Comparative Anatomy Of The Vertebrae

In mammals, ribs are connected to the sternum through costal cartilage. This cartilage acts as a flexible joint, allowing the ribs to move during breathing and providing support to the ribcage. This connection between the ribs and sternum is important for maintaining the structure and stability of the chest cavity.

The name of the second cervical vertebra found in reptiles is the axis.

Fish do not have a sternum. The sternum is a bone found in the chest of mammals, including humans, that provides support and protection to the ribcage. Fish have a different skeletal structure, with their ribs and backbone providing support and protection to their internal organs. Therefore, the statement that fish have a sternum is false.

The statement is false because the vertebrae of condrichthyeans, which are cartilaginous fish like sharks and rays, do not have the same anatomy as modern mammals. While both condrichthyeans and mammals have vertebrae, the structure and composition of their vertebrae are different. Mammals have bony vertebrae, while condrichthyeans have cartilaginous vertebrae.

The top shell of a turtle is called a carapace. This hard, protective structure covers the turtle's back and serves as a shield against predators and environmental hazards. The carapace is made up of fused bones and is an essential part of the turtle's skeletal system. It provides structural support and helps maintain the turtle's shape. Additionally, the carapace also plays a role in thermoregulation, as it absorbs and retains heat from the sun, allowing the turtle to regulate its body temperature.

Yes, the thoracic ribs in amphibians do articulate with ribs. Amphibians have a bony ribcage that protects their internal organs, and the thoracic ribs are part of this structure. These ribs articulate or connect with each other and with the vertebrae, allowing for movement and flexibility in the amphibian's body. This articulation is important for various physiological processes, such as breathing and locomotion, in amphibians.

The bottom shell of a turtle is called the plastron. The plastron is a hard, protective structure that covers the ventral side of the turtle's body. It is made up of several bony plates fused together and provides important protection for the turtle's organs. The plastron, along with the top shell called the carapace, forms the turtle's shell, which is unique to this group of reptiles.

Ribs are not endochondral because they are formed through intramembranous ossification, where bone tissue forms directly from mesenchymal cells without the prior formation of a cartilage model. This process is different from endochondral ossification, which involves the formation of a cartilage template that is later replaced by bone tissue. Therefore, the statement "Ribs are not endochondral" is true.

In amphibians, the cervical vertebrae are called the Atlas. The Atlas is the first cervical vertebra that connects the skull to the rest of the spine. It allows for the movement of the head and provides support and flexibility to the neck region. This vertebra is named after the Greek mythological figure Atlas, who was known for carrying the weight of the world on his shoulders, symbolizing the important role of the Atlas vertebra in supporting the head.

The statement is true because chevron bones and haemal arches are two different anatomical structures found in vertebrates. Chevron bones are small bones that are located underneath the vertebral column and are involved in supporting and protecting the ventral side of the body. On the other hand, haemal arches are bony structures that are found in some species of fish and reptiles and are associated with the caudal (tail) vertebrae. They serve as a protective covering for blood vessels and nerves that run along the ventral side of the tail. Therefore, chevron bones and haemal arches are not homologous structures.

The name of the vertebrae that attaches to the pelvic girdle in amphibians is sacral. The sacral vertebrae are located at the base of the spine and connect the spine to the pelvic girdle. This attachment provides stability and support to the hind limbs, allowing for efficient movement on land and in water.

The fused trunk vertebrae in fish are called notarium.

The synsacrum is a fused structure found in birds that is formed by the fusion of the last thoracic, all lumbar, sacral, and first six caudal vertebrae. This fusion provides stability and support for the bird's pelvic girdle and allows for efficient flight. Therefore, the correct answer includes all of these fused bones.

The two main parts of a bicipital rib are caput and tuberculum. The caput refers to the head of the rib, which articulates with the vertebrae. The tuberculum, on the other hand, is a small projection on the rib that serves as an attachment point for muscles and ligaments. These two parts work together to provide stability and support to the rib cage.

The urostyle in frogs is a fused bone formed by the fusion of caudal vertebrae. Caudal vertebrae are the vertebrae located in the tail region of the frog. During development, these vertebrae fuse together to form the urostyle, which provides support and flexibility to the hindlimbs and helps in jumping and swimming.

The name of the elements that fill the gaps between neural arches in chondrichthyeans is dorsal intercalary elements. These elements are found in the dorsal region and serve to connect and support the neural arches, providing structural stability to the chondrichthyeans' vertebral column.

The sternebrae are the bones that make up the sternum or breastbone. The manubrium is the superior part of the sternum, located at the top, while the xiphisternum is the inferior part, located at the bottom. These two major parts of the sternebrae are important for providing support and protection to the thoracic organs, as well as serving as attachment points for various muscles and ligaments.

The added element, the haemal arch, is found in Fish and Amphibia. This is because the haemal arch is a structure that supports the blood vessels and is present in the tails of these two groups. Reptilia, aves, and mammalia do not have haemal arches in their anatomy.

The four major parts of a vertebra are the centrum, neural arch, neural spine, and transverse processes. The centrum is the main body of the vertebra, providing support and weight-bearing. The neural arch is a bony ring that surrounds and protects the spinal cord. The neural spine is a projection from the neural arch that provides attachment points for muscles and ligaments. The transverse processes are bony projections that extend out from the sides of the vertebra, allowing for muscle attachment and providing points of articulation with adjacent vertebrae.

Ribs develop from a structure called the sclerotome. The sclerotome is a region of mesodermal cells that form during embryonic development. These cells give rise to the vertebrae and ribs in the body. As the sclerotome cells differentiate and mature, they form the bony structures of the ribs. Therefore, the correct answer is sclerotome.

The three caudal fins mentioned in the answer are heterocercal, diphycercal, and homocercal. These terms refer to different types of tail fins found in fish. Heterocercal fins have an asymmetrical shape with the upper lobe larger than the lower lobe. Diphycercal fins are symmetrical and extend along the entire length of the tail. Homocercal fins are also symmetrical but have a notch at the end. These variations in caudal fins help fish with different swimming abilities and adaptations to their environment.

The pygostyle is a fused structure found in the tails of certain birds. It is formed by the fusion of the last few caudal vertebrae, typically the last five. This fusion creates a rigid structure that provides support for the tail feathers, aiding in flight and balance. The fusion of these vertebrae also helps to strengthen the tail, allowing for more precise control of the feathers during flight maneuvers.