Jaw – agnathia (absence), micrognanthia
(faulty development), brachygnathia
(shorter) and prognanthia (longer). Agnathia
always associated with microglossia or
aglossia and snotia (fusion of ears).
Brachygnathia superior (shortened upper jaw
/ maxilla) may be an inherited condition in
dogs and swine. In Jersey cattle, it’s
associated with chondrodysplasia. Its
progressive development leads to mal-
position of incisor and check teeth. In pigs, it
may be confused with atrophic rhinitis.
Shortening of mandibles (Brachygnathia
inferior or micrognathia) is common in calves
(hereditary). Prognathia mostly affect the
mandibles. Malformation is relative and
whether the jaw is absolutely long or nearly
so is not easy to determine. In sheep it may
VPMP- UoN – Dr Karanja Digestive System Notes 3
, develop in animals recovering from calcium
deficiency.
Tongue – aglossia, rare, microglossia more
common, macroglossia (excessive
development) and glossoschisis (cleft
tongue), smooth tongue (absence of
papillae) and curled tongue- tip curled
backwards have been reported in turkeys
and chicken.
Epitheliogenesis imperfecta – just like the
skin, affect stratified squamous epithelium
eg tongue
(iii)Metabolic disturbances
-Atrophy (senility) – normal aging process - in
old age most tissues are gone and tooth
sockets flatten leading to senile loss of teeth.
Atrophy of lingual muscle occur after injury
to nerves
- Vitamin deficiencies
Vitamin A – Exerts a steroid-like effect on
squamous epithelium cause differentiation.
Defeciency, simple type becomes
stratefiedThe epithelium of mucosal surfaces
and glands of mouth, pharynx, tongue,
VPMP- UoN – Dr Karanja Digestive System Notes 4
COLLEGE OF AGRICULTURE AND VETERINARY SCIENCES
DEPARTMENT OF VETERINARY PATHOLOGY AND
MICROBIOLOGY
SYSTEMIC PATHOLGY: THE ALIMENTARY SYSTEM (class
Notes)
By: DR KARANJA D.N. (PhD, MSc, BVM)
Introduction: The digestive system consists
of a long muscular tube that begins at the
lips and ends at the anus, and certain large
glands (salivary glands, liver, gall bladder
and pancreas) that empty their secretion into
the tube. The latter develop from the same
epithelial lining.
2. MOUTH and PHARYNX/ ORAL
CAVITY
(i) Post mortem changes
These include (i) dryness of exposed parts of
mucus membranes, (ii) contamination by
stomach contents vomited during agonal
period or discharged post mortem, (iii)
impression of teeth on tongue as a result of
rigor mortis affecting the jaws and (iv)
maggots from eggs deposited in open mouth
VPMP- UoN – Dr Karanja Digestive System Notes 1
,whose stage of development may be an
indicator to time of death.
(ii) Malformations
Development of normal face and oral cavity
depends on a large number of embryonic
processes, hence abnormalities are common.
These include:
Cleft lip, jaw and /or palate. Commonly
involve lips in small animals. Cleft lip (hare
lip, chelloschisis) results from disturbances of
jaw and face during embryonic development.
Cleft of the lower lip is rare and occurs in
midline while cleft of upper lip occurs usually
at the junction of the pre-maxilla and
maxilla. Cleft palate (palatoschisis) is
occasionally seen in newborns of all species.
Previously, this malformation was thought to
be hereditary, but more recently, it has been
associated with toxic agents, use of steroids
or viral infections during pregnancy. Cleft lip,
jaw and/ or palate
(cheilognathopalatoschisis) in man is
bilateral with communication between oral
cavity and nasal cavity. Cleft palate and
VPMP- UoN – Dr Karanja Digestive System Notes 2
,arthrogyposis, both hereditary, frequently
occur together in Charolis calves.
Face- aprosopia (absence), ateloprosopis
(defective)
Lips – acheilia (absence), microcheilia
(defective).
Jaw – agnathia (absence), micrognanthia
(faulty development), brachygnathia
(shorter) and prognanthia (longer). Agnathia
always associated with microglossia or
aglossia and snotia (fusion of ears).
Brachygnathia superior (shortened upper jaw
/ maxilla) may be an inherited condition in
dogs and swine. In Jersey cattle, it’s
associated with chondrodysplasia. Its
progressive development leads to mal-
position of incisor and check teeth. In pigs, it
may be confused with atrophic rhinitis.
Shortening of mandibles (Brachygnathia
inferior or micrognathia) is common in calves
(hereditary). Prognathia mostly affect the
mandibles. Malformation is relative and
whether the jaw is absolutely long or nearly
so is not easy to determine. In sheep it may
VPMP- UoN – Dr Karanja Digestive System Notes 3
, develop in animals recovering from calcium
deficiency.
Tongue – aglossia, rare, microglossia more
common, macroglossia (excessive
development) and glossoschisis (cleft
tongue), smooth tongue (absence of
papillae) and curled tongue- tip curled
backwards have been reported in turkeys
and chicken.
Epitheliogenesis imperfecta – just like the
skin, affect stratified squamous epithelium
eg tongue
(iii)Metabolic disturbances
-Atrophy (senility) – normal aging process - in
old age most tissues are gone and tooth
sockets flatten leading to senile loss of teeth.
Atrophy of lingual muscle occur after injury
to nerves
- Vitamin deficiencies
Vitamin A – Exerts a steroid-like effect on
squamous epithelium cause differentiation.
Defeciency, simple type becomes
stratefiedThe epithelium of mucosal surfaces
and glands of mouth, pharynx, tongue,
VPMP- UoN – Dr Karanja Digestive System Notes 4
