study of behaviour (ethology)

Behaviour may be defined as the outwardly expressed course of action produced in organisms in response to stimuli from a given situation. The action modifies, in some way, the relationship between the organism and its environment and its adaptive significance is the perpetuation of the species. All living organisms exhibit a variety of forms of behaviorism activity deter-mined by the extent to which they are able to respond to stimuli. This varies from the relatively simple action of the growth of a plant stem towards a light source, to the complex sexual behavior patterns of territory defense, courtship and mating seen in birds and mammals. Plant behavior is restricted to movements produced by growth or turgid changes and is stereotyped and predictable. The two main activities associated with plant behavior are tropisms and taxes and details of these are described in section. Animal behavior is far more complex and diverse than plant behavior and therefore it is extremely difficult to investigate and account for with any degree of scientific validity. The three main approaches to behavioral studies are the capitalistic, mechanistic and ethological approaches. 

Vitalistic approach

This seeks to account for behavioral activities in terms of what animals are seen to do, and attempts to relate this to changes in the environment. It involves the total rejection of any study of the animal outside its natural environment. The technique has its foundations in natural history and has provided a wealth of valuable data, but it is essentially non scientific since all the observations relate to past events which cannot be tested experimentally.

The meninges and cerebrospinal fluid....

The central nervous system is surrounded by three layers or 'membranes' called meninges  and is completely encased within the protective bones of the skull and vertebral column. The outer membrane forms the tough dun mater which is attached to the skull and vertebrae, and the inner membrane forms the thin Pia mater which lies next to the nervous tissues. Between the two is the arachnid 'membrane'. This includes a space, the arachnophobia space, strands of connective tissue, blood vessels and cerebrovascular fluid (CS). Most of this fluid is contained in the central canal of the spinal cord and continues forward to occupy four expanded cavities within the brain called the ventricles. The fluid therefore comes into contact with the outside and inside of the brain, and blood vessels lie within it for the supply of nutrients and oxygen to the nervous tissues and the removal of wastes. It also contains lymphocytes to protect against infection. Meningitis is caused by an infection of the meninges. About 100 cm3 of fluid is present in the CNS and, apart from its nutritive, excretory and defensive functions, it supports the nervous tissues and protects them against mechanical shock. A continual circulation of fluid is maintained by cilia ted cells lining the ventricles and central canal. 

The Spinal Cord

The spinal cord is a cylinder of nervous tissue running from the base of the brain down the back. It is protected by the vertebrae of the backbone (vertebral column) and the meninges. It has a shaped central area of grey matter, composed of nerve cell bodies, dendrites and synapses surrounding a central canal which contains cerebrovascular fluid. Around the grey matter is an outer layer of white matter, containing nerve fibers whose fatty myelitis sheaths give it its characteristic color. There are 31 pairs of spinal nerves and these divide dose to the spinal cord to form two branches called the dorsal root and ventral root. 

 

The hip and thigh

The lower limb, similar in structure to the upper, is modified by its functions of support and propulsion of the body. During its development there is rotation medially on its long axis, so that the flexion surface lies posterior and the sole of the foot faces backwards and then downwards. The pelvic girdle, unlike the pectoral girdle, is firmly attached to the vertebral column, which allows the transmission of the body's weight through it to the lower limb. In the standing position the center of gravity passes behind the hip and in front of the knee and ankle joints. The weight is distributed between the heel and the balls of the toes, most of it being carried by bones and ligaments, with only a minimal amount of muscle activity being required to maintain balance.

The Deep Fascia

 The deep fascia of the gluten region and thigh forms a investigating layer, the fascia lats, from which medial and later inter muscular septa divide the thigh muscles into distinct com departments. Proximal it is attached in a continuous line to the inguinal ligament, lilac crest, posterior sacrum, sacra tuberous ligament, Islamophobic rams and the body of the pubic . Three centimeters below and 1 cm lateral to the pubic tubercle an oval deficiency in the fascia, the sousaphones opening, transmits the great sousaphones vein. The fascia lam is thickened on the lateral side of the thigh, the tibial tract, which is attached distally to the lateral tibial cotyledon. Glutenous maxims and tensor fascias latte gait Impeachment to the tract. Thus they may assist in extension and mobilization of the knee. Over the political fossa the fascia is by the small sousaphones vein. The fascia a is rather like a pair of women's tights.