Download Lec

Lec. 16
Pigeon
Practical Biology
* Respiratory system:
1- Two External nostrils and internal nares, are two narrow slits lying close together
in the roof.
2- The upper larynx, which opens by the glottis into the pharynx.
3- The trachea, that lies ventral to the esophagus and is supported by partially ossified
rings. In the thorax, it divides into two bronchi, to the two lungs.
4- The syrinx, or vocal organ, is formed by the posterior end of the trachea and the
adjacent portions of the two bronchi
5- The air-sacs, which are membranous extensions of the two bronchi. Nine air-sacs
are found:
A- The cervical air-sacs, two in number, lying at the base of the neck.
B- The interclavicles air sac, single and lies between two clavicles. It is gives off
axillary air-sacs.
C- The anterior thoracic air-sacs, are two in number, and cover the ventral surface of
the anterior parts of the lungs.
D- The posterior thoracic air-sacs, are also two in number, and lie posterior to the
former.
E- The abdominal air-sacs are the largest of the air-sacs, two in number and lie
dorsal to the intestine.
* Note: the air-sacs of each side are separated from the viscera by the oblique
septum, which is a fibrous membrane attached to the pericardium and
extends backwards.
1
* Circulatory system:
1- The heart is 4 chambered, consisting of two atrium and two ventricles. Examine
the heart from the exterior and note it is comparatively large size (characteristic
feature); it is conical shape with the apex directly backwards and slightly to the left
side.
2- Venous system:
- The venae cavae, are three big veins opening into the right atrium, right and left
anterior venae cavae and a posterior vena cava.
3- Arterial system:
- The pulmonary arch, from the right ventricle, divides into two pulmonary arteries to
the lungs.
- The aortic or systemic arch is single and turns to the right (characteristic feature).
* Nervous system: is consisting of brain and spinal cord which are covered by
duramater and piamater.
- The brain is consist of two cerebral hemispheres, very large and attached to them
are two very small olfactory lobes; pineal body; two large optic lobes; large
cerebellum; medulla oblongata.
2
*Urinogenital system
A- The urinary system: this consists of:
1- Two kidneys and two ureters, there is no urinary bladder. The kidney has three
lobbed lie in fossae of sacral region.
2- The ureter is leaved the kidney and opens on the dorsal wall of the cloaca.
B- The male genital system: this consists of
1- Two testes and two vasa deferentia. Each testis is an oval body, cream white in
color and attached by mesentery to the inner border of the anterior lobe of kidney.
2-From inner border of testis, vas deferentia emerge and open into the cloaca. The
vas deferens is dilates into small vesicula seminalis before connection with cloaca.
3-There no copulatory organs, the copulation occur by contact of the cloaca of the
male with that of the female.
C- The female genital system: this consists of
1- One ovary and one oviduct (left), the left ovary is attached to the body wall at the
anterior end of the left kidney by a mesovarium, the right ovary is disappeared.
2- The left oviduct (infundibulum, magnum, isthmus, uterus and vagina) is a wide
convoluted tube which opens into the body cavity by a funnel-shaped internal
3
opening and into the cloaca by an aperture which lies lateral to that of the left
ureter.
The male
The female
4