Connective tissueConnective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells.
Cell cycleThe cell cycle, or cell-division cycle, is the series of events that take place in a cell that causes it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm, chromosomes and other components into two daughter cells in a process called cell division. In cells with nuclei (eukaryotes, i.e., animal, plant, fungal, and protist cells), the cell cycle is divided into two main stages: interphase and the mitotic (M) phase (including mitosis and cytokinesis).
Body cavityA body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and the dorsal body cavity. In the dorsal body cavity the brain and spinal cord are located. The membranes that surround the central nervous system organs (the brain and the spinal cord, in the cranial and spinal cavities) are the three meninges.
OntogenyOntogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of a species.
Control of ventilationThe control of ventilation is the physiological mechanisms involved in the control of breathing, which is the movement of air into and out of the lungs. Ventilation facilitates respiration. Respiration refers to the utilization of oxygen and balancing of carbon dioxide by the body as a whole, or by individual cells in cellular respiration. The most important function of breathing is the supplying of oxygen to the body and balancing of the carbon dioxide levels.
