A & P 101

Some humans may have both features, luck of the DNA draw and completely normal as well. Photo is from The Anatomy Coloring Book by Wynn Kapit & Lawrence M. Elson

did-you-kno:

On a lush tropical island in a remote area of the Caribbean something, very peculiar is happening. The young girls in one village are turning into boys.  This startling sex change is occurring naturally, and a team of scientists sent to the island believes it could throw a new light on fundamental aspects of human nature and sexual identification.  It has all been revealed in a fascinating documentary shown recently on BBC television, called The Fight to be Male.

Source

(via purv-dawg-deactivated20120207)

houseofmind:

Why do many psychiatric disorders emerge during adolescence? 

Adolescence is a critical developmental time period marked by the increased incidence of a myriad of psychiatric illnesses, including but not limited to: anxiety and mood disorders, eating disorders, substance abuse disorders and psychosis. It is believed that abnormalities in maturational events that typically accompany adolescence may contribute to psychopathologies. 

Areas of research that study the effect of aberrant brain and neural development typically focus on studying and understanding: 

• Trajectories of grey/white matter volume and cortical thickness: MRI evidence suggests that cortical grey matter and cortical thickness decrease during adolescence, which has commonly been interpreted as being the result of synaptic pruning, a process by which redundant (and therefore unnecessary) synapses are eliminated through an experience-dependent process throughout early development. However, these decreases in volume/thickness do not apply to all brain areas, as some display a nonlinear relationship with age. Volumes of white matter usually show a linear increase throughout childhood and adolescence.
• Changes in myelination and synaptic pruning and their effect in forming functionally interconnected circuits: This is one of the most popular areas of study, as changes in synaptic pruning and myelination have been the most popular explanations for the structural differences in the adolescent brain. Early post-mortem studies have indicated a decrease in the number of synapses during childhood and adolescence. Newer evidence, however, has indicated that the gradual decrease of synapse number begins in childhood (in several cortical regions) and continues through adolescence. 
• Changes in brain activity of neural networks: Age-related changes in neural connectivity and neurotransmission are thought to underlie the functional changes associated with adolescence. Using fMRI techniques, researches have found that adolescents show differential functional connectivity across multiple circuits. Some of these include: the action-observation network, considered by many to be the neural substrate of imitation; the biological-motion processing network, also known as the superior temporal sulcus (STS) network, implicated in the extraction and encoding of socially relevant cues imparted by movement (i.e. eyes, hands, etc); and, the executive network, which underlies multiple cognitive processes involved in decision-making and working memory. Adolescents have also long been regarded as being high risk takers and displaying increased novelty-seeking behaviors.
• Neurochemistry: Finally, the efficacy of communication and integration of neural networks depends on neurotransmission and the state of these transmitter systems. Due to the experimental constraints of studying human children and adolescents, the scientific knowledge of developmental changes in neurotransmitter systems is limited. Most of the known data comes from post-mortem or nonhuman primate studies. However, one of the better studied systems is the developmental changes in dopamine neurotransmission and its relation to adolescent-specific changes in motivational behavior. The mesolimbic dopamine pathway, a key circuit implicated in reward and addiction, has been found to be anatomically and functionally distinct in adolescents. 

After reading all of this, one thing is clear: there is no single answer. Adolescence is the product of many integrated developmental and functional changes. Both our body and our brains are constantly changing to reflect what we’ve learned and what is necessary for survival. Additionally, many other factors come into play in influencing healthy and normal development like sleep patterns, history of disease, hormonal changes underlying puberty, dietary habits and teenage smoking/drinking. 

Makes you feel like going back in time and taking better care of yourself as a teen doesn’t it? 

Source: 

Paus, T., Keshavan, M., and Giedd, J. 2008. Why do many psychiatric disorders emerge during adolescence? Nature Reviews Neuroscience. 9 (12): 947-957. 

butterflieswhispertodeath:

Tibetan Hentai - Masturbating by candygears

(via montycantsin)

houseofmind:

A novel method of gaining a clear view of the brain (literally) emerges

(Clicking on the image links back to the original article featured in the NY Times). 

Japanese neuroscientists at the Riken Brain Institute may have found a way to visualize the brain’s gray matter, which consists of a neuronal cell bodies, neuropil, glia and such. They have created a chemical concoction, termed Scale, that makes dead and opaque (biological) tissue into a clear and jelly-like substance. Thus, soaking brains into this special solution enables scientists to preserve and physically observe what’s inside the brain. The development of this new chemical approach towards visualizing the brain may be revolutionary in the study of the brain’s neural architecture and connectivity as well as neural development. 

Click here for the link to the original article published in Nature Neuroscience.  I highly recommend you check out the original article- the images are just too cool!

Oh, and I forgot to mention: there’s already talk of international collaborations that would apply this method to study HUMAN brains. What what?!

wateroftheclearestblue:

zenlikeme:

Vitruvian Man

based on the Roman architect Vitruvius’s measurements of the perfectly proportioned human being.

from the Wikipedia article

Leonardo is clearly illustrating Vitruvius’ De architectura 3.1.2-3 which reads:

For the human body is so designed by nature that the face, from the chin to the top of the forehead and the lowest roots of the hair, is a tenth part of the whole height; the open hand from the wrist to the tip of the middle finger is just the same; the head from the chin to the crown is an eighth, and with the neck and shoulder from the top of the breast to the lowest roots of the hair is a sixth; from the middle of the breast to the summit of the crown is a fourth. If we take the height of the face itself, the distance from the bottom of the chin to the under side of the nostrils is one third of it; the nose from the under side of the nostrils to a line between the eyebrows is the same; from there to the lowest roots of the hair is also a third, comprising the forehead. The length of the foot is one sixth of the height of the body; of the forearm, one fourth; and the breadth of the breast is also one fourth. The other members, too, have their own symmetrical proportions, and it was by employing them that the famous painters and sculptors of antiquity attained to great and endless renown. Similarly, in the members of a temple there ought to be the greatest harmony in the symmetrical relations of the different parts to the general magnitude of the whole. Then again, in the human body the central point is naturally the navel. For if a man be placed flat on his back, with his hands and feet extended, and a pair of compasses centred at his navel, the fingers and toes of his two hands and feet will touch the circumference of a circle described therefrom. And just as the human body yields a circular outline, so too a square figure may be found from it. For if we measure the distance from the soles of the feet to the top of the head, and then apply that measure to the outstretched arms, the breadth will be found to be the same as the height, as in the case of plane surfaces which are perfectly square.^[5]

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nymphe:

laura hynd.