NobleKnight

Thank You So Much .... I really appreciate your help Both of you ... Daniel and Swansont

I find difficulty in understanding what the text want to say . i mean to discriminate two sources of light at a length of 10 meters we need them to be far from each other by 1.5 to 2 millimeters ... okay what if we want to see at further distance for example 1000 m or more ... i think the distance between the two sources shall differ .. I want to know what formula determines this and the second part of the text above is not really understandable for me ... i mean saying the fovea is less than 0.5 mm and this means that visual acuity is less than 2 degrees of the field ... i don't understand how ... so please if you can clarify it please do it or lead me to better source so i can read it

Thank you Very much John and Studiot ... Studiot ... I really appreciate your clarification ... sounds pretty much solid and persuading but as you mentioned PADI and looks that you have experience in the filed ... This table over here ... taken your example of Lyme Bay ... You can stay from 3 up to 10 mins maximum ( same as you said ) ... saying you have been down for the 10 mins ... You have to go up to surface and stay for an hour outside water ... Now you're Group B pressure ... So if you want to go down again ... You can't stay in the depth of 130 feet for more than 5 mins ... Right ?? and another question .... what if after staying for 10 mins at 130 feet and going out ... for 5 hours ( which is exceeding the maximal written Surface time ) .... Does staying for 5 hours means that you can dive as you haven't been in water for a week ... I mean without taking into consideration ( the surface time interval ) Really appreciate your help!

I'm not very aware of diving ... So what i understood from this text ... is that if you dive undersea for an hour at depth of 190 feet ... you need to ascend to the sea level gradually for 3 hours to avoid decompression sickness hazards ? and this schedule in the text ... means that the divers should wait for 10 minutes when he ascend to 50 feet then 17 mins wait at the 40 feet and so on ? Am i right or wrong ... if wrong please clarify it to me ... & thank you

Value of the Sympathetic Nervous Reflexes. In the absence of the sympathetic reflexes, only 15 to 20 percent of the blood volume can be removed over a period of 30 minutes before a person dies; in contrast, a person can sustain a 30 to 40 percent loss of blood volume when the reflexes are intact. Therefore, the reflexes extend the amount of blood loss that can occur without causing death to about twice that which is possible in their absence. This is what Guyton says about it ... but i have difficulty understanding it ... Does it mean that with the nervous reflexes body can decrease the loss of blood in hemorrhage to 40 % and without it we possibly loss 20% ?