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In many cases, spines are a defense mechanism that help protect the animal against potential predators. Because spines are sharp, they can puncture skin and inflict pain and damage which may cause the predator to avoid that species from that point on. The spine of some animals are capable of injecting venom. In the case of some large species of ...
Unlike other Cambrian animals, these groups had the basic vertebrate body plan: a notochord, rudimentary vertebrae, and a well-defined head and tail, but lacked jaws. [29] A vertebrate group of uncertain phylogeny, small eel-like conodonts , are known from microfossils of their paired tooth segments from the late Cambrian to the end of the ...
The number of vertebrae in a region can vary but overall the number remains the same. In a human spinal column, there are normally 33 vertebrae. [3] The upper 24 pre-sacral vertebrae are articulating and separated from each other by intervertebral discs, and the lower nine are fused in adults, five in the sacrum and four in the coccyx, or tailbone.
However, the cervical spine is comparatively mobile, and some component of this movement is due to flexion and extension of the vertebral column itself. This movement between the atlas and occipital bone is often referred to as the "yes joint", owing to its nature of being able to move the head in an up-and-down fashion.
In other animals, the vertebrae take the same regional names except for the coccygeal – in animals with tails, the separate vertebrae are usually called the caudal vertebrae. [19] Because of the different types of locomotion and support needed between the aquatic and other vertebrates, the vertebrae between them show the most variation ...
Argonauts exhibit extreme sexual dimorphism in size and lifespan. Females grow up to 10 cm and make shells up to 30 cm, while males rarely surpass 2 cm. The males mate only once in their short lifetime, whereas the females are iteroparous, capable of having offspring many times over the course of their lives.
Ischial spine, part of the posterior border of the body of the ischium bone of the pelvis; Mental spine, on the mandible; Anterior nasal spine, a bony projection in the skull; Posterior nasal spine, for the attachment of the musculus uvulae; Spine of scapula, a prominent plate of bone; Spine of sphenoid bone (spina angulari) and ethmoidal spine
A spinous ventral process emerging from the haemal arch is referred to as the haemal spine. Blood vessels to and from the tail run through the arch. In reptiles, the caudofemoralis longus muscle, one of the main muscles involved in locomotion, attaches to the lateral sides of the haemal arches.