S e c t i o n 1

General Anatomy

About General Anatomy1. A cell is a structural and functional unit of the body. The cells and the tissues are the fundamentals of

the body.2. General gross anatomy gives the general survey of the organs and systems of the human body including

their working.3. General embryology depicts the picture of the development of the human embryo in the womb of

the mother during fi rst 3 weeks of intrauterine life and also the basis of understanding the congenital anomalies.

Human Anatomy

Defi nitionAnatomy is a word of Greek origin which means ‘cutting’. Its Latin equivalent is anatomia which means ‘dissection’ and French word is anatomie. Up to this 21st century, there has been too much advancement in the fi eld of anatomy, especially in human anatomy. At present, anatomy is a branch of medicine and biology which deals with the study of structure of the body.

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CHAPTER

12 History of AnatomyCHAPTER

1In Italy (Bologna), Malphigi worked on histology of kidney,

spleen and other organs and established that capillaries intervened between arteries and veins.

In London, Hooke wrote a book on histology, ‘Micrographia’, and he was the first to use the term ‘cell’.

Towards the end of the 19th century, histology was established as a separate discipline of human anatomy. There was a great volume of histological work by Henle, Deitors, Purkinje, Leydig, Golgi, Nissl, Weigert, Clarke, Schwann and many others.

Schwann established the cell theory and proposed that a cell is the structural and functional unit of the body.

During the 20th century, Virchow, a German, established that disease is an abnormality in the cell. By the 20th century, histochemistry was invented, by means of which chemicals could be identified in the tissues, for example proteins, DNA, RNA, carbohydrates and lipids.

In 1950, electron microscope, with a resolution power of 1000 times and magnification by 1 million times, was invented. The powerful technique of X-ray diffraction in electron microscopy resolved the structure of DNA. Recently, various other methods have advanced, for example autoradiography, immuno-histochemistry and scanning electron microscopy.

NeuroanatomyBy the 20th century, a vast knowledge of the nervous system had accumulated following dissection done by Vesalius, Willis and many histologists named before. Schwann discovered the neuron, which is the functional and structural unit of the nervous system. Brodmann (1909) established the functional areas of cerebral cortex by cyto-architectonic method and a ‘Brodmann map’. This map indicates numbers to the areas such as motor areas —area 4, 6, 8, visual areas —area 17, 18, 19 and motor speech area 44, 45, also known as ‘Broca’s area’.

With the help of immuno-histochemistry, neurotransmitters and associated enzymes of brain have been identified.

Living Anatomy and Radiological AnatomyThe advent of diagnostic instruments has revolutionized the teaching of living anatomy, for example ophthalmoscope for visualizing the interior of the eye or laryngoscope for visualizing the throat.

IntroductionThe evolution of human race as Homo sapiens took place 35,000 years ago. When the human race came into existence, disease also came into existence and there was no knowledge of human body.

In 2000 BC, Greek philosophers gave the concept that human body is made up of four elements, fire, air, water and earth and disease occurs due to a disturbance in these four humours.

Gross AnatomyHippocrates (400 BC), who separated medicine from the above philosophy, is considered to be the Father of Medicine. Alexander the Great established the first medical school in Alexandria in 300 BC In the same school, Galen (129–199 AD) made contribution to expansion of the knowledge of anatomy by dissecting and observing anatomy in lower animals. According to him, a disease was caused by a disturbance in parts of the body. The dissection of the human body was prohibited because of the sanctity imposed by the religion.

During the 12th century, universities started in Oxford, Cambridge, Paris, Bologna and Padua. During the 15th and 16th centuries, Leonardo Da Vinci and Vesalius at Padua revised human anatomy by dissecting and studying the body.

During the 18th century in England, William Hunter established a museum of 13,000 specimens of various animals.

Morgagni, an Italian anatomist and pathologist, advocated that disease was caused by changes in organs. Wechat dissected 600 cadavers during one winter session in London and concluded that the organs are made up of tissues. William Cheselden, a surgeon, started a private anatomy school in England, where Barber surgeons used to attend classes. Only in 1832, ‘Anatomy Act’ was passed in England. Henceforth, departments of anatomy were provided with a regular source of bodies for student dissection. As a result, a practically good knowledge of gross anatomy has been compiled by now.

HistologyDuring period of 17th to 19th century, advances in human anatomy shifted from gross anatomy to histology due to invention of microscopes and many optical equipments.

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SECTION 1 General Anatomy4

Recently, scientists have developed genetic engineering or gene cloning. This method is being used for medical and commercial purposes like production of human insulin, somatostatin growth hormone (SGH), interleukin, interferon, hepatitis B vaccine, erythropoietin etc. Colony stimulating factors and receptors have been synthesized using genetic engineering such as CD4+ (cluster of differentiation) receptors in cells to understand the pathogenesis of, and hence therapy against HIV and AIDS.

Moreover, cloning may also be used to create genetically altered animals for harvesting major organs for transplantation into human beings.

ConclusionHuman anatomy, after conquering the knowledge of structure of the human body, is now marching into the future for the service of mankind. However, it should be remembered that the present achievements have had their foundation in the past.

Branches and Scope of Human AnatomyHuman anatomy comprises the following branches:

1. Gross AnatomyIt deals with the knowledge of anatomy visible through the naked eye. It is again divided into two major branches:

A. Regional AnatomyThis deals with the structures region wise. Broadly, the human body is divided into the following regions: (i) Head and neck, including brain and organs of special

senses (ii) Thorax (iii) Abdomen and pelvis (iv) Limbs (a) Upper limb (b) Lower limb

Again there are subregions or smaller parts in each of the above broad categories.

B. Systemic AnatomyThis deals with the anatomy of the structures and organs system wise, for example: (i) Nervous system (ii) Special organs (iii) Respiratory system (iv) Circulatory system (v) Digestive system (vi) Urinary system (vii) Genital system (viii) Ductless glands (ix) Musculoskeletal system

X-rays were discovered by Roentgen in 1895, following which many new inventions and study of deeper body organs began. In 1927, Moniz discovered cerebral angiography and studied blood vessels of the brain, for which he received the Nobel Prize. In 1967, the invention of computerized axial tomography (CAT) yielded a safe, accurate and sensitive technique for studying human anatomy throughout the body.

In 1973, the invention of nuclear magnetic resonance imaging (MRI) gave a better imaging of the body and means of assessing the function of human nervous system. Ultrasonography is being used for localization of anatomical structures—normal or abnormal, including the growing fetus inside uterus.

EmbryologyIn the 17th century, De Graff (1672) described the ‘ovum’, which is secreted from the matured ovarian follicle of the ovary. During the 18th century, Spallanzani (1775) proposed that spermatozoa separated from the male testis were the fertilizing agent for the ovum. von Baer (1872), during the 19th century, made significant advances in embryology and is regarded as Father of embryology.

During the 20th century, Tijo and Levan (1956) reported that there were only 46 chromosomes in each human embryonic cell. By means of ultrasonography, a complete picture of the growing embryo can be obtained and the sex of the baby can be determined.

Starting from 20th century, there were great advances in organ transplantation and in vitro fertilization (IVF). G. Harison started the work in modern tissue culture. Carrel grew tissues in flask and was involved in transplantation of organs, for which he received the Nobel Prize in 1912. In 1967, the first transplantation of the heart was done by C. Barnard in Cape Town. At present, transplantation of kidney and liver has become popular. There is also transplantation of the heart, lung and bone marrow.

In 1970, Edwards and Steptoe reported for the first time the fertilization of human egg in vitro (IVF). Then they developed the model to procure embryo transfer (ET) in human to produce pregnancy. They reported the successful birth of the first child from IVF-ET in 1978.

At present in vitro fertilization has become popular as a branch of human anatomy known as reproductive biology.

GeneticsIn the 19th century, Charles Darwin (1859) published The Origin of Species. The principle of heredity was developed in 1865 by an Austrian monk, Gregor Mendel. In 1940, Oswald, working at the Rockefeller Institute, showed that certain characteristics could be transferred from one bacterium to another through a substance called DNA. In 1959, Crick and Watson proposed the chemical structure for DNA.

In 1970, an Indian, Hargobind Khorana synthesized the gene, for which he received the Nobel Prize.

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CHAPTER 1 History of Anatomy 5

2. Histology or Micro anatomyIt deals with knowledge of anatomy visible only through a microscope. It is again of two types:

A. Light MicroscopyIn this, the source of illumination for the microscope is light—sunlight or artificial light. This method increases the magnification and resolution of an object. This defines the structure of the object, also known as histological picture.

B. Electron MicroscopyIn this, the source of illumination is electrons. Here, the magnification can be increased up to 1 million times and resolution up to 1,000 times. This defines the ultra structure of the object, also called as electron microscopic picture.

C. HistochemistryHistochemistry deals with identification of chemicals in the tissues, for example proteins, enzymes, DNA, RNA, carbohydrates and lipids.

D. ImmunohistochemistryThis method involves the production and identification of sites of antigen—antibody interaction in the tissue section. This can also localize neurotransmitters and their enzymes, pituitary hormones and their releasing factors.

3. NeuroanatomyThis is a part of anatomy which deals with the knowledge about nervous system, brain and spinal cord along with the peripheral nerves, which control the activities of the human body.

4. EmbryologyThis deals with the prenatal and post natal development of the human body. Through special methods such as ultrasonography, a complete picture of a growing embryo can be obtained. This branch has also facilitated development of organ transplantation and in vitro fertilization.

5. GeneticsThis branch deals with genes and hereditary characteristics. The knowledge in this field has opened an era of genetic engineering called cloning.

6. Comparative AnatomyThis branch deals with the development and morphology of human body, or its organs, in relation with the lower animals.

7. Physical AnthropologyThis branch deals with the physical characteristics, the evolution and various races of human beings. This also deals with the ‘fossils’, which aid in understanding the evolution of man.

8. Radiological AnatomyThis branch deals with the knowledge of anatomy through the use of X-rays. More recently, a good picture of the organs can be obtained with the help of CAT (computed axial tomography) scanning, ultrasound sonography and MRI (magnetic resonance imaging).

9. Morbid AnatomyThis branch deals with the changes in human body brought about by ageing or any pathological conditions.

10. Surface AnatomyThis branch deals with the study of the configuration of the surface of the body, especially in relation to its internal parts.

11. Clinical Anatomy or Applied Anatomy or Surgical AnatomyThis branch deals with the application of the knowledge of anatomy gained through any of the above disciplines to diagnose a disease and plan treatment, including surgery.

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