term 3 Flashcards
pneuamtisided bone in birds
humerus
femur sternum pelvis and cervival and thoratic vertbrae
medulla of boe conbtains airsacks
reduces mass to allow for flight
types of bone
Compact/Cortical bone- Diaphyses of long bones Spongy/Cancellous- bone Epiphyses of long bones Vertebrae Skull Medullary bone- Calcium reservoir Forms c. 2 weeks before laying Formed from endosteum Hormonal control
Pneumatised bone
Bone marrow
medullary bone
found in birds Calcium reservoir Forms c. 2 weeks before laying Formed from endosteum Hormonal control present throught laying period skeletal weight increases medullary bone is reabsorbed polyostoic hyperostosis- found to varying degrees in many species when the female is ovulatory. The calcium storage in bone changes the pneumatic appearance to a solid mineral dense appearing medullary canal. The long bones of the legs are most often affected, and the long bones of the thoracic limbs are also involved in more pronounced cases. In females where the calcium/Vitamin D3 is insufficient, a moth-eaten appearance to these bones often occurs.
polyostoic hyperostosis-
found to varying degrees in many species when the female is ovulatory. The calcium storage in bone changes the pneumatic appearance to a solid mineral dense appearing medullary canal. The long bones of the legs are most often affected, and the long bones of the thoracic limbs are also involved in more pronounced cases. In females where the calcium/Vitamin D3 is insufficient, a moth-eaten appearance to these bones often occurs.
Cartilagenous skeletal template in birds
In adult
Hyaline cartilage at articular surfaces
Intervertebral discs
Menisci
decribe muscle in birds
Muscle bellies proximal
Less connective and adipose tissue cf mammals
Higher muscle fibre density
Basic muscle structure similar
Light (white) muscle-
Higher concentration of muscle fibrils
Less myoglobin & Cytochrome
Fast contraction, rapid fatigue (Fast twitch fibres)
Dark (red) muscle- Fewer myofibrils
More myoglobin
Slow contraction, slow fatigue (Slow twitch fibres)
Intermediate muscle
No diaphragm
Muscles of thoracic and abdominal wall
describe the avian skull and beak
Single occipital condyle Quadrate bone Pterygoid bone Large orbits Scleral ossicle Sole auditory ossicle- Columella, Extracolumella processes
beak- Wide species variability Maxilla- Pre maxillary and maxillary bones Mandible- Laterally flattened 5-6 pairs of fused bones Dental bone Splenial bone Angular bone Supra-angular bone Pre-articular bone Articular bone Mandibular symphysis
Chicken vertebral formula:
C14:T7:L+S 14:Cd4-9
thoratic vertebrae are fused
t7, lumbar, sacral, Cd1 vertebrae fuse to make the synsacrum
Caudal Vertebrae & Pygostyle
Spinal cord extends to last vertebral segments
describe the aviam trunk skeleton
Ribs Sternal & Asternal ribs 7-9 pairs Cartilagenous intercostal joint Uncinate processes Sternum Dorsally concave plate Carina/Keel Joints Atlantooccipital Atlantoaxial Flexible cervical spine T1, T6 Caudal vertebrae/pygostyle
avian Pectoral Girdle
Supports flight Coracoid Scapula Clavicles (fused to make Furcula) Foramen triosseum Muscles
avian thoratic limb
Humerus-Pneumatised Radius Ulna Carpometacarpals Digits Propatagium Pinioning
pectoralis responsible for downsroke supracoracoidus- upstroke ulna is wider and stronger bone central carplas fused alula-basterd wing
Anisodactyly
Most common toe arrangement Digits 2,3 & 4 Forward pointing Digit 1 (Hallux) Backward pointing Most common toe formation Suited to perching and grasping E.g. passerines, fowl and poultry, pigeons, raptors, gamebirds
Zygodactyly
Pairs of digits 1 & 4 Backward pointing 2 & 3 Forward pointing Useful for climbing and grasping E.g. Psittacines, woodpeckers, owls, cuckoos
Heterodactyly
Digits 3 & 4 forward pointing
Digits 1 & 2 backward pointing
Trogons only
Syndactyly
Similar to anisodactyly
Digits 2 & 3 joined
E.g. Kingfishers, Hornbills
Pamprodactyly
Digits 2 & 3 forward pointing
Digits 1 & 4 rotate forward & backwards
E.g. Swifts & Mousebirds
Didactyly
Only 2 forward pointing digits
Ostrich only
Palmate
Digits 2-4 united by webbing
E.g. waterfowl, gulls, flamingos, loons
Toe formation in birds can be…
Zygodactyly Anisodactyly Heterodactyly Syndactyly Pamprodactyly Didactyly
webbing formation in birds can be
Palmate
Totipalmate
Semipalmate
Lobate
Totipalmate
Webbing unites all 4 digits
E.g. gannets, boobies, pelicans, cormorants
Semipalmate
Small web between digits 2-4
E.g. Plovers, sandpipers, herons
Lobate
Lobes of webbing on digits 2-4
Some diving ducks have lobate D1
E.g. Grebes, Coots
Avian Adaptations for Flight
Skeletal adaptations Egg laying Eyesight Feathers Rigid Lungs, air Sacs and unidirectional air flow Seasonal reproductive organ enlargement No urinary bladder
Skeletal adaptations for locomotion – Flight
Carinate birds Pneumatised long bones- Internal struts for strength, Not all species Skeletal fusions Vertebral, carpus/manus, tarsus/pes Uncinate processes (ribs) Large sternum Coracoid bones
A & P Differences in diffrent birds accroding to flight
Long keel for propulsive take off- Pigeons, Parrots
Pectoralis: Supracoracoideus mass
Wing shapes
Adaptations for altitude/metabolic rates- Baffles Pulmonary oxygen extraction efficiency Cardiac output PCV
Flightless bird families
Ratites (Struthioniformes) Penguins (Spheniscidae) Kakapo Galapagos cormorants Some junglefowl Domestic ducks
Perching
Different foot formations
Automatic digital flexor mechanism
Digital tendon locking mechanism
Allows perching without spending energy
avian climbing
Arboreal species Woodpeckers/Tree creepers/Nuthatches Zygodactyl feet Tail assistance Direction Psittacines Zygodactyl feet Beak assistance
avain swimming
Propelled by pelvic limbs-
Flexion and extension of intertarsal joint
Alternate limb movement
Digital tendon locking mechanism
Underwater flight- Penguins
Porpoising- Diving in and out of water
Surface swimming- Decreases water resistance
Breathing
avian diving
Dabbling waterfowl
Surface divers
Plunge divers
Adaptations- Fewer or less pneumatised bones
Legs positioned caudally on pelvis
Internal nares
Adaptations in neck length and musculature
Subcutaneous air sacs
Poor waterproofing (Cormorants)
avain Integumentary homeostasis
Calcium- Vitamin D synthesis
UVB & Heat requirement
Thermoregulation- No sweat glands Feathers – insulation Feather colour Arteriovenous anastomoses Apteria
Water homeostasis- Nasal glands
avain Innervation and blood supply
Sparse innervation generally- Feather follicles
Beak
Blood supply- Subcutis & Dermis
Subepithelial capillaries
Dermal papillae
Arteriovenous anastomoses- Feet (Toes, pads, interdigital webbing)
Brood patch
Face
Avian Skin
Epidermis
Structure similar to mammals
Stratum corneum – horny layer covering exposed skin
surface
Stratum germinativum – living cells producing corneum
Membrana basalis – dermoepidermal junction
Dermis
Stratum superficiale – loose connective tissue with discrete dermal papillae associated with feather follicles
Lamina elastica - thin layer of elastic fibres
Subcutis
Mobile layer of tissue connecting skin to underlying structures
Feathers
Unique to birds Arise from epidermis β-keratins Specialised feather types Often brightly coloured Sexual dimorphism UV reflective patches
Flight Insulation Thermoregulation Waterproofing Camouflage Communication Protection Nest Lining
Follicle Shaft (Scapus) Rachis Calamus- quill Vane (Vexillum) Afterfeather (Hypopenna)
Micro Anatomy of a feather
Barbs -(Rami)
Barbules- (Radii/Barbulae)
Hooklets- (Hamuli/Barbicels)
Feather Types
Pennaceous/Vaned feathers- Contour Feathers- Coverts
Flight feathers
Tail feathers
Down Feathers-
Down feathers
Semiplumes
Powder Down
Feathers
Filoplumes
Bristles
Contour Feathers
Pterylae- Coverts (Tectrices)- Afterfeathers
Very variable
Flight feathers of the wings (Remiges)- Primary
Secondary
Tail Feathers (Rectrices)
Downy Feathers
lack hooklets
Natal down- seen in chicks
Down Feathers - Plumules, seen in adults for insulation
Powder Down - Pulviplumes, a cross between down and contour feathers and
Semiplumes
Filoplumes- assists in sensation
Bristles (feahters)
Rictal bristles
Sensory function
Eyes
Bill
avian moult
Species variability
Post breeding moult
Post juvenile moult
Shock moult- response to stress
Hormonal influence-thyroid horone
some become flightless
some taker turns to moult with mate
Featherless Regions
Thicker stratum corneum Specialisations Beak/Bill Cere Webbing Scales Pads Claws Spurs Cranial cutaneous structures
structure of beak
Keratinised epidermis
Rhamphotheca- the outer surface of the beak consists of a thin sheath of keratin called the rhamphotheca
Maxillary rhamphotheca
Rhinotheca
Mandibular rhamphotheca
Gnathotheca
Shapes Egg Tooth Lamellae Nail Bill tip organ Corpuscles of Herbst
avian Scales
Tarsometatarsus
Digits
Scuta (Dorsal)
Scutella (Plantar)
Apteria
one of the bare spaces between the feathered areas on the body of a bird.
Feather tracts
Pterylae
Featherless tracts Apteria Down feathers and semiplumes Contour feathers absent Surgical/Clinical landmark
Brood/Incubation patch
Females and males (spp. Differences)
Patagia
a membranous structure that assists an animal in gliding or flight
Cranial
Patagium cervicale
Propatagium
Patagium alulae
Caudal aspect
Metapatagium cervicale
Postpropatagium
avian Glands
No sweat glands
Epidermis is secretory
Sebaceous glands
Uropygial (Preen) Gland
Cloacal glands
Auricular glands
Salt glands
Marine species
Not sebaceous glands
Uropygial (Preen) Gland
Dorsal tail base (Cd4-pygostyle) Bilobed, symmetrical gland Excretory ducts Uropygial papilla Species variation Feathered vs unfeathered Presence/absence/papilla Preen oil Feather integrity Vitamin D Cosmetic effect
Overview of the Avian Digestive Tract
Very diverse feeding strategies Carnivores Omnivores Herbivores Specialised feeders Huge variation in gastrointestinal A & P Beaks Stomachs Intestinal length
avian Beak & Oropharynx
Beak/Bill- Rhamphotheca
Rhinotheca
Gnathotheca
Tomium
harder in granovores and carnivores and rubbery in water fowl
Choana- Oropharynx connected to nasal cavity
Tongue closes choana during inspiration
Choanal papillae- become blunt in absense of vit A
no soft pallet
Variable salivary glands
Tongue- Variable size, form and function
Lingual papillae
Sparse taste buds compared to mammals
Bitter taste
avain Oesophagus & Crop
Oesophagus - Dorsal to tracheal cervically Right side of neck Wide diameter Thin walled Longitudinal folds
Crop (Ingluvies)-Dilatation of the oesophagus
Proximal to pectoral cavity/thoracic inlet
Larger in granivorous/carnivorous species
Crop milk
Waterfowl/Owls– no true crop
Avian Coelom
No diaphragm Cranial coelom Caudal Coelom 2 x pleural cavities 4 x hepative peritoneal cavities Intestinal peritoneal cavity Pericardial cavity Air sac endoscopy Intraperitoneal injections
Proventriculus & Ventriculus (Stomachs)
Proventriculus – Glandular
Digestie Enzymes
True stomach
Ventriculus (Gizzard) – Muscular More developed in granivores Grit Masticatory Raptor pellets
raptors rely on chemicla digestion
Isthmus- Bridge
Aglandular
avian liver
Simple two lobed liver
Cardiohepatic silhouette
Gall bladder- Variable presence
Bile pigments
Biliverdin- green colour of urate
Hepatic Artery
Hepatic Vein
Hepatic portal vein
vit ADEK
carbohuydeate digestion
blod cell destruction
vit c production
avian Small Intestine
Relatively short- adaptation for flight
variatiom accroding to diet
Villi
Duodenum- Pancreas
Bile Ducts
Pancreatic Ducts
Jejunum
Ileum
Meckel’s diverticulum- differentiateds between jejunum and illium
avian Pancreas
Mesoduodenum- Between two duodenal limbs Pale yellow to pink Trilobed- Dorsal Ventral Splenic
Exocrine
Endocrine
AviannLarge Intestine
Caeca- Paired
Not in all speices
Rectum (prev. Colon)
Cloaca
Gut Associated Lymphoid Tissue (GALT)
avian
Diffuse lymphoid cells
Lymph Tonsils- Pharyngeal Tonsil Diffuse oesophageal lymphoid tissue Oesophageal tonsil Proventricular lymphoid tissue Pyloric Tonsil Peyers Patches Meckel’s diverticulum 2 x Caecal Tonsils Diffuse rectal lymphoid tissue Bursa of Fabricius Diffuse proctodeal lymphoid tissue
avian Cloaca
Common excretory passage-
Digestive
Urinary
Reproductive
Three sections
Coprodeum
Urodeum
Proctodeum
Coprourodeal fold
Uroproctodeal fold
Vent
Urine, urates, faeces all voided together from cloaca
Can be challenging to differentiate- Polyuria
Diarrhoea
Contamination of samples
Different dietary strategies
Granivorous birds
Short strong beak, often conical Large glandular crop Well developed ventriculus Longer intestines Distinct caeca
Different dietary strategies
Insectivorous birds
Finer, longer beak Rudimentary ventriculus Well developed proventriculus Short Intestine Rudimentary Caeca
Different dietary strategies
Carnivorous birds
Piscivorous birds
Carnivorous birds Strong, curved, often hooked beak Variable presence of crop Well developed proventriculus Rudimentary ventriculus Short intestine Well developed pancreas Rudimentary caeca
Piscivorous birds
As for carnivores but often longer beak
Different dietary strategies
Frugivorous birds
Rudimentary crop
Less well developed ventriculus
Short Intestine
Rudimentary Caeca
General Bird Handling considerations
Minimise handling time Gloves for wild birds Consider risk Warn owners of risk Mask clinical signs of disease Prior history & Distance Exam essential Preparation Key Equipment Recapture equipment Remove obstacles Positioning and ventilation Air sacs- best position is uprightso as to not compromise air sacs
May not be approprato get hands on at all
Observe whilst acclimatising Assess stability for physical examination Droppings Posture/Stance ODemeanour Respiratory rate/effort- not useful to take when handling bird Weigh in box if possible Behaviour Obvious abnormalities
Stress polyurea
Birds under stress produce wet dropping that can be mistaken for clinical signs
Avian Ventilation
air flows through the lungs in the same direction during both inspiration and expiration. In addition, both the intaking of air and the expelling of air are active processes, requiring muscle contraction.
During inspiration, the ribs are drawn forwards and the sternum lowered, the caudal air sacs receiving fresh air. Simultaneously, the Cranial air sacs receive air which was inhaled at the previous inhalation which is drawn from the lungs, this air has lost much of its oxygen content.
During expiration, the sternum is drawn caudal and dorsal, the air sacs are compressed, air from the caudal air sac passes through the lungs, while the air in the cranial air sac leaves via the trachea. Thus, oxygenated air passes through the lungs on both inspiration and expiration.
Avian Gas exchange takes place not in alveoli, as in mammals, but within air capillaries which are extensions of the parabronchial lumen. They are an interconnecting network of loops, and closely intertwine with blood capillaries. The air capillaries and blood capillaries are arranged so that flow is crosscurrent. This makes the gaseous exchange, which occurs from one to the other, extremely efficient.
describe female avian reproductive tract
Ovary
In the first 5 months after hatching, the ovary gradually develops from a small irregular structure with a finely granular surface into one where individual follicles can be observed.
Most birds have only left ovary but 2 ovaries are typical of many raptors.
Left Ovary lies caudal to the Adrenal Gland, close to the cranial tip of the Kidney.
Consists of:
Medulla: vascular with nerve fibres and smooth muscle
Cortex: peripheral
Suspended by the mesovarium.
Blood supply from the cranial renal artery
Artery is very short, making ovariectomy very difficult with risk of haemorrhage.
Contains from 500 to several thousand primary oocytes.
Follicles are pedunculated, suspended by a stalk containing smooth muscle that has a rich vascular and nerve supply.
Large, pendulous Follicles may contact the stomach, spleen and intestines.
Each consists of a large, yolk-filled oocyte surrounded by a highly vascular follicular wall.
Shortly before ovulation, a devascularized white band (stigma) appears opposite the stalk, indicating where the wall will rupture at ovulation.
The empty follicle (calix) regresses following ovulation and disappears in a few days.
No Corpus Luteum is required, since there is no embryo to maintain as there is in mammals.
oviduct:
The oviduct may be divided into the infundibulum, magnum, isthmus, uterus and vagina. The oviduct not only conducts the fertilized ovum to the Cloaca, but adds substantial amounts of nutrients. It also encloses the ovum within membranes and a shell, providing protection for the embryo. It conveys spermatozoa to the ovum for immediate fertilization and stores them for future use. One insemination is sufficient to fertilize the ova released during the following 10 days.
The right oviduct regresses in development under the influence of MIH.
In most birds only the left oviduct is present and functional. The right oviduct can be identified as a strand of tissue on the right side along the ventral side of the caudal vena cava
ccupies the left,dorsal part of the body cavity.
Related to the Kidney, intestines and gizzard.
Massive coiled structure approximately twice body length when fully functional..
Much reduced in juveniles and during the non-laying period.
Suspended from the roof of the body cavity by a peritoneal fold (mesoviductus).
Some coils are connected by a ventral continuation that forms the muscular ventral ligament.
Cilia are found along the entire length of the Oviduct. These facillitate sperm transport.
Egg transported by contractions of the Oviduct musculature.
Infundibulum
Consists of a fluted and tubular part.
Fluted part is thin-walled and stretched to form a slit (Infundibular Ostium).
Lateral end is attached to the body wall near the last rib.
Ostium is positioned by the left abdominal air sac in such a way that it can grasp the newly released oocyte.
Subsequent to ovulation, the ovum is engulfed by the Infundibulum.
Ovum resides here for 15-30 minutes.
Fertilization must take place in the funnel section of the Infundibulum before the oocyte gets surrounded by albumin.
Penetration by sperm usually occurs within 15 minutes of ovulation.
Infundibular glands provide the chalaziferous layer, the thin coating of dense albumin around the yolk.
Chalazae, the coiled strands that suspend the yolk and allow it to rotate so that the ferminal disc remains uppermost, develop further along the genital duct.
Some species have a sperm host gland in this area to store sperm for later fertilization.
Magnum
Longest part of the Oviduct.
Ovum resides here for ~2-3 hours.
Coiled with numerous tubular glands, giving it a thickened appearance.
Oestrogen stimulates epithelial stem cells to develop into three morphologically different cell types:
Tubular cell glands: Produce ovalbumin,lysozyme and conalbumin under the influence of Oestrogen. This gives the lumen a milky-white colour.
Ciliated cells
Goblet cells: synthesize avidin following exposure to Progesterone and Oestrogen.
Calcium, sodium and magnesium are added.
Isthmus
Demarcated from the Magnum by a narrow aglandular zone.
Folds less prominent than the Magnum, but the glands secrete more albumin.
Divides the Magnum from the Uterus.
Present in poultry but not in Psittacines.
Ovum resides here for ~1-2 hours
Inner and outer shell membrane formation.
Uterus
Holds the egg during shell formation.
80% of time is spent here.
Very vascular to aid calcium deposition.
Calcification first occurs slowly, increases, then decreases again ~2 hours prior to oviposition.
Shell pigments (primarily protoporphyrin and biliverdin) are deposited via ciliated cells over 3 hours until 30 minutes before oviposition.
Vagina
Muscular S-shaped tube through which the completed egg passes when it is expelled.
Vagina is separated from the Uterus by a vaginal sphincter which terminates at the Cloaca.
Ends at a slitlike opening in the lateral wall of the Urodeum.
Smooth muscle more powerful than the rest of the oviduct.
Numerous mucosal folds lined by ciliated and non-ciliated cells.
Few tubular mucosal glands with secretory function.
No role in egg formation.
In some species, egg can remain here for hardening before passing out of the oviduct to the Urodeum.
Sperm Host Glands
Sperm host glands are at the uterovaginal junction of domestic fowl.
Sperm can be stored here and remain viable for 7-14 days in the Chicken or over 21 days in the Turkey.
No innervation or contractile tissue.
Well-developed vascular system.
Raptor A & P Considerations
Large crop except owls- Rehydration pre feeding Owls good night vision Casting indigestible material- Variable Owls feathered legs Talons Beaks (Tomial tooth) Nares- Operculum (Don’t confuse with rhinolith) cartelagenous flap that sits in nare Baffles- protects from wind speeds
Poultry Clinical Exam
Stance Pin bones Wattle & Comb colour Sinuses Ear lobe colour Feathers- Parasites, NB Red mite lie off host Vent Legs/scales Pododermatitis
Waterfowl A & P Considerations
No apteria- featherless tract for blood sampling No true crop Webbed feet Feathered preen gland Drake curl in male duck Feather/Moult abnormalities Do they fly?
Pigeon A & P Considerations
Cervical plexus Blue cervical skin Powder down Flash moult under stress Crop- Crop milk Vestigial uropygial gland
Microchipping birds
Standard microchips
Subcutaneous implantation
Intramuscular in large/thin skinned species
Tissue Glue
BVZS
Left pectoral standard
Otriches - Pipping muscle inback of head
Penguins - Subcutaneously at base of neck
WSAVA
Psittacines & Falconiformes – Left Pectoral
Old & New World Vultures – Base of Neck
Large (>1.5kg or long legged) – Dorsally at juncture of neck & body
Small – Medium (<1.4kg) Left pectoral
BTO Rings
Wild Birds Passive monitoring British Trust for Ornithology (BTO) rings Open rings Unique code Data stored at NH Museum London Longevity Survival Migration patterns Population changes NB differentiate between open/split- wild and closed rings- captive birds
Tattoos/Ink stamps Racing Pigeon Rings GB – Royal Pigeon Racing Association NPA – National Pigeon Association NEHU- North of England Homing Union NWHU – North West Homing Union SU – Scottish Union IHU – Irish Homing Union WHU – Welsh Homing Union
Uncinate processes of ribs
The uncinate processes of the ribs are extensions of bone that project caudally from the vertical segment of each rib. (Uncinate means hooked from Latin uncinatus, from uncinus, barb, from uncus, hook.) They are found in birds (except for screamers)
These processes can serve to attach scapula muscles,[1] and help to strengthen the rib cage overlapping with the rib behind them.[1][2] They are also shown to have a role in respiration by increasing the effectiveness of muscles involved in inspiration including the appendicocostal muscles.[3] The processes are short in walking birds and long in diving species and are of intermediate length in non-specialist birds
gizzard
lso referred to as the muscular stomach or ventriculus. It is connected by the isthmus to the proventriculus and to the duodenum.
The gizzard allows mechanical reduction of tougher material through powerful muscular development
The gizzard consists of two thick masses of muscle that insert on tendonous surfaces. In seed eating birds, grit is digested to increase the grinding down of food particles. Its surface is covered by a glistening tendonous layer. The cranial and caudal extremities are formed by a powerful red muscular tissue. A circular aponeurosis is present, connecting the cranial end of the gizzard to the isthmus and the caudal end to the duodenum. It appears yellow due to bile reflux from the duodenum. When the thin muscles of the gizzard contract, food passes from the gizzard into the duodenum, when the thick muscles of the gizzard contract, food moves back into the proventriculus.
The gizzard has a thin, but tough mucous membrane. It has a pale, thin lining raised into ridges with three layers of lamina muscularis. The gizzard also has cuboidal epithelium and some tubular glands present. There is a thick keratin layer to protect the muscle.
The cuticle of koilin is a carbohydrate complex, present due to the solidifying of the glandular secretion. It is replenished as it is worn down.
There is no gizzard in falconiformes (raptors etc.) or in stringiformes (owls etc.). There is also no gizzard in gulls.
Avian Ventilation
air flows through the lungs in the same direction during both inspiration and expiration. In addition, both the intaking of air and the expelling of air are active processes, requiring muscle contraction.
During inspiration, the ribs are drawn forwards and the sternum lowered, the caudal air sacs receiving fresh air. Simultaneously, the Cranial air sacs receive air which was inhaled at the previous inhalation which is drawn from the lungs, this air has lost much of its oxygen content.
During expiration, the sternum is drawn caudal and dorsal, the air sacs are compressed, air from the caudal air sac passes through the lungs, while the air in the cranial air sac leaves via the trachea. Thus, oxygenated air passes through the lungs on both inspiration and expiration.
Avian Gas exchange takes place not in alveoli, as in mammals, but within air capillaries which are extensions of the parabronchial lumen. They are an interconnecting network of loops, and closely intertwine with blood capillaries. The air capillaries and blood capillaries are arranged so that flow is crosscurrent. This makes the gaseous exchange, which occurs from one to the other, extremely efficient.
describe female avian reproductive tract
Ovary
In the first 5 months after hatching, the ovary gradually develops from a small irregular structure with a finely granular surface into one where individual follicles can be observed.
Most birds have only left ovary but 2 ovaries are typical of many raptors.
Left Ovary lies caudal to the Adrenal Gland, close to the cranial tip of the Kidney.
Consists of:
Medulla: vascular with nerve fibres and smooth muscle
Cortex: peripheral
Suspended by the mesovarium.
Blood supply from the cranial renal artery
Artery is very short, making ovariectomy very difficult with risk of haemorrhage.
Contains from 500 to several thousand primary oocytes.
Follicles are pedunculated, suspended by a stalk containing smooth muscle that has a rich vascular and nerve supply.
Large, pendulous Follicles may contact the stomach, spleen and intestines.
Each consists of a large, yolk-filled oocyte surrounded by a highly vascular follicular wall.
Shortly before ovulation, a devascularized white band (stigma) appears opposite the stalk, indicating where the wall will rupture at ovulation.
The empty follicle (calix) regresses following ovulation and disappears in a few days.
No Corpus Luteum is required, since there is no embryo to maintain as there is in mammals.
oviduct:
The oviduct may be divided into the infundibulum, magnum, isthmus, uterus and vagina. The oviduct not only conducts the fertilized ovum to the Cloaca, but adds substantial amounts of nutrients. It also encloses the ovum within membranes and a shell, providing protection for the embryo. It conveys spermatozoa to the ovum for immediate fertilization and stores them for future use. One insemination is sufficient to fertilize the ova released during the following 10 days.
The right oviduct regresses in development under the influence of MIH.
In most birds only the left oviduct is present and functional. The right oviduct can be identified as a strand of tissue on the right side along the ventral side of the caudal vena cava
ccupies the left,dorsal part of the body cavity.
Related to the Kidney, intestines and gizzard.
Massive coiled structure approximately twice body length when fully functional..
Much reduced in juveniles and during the non-laying period.
Suspended from the roof of the body cavity by a peritoneal fold (mesoviductus).
Some coils are connected by a ventral continuation that forms the muscular ventral ligament.
Cilia are found along the entire length of the Oviduct. These facillitate sperm transport.
Egg transported by contractions of the Oviduct musculature.
Infundibulum
Consists of a fluted and tubular part.
Fluted part is thin-walled and stretched to form a slit (Infundibular Ostium).
Lateral end is attached to the body wall near the last rib.
Ostium is positioned by the left abdominal air sac in such a way that it can grasp the newly released oocyte.
Subsequent to ovulation, the ovum is engulfed by the Infundibulum.
Ovum resides here for 15-30 minutes.
Fertilization must take place in the funnel section of the Infundibulum before the oocyte gets surrounded by albumin.
Penetration by sperm usually occurs within 15 minutes of ovulation.
Infundibular glands provide the chalaziferous layer, the thin coating of dense albumin around the yolk.
Chalazae, the coiled strands that suspend the yolk and allow it to rotate so that the ferminal disc remains uppermost, develop further along the genital duct.
Some species have a sperm host gland in this area to store sperm for later fertilization.
Magnum
Longest part of the Oviduct.
Ovum resides here for ~2-3 hours.
Coiled with numerous tubular glands, giving it a thickened appearance.
Oestrogen stimulates epithelial stem cells to develop into three morphologically different cell types:
Tubular cell glands: Produce ovalbumin,lysozyme and conalbumin under the influence of Oestrogen. This gives the lumen a milky-white colour.
Ciliated cells
Goblet cells: synthesize avidin following exposure to Progesterone and Oestrogen.
Calcium, sodium and magnesium are added.
Isthmus
Demarcated from the Magnum by a narrow aglandular zone.
Folds less prominent than the Magnum, but the glands secrete more albumin.
Divides the Magnum from the Uterus.
Present in poultry but not in Psittacines.
Ovum resides here for ~1-2 hours
Inner and outer shell membrane formation.
Uterus
Holds the egg during shell formation.
80% of time is spent here.
Very vascular to aid calcium deposition.
Calcification first occurs slowly, increases, then decreases again ~2 hours prior to oviposition.
Shell pigments (primarily protoporphyrin and biliverdin) are deposited via ciliated cells over 3 hours until 30 minutes before oviposition.
Vagina
Muscular S-shaped tube through which the completed egg passes when it is expelled.
Vagina is separated from the Uterus by a vaginal sphincter which terminates at the Cloaca.
Ends at a slitlike opening in the lateral wall of the Urodeum.
Smooth muscle more powerful than the rest of the oviduct.
Numerous mucosal folds lined by ciliated and non-ciliated cells.
Few tubular mucosal glands with secretory function.
No role in egg formation.
In some species, egg can remain here for hardening before passing out of the oviduct to the Urodeum.
Sperm Host Glands
Sperm host glands are at the uterovaginal junction of domestic fowl.
Sperm can be stored here and remain viable for 7-14 days in the Chicken or over 21 days in the Turkey.
No innervation or contractile tissue.
Well-developed vascular system.
what methods can be used to determine the sex of a bird
DNA:
Bird Sexing by DNA, using samples of feathers, blood or eggshells is currently the most advantageous method, representing the following prominent benefits:
No surgical intervention such as anaesthetics required
Applicable to birds of any age, any time of the year
The birds are not subjected to the stress of transport
Reliable method applicable to most species
Sexual dimorphism:
mosrt apparent during spring and summer so sometimes season dependent
sometimes difficult
can tbe used for chicks
Size: hard without comparison or experience
behaviour: singing, fighting, migration
chromosome inspection
surgery: invasive
avain cardiovascular system
Heart is proportionately large relative to body size compared to mammals to meet the metabolic demands of flight
Cardiac output is higher attributed to a higher heart rate (up to 1000bpm!). very efficient. linked to sixe
Nucleated red blood cells- in mammels theyre anuclear
Additional renal portal system- same as reptiles
right atrioventricular valce has two cusps as in dogs and cats and heart strings
left atrio ventricular valve has one cusp and no heart srtings
aorta goeas to brachisophalic trunk then splits into two breachisophalic arteries, then to the cephalic and subclacvian
also becomes intercostal arteries then crainial and cadal mesenteric, then to kidneys and hindlimbs
3 vena cave return vlood to hear- 1 caudal 2 cranial
only 1 pulmanary vein
renal portal system
system of shunts that move blood from hindlimbs to kidneys
regulation of body fluid- esspecially usefull for dehydration
when injecting into hind lombd srug will go throughn renal system- toxisity, breakdown of drug
blood sampling in birds
Wing vein /cutaneous ulna vein
Medial tarsal/ medial tarsal metatarsal
Jugular vein (right bigger then left) species specific
Occipital venous sinus (under anaesthetic only)
Wing vein /cutaneous ulna vein
injection
blood sampling
just beyond point of elbow
Occipital venous sinus
done only under anethesia
head must be flexed to open up sinus caudal to the occiput
back of head
describe the upper respiratory tract of birds
nostral links to nasal cavity
nasal septum divides nasal cavity
concha- bone structures that increase surface area in nasal cavity, traps dust
the caudal choncha is most rostral followed by the middle and rotral choncha
all connect to the infraorbital sinus by narrow space
sinus not engulfed in bone. just sit under skin ans so sinusitis can cause swelling of the head
trachea and syrinx of bird
No vocal folds, syrinx is responsible for vocalisations further down. absence of vocal folds
Trachea held open by complete cartilage rings, palpable on right hand side
Syrinx is found at junction between trachea and primary bronchi. Membranes of primary bronchi resonate to create a vocalisation. area of no cartilage rings
The male duck and swan have an osseus bulla on the left of the syrinx believed to be a resonator
Song birds have more muscles attached to syrinx to allow for more variation of noised
e.g. sternotrachialis foes form sternum to trachae
describe the lungs in birds
relativly small
not expansile due to ridgid thorax
no lobes
no pleural cavity- thorax and abdomen in single cavity
Parabronchii for efficient gas exchange- much more efficint gas exchange, bird equvilent of alvioli
doubly efficent as parabonchi are tubes and not dead ends
oxygenated air travels through on both inspiration and expiration
lungs sit against dorsal body wall
describe airflow beteen the parabronchi and airsacks
Chicken parabronchi (tertiary bronchi) are organized in parallel connection, and the air flows in one way during inspiration and expiration due to the air sacs. Thus, birds have a more efficient gas exchange than human, whose airways end blindly and air moves in and out during ventilation , leaving a physiological dead space.
air moves form trachea to parabornchi to air sacs throught body
then passes through parabronchi into other airsac and then out again
airsacs act like bellows that draw in air
gas exhange takes place in the parabronchi- countercorent exhange as blood flows oposite way to air
desciebe the avian respiritory cycle
- On first inhalation, air flows through the trachea & bronchi, primarily into the posterior (rear) air sacs
- On exhalation, air moves from the posterior air sacs into the lungs
- With the second inhalation, air moves from the lungs in to the anterior (front) air sacs
- With the second exhalation, air moves from the anterior air sacs back into the trachea and then out
Air sacs
Respiration but not gas exchange
Move air through the lungs on inspiration and expiration
Makes body lighter
airsacs extend into pneumatised bones
cervical air sack, interclavicular air sack, humeral,
anterior airsack, posterior thoratic (paired) airsac, abdominal airsac (paired)
also grouped into cranial (exten form crainial aspect to humerus which is pneumitised) and caudal airsacs (etends into pelvis)
if pneumatised bone is broken, infection can spread to lungs
Pneumatic bones
The pneumatic bones are important to the chicken for respiration. They are hollow bones which are connected to the chicken’s respiratory system and are important for the chicken to breathe.
Examples of pneumatic bones are the skull, humerus, clavicle, keel (sternum), pelvic girdle, and the lumbar and sacral vertebrae.
rle in thermoregulation
cranial air sac
cervical airsac
intercavicular airsac
anterior thoratic air sacs, humeral air sac
caudal airsac
posterior thoratic airsacs
abdominal airsacs
countercurrent exchange in birds
blood flows oposite direction to air in parabronchi as gas exchnge takes place
oxyge content in air depleats as it moves through parabronchi, oxygen content in blood parrallel to parabronchii increases in oposite direction
creats gradient that drives oxygen to move into blood
efficient air exchange for high metabolic demant and allows birds to deal with low levels of oxygen at high altitude
very good thermoregulation via blood stream and out through repiritory system due to this
avain endocrine system
Pituitary
Anterior- TRH ACTH Adrenocorticotrophic hormone Sex hormones LH, FSH Melanin stimulating hormone Growth hormone Prolactin
Posterior-
Anti-diuretic hormone
Oxytocin
Adrenals- Corticosterone Aldosterone Norepinephrine Epinephrine
Thyroid-
Thyroid hormone
Parathyroid-
Parathyroid hormone
Ultimobrachial bodies-(anatomically distinct from the thyroid)
Calcitonin
Pineal body-
Melatonin
Pancreatic Islets of Langerhans-
Insulin
Glucagon
Gonads-
Androgens
Oestrohens
avain female reproducitve anatomy
One ovary and oviduct
Regression on the R oviduct occurs from day 10 of incubation
left oviduct develops rapidly at about 16 weeks
birds come into lay with increae in photoperiod
birds that have two ovaries e.g sparrow hawk, long eared owl, buzzard
there are pin bones around cloaka that increase in distance from eachother when bird is in lau “about three finger width”
ovary not attached to oviduct so infandibulum mut cathc egg. can lead to yolk in peritoneal cavity and egg peritonitus
pathology involved in the hens reproductive cycle
Ovarian pathology - Internal ovulation - Egg peritonitis - Neoplasia Oviduct pathology - Salpingitis - Proplase - Egg binding/dystocia - Neoplasia Bone pathology - Osteoporosis - Keel bone fractures Mating injuries
What to look out for in the clinical exam of a hen
Hunched Penguin-like stance Abdominal distention Gently palpate abdomen Laying deformed or soft shelled eggs Reduced activity levels Reduced feed and water consumption Frequent eye closing Check body condition Find out about diet, housing and ventilation
describe the path of the egg in the female chicken
from the ovary it is caught by the infandibulum where it spends 15 mins nd is fertalised, then goes through the magnum and stays for around 3 hours and gains albumen and isthmus where it spends around 1.25 and gains a soft shell hours to the shell gland where it spends 21 hours getting a hard shell and is then expelled via the vagina and cloaca
yolk protein is formed in..
the liver and is transpirted to ovary via blood supply
post ovulatory follical
contains granuloma and foecal cells
magnum of the abian reproductive tract
albumin is added
has spiral ridges to keep yolk suspended in middle of albumin
isthmus of the abian reproductive tract
salmonella may reside here
mesh like inner membrae, outer shell and albumin added
shell gland of the abian reproductive tract
albumin shell and pigments added
protien cuticle formation
calcium is needed from the diet for this or it may result in parathyroid hormone release and therefor ebone stress
expulsion of the egg
egg turns from pointy end down to blund end down
Vagina has a sphincter to the cloaca which is relaxed by oestrogenic activity
thsi can increase risk of an asending infection
abdominal muscles relax
change in temperature causes contraction of membranes in egg creating air space
peak production is 27 weeks
chicken moult
Feather follicles enter anagen phase
Replacement of feathers
Regression of reproductive organs
Cessation of lay
Thyroid hormones are necessary for reproductive function, but high thyroid concentrations have anti-gonadal affects. Increased thyroid hormones and decreased oestrogens are important for inducing the moult.
Moult can be induced artificially by manipulating
lighting and feed intakes
Determinate layers
produce fixed numbers of eggs within a clutch. They can not replace an egg if one is lost
Indeterminate layers
can theoretically lay as may eggs as needed to fill out their clutch. This is thought to be closely linked to the brood patch: the bald area where birds are thought to detect the number of eggs she is sitting on
matting behaviours of chickens
Male initiates courtship behaviour by dropping one wing and circling courtly dance around her
The hen will crouch
Cockerel mounts the pullet grabbing her neck feathers while he is treading her
Cloacal contact
<30 seconds!
cockrel reproductive system
2 testes produce sperm
Sperm travel through the vas deferens to the cloaca
No penis
Spermatogenesis
Light is the primary environmental factor that influences spermatogenesis via the hypothalamus-pituitary axis
Testosterone activity of the sertoli cells
Testes within the body cavity
Blood flows to each testis from the abdominal aorta to the testicular artery
This branches off to smaller vessels that wrap around the seminiferous tubules
Lymphatic vessels to the testis have not been well characterized, but are present within Leydig cells
Incubation/Hatching of hens
In nest Commercially in incubators/ nestboxes Hatching on farm 21 day process Increased thyroid hormone concentrations appear to stimulate a variety of developmental and metabolic processes.
the chick breaks membrane to air cell- internal pipping.
chicks lungs inflate before hatching
sexing chickens
Dependent on breed
Adults: sexual dimorphism: appearance, vocalisation
Chicks: vent sexing- takes 2 years of training, feather sexing- depends on breed is fadt feahtering or slow feathering, down colour in some breeds
avian sexing
Non sexually dimorphic breeds e.g. grey parrots, macaws rely egg laying to distinguish, or karyotyping
Coelioscopy appropriate in most species to visualise the ovary/testes
Vent sexing done in ratites and waterfowl
Central Nervous System of birds
Brain & Spinal Cord Lissencephalic brain- smooth brain Occipital lobes- large Cerebellum- large Optical centre
Spinal Cord- Full length of vertebral column
Most vulnerable between notarium & synsacrum
avian Peripheral Nervous System
Somatic nerves
12 cranial nerves
Brachial plexus- innervates muscle of pectoral girdle and wing- last cervical and forsth thorasic spimal nerves
Lumbosacral plexus- sacral nerves 2-9, pelvise, tail, hindlimbs
Autonomic nervous system-
Parasympathetic
Sympathetic
avain eyes and vision
Similar structure to the mammalian eye Large eyes Scleral Ossicles- small bones within eye for support Pear shaped globe unlike mammels Interorbital septum Iris colour- Age, Gender
diurnal birds have deep orbit
crepuscular birds have shallow orbit
Extrinsic Muscles- Very variable eye mobility Palpebrae- levator palpebrae superioris muscle is a small muscle of the superior orbit that elevates and retracts the upper eyelid Nictitating membrane (Third Eyelid)- Dorsonasal > ventrotemporal
Glands- No meibomian gland Lacrimal Gland (and ducts) Harderian gland (Gland of the NM) Nasal gland
Asymmetrical globe
Scleral ossicles
Thin cornea
Iris & ciliary body- Striated muscle & Conscious pupil control- asymetirical iris apearence can be normal
Choroid- No choroidal tapetum lucidum
Retina- Avascular- nutrients are expeled into vitriuos humour
Cones
Rods
Pecten oculi
Lens
Optic Nerve- Complete decussation
Large eyes in orbit > limited ocular mobility
Lateral eyes
Wide field of vision
Stereoscopic vision limited
Cones and Rods- Can perceive colour
Red, Yellow, Green > Blue
Perceive visible and UV spectrum light
Specialist adaptations- Raptors
Nocturnal species
Avian Ears
External ear- No pinnae Ear lobes, auricular feathers External acoustic meatus caudal to quadrate bone Auricular glands Tympanic membrane
Middle ear- Air filled tympanic cavity
Single auditory ossicle – Columella
Three extracolumella processes
Inner Ear- Vestibular organ
Cochlear organ
Low Frequency hearing
Infrasound
Specialist adaptations for hearing- Funnel shaped ears Nocturnal species Asymmetrical ears Facial discs Skin folds
Echolocation
Ossicle variation
avain Tactile Sensation
Skin relatively poorly innervated
Large numbers of specialised sensory receptors- Feather follicles
Beak tip/probing beaks
Oral Cavity
Rictal/Facial bristles
Perception of pain and temperature
Corpuscles of Herbst
Merkel cells
Grandry cells
Avian Olfactory & Gustatory Function
Olfaction- Limited function (?) Food location Role in migration Behaviour Nest localisation Familiar odours Paired nares Olfactory epithelium
Gustation- Poorly developed
Bitter taste perception
avain migration senses
Navigational mechanisms not well understood
Triggered by photoperiod
Navigation
Vision- Sun compass (Polarised light)
Physical landmarks
Stars
Wind Direction
Olfactory Cues
Earth’s magnetic field
blastocyst formation
Fertilization- Oocyte release from Ovary.
moved through uterine tube
Fertilized early in uterine tube to form zygote.
Undergoes division in uterine tubes (Two-cell
Four-cell
Eight-cell
Morula (16 cells)- can no longer easily distinguish number of cells visually
Blastocyst (70-100 cells, starts to form patterns in cell mass. differentation begins) ) to form blastocyst and implants in uterus
forms
Inner cell mass = Embryo.
Trophoblast or outer cell mass = placenta
Blastocoel = Fluid nourishment.
in uterus
implantaion of blastocyst
Blastocyst implants within the uterine wall.
Digests uterine mucosa
Endometrium grows over the embryo fully securing to the uterine membrane.
the balstocyst develops into…
Epiblast
Hypoblast
differentiaes into two fluid filled sacs:
Amniotic sac from the epiblast.
Yolk sac from the hypoblast.
Bilaminar Embryonic Disk
amniotic sac (epiblast cells) and yolk sac (hypoblast cells) develope as disk
forms primitive streak- invagination of epiblast cells- first pattern to form
Formation of Trilaminar disk
gastrolation: formation of
Ectoderm
Endoderm
Mesoderm
these layers give rise to embryo
at primitive streak
Hypoblast replaced by Endoderm- origin of hair fur nails and neuro
Epiblast replaced by Ectoderm- origin of epitheliam
Mesoderm forms as a layer in-between- origin of everything else; organs ect
Notochord Formation
end poitn of gastrolation
Primitive node epiblast cells invaginate and migrate out of the primitive streak anteriorly with some endoderm cells
Rod running through the blastocyst the body axis is formed
Future site of the vertebral column
Body axis defined
Notochord establishes anterior vs posterior axis- head and tail poition established
cells making the nervous system are first cells to form pattern within blatocyst
Neurulation
development of the nervous system
gives pattern for rst of body formation
some ectoderm diffirentaites to thicken neral plate
difference between neural plate cells and neural plate borser cells
neural palte cells can defrintate to become central neroun cells
the neural plate begins to bend and two ends joun at point of neural crest cells
ectoderm reform over top
neural tube forms primitive spinal cord
neural crest becomes peripheral nervous system
closure of neural tube disconnects neural crest form epidermis
ectoderm forms over neural tube
Notochord signals overlying ectoderm
Formation begins of spinal cord and brain (neurulation)
Neural plate to neural groove to neural tube: pinched off into body
Mesoderm begins to differentiate- Lateral to notochord, week 3
Extends cranially and caudally
Division of mesoderm into three regions
Somites: 40 pairs of body segments (repeating units, like building blocks) by end week 4
Intermediate mesoderm: just lateral to somites
Lateral plate: splits to form coelom (“cavity”)- forms the varius cavities of body
Closure of neural tube: begins at end of week 3; complete by end of week 4 (folic acid important for this step)
Extends cranially (eventually brain) and caudally (spinal cord)
Neural crest, lateral ectodermal cells, pulled along and form sensory nerve cells and other structures.
Embryonic Folding
begins at end of neuralation
three layers are stil in disk formation
Beginning of morphogenesis (formation of body form).
Requires gastrulation of the three germ cell layers (ectoderm, mesoderm, endodrem
Initial fold forms the primitive digestive system.
Different to neurulation.
bosy is two tubes: spinal cord, digestive tract
Somitogenesis:
Body Formation
Beginning of formation of body systems and organs.
Main function of the mesoderm.
Five types: Chorda mesoderm Paraxial mesoderm Intermediate mesoderm Lateral mesoderm Head mesoderm
Somites- are symmetrical, segmental structures appearing in specific timeframes lateral to the neural tube.
Originate from paraxial mesoderm.
Differentiate into: Vertebrae, including intervertebral discs Major skeletal muscles. Dermis Ribs
Somite formation follows specific development time pattern.
Used to ‘age’ development.
can get idea of if something may go wrong- somites developing out of sync
Somites differentiate after formation into three main forms:
Sclerotome- diffrent types become different types of bone
Syndetome- in the middle
Dermomyotom- form on external part of somite
Bone Formation
verntral sclerotome- corpus vertebrae, didcus vertebrae
lateral sclerotome: distal ribs
medial sclerotome- menigges and vessels
arthrotome sclerotome- discus invertebralis, proximal ribs
dorsal sclerotome-
central sclerotome
pair up- caudal and cranial sclerotome will form vertebrae- caudal segment compact, cranial segment loose
motoneuronds form neural tube pass through loosened cranial segment and innervate myotome
Somitogensis: Muscle Formation
Epaxial myotome- Spinal muscles
Hypaxial myotome- Intercostals, Obliques, Abdominal and Limb
sydertome
Tendon Formation
sits between sclerotome and myotome and developes as skeletal muaslce developes
development of the bladder
developes form urachus
urachus-The urachus is a canal that exists when the fetus is developing before birth. This canal runs from the bladder of the fetus to the belly button (umbilicus). It drains the urinary bladder of the fetus.
amplical cord severed at birth and uracus shrinks down to become bladder- bladder had scar
reminents of urachius become median ligament to connect blader to ventral wall
umilical arteries become lateral ligament ot connect bladder to body wall
development of the kidney
dog, sheep- kidney bean shape
cow, dolphin- lobular
pig- elongated kidney bean
medulla and cortex can be partially divided, completly divided ot not divided, or with no differentiation of pyramids
cat has exterior veins
still similar structure- cortex, medulla, hylinx, renal vein and artery, pyramids
kindeys develop from mesoderm
Three stages of development-pronephros; developes in thorasic region and then regresses -mesonephros-metanephros
At different stages of development the urinary system resembles that of more primitive animals
mesonephric stage- pronephirc duct joins cloaca and joins multiple glomeroli
metanephric phase- mesonephroc pahse regresses. reflecs fully developed kidney, metanephric duct becomes ureter
uriteric bud- provides ductal sytem of kidney
development of reproducitve tract
Genital ridges form from intermediate mesoderm and epithelium
Endoderm from the yolk sac travels doen and combines with this to form sex cords
The sex cords can give rise to either testes or ovaries
two ducts ajacent to this ridge
mullerian duct- gives rise to female tract
wolffian duct- gives rise to male tract
Sex determination - female
No SYR gene owing to lack of Y chromosome.
Sex cords degenerate in absence of SYR gene
Epithelium proliferates to produce primordial follicle that associates with a germ cell
germ cells travel form yolk sac through mesentary and become the hugonian
Mullerian duct
The Mullerian duct becomes the oviduct, uterus, cervix and upper vagina
Sex determination - male
The SRY gene on the Y chromosome stimulates the sex cords to develop into testes
Germ cells form
Sertoli cells from epithelium
Leydig cells from from intermediate mesoderm. These produce testosterone to drive development of the genitalia
germ cells travel form yolk sac through mesentary
from genatal ridge an outpouch forms giving rise to testes
tunica albugina develops form epithelium
gentile ridge developes and beocomes testicle
cords become read testes
wolfian duct ( mesonephric duct)- becomes sstructures that carry sperm for testes
antimallerian hormone regressen melarian
Wolffian Duct
The Wolffian duct becomes the epididymis and vas deferens
Testicular descent
pre- or post partum
decend through ingunal canal
Avian Urinary tract
Clearance of waste Detoxification Conserve water and electrolytes Regulation of blood volume Regulation of blood pressure
Three lobed kidneys with nephrons as functional unit
No bladder
Cloaca- common site for ureters, deferent duct/oviduct to join
Solids in urine=uric acid (product of protein metabolism) combined with faeces- more costly to produce but allows conservation of water
Renal portal system- Blood flows back from iliac arteries to kidneys
avain kidneys
Kidneys – paired, variable number of lobes (3 lobes most common)
Cortex and medulla, 200,000 nephrons in chicken including both mammalian and reptilian nephrons. Mammalian nephrons have loop of Henle so are able to concentrate urine, reptilian nephrons don’t have loop of Henle and cannot concentrate urine
Kidneys and liver convert ammonia (toxic) into uric acid- clinically relevant, if kidney blocked up, uric aci can form build up- gout, stones
poultry meat inspection- faults
water belly, green muscle disease, green leg, spots on liver
lamb meat inspection
c.ovis- tapeworm
beef meat inspection
c.bovis- muscle
TB lesion- lymphnodes, liver, heart, lungs
pork meat inspection
absesses (up spinal cord)- from tail bite, fighting, stress
goat meat inspection
same as lambs
look emaciated
halal and kosher slaughter
no stunning
halal more relaxed about stunning
kosher more strickt- about inpections as well
sticking
a method to cut the carotid artery and jugular vein
the carotid is cut for the pumping action to increase blood loss
jugular is cat to starve brain of oxygen
pse
pale, soft and exudative
can result in carcus form stress
Ante-mortem inspection procedures
Observations
The OV must observe each animal (except poultry) moving and at rest.
The inspection must be sufficient to identify animals showing neurological symptoms, respiratory symptoms, alimentary tract abnormalities, change in gait, or external abnormalities.
Initial check
Routine ante-mortem inspection may begin with an initial check done by the MHI.
Where a suitably trained MHI assists the OV in carrying out the initial check, the OV should subsequently observe all the animals interacting with each other in their pens during ante-mortem inspection.
The initial check, if undertaken by the OV, may suffice as to constitute an adequate ante-mortem inspection.
Clinical inspections
In addition to routine ante-mortem inspection, the OV is required to carry out a clinical inspection of all animals which do not appear to be ‘normal’ and those that the FBO or an MHI may have put aside
To be able to carry out satisfactory ante-mortem inspections, clinical inspections and detailed examinations, the OV must have available the following facilities and equipment:
adequate lighting
adequate space
adequate access
adequate separate facilities for detailed examination (a crush or equivalent is desirable but not legally required – the OV should arrange suitable facilities with the FBO)
isolation pen(s) for suspect animals with separate drainage and situated as to avoid contamination of other animals (not needed in all establishments)
staffing assistance (for handling or restraint)
sufficient time
proper equipment, for example, thermometer and stethoscope
The inspection must take place within 24 hours of arrival at the slaughterhouse and less than 24 hours before slaughter.
In some cases, ante-mortem inspection may need to be repeated. The OV may inspect the animal(s) at any other time.
Animals are inspected before they are slaughtered to:
Identify any clinical signs of disease (e.g. Tetanus, rabies, poisoning):
Could be transmitted to humans (ZOONOSES) or other animals (e.g.Anthrax, Foot and mouth disease)
Make the meat unfit for human consumption
Identify animals which have had medications
Identify injured animals
stunning methods
With large animals, stunning is important to immobilize the animal to facilitate severing the blood vessels (sticking) to kill it.
Operator safety would be severely compromised by trying to stick a conscious animal unless it was fully restrained.
Manual restraint is feasible for small animals like sheep but not for cattle.
Restraint in specially designed pens is a feature of Jewish slaughter in high throughput plants in Europe and North America.
The stunning process must render the animal insensible immediately, or if it is not immediate, the process must be completely pain and stress free.
By relaxing the body, some stunning techniques may also benefit carcass quality.
There are different ways in which animals can be stunned.
The first is use of a mechanical instrument (captive bolt pistol, percussion stunner or free bullet) which traumatizes the brain so that the animal loses consciousness instantaneously.
The second is use of an electrical current passed through the brain.
The third is the induction of unconsciousness by immersion in an anaesthetic gas such as carbon dioxide.
Recognizing An Effective Stun
Tonic phase (lasts 10– 20 s ) Effective percussion stunning leads to the animal immediately collapsing, stopping rhythmic breathing and becoming rigid with head extended- stunning should be done in this phase
The position of the eyeball is fixed.
Clonic phase
Period of involuntary kicking movements of its legs (the). Gradually the animal relaxes- sticking should not procede at this phase
Post-mortem inspection
The carcass and viscera are inspected as soon as possible after slaughter.
As in ante-mortem inspection, this is to identify abnormalities or disease that would make the meat and edible offal unfit for human consumption.
To this end it is important that the carcass retains its identity with the parts and viscera removed from it.
by synchronized parallel line systems.
Inspection is normally carried out by specially licensed veterinarians or meat inspectors.
As well as inspection, they will often have other roles, including overseeing animal welfare and hygiene standards.
have characteristic lesions. Tissues and organs are examined by
visual inspection
palpation
incision
Considerable attention is paid to routine incision of lymph nodes to detect disease states. In infection, bacteria collect in the lymphatic system and are concentrated and destroyed in the lymph nodes.
In disease they become swollen and abnormal in colour.
Conditions such as pneumonia and tuberculosis
Listeria monocytogenes
Causes abortion in sheep
Found in variety of mammals, birds, fish
Commonly found in:
Raw and RTE meats and poultry, dairy products, raw vegetables, raw seafood and cooked seafood salads
Growth range -1°C to +45°C
“Ubiquitous” in the environment (decaying vegetation, soil, animal feed, sewage, water)
Affects susceptible populations = high mortality rate (~30%)
Pathogenic E. coli (O157:H7 and others)
Predominantly associated with cattle faeces
Associated internationally with:
Raw and undercooked red meats
Raw milk
Vegetables, sprouted seeds, unpasteurised fruit juices
Untreated water
Survives acidity to pH 3.6
Very low infective dose
Can cause kidney failure (HUS) and death in at-risk groups
Salmonella spp.
All salmonellas (>2200) presumed pathogenic “Enteric” origin – animals & birds
Historically associated with:
Raw eggs, poultry, meat & meat products
Has caused outbreaks internationally:
Almonds, tahini, tomatoes, melons & pawpaws, juices, sprouted seeds
Inadequate cooking also a factor
Campylobacter
Common commensal adapted to intestinal conditions Raw poultry (including offal) Raw milk and meat Untreated water Occupational exposure Low infectious dose ~500 cells Many cases, few outbreaks… Shows seasonality trends Is it more robust than we think?
UKZADI
Independent committee made up of experts from across the agricultural and public health departments:
Brings together agricultural and human health groups
Co-ordination of public health action at national and local level with regard to:
Existing and emerging zoonotic infections
Trends in antimicrobial resistance
Animal-related chemical risks to the food chain
Next generation sequencing:
Faster
Greater scale
Cheaper
miniturised
high-throughput parralled sequencing technology
whole genome sequencing
Method to determine the order of bases of an individual’s entire genome
Exome:
The part of the genome that is composed of exons (coding regions)
Genome
Entire set of DNA found in a cell
What is clinical sequencing
Compare the genomes of healthy and sick individuals
Genetic factors contributing to disease
Candidate genes
The more individuals we compare and the greater the depth of analysis the better
Genome-wide association studies (GWAS)
Observational study (non-candidate-driven)
Compares variants across entire genome in different individuals
Is a variant associated with a trait
Participants classified by clinical manifestation
Variant more common in those with disease
Variant associated with disease
Risk allele
Data-driven approach to medicine
Drug and diagnostic development
Prognostic accuracy
Personalised medicine (tbc)
Risk allele:
Version of a gene that is associated with higher incidence of disease trait
Single nucleotide polymorphism (SNP):
A single base-pair difference in the DNA of an individual
Copy number variant (CNV):
When the number of copies of a specific segment of DNA varies among different individuals
EG. do cancer patients have a higher incidence of this gene than others
Quantitative trait locus
Region of DNA identified to be associated with a particular phenotypic trait
Candidate gene:
: A gene believed to be related to a particular trait or phenotype. Suspected due to genomic location or known function
Phenome:
The sum of an individuals phenotypic traits (phenotypes of cells, tissues, organs and organism)
describe the pathophysiology of parvo
After a susceptible dog has oronasal exposure to secretions containing a CPV-2 virus
the organism infects lymphoid tissue and induces viremia for 1 to 5 days.
CPV-2 preferentially infects rapidly dividing cells of multiple tissues- calls that replace constantly- gut cells, bone marrow
Villus blunting of the crypt epithelial cells results in decreased absorption, inflammation, and necrosis. This is responsible for the classic signs of vomiting and diarrhoea, the latter of which frequently contains blood.
The severe inflammation and necrosis allow translocation of enteric flora that is commonly associated with sepsis.
CPV-2 are shed for approximately 3 to 14 days after infection and shedding can begin prior to clinical signs. CPV-2 are environmentally resistant.
disease of young dogs
called feline panluekopeia virus in cats
affects:
Gastrointestinal
Bone marrow – myelopoiesis
Cardiovascular (rarely)
describe the diagnosis of canine parvo
snap test
haemotology- leukopenia- low neutrophils and lymphocytes
name the canine salivary glants
mandibular
sublingual
parotid
temporary dental formula for dog
3130/3130
perminent dental formula for dog
3142/3143
describe the steps of gastrointestinal mobility
The walls of the GIT are muscular and exhibit slow waves of electrical depolarisation
Propel ingesta
Retain ingesta for digestion, absorption, storage
Break up and mix food with digestive secretions
PREHENSION:
Highly co-ordinated activity of small voluntary skeletal muscles
Horses use lips
Cattle use tongues
Co-ordinated by CNS and involves facial glossopharyngeal and trigeminal nerve
MASTICATION:
Breaks food particles down to a size that will pass into the oesophagus
Mixed with saliva to moisten and lubricate
DEGLUTITION:
Voluntary control: formation of bolus and pushed into pharynx
Involuntary control: swallow reflex
Controlled by lower motor neurons in brain stem, efferent fibres travel in the facial, vagus, hypoglossal, glossopharyngeal and trigeminal nerves.
Oesophagus remember is striated in most domestic animals, in horses, primates and cats a portion of the distal oesophagus is smooth muscle.
Rapid transferring of food from pharynx to stomach
Upper and lower sphincters constricted in between swallowings
Oesophagus enters stomach at oblique angle, Lower oesophageal sphincter particularly well developed in horse making reflux extremely rare!
STOMACH
Storage function (proximal region) – weak continuous contraction and adaptive relaxation
Grinding and sieving function (distal region) – intense slow wave activity and strong peristaltic waves
Gastrin secreted from antrum enhances motility, CCK, secretin and gastric inhibitory peptide supress gastric motility
Pylorus allows passage of particles below a certain size
Rate at which food leaves the stomach regulated by contents of SI
SMALL INTESTINE
Reflexes originate in SI to slow gastric emptying when digestive capacity is reached, receptors in duodenum activated by low pH, high osmolality and presence of fat (enterogastric reflex) Contribution of GI endocrine system suspected CCK secreted in response to fat and secretin in response to low pH (into dd), GIP secreted in response to carbohydrate(stimulates insulin)
Liquid meals cleared from stomach in around 1 hour and solid meal 3-4hours if relatively low fat
Motility of SI occurs in 2 phases a) digestive period b) inter-digestive period
Digestive phase: segmentation/non propulsive milking contents and mixing digestive juices, peristalisis/ propulsive movement in slow waves pushing ingesta through gut in short segments
Interdigestive phase: waves of powerful peristalsis contractions sweep entire length of small intestine
LARGE INTESTINE
ICCJ prevents movement of colon contents back into the ileum
Colon absorbs water and electrolytes, stores faeces and is involved in fermentation of organic matter(variable across species)
Horse, rabbits make extensive use of fermentation products for nutritional needs and have large and complex colons
Ruminant fermentation chamber is the stomach
Canine and felines have simple colons and don’t rely on fermentation
Mixing achieved by segmental contractions – absorption +/- fermentation
Horse and pig colonic segmentation is pronounced and formed sacculations or haustra assist with this
Retropulsion/antiperistalsis – slow waves from pacemaker sites which vary (accumulation of material)
In dogs colon is relatively simple – short caecum, ascending, transverse and descending segments.
describe the changes parvo causes to the intestinal crypts
villa- digetiona dn absorbtion funtions at tip
parvo blunts villi- decresed absorbtion, inflamation, necrosis, hemoragig dioreahia
crypt cells are damaged
what is the equine dental formula
Temporary formula 3- 0 -3 /3-0-3
Permanent formula 3-1-3(4)-3/3-1-3-3
what arises from lymphoid stem ceels
b and t cells
what arises from meyloid stem cells
eyrythrocites
platlets
granulocytes
monocutes
canine parvovirus 2 affects lympoid tissues, why is the depletion of diffrent lymphoid cells seen at diffrent times
neutrophils flee to site of inflamation and have shorted lifspan so a depeltion is seen in these first
red blood cells last 120 days in circulation
neutrophils less than 24 hours
If parvovirus is acquired perinatally it can cause …
inflammation and fibrosis in the heart muscle. This is incredibly rare due to the use of vaccinations
decribe the parts of an ecg
p= atrial depolarization (sinoatrial node) q= early ventricular depolarisation (AV node) r= ventricular depolarisation (purkinje fibres) s= late ventricular depolarisation t= ventricular repolarisation- relaxation of heart
in what intercostal space can the left atriovetntricular valve be oscultated in the dog
low 5th on the left
in what intercostal space can the pulmanory valve be oscultated in the dog
low third on left
in what intercostal space can the aortic valve be oscultated in the dog
fourth on the left
in what intercostal space can the right atriovetntricular valve be oscultated in the dog
high fourth on the right
common places for pulse rate in horses
digital
facail under ga
common places for pulse rate in ruminents
tail- coccygela artery
what are the lobes of the canine lung
RIGHT: Cranial, caudal, middle, accessory lobes (Larger)
LEFT: Cranial lobe(divided), Caudal lobe
Deep fissures divide the lobes
what are the lobes of the equine lung
Lungs almost equal in size Lt/Rt Less lobulated appearance right- crainial divided lobe middle caudal
left- crainial divided lobe and caudal
describe the avain lung
Relatively small unlobed bright pink non expansile lungs
Soft and velvety to touch due to increase in cartilage content
Confined to craniodorsal part of the body cavity, fail to cover the lateral surfaces of the heart as they do in mammals
Air sacs are blind thin walled enlargements of the bronchial system that extend beyond the lung in close relationship to the thoracic and abdominal viscera
Increased efficiency of gas exchange: thin blood gas barrier, cross current blood flow, one way air flow, pulmonary rigidity.
what are the components of the upper respiritory tract
Nares, nasal passages, pharynx, larynx
Defence
Thermal
Warm, humidifies air
Respiration
ventilation and gas exchange
Ventilation
transport of air to and from the lungs (or breathing)
Gas exchange
transport of o2 and CO2 between the air in the lungs and the cells in the body
what are the components of the lower respiritory tract
Defence Respiration Ventilation Gas Exchange Other
nasal plate (nasal labial plate)
hairless streach of ibtegrumetn around the nares
meets mucosa as it goes into the vetebule of the nares
Dilators of nostrils:
Levator nasolabialis
Caninus Muscle
Lateralis nasi
innervate dby facial nerve nd supplied by facial artery
Nasal Cavities
Functions: Conduction of air Moisten air Warm air Filters particle Olfaction
Creates:
Dorsal Meatus – olfactory mucosa
Middle Meatus – sinuses
Ventral Meatus – airway
cilliated epethelial cells
sinuses communicate with nasal cavities
nasal conchae
Further diide nasal cavities into nasal meatuses
Further increase nasal surface area
Highly vascular structure
more comples= greater sense of smell
Paranasal sinuses- horse
Frontal sinus- comunicates indirectly with caudal maxillay sinus via forntal maxillary opening
Caudal maxillary sinus
Rostral maxillary sinus- divided into lateral and medial compartments by infraorbital canal
can comunicate and drain intomiddle nasal meautus vis nasomaxillary opening
sphenopalatine sinus
sinuses- cattle
Lateral frontal sinus Medial rostral frontal sinus Caudal frontal sinus has cornual diverticulum Maxillary sinus Rostral frontal sinus Caudal frontal sinus Dorsal conchal sinus
Pharynx
Common to nasal and oral cavities- Large air filled cavity
Oropharynx- eustation tubes- connetion with middle ear
Nasopharynx
Laryngopharynx
Stratified squamous epithelium- Resistant to abrasion
Mechanisms to prevent inhalation of food
arytenoids
either of a pair of cartilages at the back of the larynx, used in the production of different kinds of voice quality
Alveoli
Site of gas exchange Single layer flattened epithelial cells Simple squamous Type 1 alveolar cells Specialised epithelial cells Type 2 alveolar cells Surfactant Reduce surface tension Prevents alveolar collapse Innate immune function Alveolus:Capillary network
Pleura
Visceral pleura
lung
Parietal pleura
Costal, diaphragmatic, mediastinal
Pleural Space negative pressure (Intra)Pleural fluid Adhesive forces on the two pleural surfaces Reduces friction
phrenic nerve
innervates the diaphram
fundic region of glandular stomcach
mucosa- cheif cells: pepsinogen and chymosin. Pepsinogen is activated into the digestive enzyme pepsin when it comes in contact with hydrochloric acid produced by gastric parietal cell. perietal cells: epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsic factor goblet cells: protective mucus submucosa tunica muscularis serosa
ruminant stomach
fermentation provides 60-70% of energy
microbes that break down celulose cells wall
rumen- microbes. volatile fatty acids readily absorbed. saliva buffers
recticulum- filters structures going to omasum
omasum- reabsorbs water, squaeses ingesta
abomasum- protien digestion and connects to duodeum. glandular
innervated by vagus nerve
what does the colon secrete and regulate
secretes bicarbonate
regulates absorbtion of water
regualtes MA, CL , K
splanic circulation
coeliac artery- hepatic, splenic and gastric artery
cranial mesenteric artery- duodenum to transverse colon
caudal mesenteric artery- transverse colon to rectum
what is the significance of raised fibrinogen levels in a cow
acute phase reactive protien
liver increases production in reaction to inflamitory cytokines concentrations increase within 24 hours of an inflamitory stimulus
similar to amyloid A in horses, haptoglobin in cattle
builds up within body cavities
indictes acute inflamation
ligament healing
acute phase- blood collects, platlets interact to creat clot and release groeth factore
proliferatvive- relases of GF and cytokines, fibroblast proliferation to rebild tissue matrix
disorganised scar tissue
remodling- collagin maturation occurs for months to years
tissue matrix resembes normal matrix
muscles fibre
individual fasicles bound in a group.
muscle facicle
muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.
articular cartilage
foind on end of long bone
compact bone tissue
Compact
Trabecular- struts across middel. add streanght to bone
Osteocytes- bone remodles acording to weight palced on it. osteocyts signal this
osteoblasts- lay down bone matrix
osteoclasts- absorbe bone
Scaffolding, leverage, protection
Calcium reservoir
forelimb stay apperatus
biceps brachii- lacertus fibrotus- extensor capri radialus: when weight presses down the shoulderjoimt is held open by these muscles
check ligaments reat a pull via their connects to the sdft and ddft
suspensory ligament
all creat sling
hindlimb stay apperatus
3 patella ligaments- medial middle and lateral- (dog only has one)
when quads contract the patela is pulled proximally- patellar catelage and ligaments hooks over medial epiconduile of femur to lock
reciprical arrangment of peroneus tertius and superficial digital flexor
layers of the scrotum
Skin
Tunica Dartos - Smooth muscle
Long term elevation of the testes
Scrotal fascia- external spermatic fascia
also has cremaster muscle here.
Internal spermatic fascia
- Parietal vaginal tunic
- Visceral vaginal tunic
- Tunica Albuginea
Dense connective tissue - Closely related with secretory tissues of testicle
Testes – functional overview
Functions:
Produce male germ cells (spermatozoa)
Produce male steroid hormone (testosterone)
Produce inhibin and oestrogen, and other proteins
2 main areas:
The connective tissue and vascular layers that penetrate into the testes
Tunica vaginalis
Tunica albuginea- split testes into lobules, medianstimal testes
The parenchyma region- seminiferous tubule site of sperm production consists of 2 cell types germ cells (eventual sperm cells) Sertoli cells provide structural and metabolic support to the developing spermatogenic cells
Interstitium (Leydig cells)
located between seminiferous tubules
produce androgens (testosterone)
dreains into efferent duct then the head of the epididimus
edpisydimus
store and aid in maturation of spermatozoa
once reaches tail the spem are mature
moved along from the head to the tail by rhythmatic peristalisis of smooth musle
in the tail sperm are stored in a viable but non motile state prior to ejaculatuion- must be diluted by appropriate buffer solution
connects to ductuas deferens and then pelvi urethra
Spermatic cord
Blood – testicular artery and vein
Lymphatic vessels, nerves
Vas deferens (deferent duct)- transport sperm
Cremaster muscle
Striated – short term elevation- primary muslce supporting testes, helps controle temp
Functions:
Thermoregulation
Pampiniform plexus - meshwork of veins that surrounds testicular artery. extremly important for thermoregulation. arterial blood cooled by veins to maintain optimun temperature fo sperm.
Pulse pressure
elimination at ingunal canal
peritoneal folds in testes
mesorchium
mesoductus deferens
Accessory reproductive glands
produce seminal plasma
Enter pelvic portion of the urethra
Prostate- Body (corpus prostate), Disseminate prostate- all species
Bulbourethral Gland- cat, bull, stallion
Ampulla of deferent duct- ct, stallion
Vesicular Gland- bull stallion
all glands paired except prostate
depenent on testosterone for prodution and maintanence
muscles in the penis
Urethral muscle- surrounds the pelvic urethra
Bulbospongiosus muscle- surrounds the bulbourethral glands and penile urethra
Transport of semen
Ischiocavernosus muscle- Encloses crura penis
Erection
retractor penis muscle- retracts penis into sheath
Fibroelastic penis
Boar, Bull, Ram Little increase in length and girth large emounts of fibrous and elastic tissue with little erectile tissue non expandabel connective tissue sheath sigmoud flexure
Musculocavernosus penin
Stallion, Dog
Significant increase in length and girth
lots of cavernous tissue
dog penis
Musculocavernous penis Distal part within prepuce (epithelial tissue) Os penis Pars longis glandis, bulbus glandis Prostate only (+ ampulla?)
cat penis
muscolocavernosus penis Caudoventral Penis Keratinised spines Androgen dependent Prostate Bulbourethral Glands Lack ampullae & vesicular glands
horse penis
Full set of accessory glands
Vesicular glands are lobulated
Pronounced ampullae
H shaped prostate gland corpus only
Musculocavernous penis
bull penis
fibroelastic penis Full set of accessory glands Vesicular glands are lobulated Prostate corpus + disseminate Fibroelastic penis Sigmoid flexure
boar penis
Very large bulbourethral glands Well developed vesicular gland Lack ampullae Prostate Heart shaped corpus prostate Disseminate = major portion Fibroelastic penis Corkscrew configuration of glans penis- ejaculation in cervix
Female Reproductive Tract Overview
Broad ligaments: Mesometrium- supports main body of uterus
Mesovarium- suports ovary
Mesosalpinx- supports oviduct and infandibulum (a fusion of the peritoneum during maturation)
mesovaruim and mesosalppinx form ovaruim bursa
Proper ligament of the ovary (Ovary to uterine horn)
Suspensory ligament of the ovary (O to dorsal bodywall)
Round ligament of the uterus- passes through ingunal canal, reminent of male repro
duplex uterus
2 cervical canals
separate uterine horns
rabbit
marsupeals
bicornate uterus
2 uterine horns
small uterine body
mare, cow, bitch, queen, sow
Uterine Tissue structure
Perimetrium (serosa)
Myometrium (muscularis)
Endometrium (submucosa & mucosa)
cervix
Multiple transverse interlocking folds
mucosa and muscle in cow and ewe
Multiple cervical folds
Long
Corkscrew/spiral- in sow
Loosely apposed folds- in mare
Fornix
Bitch, Cow and Mare
absent in sow
e fornix of the uterus (known in medical Latin as the “fornix uteri”) refers to the anterior (front) and posterior (back) recesses into which the upper vagina is divided. These vault like recesses are formed by protrusion of the cervix into the vagina
repro differences in cow
Caruncles: placental site of attachment
Intercornual Ligament - retracts uterus
Horn curl so ovary is close to body of uterus
Transverse folds in cervix
Suburethral Diverticulum- near urethral orifice
repro differences in sow
Extremely long horns, coiled
Corkscrew mucosal prominences in cervix
Suburethral Diverticulum
repro differences in mare
Ovulation only at oarian fossa
T-shaped uterus
Cervix – loose endometrial fold
fetal membranes
mammals.
Chorion (outermost)- Foetal portion of placenta
Yolk sac- Surrounds yolk in reptiles and birds
Amnion- Protective function
Allantois- Sac from hindgut
Collects waste
They are derived from the zygote.
3 stages of implantation
Apposition-blastocyst or foetal membranes become closely apposed to uterine lining (epithelium)
Adhesion- a complex biochemical interaction between molecules on the trophoblast and epithelium
Attachment (OR invasion)- Firm attachment OR invasion of trophoblast into uterus
Two types of foetal membranes that form:
Choriovitelline (Non mammals and marsupials)- A choriovitelline placenta is a placenta formed by the yolk sac and chorion. In a choriovitelline placenta, the yolk sac fuses with the chorion and subsequently wrinkles develop that hold the embryo to the uterine wall and the embryo, thus forming the choriovitelline placenta.
Chorioallantoic (ruminants, pigs)- forms outer layer that creats placenta- Chorioallantoic placentas (i.e., a large chorion fused with a large allantois) occur in certain lizards, in marsupials with long gestation periods, and in mammals above marsupials. The yolk-sac placenta does not invade maternal tissues, but intimate interlocking folds may occur between the two.
Horses, carnivores and rodents are Choriovitelline then chorioallantoic
types of placenta
Discoid (rodents)- 1-2 points of contact, discoid in shape
Cotyledonary (ruminants)- Multiple discrete areas of attachment (cotyledons) which interact with endometrium (caruncles) to form placentome
Zonary (dogs and cats)-Prominent band of tissue surrounding fetus
Diffuse (horses and pigs)- Almost entire surface of allantochorion involved
Cell layers at the maternal; Foetal interface
The tissues of the maternal placenta tend to be the prefix of the word, and the tissue of the fetal placenta the suffix.
Just prior to formation of the placenta, there are a total of six layers of tissue separating maternal and fetal blood. There are three layers of fetal extraembryonic membranes in the chorioallantoic placenta of all mammals, all of which are components of the mature placenta:
Endothelium lining allantoic capillaries
Connective tissue in the form of chorioallantoic mesoderm
Chorionic epithelium, the outermost layer of fetal membranes derived from trophoblast
There are also three layers on the maternal side, but the number of these layers which are retained - that is, not destroyed in the process of placentation - varies greatly among species. The three potential maternal layers in a placenta are:
Endothelium lining endometrial blood vessels
Connective tissue of the endometrium
Endometrial epithelial cells
It is important to recognize that there normally is no mixing of fetal and maternal blood within the placenta.
Foetal membranes of the dog
choriovitelline then chorioallantoic,
zonary, central,
endotheliochorial
Epitheliochorial, diffuse placenta of the horse
(choriovitelline then chorioallantoic)
Chorionic girdle Endometrial cups -equine chorionic gonadotropin (eCG)
). The CG cells begin migrating from the conceptus through the endometrium at days 36-38 to form (B) the equine chorionic gonadotropin-producing endometrial cups (EC)- fully formed around day 44
Ruminant foetal membranes
Chorioallantoiccotyledonary central epitheliochorial villous
Caruncles = maternal component
Cotyledons = fetal component
Caruncle + cotyledon = placentome
