Which organ is the part of both the male reproductive system and the urinary system?

The ureters are long, narrow tubes that transport urine from the kidneys to the urinary bladder. Each kidney has one ureter, which emerges from the renal pelvis (a funnel-shaped cavity in the kidney) and descends downward, passing behind the peritoneum and along the back of the abdominal cavity. The ureters then enter the bladder through small openings at the base of the bladder, where they join with the urethra, a tube that carries urine out of the body.

After birth, blood is primarily produced in the red bone marrow of the infant. Red bone marrow is a spongy tissue found in the hollow centers of certain bones, such as the skull, ribs, pelvis, and long bones of the arms and legs. Red bone marrow is responsible for producing red blood cells, white blood cells, and platelets.

In adults, some of the blood production shifts to other organs such as the spleen and liver. However, in infants, the red bone marrow is the main site of blood cell production until about 5 years of age when it begins to gradually transition to the other organs.

During anaerobic respiration, some living systems use an organic molecule as the final electron acceptor. Processes that use an organic molecule to regenerate NAD+ from NADH are collectively referred to as fermentation. One type of fermentation is lactic acid fermentation, which produces lactic acid (lactate) and NAD+1. The accumulation of lactic acid can lead to a burning sensation in muscles during intense exercise.

Intramembranous ossification is a process of bone formation in which bone tissue forms directly within mesenchymal (undifferentiated) connective tissue membranes. This process is responsible for the formation of the flat bones of the skull, including the frontal, parietal, occipital, and temporal bones.

Long bones of the arms and legs, bones of the pelvic girdle, and vertebrae are formed by endochondral ossification, a different process of bone formation in which bone tissue replaces hyaline cartilage.