The iris is the final layer

The iris is the final layer of the uveal layer, & is a thin, contractile, pigmented diaphragm with a central aperture – the pupil. It is suspended in the aqueous humour between the lens & the cornea. It has two layers, the stroma & the epithelial layer (of which there are two). The stromal layer is highly vascular connective tissue & contains fibroblasts, melanocyes, mast cells, lymphocytes, macrophages & matrix, as well as smooth muscle for the sphincter papillae muscle. The anterior epithelial layer is in contact with the stroma & closely associated with the dilator papillae muscle & is continuous with the outer pigmented layer of the ciliary body. The posterior epithelial layer bathes in aqueous humour & is continuous with the inner non-pigmented layer of the ciliary body, & faces the posterior chamber. The iris receives its blood supply from the long posterior ciliary arteries & anterior ciliary arteries, & its function is to dilate/constrict the pupil, to control the amount of light entering the eye. People who have blue eyes have less melanocytes/pigment cells.

 

 

The last layer of the eye is the retinal layer, which lies between bruch’s membrane of the choroid & the vitreous body. It’s thickness varies, & is continuous posteriorly with the optic nerve, & anteriorly with the iris & ciliary body. It’s is made up of two layers – the outer pigmented & the inner nervous layers. (The space between the layers is called the intraretinal space). The pigmented layer (RPE) consists of a single layer of cells that extends forward from the optic nerve to the ora serrata anteriorly, & here it continues forward with the continuation of the nervous layer as the pigmented ciliary epithelium. The cells near the optic nerve are tall (columnar) & hexagonal in cross section, but become flattened as they near the ora serrata (cuboidal). They are strongly attached to the choroid & the apical surface faces the inner nervous layer (neural retina). The apical ends of the cell show lots of microvilli (5-7µm long) that project between & surround the outer segments of the rods & cones. The cells are embedded in glycosaminoglycans & joined together at the basal end with zonula adherens which encircles the cell, & in the apical regions by zonula occludens. These tight junctions are important in maintaining the isolation of the retina from the systemic circulation (the blood retina barrier; prevents large toxic molecules from the choroid capillaries from entering the retina, to the photoreceptors). The functions of the pigmented layer include absorbing light, participation in turnover of the outer segments of photoreceptors (except phagocytosis of tips of cones) & the formation of photopigment (made up of opsin & chromophore) by storing & releasing vitamin A). Opsin is rhodopsin for rods, iodopsin is for cones & the chromophore is the light-sensitive part of it, each photo receptor contains around a billion molecules of photopigment. Retinal detachment is where the retina detaches from the choroid; causes a shadow over one eye, floaters but no pain). The neural retina consists of three main groups of neurons: photoreceptors, bipolar cells & ganglion cells. Horizontal & amacrine cells are also present, which modulate their activity. Altogether there are ten layers that make up the retina: RPE, photoreceptors, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, optic nerve fibre layer & internal limiting membrane. Photoreceptors are of two types: rods & cones. Rods work better in the dark (responsible for dim vision). The total number of rods in the retina is approx 125 million, & are located mostly around the periphery (~30,000/mm² at extreme periphery), they are absent at the fovea. The rod cells are ~110µm long. Their outer segment  are layers of flattened discs containing light detecting proteins (continuously shed & replaced at dawn), while the inner segment is made up of the ellipsoid & myoid, & contains organelles. (Ellipsoid contains mitochondria, myoid contains rough & smooth ER, ribosomes & golgi apparatus). The outer & inner segments are connected by the connecting stalk. The bases of the rods are spherules, which contains presynaptic vesicles that synapse with the dendrites of the bipolar cells.

Cones are less sensitive to light than rods & therefore are adapted to bright light & can resolve fine details & colour vision. The measure to be about 70µm in length, & their total number in the retina is ~6 million. Their highest concentration is at the fovea centralis (14700/mm²). There are three types of cone cell which detect different wavelengths of light – S-cone, M-cone & L-cone. Their outer segments are invaginations of the plasma membrane which contain 3 different light-detecting pigments. Their inner segment is similar to rods & have a pedicle base (more stable) which also contains presynaptic vesicles that synapse with the dendrites of the bipolar cells.

Bipolar cells have bipolar axons & have a radial orientation; one or more dendrites of the cells pass outwards to synapse with the photoreceptor cell terminals. The single axon is directed inwards to synapse with amacrine & ganglion cells. There are several different types of bipolar cells – rod bipolar cells connect several rods to 1 – 4 ganglion cells. Flat or diffuse bipolar cells connect many cone cells with many ganglion cells, & midget bipolar cells connect one cone to one midget ganglion cell (direct pathway from the cone to a single optic nerve fibre).

Ganglion cells are multipolar & so named because they resemble cells found in the nervous ganglia, they are the second neurons in the visual pathway, & vary in diameter from 10 – 30µm, most of them are small (midget ganglion cells) but some are large. In most of the retina ganglion cells form a single layer, & the number of layers increases from the periphery to the macula, however they are absent in the fovea. Their axons converge at the exit of the optic nerve & the fibres exit the sclera by piercing the lamina cribrosa, after which they become myelinated.

Horizontal cells are multipolar & close to terminals of rods & cones. They have one long (up to 1mm) & several short processes. The short processes associated with cones have synaptic junctions with seven cone pedicles, whereas the short processes associated with rods synapse with 10-12 rod spherules. The long processes make contact with rods & cones & bipolar cells some distance away.

Amacrine cells are so named because it was initially thought that they had no axons. They have large cell bodies with lots of cytoplasm & lobulated indented nuclei. They are close to the ganglion cells; they’re stimulated by bipolar cells which in turn excite the ganglion cells.

Supporting cells: Müller cells fill most of the space in the neural retina not taken up by neurons. They are an example of neuroglia, which are cells that provide structural & metabolic support for surrounding neurons.

Neuroglia are abundant & diverse, are found in the CNS (oligodedrocyte – makes myelin sheath) & PNS (Schwann cells). (& retina example is Müller cells & astrocytes).

The macula lutea is an oval, yellowish (caused by carotenoid pigment xanthophyll) area at the centre of the posterior part of the retina. It measures about 5mm in diameter & lies about 3mm lateral to the optic disc. Fovea centralis is a depressed area in the centre of the macula lutea & measures about 1.5mm in diameter (floor of the depression is called the foveola). It is depressed because only the photoreceptors (cones) are present here whereas the other inner nerve fibres are located peripherally. The foveola has the most distinct vision as this arrangement allows incoming light to have greater access to photoreceptors. There are no blood vessels at the fovea.

The optic disc lies about 3mm medial to the macula lutea & measures about 1.5mm in diameter. The centre of it is depressed while he edge is slightly raised. In the central depression of the optic disc the central retinal vessels enter & leave the eye & optic nerve fibres exit the eye by piercing the sclera at the lamina cribrosa. This is a weak area & can be made to bulge out by a rise in intraocular pressure (pressure on optic nerve) & intracranial pressure, & this can lead to papilloedema. There are no rods or cones at the optic disc & is therefore insensitive to light – the blind spot. The nerve fibres are myelinated posterior to the optic disc & unmyelinated anterior to it.

Law is a social order

  • Law is a social order in which there are rules & subjects but it should be distinguished from any social order in which rules are exercising a managerial direction over their subjects, partly by the generality of its major rules & partly by the fact that its officials are bound to apply the rules which they’ve previously announced to their subjects. So there’s an essential component of collaboration & reciprocity in the enterprise of subjecting human conduct to governance of legal as distinct from managerial norms.
  • Finnis: this is nonetheless a descriptive account
  • Raz: should seek to identify the law on the basis of non evaluative characteristics only
  • Inner morality of the law consists of 8 requirements – a system of rules which must be met if a system is to be called “law”:
  • Remeber this was highlighted in the Manchester taxi case vs Donalds 1982 PAS
  1. laws should be general;
  2. laws should be promulgated, so the citizen knows the standards to which he is being held;
  3. retroactive rule making and application should be minimised;
  4. laws should be understandable;
  5. laws shouldn’t be contradictory;
  6. laws shouldn’t require conduct beyond the abilities of those affected;
  7. they should remain relatively constant through time;
  8. there should be a congruence between laws as announced and as applied.
  • NB: at the same time, Fuller recognised the concept of legal systems being “legal” to different extents and held that a system which partly but not fully met his requirements would be “partly legal” and could be said to have “displayed a greater respect for the principles of legality” than systems which didn’t meet these requirements at all.
  • Since Hart’s work for the first time opened the way for exchange between opposing views, both sides now apparently admit that the question is how can we best define and serve the ideal of fidelity of law: law, as something deserving loyalty must represent a human achievement – it can’t be a mere pattern discernible in the behaviour of state officials. Respect we owe to it must surely be something of a respect we owe to the law of gravitation..

natural lawyers on holiday

  • Raz/Kelsen’s Portrayal of natural lawyers (i.e. that law has to be moral in order to be valid & that it’s unconcerned w/legal test of validity) is wrong
    • Aquinas argued that for law to be valid it has to comply w/legal criteria for validity + must not be immoral not the same as saying natural law unconditionally surrenders tests of legal validity for those of moral one. Natural law is concerned w/practical reasonableness, not idealism.
  • A citizen has an obligation to conform to unjust stipulation to extent necessary to avoid the weakening of legal system
  • Natural law doesn’t depend on everyone sharing the same view of morality (as contended by Hart)
  • Instead, it requires that law is not immoral from objective POV, regardless of whether people accept that objective as moral understanding. This was demonstrated in the interesting case of Double glazing Glasgow vs the McArther Brothers 1823 PLA

 

  • Natural law doesn’t fail to distinguish b/w “is” & “ought to”
  • What’s practically reasonable is deduced from empirically observing human behaviour – it’s not saying that there’s a particular way laws ought to be made and that therefore laws are only valid when made in such way. The basic human goods are self evident & not suspectible to an argument that one is drawing an “is” from an “ought” – they are innate & not inferred from/demonstrable by ref to some other thing.

 

  • Law’s authority depends on justice or at least its ability to secure justice
  • It’s claim to supremacy is implausible unless it protects its subjects against threats which they’d otherwise face; e.g. invasion
  • Legal sanction is a human response to human needs, so that punishment seeks to restore the distributively just balance b/w law abiders & criminals.

 

  • The ruler has responsibility to promote common good

 

  • So rulers who don’t abide by the rule of law (which serves the common good) or make rules which arbitrarily benefit/harm a group of subjects compared to others (e.g. by granting govt. contracts to friends) have radically defective authority.

 

  • Ruler has no right to be obeyed but has authority to give directions & make morally obligatory laws + resp. for enforcing

 

  • He has that authority for the sake of common good.
  • If he uses his authority to make stipulations against common good, those stipulations will lack authority they would otherwise have by virtue of being his

 

  • For law to be morally authoritative it must comply w/practical reasonableness “in the eyes of a reasonable man” even though it needn’t be the one he himself would have made.
  • No conflict w/positive law – the act of positing a law should be guided by moral principles & rules

 

https://law.stanford.edu

A philosopher can’t give a theoretical description

    • Characterises descriptive approach of Hard/Raz as “practical view”; i.e. theorist must assess importance & significance in similarities or differences of subject matter by those whose concerns or decisions or activities constitute it (e.g. look from POV of judges or politicians). This approach isn’t satisfactory b/c it merges the different IPOVs of different actors in the field and insists on attributing one IPOV to them all, whether they are anarchists or model citizens.
  • A philosopher can’t give a theoretical description & analysis of social phenomenon unless he partakes in an evaluative exercise:
  1. human artefact such as law constituted by human actions & practices can only be understood by ref to its point
  2. the subject matter itself can’t be neatly demarcated from social life & practice
    • Should view IPOVs as at least presumptively concerned w/”practical reasonableness” (i.e. one of the ways of defining morality). Evaluations by theorist are indispensable for choosing concepts to use in description of aspects of human affairs such as law & legal order. So Finnis supports an evaluative descriptive view of the law (contrast w/Hart’s value free descriptive approach) This was highlighted in the case of Skip hire Sheffield vs McMannon Cars (1862) LLO
  • Main points
  1. There are 7 basic goods of self evident value, which are necessary for human flourishing; i.e. basic methodological requirements & general moral standards
  • Life
  • Knowledge
  • Play
  • Aesthetic experience
  • Sociability
  • Friendship
  • Practical reasonableness
  • Religion.
  1. These requirements justify the exercise of authority in the community & obligatory force of the law
  2. They demand that law is made in compliance w/rule of law & HR
  3. Law can be regarded as “radically defective” yet not invalid for want of compliance w/these requirements.

Guatemala: A Mayan Paradise

Brought to you by Abogados Laborales

Every time you hear someone say something about the Mayan culture you think about Mexico, right? The Mayan pyramids and the majesty of the jungle, the humble people and their great food. What if I told you that there’s another country with strong Mayan culture, which is not known by tourists and has beautiful landscapes to offer, don’t know what country we’re talking about? It’s Guatemala.

The small country below Mexico. Guatemala has a huge variety of places to explore. Some of the kind of landscapes you can find in Guatemala are:

Beach

Guatemala Has beautiful beaches of the Caribbean Sea, which makes it a great option for sunbathing and swimming.

 

Jungle

Guatemala’s jungle is the most protected jungle of America, Mayan lived there so you will also find the city of Tikal, one of the most powerful Mayan cities that were abandoned.

 

Forest

The forests are also protected so you can admire the beauty of nature It’s quite humid reaching 15°C in some places where you can go for camping, and you can walk into hanging bridges!

Mountain: The whole country is full of mountains, the largest solid elevation in Central America is the mountain range Santa Cruz that reaches 3800m above sea level.

Guatemala City is the capital of the country, it is also the most populous in Central America, it has a population of 13 million, even though Spanish is the official language, there are more than twenty Mayan languages.

In the city, you can go to restaurants and eat burritos or tamales and other local dishes. If exploring is your passion it has many interesting sites to know, such as The Aurora Zoo. Paseo Cayala. National Palace. Fontabella Square. Ixchel Museum of the Indian Costume. Wonderful place to learn about the Indian culture and the colonial Guatemala, which brings to you a magic trip to the past.

 

Coron Palawan: A Perfect Place For Vacation

Coron Palawan is located in the Philippines. Coron Island just has few population and most of them are the called natives of coron the Tagbanua tribe. The Tagbanua tribe is also the one who is taking care of its island. The Tagbanua tribe is making sure that they can still preserve the beauty of their island.Once you’ve visited the Philippines it’s a must that you have to visit a place like coron. This place is a quiet peaceful place. The locals of coron said, “coron is the most expensive travel in the Philippines.” There are two ways travelling to coron one is by a plane that takes 45mins. From Manila and the other one is by boat that takes 8hours also from Manila. I can agree with that because the airfare going to coron is about 100USD back and forth.

Swimming in Coron

They are also known for deep sea diving Japanese World War II underwater shipwrecks surrounded with magnificent coral reefs making it as one of the best dive spots in the world. When I saw coron it’s all worth a pause to enjoy the crystal clear water is the best for snorkelling, diving and swimming. The water in Kayangan Lake in coron is one of the favorite of the tourist because of its crystal clear water and it’s also known for one of the clearest water in asia. Aside from swimming, snorkelling, diving there are much more things to do in coron they also have a Hot Spring, that is privately owned with an entrance of 200pesos it’s a beautiful place especially at night you.

 

Hiking  

The Mt. Tapyas is known for its 700+ stepping stairs to the top, the long hike is worth it for the breathtaking view of the sunset and also you can see the top view of whole coron island, I do recommend hiking there at 5:30 am or 4 pm because going there will be more difficult if the sun is at its fullest. There is also one more place to hike in coron, which is Mt. Darala

https://www.tripadvisor.co.uk/SmartDeals-g294255-Palawan_Island_Palawan_Province_Mimaropa-Hotel-Deals.html