Portal:Anatomy

An anatomical variation, anatomical variant, or anatomical variability is a presentation of body structure with morphological features different from those that are typically described in the majority of individuals. Anatomical variations are categorized into three types including morphometric (size or shape), consistency (present or absent), and spatial (proximal/distal or right/left).

Variations are seen as normal in the sense that they are found consistently among different individuals, are mostly without symptoms, and are termed anatomical variations rather than abnormalities.

Anatomical variations are mainly caused by genetics and may vary considerably between different populations. The rate of variation considerably differs between single organs, particularly in muscles. Knowledge of anatomical variations is important in order to distinguish them from pathological conditions. (Full article...)

The breast is one of two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryological tissues. The relative size and development of the breasts is a major secondary sex distinction between males and females.

In females, it serves as the mammary gland, which produces and secretes milk to feed infants. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, and these tissues give the breast its distinct size and globular shape. At the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. During pregnancy, the breast responds to a complex interaction of hormones, including estrogens, progesterone, and prolactin, that mediate the completion of its development, namely lobuloalveolar maturation, in preparation of lactation and breastfeeding.

Humans are the only animals with permanently developed breasts in females. At puberty, estrogens, in conjunction with growth hormone, cause permanent breast growth in female humans. This happens only to a much lesser extent in other primates—breast development in other primates generally only occurs with pregnancy. Along with their major function in providing nutrition for infants, a number of cultures ascribe social and sexual characteristics to female breasts and may regard bare breasts in public as immodest or indecent. Breasts have been featured in ancient and modern sculpture, art, and photography. They can figure prominently in the perception of a woman's body and sexual attractiveness. Breasts, especially the nipples, are an erogenous zone. (Full article...)

Brain of a chimpanzee

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing those information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system).

While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. All vertebrate brains can be embryonically divided into three parts: the forebrain (prosencephalon, subdivided into telencephalon and diencephalon), midbrain (mesencephalon) and hindbrain (rhombencephalon, subdivided into metencephalon and myelencephalon). The spinal cord, which directly interacts with somatic functions below the head, can be considered a caudal extension of the myelencephalon enclosed inside the vertebral column. Together, the brain and spinal cord constitute the central nervous system in all vertebrates. (Full article...)

ʿAlāʾ al-Dīn Abū al-Ḥasan ʿAlī ibn Abī Ḥazm al-Qarashī (Arabic: علاء الدين أبو الحسن عليّ بن أبي حزم القرشي ), known as Ibn al-Nafīs (Arabic: ابن النفيس), was an Arab polymath whose areas of work included medicine, surgery, physiology, anatomy, biology, Islamic studies, jurisprudence, and philosophy. He is known for being the first to describe the pulmonary circulation of the blood. The work of Ibn al-Nafis regarding the right sided (pulmonary) circulation pre-dates the later work (1628) of William Harvey's De motu cordis. Both theories attempt to explain circulation. The 2nd century Greek physician Galen's theory about the physiology of the circulatory system remained unchallenged until the works of Ibn al-Nafis, for which he has been described as "the father of circulatory physiology".

As an early anatomist, Ibn al-Nafis also performed several human dissections during the course of his work, making several important discoveries in the fields of physiology and anatomy. Besides his famous discovery of the pulmonary circulation, he also gave an early insight of the coronary and capillary circulations. He was also appointed as the chief physician at al-Naseri Hospital founded by Sultan Saladin. (Full article...)