Avian Anatomy PDF

Avian Anatomy Dr. Attia Moselhy  AVIAN ANATOMY Hen Chick ‫كتكوت‬ ‫دجاجة‬ Cockerel Rooster ‫ديك‬  Chick: a baby chicken of either sex  Pullet: a female chick (immature chicken)  Hen: a female adult chicken  Cockerel:...

Avian Anatomy Dr. Attia Moselhy  AVIAN ANATOMY Hen Chick ‫كتكوت‬ ‫دجاجة‬ Cockerel Rooster ‫ديك‬  Chick: a baby chicken of either sex  Pullet: a female chick (immature chicken)  Hen: a female adult chicken  Cockerel: a male chick (immature chicken)  Rooster: a male adult chicken  Dual Purpose: chicken practical for meat and egg production CHICKEN SKELETON  CHICKEN SKELETON Axial skeleton Appendicular skeleton 1.skull. 2. Vertebral column 1. Wing bone. 3. bony thorax 2. Pelvic limb  Skull, assist the extreme opening of the mouth)  The vertebral formula in fowl is C14 T7 S14-16 Cd10  The Vertebral Column Region Fowl Cervical 14 Thoracic 7 Synsacrum 14 -15 Caudal 10 The skeleton of birds are adopted for flying through:  The bones of the fore limb are suitably constructed for adaptation to the wings, with a well developed shoulder girdle.  The presence of large sternum.  There is a considerable vertebral fusion; a- Thoracic region (2-5) notarium b- Lumbosacral region (7th T+4L+5S+5C) synsacrum c- Some Coccygeal vertebrae (last 2-3) pygostyle  The cervical vertebrae are highly mobile.  The pelvis are fused with the synsacrum and is situated forward in order to place the center of gravity on the hind limb.  The high mineral content make the avian bones harder, stronger and are lighter because many are pneumatic.  Absence of teeth.  SKULL a. Cranium:. b. Mandible: two thin bone fused rostrally. c. hyoid bone : frame work of tongue.  Notarium Cervical vertebrae Notarium Synsacrum Os lumbosacrale pyostyle  BONY THORAX 1. Ribs : 7 pairs, first two ribs are floating.  uncinate processes: are found in all ribs except the first and last rib, they overlapped the succeeding ribs and give rigidity to ribcage 2. sternum (breast bone) Carina   Appendicular skeleton: Pectoral girdle: pair of fused clavicle coracoid (furcula or wish bone), coracoid, scapula scapula. clavicle  Furcula (good luck bone) is a slender rod like bone fused ventrally and connected to the sternum by hypocleidial lig. furcula Pelvic girdle: 1. Ilium (pre acetebular) 2. Ilium (post acetebular) 3. ischium 4. Pubis 5. Acetebulum 6. Obturator foramen 7. Ilioischiatic foramen Wing bone: humerus 1. Humerus. (largest one) 2. radius 3. ulna is larger than radius 4. carpal bone (just 2) 5. carpometacarpal (lower row of carpal with II, III, IV fused) 6. digits II, III, IV radius 7. Phalanges (II, IV has one phalanges while III has two ulna phalanges IV Carpal bone Carpo-metacarbal bone II III Digits Hind limb: 1. Femur (thigh bone) 2. patella 3. tibio-tarsus (longer than femur) (drum stick) 4. fibula 5. sesamoid bones 6. Tarso-metatarsus (shank) 7. Digits (toe) I, II, III, IV 8. Phalanges  Hallux (digit I)short posterior directed toe consist of 2 phalanges.  Digestive system It consists of:  Oropharynx  Esophagus (crop)  Stomach (proventriculus – gizzard)  Intestine (small – large)  Cloaca  Accessory glands includes : salivary glands, liver and pancrease N.B.:1- Absence of teeth and soft palate 2- The salivary glands are mucous, unlike the mammals are lubricants or coat the tongue to trap insect  OROPHARYNX It is usual to refer to a common oropharyngeal cavity in birds because:  The soft palate, which forms a separation between the mouth and pharyngeal cavities in mammals, is absent.  The lips and teeth are absent and are replaced by the hard epidermal Beak. The roof of the Oropharynx :  Is formed by an incomplete hard palate.  It continuous with the nasal cavity through the choanal slit.  Infundibular cleft, which is the common opening of the right and left auditory tubes.  SALIVARY GLANDS The salivary glands are best developed in birds which have a relatively dry type of diet. they are mucus- secreting and have a large number of openings in the roof and floor of the oropharynx. saliva is lubricating material during swallowing.  ESOPHAGUS It connects the oropharynx to the stomach, and divided into the longer cervical part and shorter thoracic part.  The cervical part cranially lies in the midline dorsal to the larynx and trachea.  Immediately cranial to the thoracic inlet it returns to the midline and enlarge ventrally to form a saccular diverticulum (crop).  The crop (ingluvies)  A thin walled ventral In pigeons, saccular diverticulum the crop is  Strongly attached by the divided into two skin and when filled is readily visible and large lateral palpable. sacs.  Well developed in seed eating birds In ducks and Fun:  The crop is capable of geese the crop storing less easily digested is a simple food for a short time to fusiform widing expose to saliva.  Production of Crop milk of esophagus.  In pigeons, the more highly vascularized crop mucosa of both sexes (parents) produces so called crop milk. IT consisting of desquamated surface epithelium undergone fatty changes with other crop contents. It is regurgitating to the nestling , controlled by prolactine production, It resembles the mammalian milk, rich in protein & fat and lack in carbohydrate & calcium.  STOMACH The stomach of the birds has two parts separated by constriction isthmus (isthmus), and consists of the glandular stomach (ProventricuIus) and the muscular stomach (Gizzard).  GLANDULAR STOMACH (PROVENTRICULUS)  It is spindle shaped measures about 4 cm in length.  It lies in the left ventral part of the body  The internal surface showing a number of low, wide visible papillae.  MUSCULAR STOMACH (GIZZARD)  Its function as a masticatory organ.  It is shaped like a biconvex lens and it is firm and red in color.  It lies in in the left ventral part of the body cavity.  The main parts of the gizzard are the body, separates the two craniodorsal and caudoventrally blind sacs.  Near the edge of the craniodorsal blind sac and on the right surface there is the duodenal opening (pylorus).  The wall of the muscular stomach is formed from four muscles;  The internal surface is covered by brown, green or yellow tough membrane, the tunica cuticula or kolin layer. The internal surface is covered by brown, green or yellow tough membrane, the tunica cuticula or kolin layer which help in digestion with internal folds and the stones present in the lumen  SMALL INTESTINE It divided into: 1. Duodenum: Forms "U" shaped loop, embrace between their straight parallel limbs (descending and ascending limbs), the elongated pancreas. 2. Jejunum: Is the longest intestinal segment and occupies most of the right caudal quarter of the body cavity. A short blind reminant of the yolk sac and yolk stalk (Meckel's diverticulum) is present on the coil of jejunum. 3. Ileum: Is marked by iliocecal ligaments.  LARGE INTESTINE It consists of paired ceca and colon (rectum). 1. The ceca measure 12-15 cm in the fowl  They extend parallel to the ileum and fixed by ileocecal ligaments.  Each cecum has proximal (base), middle (body) and distal (apex) parts.  The wall of the proximal part contains lymphoid tissue (cecal tonsil). 2. The colon (rectum) is 8-11 cm extends caudally below the synsacrum as straight tube and ends in the coprodeum of the cloaca.  THE LIVER  The color: varies from red-brown to light brown except firs two week after hatching it is yellow color due to yellow pigment (yolk).  Position: it is suspended by peritoneum coelomic cavities The greater part is covered by ribs while other part lie against sternum. Lobation:  The liver consists of large nearly heart-shaped right and somewhat smaller prismatic shaped left lobes.  The caudal part of the left lobe is divided into (left medial) and (left lateral) parts. Surfaces: parietal or ventral and visceral or dorsal.  GALL BLADDER The gall bladder is embedded in the caudal half of the visceral surface of the right lobe of the liver Shape: 1) pear shape in fowl 2) tubular shape in aquatic birds 3) absent in pigeons and parrots  THE PANCREAS  It is reddish or pale yellow in color and ribbon-like present between the two limbs of the duodenum and enclosed within the pancreaticoduodenal ligament.  It has dorsal, ventral and splenic lobes.  The gland has three main excretory ducts; two of which arise from the ventral and one from the dorsal lobe.  The splenic lobe has no separate excretory duct.  the pancreatic and bile ducts open into duodenum opposite the cranial part of the gizzard.  RESPIRATORY SYSTEM It consists of:  -Nostril (external nares)  -Nasal cavity  -cranial Larynx  -Trachea  -caudal larynx (syrnix)  -Lungs  -Air sacs NOSTRIL THE NOSTRIL IS AN ELONGATED NARROW SLIT IN THE UPPER BEAK BOUNDED DORSALLY BY A SHEET OF HORNY SKIN, CALLED OPERCULUM.  The Nasal Cavity  Is cone-shaped with the pointed apex rostrally.  The nasal septum separates the left and right side completely  Each cavity can be divided into 3 communicating parts: 1. Nasal vestibule contains the rostral concha. 2. respiratory compartment contains the middle concha. 3. olfactory compartment contains the caudal concha.  The infraorbital sinus: is a triangular paranasal sinus, situated rostroventral to the eye.  The choanal opening: It is a median elongated opening through which the nasal cavity communicates with the oral cavity. Salt gland=Nasal gland It is formed from two lobes (M.&L.). It lies over the dorsal aspect of the eye ball and continue with the nasal cavity. Its function is osmoregulation, it secretes 5% Nacl in marine birds.  Cranial Larynx in the most caudal part of the floor of the oropharynx. The laryngeal mound carrying the opening into the larynx, the glottis (laryngeal inlet). The vocal cords are absent. The laryngeal cartilages are four in number; the median cricoid, procricoid and the paired arytenoid cartilages. Thyroid and epiglottis are absent.  TRACHEA It follows the cranial larynx ventrally along the neck.  In fowl, there are 100-130 tracheal rings with annular ligaments between them.  The terminal part of the trachea and the first part of the main bronchi are modified to form the syrinx (caudal larynx).  SYRINX (CAUDAL LARYNX)  It is present at the junction of the end of the trachea with the beginning of the Rt. & Lt. primary bronchi.  It is formed by four cartilaginous group: 1- Three-four cranial cartilages 2- C-shape four intermediate cartilages 3- Wedge shaped pessulus 4-Caudal C-shaped three cartilages The function of syrinx are production of voice and known as Tympanum. The voice is produced by two pairs of thin membranes lateral tympanic membrane andMedial tympanic membrane.  LUNG  The birds have two lungs, bright red in color , not lobed and both are similar in shape and size.  It is rectangular structure lies dorsally in the pulmonary cavity. Primary bronchus: secondary bronchi: Tertiary bronchi (parabronchi): N. B.: absence of alveoli and their replacement by air capillaries provides the birds with a large respiratory surface. This explains how intensive gaseous exchange may occur despite the small total volume of the avian lung.  AIR SACS  It is characteristic of the respiratory system of birds.  It have poor BL.S. Thus they do not enter in the process of gaseous exchange.  They act to ventilate the lung.  they contribute to the reduction of the specific gravity of the avian body  play a role in regulating the body temperature.  In adult there are 8 air sacs (cervical- clavicular- 2 cranial thoracic- 2 caudal thoracic and 2 abdominal), while in the embryo there are 10 air sacs. AIR SACS