1 The bitch has been pushing hard for an hour with no results. 2  A puppy presents rear end first and the head is too large to clear the pelvic bones.  There has been more than two hours between births, but you can still feel puppies inside.
Bronchus / Bronchi / Bronchioles. The airways of the lungs. When a person takes in a breath of air, the air travels through the nose or mouth, into the larynx, then into the trachea, which is the main passageway into the lungs. The trachea divides into a right and left main bronchus.
Respiratory | Trachea, bronchioles and bronchi. The conducting portion is made up of: nasal cavities, nasopharynx, larynx, trachea, bronchii and bronchioles. The trachea branches to give rise to two primary (main) bronchii. These then branch successively to give rise in turn to secondary and tertiary bronchii. These then branch to give rise to several orders of progressively smaller airways called bronchioles, the smallest of which are called terminal bronchioles.