Synapsids, formerly referred to as “mammalian reptiles,” are a group of insectivores formed in the Pennsylvanian subperiod at the end of the Carboniferous Period; they were the dominant group of terrestrial vertebrates in the Permian Period and early Triassic Period. ¹⁾

All bone tissue cells are involved in the regeneration of damaged bone. Osteoclasts (bone-depleting cells) enable the destruction of dead or redundant bone tissue. Osteoblasts (bone-forming cells) build bone and are responsible for bone regeneration [e.g. after fractures]. Osteocytes (bone cells) are transformed bone-forming cells that are a permanent component of bone. ²⁾

Squamous cartilage tissue is resistant to abrasion and has the ability to remineralize. It is found on articular surfaces, sternal parts of ribs, in the wall of the trachea, bronchi and larynx. ³⁾

The cuboid bone in the foot has an uneven cube shape and lies forward of the calcaneus on the lateral edge of the tarsus. Its medial surface is longer than its lateral surface. The cuboid bone usually fuses with four bones: the calcaneus, the lateral cuneiform, and the metatarsal bones IV and V. It also sometimes fuses with the scaphoid bone. ⁴⁾

The slender snipe eel (Nemichthys scolopaceus) is a species of eel-like fish. Nemichthys scolopaceus has the largest number of vertebrae of any vertebrate: at least 750. The species was first scientifically described by the Scottish physician and naturalist John Richardson in 1848. Its long jaws resemble a bird's beak, hence the species epithet. ⁵⁾

At birth, we have nearly 300 bones. Later, some of them fuse together so that there are 206 in an adult human. ⁶⁾

The male skull differs from the female skull in 14 elements, including the slope of the forehead, the thickness of the eyebrow arch, the mandibular joint, etc. ⁷⁾

The total weight of the bones in an adult male is about 12 kg and in a female about 10 kg. ⁸⁾

Bone is composed of organic and inorganic components. Organic elements include ossein, which is responsible for the elasticity and flexibility of bone. Inorganic elements include minerals: calcium phosphate, calcium carbonate, calcium chloride, calcium fluoride, magnesium phosphate, or alkaline sodium and potassium salts. In addition to these, bones consist of about 21% water. ⁹⁾

The main role of bone is to form the scaffolding or skeleton. It provides protection for internal organs, a place for muscles to attach, and bears the weight of the body. ¹⁰⁾

Bones are hematopoietic organs, as they house the bone marrow that produces blood cells. ¹¹⁾

Is it possible to live without bone parts? Yes, fragments of the skull, vertebrae, sternum, and pelvis are sometimes removed. ¹²⁾

Despite their great hardness, bones have plastic properties. Bone is able to adapt its appearance, shape, and thickness to the prevailing conditions. ¹³⁾

Some conditions leave permanent marks on the structure of the bones, such as syphilis causes the skull to be covered with tubules that look as if woodworms have passed through. ¹⁴⁾

Bone strength reaches a maximum level around age 30, then declines steadily. ¹⁵⁾

It is assumed that 10 ten minutes of sun exposure each day is enough to ensure adequate levels of vitamin D essential for bones. ¹⁶⁾