Tag Archives: thermoregulation

Ontogenetic changes in human crania

cranial-growth-postThe brain growth pattern in humans is distinctive among primates. In the past decades several hypotheses have been proposed to analyze cranial ontogenetic changes (i.e shape and size variations) in humans (e.g. Moss and Young, 1960; Lieberman et al., 2002; Bruner, 2004; Neubauer et al., 2009). The recent study conducted by García Gil et al. (2015) presents a preliminary approach to the histological variations of the vault bones in three individuals of different ages (child, adolescent and young adult). According to their results, it is possible to identify three different histological phases of cranial growth. In the child, vault bones are primarily composed of avascular lamellar bone (widely vascularized). In contrast, the adolescent bones show a larger extension of mineralized regions (highly remodeled areas) and low levels of vascularization, with a much reduced diploe. In the adult, the vault bone is highly vascularized and the diploe is largely expanded. The authors suggest that the sealing of the cranial bone surfaces helps to minimize the bone porosity while increases bone expansion (during childhood) and thickness (during youth). This “sealing process” could play a main role controlling head thermoregulation until the brain finishes its maturation. When confirmed on larger samples, these results can introduce new perspectives in functional craniology.

Gizéh Rangel de Lázaro

Advertisements

Head cooling device

TUntitled-1he brain thermoregulation is an important issue from anthropology to medicine. The brain thermodynamic mechanisms in humans are still not well known and additional heat regulations in certain physiological and pathological conditions are crucial to prevent irreversible damages. Namely hyperthermia is a life-threatening condition causing severe functional alterations. The brain temperature can increase as a consequence of drug abuse, head injuries, strokes, etc. Releasing of the heat stress can be treated by plenty of invasive and non-invasive methods, systemic or selectively aimed. However, establishing new effective thermodynamic techniques to treat pathological conditions is still relevant issue. In craniotomies, the cooling method can consist of simple system of drainage tubes directly attached to the dural layers or brain passing a cooling liquid directly to the affected tissue. Such selectively aimed device can help the post-operative recovery and prevent possible complications. The principles of the device remotely reminds of radiator theory, possible thermoregulatory adaptation in human lineage ancestors proposed in paleoanthropology few decades ago.

Hana Pisova