By M. Ronar. Edgewood College. 2017.
Female Reproductive © The McGraw−Hill Anatomy generic ibuprofen 400 mg on line, Sixth Edition Development System Companies, 2001 730 Unit 7 Reproduction and Development Primary follicles Vesicle Secondary follicle (a) Granulosa cells Antrum Corona radiata Secondary oocyte Zona pellucida Cumulus oophorus Theca interna (b) FIGURE 21. In- By about the tenth to the fourteenth day following day 1 of a terestingly, the follicular cells produce estrogen from its precursor menstrual period, usually just one follicle has matured fully to be- testosterone, which is supplied by a layer of cells immediately come a vesicular ovarian (graafian) follicle (fig. This does not form two complete cells, that it forms a bulge on the surface of the ovary. Under proper however, because only one cell—the secondary oocyte—gets al- hormonal stimulation (a sudden burst of luteinizing hormone most all of the cytoplasm. The other cell formed at this time be- from the anterior pituitary, triggered by a peak level of estrogen), comes a small polar body (fig. The secondary oocyte enters the second meiotic and extrude its secondary oocyte into the peritoneal cavity near division, but meiosis is arrested at metaphase II and is never the opening of the uterine tube in the process of ovulation (ov-yu˘- completed unless fertilization occurs. Female Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 Chapter 21 Female Reproductive System 731 (a) (b) FIGURE 21. Ovarian cortex Tunica albuginea Ovarian medulla Primordial Maturing follicles follicle Broad ligament FIGURE 21. Female Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 732 Unit 7 Reproduction and Development Fimbriae of uterine tube Knowledge Check 4. Describe the position of the ovaries relative to the uterine tubes and describe the position and functions of the broad Oocyte ligament and mesovarium. Compare the structure of a primordial follicle, primary fol- licle, secondary follicle, and vesicular ovarian follicle. Define ovulation and describe the changes that occur in the ovary following ovulation in a nonfertile cycle.
The test for factual causation discount ibuprofen 400 mg visa, what was once called “but for” causation, is whether the breach was a substantial factor in bringing about injury to the plaintiff. However, legal causation, what the law used to call proxi- mate cause, is a policy or scope of liability determination made by the court or judge. It is an aspect of negligence liability in which courts address whether they are going to draw a “bright line,” beyond which they will not impose liability as a matter of law even if the conduct at issue is deemed factually responsible for the plaintiff’s injury. Finally, as already implied, a plaintiff must prove that satisfaction of all the foregoing elements resulted in his compensable injury. In other words, a plaintiff must prove that his or her injuries are of a nature that may be redressed by monetary damages. Economic loss is damage that can be objectively measured like lost wages and medical care, both past and future. Noneconomic damage is subjective and immeasurable, like pain and suffering or loss of consortium (i. Chapter 2 / Litigation 17 Procedural and Evidentiary Rules Procedural rules determine how and when the substantive rules do or do not come into play and how information is gathered that bears on the substantive rules. Finding information that may include or lead to admissible evidence is done through the procedural rules of dis- covery. The most common procedural rules of discovery include written interrogatories, requests for admission, requests to produce documents, oral depositions, and requests for designation of experts. Procedural rules that can terminate litigation or alter its focus are the subject of law and motion practice. Evidentiary rules determine what facts get considered or precluded from consideration by the court, jury, or arbitrators to determine whether the substantive conditions of liability are satisfied.
As the trailing The gastric action potential is responsible for two compo- contraction approaches the closed pylorus cheap ibuprofen 600mg amex, the gastric con- nents of the propulsive contractile behavior in the antral tents are forced into an antral compartment of ever-de- creasing volume and progressively increasing pressure. This results in jet-like retropulsion through the orifice formed by the trailing contraction (Fig. Trituration and reduction in particle size occur as the material is Gastric action potential forcibly retropelled through the advancing orifice and back Trailing and contractile cycle Gastric contraction start in midcorpus into the gastric reservoir to await the next propulsive cycle. Plateau phase Gastric Rapid action Enteric Neurons Determine the Minute-to-Minute upstroke potential Strength of the Trailing Antral Contraction The action potentials of the distal stomach are myogenic Gastric action potential (i. The myogenic characteristics of the action poten- tial are modulated by motor neurons in the gastric ENS. Neurotransmitters primarily affect the amplitude of the plateau phase of the action potential and, thereby, control the strength of the contractile event triggered by the plateau phase. Neurotransmitters, such as ACh from exci- tatory motor neurons, increase the amplitude of the plateau Gastric action potential and contractile cycle arrive at pylorus; pylorus is closed by Onset of terminal Complete terminal leading contraction; antral contraction antral contraction second cycle starts in midcorpus Pylorus Pylorus closing closed FIGURE 26. The rising phase of the gastric action potential ac- counts for the leading contraction that propagates toward the py- lorus during one contractile cycle. Physiology of the Gastroin- is increased pressure in the terminal antrum as the trailing antral testinal Tract. In- hibitory neurotransmitters, such as NE and VIP, decrease the amplitude of the plateau and the strength of the associ- ated contraction. The magnitude of the effects of neurotransmitters in- creases with increasing concentration of the transmitter Tonic Reservoir substance at the gastric musculature. Higher frequencies contraction of action potential discharged by motor neurons release Decrease Relaxation greater amounts of neurotransmitter. In this way, motor in volume Increase neurons determine, through the actions of their neuro- Antral in volume transmitters on the plateau phase, whether the trailing pump contraction of the propulsive complex of the distal stom- ach occurs. With sufficient release of transmitter, the plateau exceeds the threshold for contraction. The action potentials in the terminal antrum and pylorus Neural mechanisms of feedback control determine intramural differ somewhat in configuration from those in the more contractile tone in the reservoir. The principal difference is the occur- rence of spike potentials on the plateau phase (see Fig.
It also stimulates the synthesis of 2 2 2 CaBP in the cells 600mg ibuprofen visa, and transport by Ca -ATPase pumps are both Ca -binding protein (CaBP) and the Ca -ATPase. Iron plays an important role not only as a compo- Normal nent of heme but also as a participant in many enzymatic re- actions. About 12 to 15 mg/day of iron enter the GI tract, where it is absorbed mainly by the duodenum and upper je- Fe for junum (Fig. Ferric (Fe ) salts are not soluble at pH 2 7, whereas ferrous (Fe ) salts are. Consequently, in the 3 duodenum and upper jejunum, unless Fe ion is chelated, it forms a precipitate. Several compounds, such as tannic acid in tea and phytates in vegetables, form insoluble complexes with iron, preventing absorption. Iron is absorbed by an ac- tive process via a carrier(s) located in the brush border mem- brane. One such transporter, the divalent metal transporter (DMT-1), is expressed abundantly in the duodenum. Iron Once inside the cell, heme iron is released by the action deficient of heme oxygenase and mixed with the intracellular free iron pool. Iron is either stored in the enterocyte cytoplasm bound to the storage protein apoferritin to form ferritin, or transported across the cell bound to transport proteins, which carry the iron across the cytoplasm and release it into the intercellular space. Iron is bound and transported in the blood by transferrin, a -globulin synthesized by the liver. Iron absorption is closely regulated by iron storage in en- terocytes and iron concentration in the plasma. Enterocytes are continuously shed into the lumen, and the ferritin con- tained within is also lost. Normally, iron in enterocytes is derived from the lumen and the blood (Fig. The amount of iron absorbed is regulated by the amount stored Iron loaded Lumen Enterocyte Blood Heme Heme Heme oxygenase Transport protein Iron Ferritin Apoferritin Transferrin Transferrin Fe Fe FIGURE 27. In healthy subjects, the DMT-1 amount of iron that enters enterocytes is regulated by the Ferritin Transferrin- amount of iron in the cells and circulating in the plasma.
NEUROTRANSMITTER FUNCTION BASIC CIRCUITRY In a classical neural pathway generic 400mg ibuprofen visa, such as that depicted in Fig. It could achieve this with one NT able to activate receptors linked to different events on B and C. Of course, neuron C would have other inputs, some of which would be excitatory and if the same NT was used it could activate the inhibitory mechanism on C as well. Also, the NT released from A might be able to stimulate as well as inhibit neuron C (Fig. Even the provision of separate receptors linked to excitation and inhibition would not overcome these problems since both would be accessible to the NT. One possible solution, used in the CNS, is to restrict the NT to the synapse at which it is released by structural barriers or rapid degradation. Also the inputs and receptors linked to excitation could be separated anatomically from those linked to inhibition and, in fact, there is electrophysiological and morphological evidence that excitatory synapses are mainly on dendrites and inhibitory ones on the soma of large neurons (Fig. Nevertheless, the problem of overlap would be eased if two NTs were released, one to activate only those receptors linked to excitation and another to evoke just inhibition, i. During his studies on antidromic vasodilation he wrote (1935) `When we are dealing with two different endings of the same sensory neuron, the one peripheral and con- cerned with vasodilation and the other at a central synapse, can we suppose that the discovery and identification of a chemical transmitter at axon reflex dilation would furnish a hint as to the nature of the transmission process at a central synapse. This it certainly has been and in the last few years much evidence has been presented to show that more than one substance (but not necessarily more than one conventional NT) can co-exist in one nerve terminal. In fact he was simply saying that if a neuron uses a particular transmitter at one of its terminals it will use it at another, although he did not add, irrespective of whether or not it uses more than one NT. This makes good sense especially since it is difficult to conceive how a neuron could achieve, let alone control, the release of different NTs from different terminals, unless the NTs were synthesised solely at the terminals independently of the cell body. In that way different substances might be released from different terminals of a neuron by arriving action potentials without the neuron having to do anything special 12 NEUROTRANSMITTERS, DRUGS AND BRAIN FUNCTION Figure 1.