X. Fraser. Florida State University.
Polarization - potassium (K ) ions are highly concentrated inside cell discount atrovent 20mcg fast delivery medicine reminder alarm, and + sodium (Na ) ions are highly concentrated outside cell order atrovent 20mcg without a prescription medicine vs dentistry. Refractory Period - when a nerve receives a second stimulus at such a close internal that no response will occur. The nerve must have sufficient time to recover from the initial stimulus before receiving an additional one. All or none response - If a stimulus is strong enough to initiate an action potential the impulse will travel along a neuron until its transmission is complete. Cervical Enlargement (C4 - T1) - nerves arising from this region are associated with the upper extremities. Lumbar Enlargement (T9 - L1) - nerves arising from this region are associated with the lower extremities. Cauda Equina - after the terminal portion of the spinal cord; composed of the roots of the spinal nerves below the 1st lumbar nerve. Dura mater (tough mother) - a tough outer layer which is fused with the periosteum of the cranial bones and vertebrae; ends at S2. Epidural space - between skull or vertebra and the dura mater; contains a protective padding of adipose tissue. Reflex arc - a neural pathway between the point of stimulation (receptor), to the brain or spinal cord, and to the responding organ (effector). Receptor - receives the stimulation; the beginning of the dendrite of the sensory neuron (see "Receptors" on page ). Each spinal nerve is attached to the spinal cord by two roots: a dorsal or posterior root and a ventral or anterior root. There are 31 pairs of spinal nerves and they are named and numbered according to the region and level of the spinal cord from which they arise: a. A spinal nerve splits right after it is formed into a dorsal ramus (goes to the posterior part of the body) and a ventral ramus (goes to the anterior part of the body) a. The plexus will yield nerves which represent their composition (or most of it) to the front and the side of the body. It is a grouping of anterior rami, and this group forms plexuses; and these plexuses yield more nerves. Cervical plexus - (C1 - C4) - muscles and skin, of posterior scalp; its major branch is the phrenic nerve (C3-C5) to the diaphragm. Brachial plexus - (C5 - T1) - neck and shoulder muscles and upper extremities; major branches are the axillary, musculocutaneous, medial, ulnar, and radial nerves. Lumbar plexus - (L1 - L4) - motor and sensory to the lower abdominal wall, external genitalia, and lower extremity; major branches are the femoral and saphenous nerves. Sacral plexus - (L4 - S3) - muscles and skin of buttocks, perineum and lower extremity; major branches are the sciatic, tibial and fibular (common peroneal) nerves. Cavities in the central nervous system - (known as the ventricular system of the brain and central canal of the spinal cord). Cerebral aqueduct (Aqueduct of Sylvius) - communicating passage way between the 3rd and 4th ventricle. Foramen of Magendie (Median Aperture) - communicating passage between the 4th ventricle and the subarachnoid space of the brain and spinal cord. Each ventricle (cavity) of the brain contains a capillary complex known as a choroid plexus, which produces C. Development of brain - during the fourth week of embryonic development, 3 primary vesicles are formed: a. During the fifth week of embryonic development, additional vesicles are formed from the 3 primary vesicles. Limbic system - group of fiber tracts contained in the cerebral hemispheres that is involved in basic emotional responses such as fear, anger, joy, grief, sex and hunger. Corpora quadrigemina - superior portion of the midbrain; it contains 4 colliculi (2 superior and 2 inferior): 1. Beta waves (14-20+) - produced during period of sensory input and mental activity, test taking, rational thoughts and tension. Theta waves (4-7 or 4-8) - are considered normal and present in children, but could indicate emotional stress if present in an adult.
The cytoplasm appears frothy or spongy because of the many lipid droplets that have been removed during processing of the tissue generic atrovent 20 mcg otc treatment kawasaki disease. The zona reticularis consists of a branching and anastomosing network of polyhedral cells smaller than those of the zona fasciculata order atrovent 20 mcg visa medications hair loss. The medulla is composed of cells that are also arranged in the typical fashion of endocrine glands, cords and clumps of cells surrounded by fenestrated medullary sinusoids. The medullary cells do not have lipid vacuoles, but if fixation is not prompt autodigestion vacuoles may appear in the cytoplasm. The tissue surrounding the central vein may not be medullary but instead may be in-growths of cortical tissue. The chromaffin reaction following bichromate fixation results in differential staining of epinephrine and norepinephrine cells, the latter are stained more darkly brown. Parafollicular cells are found interspersed within the follicular epithelium and in clusters between follicles. Cells in these glands secrete parathyroid hormone, which acts to increase calcium resorption from bone and in the renal tubules. Large intensely eosinophilic oxyphil cells may be found interspersed or in nests among the chief cells. Review the typical endocrine arrangement of anastomosing cords of cells surrounded by sinusoidal capillaries. The cells in the Islets of Langerhans are not arranged into acini (as in the exocrine pancreas) but in irregular cords and clumps surrounded by a rich capillary plexus. The alpha cells secrete glucagon, which raises blood sugar, and the beta cells secrete insulin, which lowers it. For a more detailed description of the exocrine pancreas see part two of the gastrointestinal system lab on page 82. Be certain that you understand the functional significance of the hypothalamo-hypophyseal portal system as discussed in lecture. Understand and identify the stages in spermatogenesis and the cells that play essential roles in this process. The male reproductive system consists of the testes, the excretory ducts and associated glands, the penis, and the scrotum. The testes contain many seminiferous tubules, which are lined by a germinal epithelium consisting of germinal elements (spermatogonia, spermatocytes, and spermatids) and Sertoli cells. Lying between the seminiferous tubules are the interstitial cells of Leydig, which produce the male sex hormones (androgens). When sperm leave the seminiferous tubules they pass through the following series of ducts: Ducts Characteristics 1. The male sex accessory glands are the paired seminal vesicles, the prostate gland, and the paired bulbourethral glands. The duct of each seminal vesicle unites with the ampulla of a ductus deferens to form a common ejaculatory duct. The prostate gland surrounds the ejaculatory duct and the prostatic urethra, and secretes into the latter. The mediastinum (not visible on this slide) is the mass of acidophilic connective tissue at one 67 pole through which the major vessels enter and leave the testis. At higher magnification identify the germinal elements (spermatogonia, spermatocytes and spermatids) and Sertoli cells in the seminiferous tubules. Only the Sertoli cells and spermatogonia (usually with interphase nuclei) rest on the basement membrane. The larger primary spermatocytes lie on the luminal side of the Sertoli cells and are frequently in some stage of the prolonged prophase of the first meiotic division. Beneath the basement membrane of the tubules note the myoid cells (myoepithelium) with their pale- staining elongated nuclei. In the interstitium (between the seminiferous tubules) identify Leydig cells, which are large eosinophilic cells.
Chapter 5 1 The epidermis provides protection generic atrovent 20mcg visa treatment walking pneumonia, the dermis provides support and flexibility cheap 20mcg atrovent with mastercard symptoms jock itch, and the hypodermis (fat layer) provides insulation and padding. Individuals with darker skin have darker, more abundant melanin, whereas fair-skinned individuals have a lighter shade of skin and less melanin. They are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis. They release a thicker sweat that is often decomposed by bacteria on the skin, resulting in an unpleasant odor. When the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate, and the sweat glands begin to secrete more sweat. Hormones that are especially active during puberty stimulate the release of sebum, leading in many cases to blockages. Chapter 6 1 B 3 C 5 B 7 B 9 A 11 C 13 B 15 C 17 C 19 A 21 D 23 D 25 B 27 B 29 D 31 C 33 A 35 A 37 D 39 B 40 It supports the body. Parts of the skeleton enclose or partly enclose various organs of the body including our brain, ears, heart, and lungs. The mineral component of bone, in addition to providing hardness to bone, provides a mineral reservoir that can be tapped as needed. Functionally, the femur acts as a lever, while the patella protects the patellar tendon from compressive forces. The open spaces of the trabeculated network of spongy bone allow spongy bone to support shifts in weight distribution, which is the function of spongy bone. Like the primary ossification center, secondary ossification centers are present during endochondral ossification, but they form later, and there are two of them, one in each epiphysis. The external callus is produced by cells in the periosteum and consists of hyaline cartilage and bone. To alleviate this condition, astronauts now do resistive exercise designed to apply forces to the bones and thus help keep them healthy. When this occurs in thoracic vertebrae, the bodies may collapse producing kyphosis, an enhanced anterior curvature of the thoracic vertebral column. These are the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones. The facial bones support the facial structures, and form the upper and lower jaws, nasal cavity, nasal septum, and orbit. These are the paired maxillary, palatine, zygomatic, nasal, lacrimal, and inferior nasal conchae bones, and the unpaired vomer and mandible bones. The middle fossa extends from the lesser wing of the sphenoid bone anteriorly to the petrous ridge posteriorly. There are seven cervical vertebrae (C1–C7), 12 thoracic vertebrae (T1–T12), and five lumbar vertebrae (L1–L5). The sacrum is derived from the fusion of five sacral vertebrae and the coccyx is formed by the fusion of four small coccygeal vertebrae. On the posterior sacrum, the median sacral crest is derived from the fused spinous processes, and the lateral sacral crest results from the fused transverse processes. The sacral canal contains the sacral spinal nerves, which exit via the anterior (ventral) and posterior (dorsal) sacral foramina. The supraspinous ligament is located on the posterior side, where it interconnects the thoracic and lumbar spinous processes. In the posterior neck, this ligament expands to become the nuchal ligament, which attaches to the cervical spinous processes and the base of the skull. It has a jugular (suprasternal) notch, a pair of clavicular notches for articulation with the clavicles, and receives the costal cartilage of the first rib. The manubrium is joined to the body of the sternum at the sternal angle, which is also the site for attachment of the second rib costal cartilages. The last false ribs (11–12) are also called floating (vertebral) ribs, because these ribs do not attach to the sternum at all. Instead, the ribs and their small costal cartilages terminate within the muscles of the lateral abdominal wall. This process begins with the localized accumulation of mesenchyme tissue at the sites of the future bones.
Such measures are most difficult to implement in rural areas with traditional forms of poultry holdings where chickens and ducks roam freely and mingle with wild birds or share water sources with them atrovent 20 mcg for sale medications zofran. Vaccination has been widely used in these circumstances and may also be a sup- plementary tool in the eradication process of outbreaks in non-endemic areas buy discount atrovent 20 mcg on-line medications causing thrombocytopenia. In the field of influenza vaccination, neither commercially available nor experi- mentally tested vaccines have been shown so far to fulfil all of these requirements (Lee and Suarez 2005). The risk of infection of vac- cinees with, and excretion of, virulent field virus is usually reduced but not fully prevented. This may cause a significant epidemiological problem in endemic areas where exhaustive vaccination is carried out: vaccinated birds which appear healthy may well be infected and excrete the field virus ‘under cover’ of the vaccine. The effectiveness of reduction of virus excretion is important for the main goal of con- trol measures, that is, the eradication of virulent field virus. Assuming a vaccinated and infected ßock passes on the infection on average to less than one other ßock (r0 < 1), the virulent virus is, on mathematical grounds, prone to be extinguished (van der Goot 2005). When dealing with vaccination against the potentially zoonotic H5N1 virus, reduc- tion of virus excretion also reduces the risks of transmission to humans, since a sig- nificant dose of virus seems to be required to penetrate the species barrier between birds and humans. An ideal match of vaccine and field virus, as demanded for vaccine use in humans, is not mandatory in poultry. Induction of a homosubtypic cross- reactive immunity in poultry may be sufficient for protection, due to a current lack of vaccine-driven antigenic drift in avian influenza viruses, because of the absence of widespread vaccination. Most are still based on inactivated, adjuvanted whole virus vaccines which need to be applied by needle and syringe to each animal separately. Reverse genetics will greatly aid in pro- ducing vaccines both for veterinary and medical use with the desired HxNy combi- nations in a favourable genetic background (Liu 2003, Neumann 2003, Subbarao 2003, Lee 2004, Chen 2005, Stech 2005). Currently, inactivated heterologous vac- cines are in field use in the H5N1 hot spots of South East Asia as well as in Mexico, Pakistan and Northern Italy (e. These antibodies are generated at high titres by naturally infected birds, but at considerably lower titres when inactivated vaccines are used. Vaccination is now planned to be used on a nation wide scale in several countries in South East Asia (Normile 2005). So far, H5N1 only meets two of these conditions: it is, for the vast majority of the human population, a new subtype and it has in- fected and caused severe illness and high lethality in more than 140 humans to date. A new pandemic would be at the brink should the Asian lineage H5N1 acquire properties, by stepwise adaptation or by reassortment with an already hu- man-adapted virus, for an efÞcient and sustained human-to-human transmission (Guan 2004). This instance might be just around the corner or might already have occurred while reading this article – no one knows or can foretell. The chances for such an event to occur are directly correlated to the amount of virus circulating in poultry and, thus, the exposure risks of humans. Heretically, it has been proposed in one of the internet mail- and discussion-forums that the investment of only ten percent of the money that is scheduled to be spent for the development of H5-speciÞc hu- man vaccines in the eradication of H5N1 in poultry would have a greater effect than human vaccination in the protection of the human population from a H5N1 epi- demic. Since its Þrst isolation in humans in 1997, H5N1 has failed to perform this last step towards pandemicity in human hosts. Recent studies, however, suggest that over the years, the virulence of H5N1 for mammals has increased and the host range has expanded: 1. H5N1 isolated from apparently healthy domestic ducks in mainland China from 1999 to 2002, and in Vietnam since 2003 have become progressively more pathogenic for mammals (Chen 2004). H5N1 has expanded its host range, naturally infecting and killing mam- malian species (cats, tigers) previously considered resistant to infection with avian influenza viruses (http://www. However, it should not be overlooked that while staring at the H5N1 situation in Asia, other influenza viruses with possibly even greater pandemic potential may emerge or may already have emerged in the meantime. For example, strains of the H9N2 subtype which was not found in Asia prior to the 1980s have not only be- come widespread in Asian poultry populations, but also have crossed efficiently into pig populations in South Eastern and Eastern China (Shortridge 1992, Peiris 2001, Xu 2004). The receptor of these viruses revealed specificities similar to hu- man-adapted viruses (Li 2005b, Matrosovich 2001). The H9N2 strain, which was responsible for these human infections in Hong Kong, even revealed a genotype akin to that of the H5N1 viruses of 1997 (Lin 2000).
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