The correct macthing of the organs with their organ systems is as follows.
1. Digestive system - intestines.
2. Central nervous system - brain.
3. Respiratory system - tracheal system.
4. Excretory system - bladder.
Digestive system is made up of the alimentary canal consisting of the digestive organs and the glands. Among the digestive organs, the intestines play a major role in the process of digestion. The small intestine is the site of complete digestion which is associated with the pancreas and liver. The large intestine is involved the absorption of water from the digested food and remaining waste material is stored and thrown out of the body during defecation.
The central nervous system is made up of the brain and the spinal cord. The brain makes the largest part and the functional of the central nervous system. It controls most of the activities of the body. It is made up of three parts called the cerebrum, cerebellum and medualla oblongata and is protected by the skull.
The respiratory system is divided into the upper respiratory tract consisting of the nasal cavity, pharynx and larynx, and the lower respiratory tract consisting of the trachea, bronchi, bronchioles and the alveoli. The trachea or the wind pipe is a cylindrical tube infront of the oesophagus, supported by 16-20 C-shaped hyaline cartilage. It serves as a passage for air to move in and out of the lungs.
The excretory system is made up of a pair of kidneys, a pair of ureters, an urinary bladder and an urethra. The urine produced by the kidney flows through the ureters and is collected in the urinary bladder. A spinchter (a ring of muscle) guards the opening of the bladder into the urethra and relaxes only at the time of urination under the impulse from the brain.
