Cells evolved as single, free-living organisms, but natural selection favoured more complex communities of cells, multicellular organisms, where groups of cells specialize during development to carry out specific functions for the body as a whole. This allowed the emergence of…
Cell Structure General characteristics of cells The shapes of mammalian cells vary widely depending on their interactions with each other, their extracellular environment and internal structures. Their surfaces are often highly folded when absorptive or transport functions take place across…
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This chapter brings together the regional descriptions of the arteries, veins and lymphatic vessels and their draining nodes that appear in the relevant sections of Chapter 24, Chapter 79 . The text is not illustrated: all cross-referenced figures and videos…
The peripheral nervous system (PNS) is composed of spinal and cranial nerves, their associated ganglia (autonomic and sensory) and their ramifications that transmit afferent and efferent information between the central nervous system (CNS) and the rest of the body. It…
The ankle joint (talocrural joint) is a diarthrodial articulation involving the distal tibia and fibula and the body of the talus; it is the only example in the human body of a true mortise joint. The human foot is a…
The knee is the largest synovial joint in the body. It consists of three functional compartments that collectively form a dynamic, specialized hinge joint. During gait, the knee is able to withstand impressive weight-bearing loads while conducting precision movements, providing…
The pelvic girdle consists of the paired hip bones (each composed of the ilium, ischium and pubis) and the sacrum. The two pubic bones articulate anteriorly at the pubic symphysis and the sacrum articulates posteriorly with the two iliac bones…
The structure of the lower limb is specialized for support of the body’s weight, locomotion and maintenance of body stability (balance). Indeed, adaptations for weight-bearing and stability account for the major structural and functional differences between the upper and lower…
The female reproductive system consists of the lower genital tract (vulva and vagina) and the upper tract (uterus and cervix with associated uterine (Fallopian) tubes and ovaries). Lower Genital Tract Vulva The female external genitalia or vulva (pudendum) include the…