the present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings . in the following description , numerous specific details are set forth in order to provide a thorough understanding of the present invention . it will be apparent , however , to one skilled in the art , that the present invention may be practiced without some or all of these specific details . in other instances , well known process steps and / or structures have not been described in detail in order to not unnecessarily obscure the present invention . in accordance with the present invention , fig3 a and 3b are views of one embodiment of catheter 300 , prior to and after deployment of a membrane . fig4 a through 4f illustrate the assembly of catheter 300 of fig3 a and 3b . fig4 a , 4 b and 4 c show a membrane 410 , a catheter tube 420 , and a subassembly 430 comprising membrane 410 and tube 420 . membrane 410 can be attached to catheter tube 420 by inserting tip 418 of membrane 410 into opening 421 of tube 420 , until deployable sections 414 and 416 of membrane of 410 are inside hollow 424 of tube 420 . next , a leading edge 412 of membrane 410 is snapped into a position ring 422 located on the outer surface of catheter tube 420 , as shown in fig4 c . positioning ring 422 can be machined or molded depending on the manufacturing process . other chemical and / or physical means of attaching membrane 410 to tube 420 can also be used , e . g ., adhesive , heat bonding , ultrasonic welding , chemical bonding or heat staking . as shown in fig4 d , 4 e and 4 f , subassembly 430 can be press fitted into catheter nozzle 440 , by engaging membrane edge 412 of subassembly 430 into an internal positioning ring 442 of nozzle 440 . although subassembly 430 can be sufficiently mechanically coupled to nozzle 440 , the various components of assembled catheter 300 can be further secured to each other by sonically welded or heat staked to prevent separation during deployment , such as inside the reproductive tract during artificial insemination ( ai ). alternatively , subassembly 430 can be replaced by a one - piece membrane - tube combination that can be manufactured by , for example , blow molding . another method for constructing subassembly 430 is to insert catheter tube 420 over a membrane die , similar to dies used in balloon manufacturing , dipping the die and the attached catheter tube 420 into a suitable liquid membrane media until the entire die and about half inch of the end of catheter tube 420 is coated with the membrane media . after the liquid membrane media is cured , membrane tip 418 is cut . a downward movement of catheter tube 420 detaches tube 420 from the die and also automatically inverts membrane 410 into catheter tube 420 , thereby forming subassembly 430 . membrane tip 418 can include an opening such as a slit or a circular or oval hole . alternatively , instead of an opening , tip 418 can include a soluble plug or a pre - weakened seal designed to dissolve or fail under pressure at the right time . depending on the specific application , nozzle 440 can be of different shapes and sizes , and combination thereof , including but not limited to spirals , bulbous knobs , including the nozzles illustrated by fig1 a , 1 b , 2 a , 2 b , and 2 c . although spirals are optional , approximately one to three spirals may be optimal when catheter 300 is used in swine . shorter nozzles are also possible because membrane 410 is self - sealing , longer and self - guiding . in some embodiments , nozzle 440 is tapered to aid in insertion into the tract . different membrane materials and size thickness depend on applications and target animal . for virgin sows , also known as gilts , nozzle 440 may have a smaller diameter and shorter length . conversely , for second to seventh parity sows with larger birth canals , nozzle 440 may have a larger diameter and longer length to facilitate the deposit of genetic materials and / or diagnostic instruments . for example in sows , the overall length of membrane 410 can be approximately four to eight inches and tapering gently from one - eighth of an inch . depending on the specific type and size of the target application , different materials , size , and thickness can be employed . suitable materials for nozzle 440 and membrane 410 of catheter 300 include silicone , silicone gel packs , foam , latex , cleartex ™ ( available from zeller international , new york ), polymers , plastics , metals , or combinations thereof . other candidate materials include the polyolefins , polyethylene and polypropylene , the polyacetals , ploy - butadiene - styrene copolymers , the polyfluoro and polyfluorochloro - polymers , such as teflon ™ and other polymers and copolymers . as shown in the cross - sectional views of fig8 a and 8b , other embodiments include a membrane 810 that are similar to a children &# 39 ; s party noisemaker and an inwardly - rolled embodiment 820 not unlike a condom , respectively . a twin forked - membrane 830 is also possible for deployment into the dual uterine horns of a sow , as shown in fig8 c . many variations of catheter 300 are possible . for example , catheter 300 may have multiple tubes with multiple membranes . such an embodiment may be useful in laparoscopy where one pathway is created for a camera and a second pathway is created for an instrument during surgery . alternatively , a large diameter catheter 300 can also be used to create a large pathway within which one or more smaller catheters can be deployed . fig5 a , 5 d , and 5 e , show catheter 300 , before , during and after deployment , respectively . fig5 b and 5c one embodiment of the catheter attached to two types of ai dispensers . fig7 a through 7e show the insertion and deployment of catheter 300 in a sow 780 . catheter 300 is deployed by introducing genetic material suspended in a suitable fluid under pressure into sow 780 . as shown in fig5 b and 5c , the ai fluid can be transported in a suitable dispenser , such as a squeeze bottle 560 or a pre - packaged tube 570 . referring to fig7 a , catheter 300 is inserted into vaginal cavity 782 of sow 780 . catheter 300 is gradually pushed further into sow 780 until nozzle tip 556 is fully inserted into vagina cavity 782 , as shown in fig7 b . in fig7 c , catheter 300 is then gently eased into cervical tract 784 of sow 780 until nozzle tip 556 engages at least the first cervical ring of cervical tract 784 . unlike conventional catheters , membrane 410 is not advanced until catheter 300 is positioned in cervical tract 784 , thereby preventing contaminated materials that may be contained in vaginal cavity 782 , or fluids from cervical tract 784 , from being accidentally transferred into uterus 788 or uterine horns of sow 780 . hence , bio - security of uterus 788 is maintained . next , as shown in fig7 d , ai fluid under pressure is fed into catheter 300 . pressure can be generated manually via a dispenser 560 or by a suitable pump , such as a pneumatic or hydraulic pump . the effect of the pressure causes membrane 410 to begin unfolding in an inside - out manner not unlike removing one &# 39 ; s sock by pulling from the open end . although catheter 300 includes an opening in membrane tip 418 , the ai fluid under pressure keeps the opening of tip 418 closed until membrane 410 is fully extended into cervical tract 784 . referring now to fig7 e , membrane 410 of catheter 300 continues to advance in a frictionless manner into the curved and narrow passageway of cervical tract 784 , automatically centering the ever - expanding forward most portion of membrane 410 in the direction of least resistance . it is this expansion and automatic centering action of membrane 410 that advantageously enables membrane 410 to worm its way through cervical tract 784 without damaging or irritating delicate tissues . eventually , when membrane 410 is fully extended and membrane tip 418 is near to or at the entrance of uterus 788 , the pressure causes tip 418 to open thereby allowing the ai fluid to be deposited at the deeper end of cervical tract 786 and / or directly into uterus 788 . while a slight taper of membrane 410 aids deployment in cervical tract 786 , the taper may not be necessary for proper deployment . in some applications , partial penetration of membrane 410 into the uterine horns ( not shown ) is also possible , allowing for example the introduction of embryo transplants . hence the invention eliminates the need for multiple removable sheaths by progressively feeding new portion of membrane 410 in an unfolding process . every newly extended portion of membrane 410 is sterile because there is no prior contact with other biological tissue , such as vaginal cavity or other body fluids . when a suitable amount of ai fluid has been deposited into sow 780 , membrane 410 collapses after the fluid pressure dissipates , allowing for safe and easy withdrawal of the relatively flat , flexible , smooth and lubricated surface of membrane 410 , causing minimal discomfort and posing minimal risk of trauma and damage to the recipient animal . the use of trans - cervical intra - uterine ai advantageously reduces the volume of ai fluid needed for successful insemination by delivering the genetic materials where nature intended , i . e ., into uterus 788 . for example , a normal dose of 4 - 6 billion fresh swine semen may be reduced to fewer than 1 billion for successful ai when trans - cervical intra - uterine ai is employed . in conventional ai , a small window of opportunity for a successful deposit of genetic material suspended in the ai fluid occurs during standing heat , which lasts for only five to eight minutes every one to three hours during estrus , when sow 780 is receptive to boar mounting . during standing heat , when a boar mounts sow 780 , cervical tract 784 clamps onto the boar &# 39 ; s penis to assist ejaculation , and uterine contractions draws the semen through cervical tract 784 . if conventional ai is attempted outside this small window of opportunity , sow 780 will not assist in the drawing of the semen through cervical tract 784 , and much of the ai fluid will backflow out the sow &# 39 ; s vulva and is wasted , thereby reducing the probability of a successful litter . unlike conventional ai , catheter 300 is effective during refractory heat , which is the much longer period during estrus when cervical tract 784 is relaxed , allowing easier penetration of cervical tract 784 . since catheter 300 bridges cervical tract 784 and deposits the genetic material suspended in the ai fluid much closer to uterus 788 , resistance caused by clamping cervical tract 784 during standing heat is not needed and probably undesirable . hence catheter 300 is effective during the much longer refractory heat period because semen can be deposited efficiently and with minimal restriction in cervical tract 784 . hence the advantages of trans - cervical intra - uterine ai can be combined with the relative safety and effectiveness of catheter 300 of the present invention . farmers can now use ai in the much longer refractory heat period , allowing these swine farms to operate more efficiently , since successful ai is no longer limited to the much shorter standing heat period . yet another significant advantage of the present invention is the ability of membrane 410 to deploy in a self - centering and self - directing manner , when deployed under pressure . during manufacture , a suitable lubricant may be applied to the surface of membrane 410 that may come into contact with the tract of the animal , further reducing discomfort and risk of trauma during deployment and withdrawal of catheter 300 . in addition , unlike the conventional rigid deep penetration catheters , once membrane 410 of catheter 300 has been deployed and withdrawn from cervical tract 784 , it is difficult to reinsert membrane 410 back into catheter nozzle 440 and tube 420 , thereby discouraging the reuse of the now contaminated membrane 410 . once fully extended into a tract of a recipient animal , e . g ., into the reproductive tract , respiratory tract , circulatory tract or digestive tract , catheter 300 provides a protective shield for the insertion of devices such as endoscopes , tracheal tubes , or other diagnostic and therapeutic instruments . membrane 410 shields the tract from the scraping , scarring and discomfort caused by the contact and friction of the hard , semi - blunt instruments and probes on the otherwise unprotected tract . as a result , healing time and the risk of infection are significantly reduced , thereby lowering recovery time and cost . although the described embodiment of catheter 300 uses an inverted membrane 410 which is turned inside - out during deployment , the concepts of a self - guiding , frictionless , membrane 410 which is deployed with minimal discomfort and trauma to recipient animals has many applications . in addition to ai and embryo transplant , many other applications for catheter 300 are possible . for example , catheter 300 can also be used for diagnostic and / or therapeutic applications in which pathways are created in the reproductive tract , respiratory tract , circulatory tract or digestive tract of the recipient animal or a patient . these pathways enable procedures such as embryo transplant and drug delivery to be performed . laparoscopic procedures such as introducing cameras and instruments are also possible . depending on the application , the size and shape of catheter 300 may vary . while this invention has been described in terms of several preferred embodiments , there are alterations , modifications , permutations , and substitute equivalents , which fall within the scope of this invention . it should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention . it is therefore intended that the following appended claims be interpreted as including all such alterations , modifications , permutations , and substitute equivalents as fall within the true spirit and scope of the present invention .
a method and apparatus for safer and more effective deep trans - cervical intra - uterine artificial insemination is provided . such a deep ai catheter causes minimal discomfort and risk of trauma , and does not require the services of a highly trained ai professional . first , a catheter is inserted into the cervical tract of the animal . a membrane , initially positioned inside a tube section of the catheter , is then extended from an opening in the tube and into the tract under pressure . the membrane extends into the tract without friction thereby reducing the discomfort and the risk of trauma or injury to the animal . when the membrane is fully extended into the tract , pressure causes the tip of the membrane to open thereby releasing the ai fluid and depositing the genetic material suspended in the fluid into the reproductive tract . in addition to ai and embryo transplant , other applications for the pathway include other therapeutic , diagnostic or procedures , such as introducing fluoroscopic cameras , instruments , and drug delivery .