By L. Rocko. Otterbein College. 2018.
The tendency of an atom to be stable or to react readily with other atoms is largely due to the behavior of the electrons within the atom’s outermost electron shell buy discount cleocin gel 20gm on-line acne used cash, called its valence shell. Helium, as well as larger atoms with eight electrons in their valence shell, is unlikely to participate in chemical reactions because they are stable. All other atoms tend to accept, donate, or share electrons in a process that brings the electrons in their valence shell to eight (or in the case of hydrogen, to two). Ions are charged atoms that form when an atom donates or accepts one or more negatively charged electrons. Molecules with nonpolar covalent bonds are electrically balanced, and have a linear three-dimensional shape. Molecules with polar covalent bonds have “poles”—regions of weakly positive and negative charge—and have a triangular three-dimensional shape. Hydrogen bonds link hydrogen atoms already participating in polar covalent bonds to anions or electronegative regions of other polar molecules. Hydrogen bonds link water molecules, resulting in the properties of water that are important to living things. Kinetic energy, the energy of matter in motion, fuels the collisions of atoms, ions, and molecules that are necessary if their old bonds are to break and new ones to form. Four forms of energy essential to human functioning are: chemical energy, which is stored and released as chemical bonds are formed and broken; mechanical energy, which directly powers physical activity; radiant energy, emitted as waves such as in sunlight; and electrical energy, the power of moving electrons. Synthesis reactions bond reactants together, a process that requires energy, whereas decomposition reactions break the bonds within a reactant and thereby release energy. The rate at which chemical reactions occur is influenced by several properties of the reactants: temperature, concentration and pressure, and the presence or absence of a catalyst. Water is a lubricant and cushion, a heat sink, a component of liquid mixtures, a byproduct of dehydration synthesis reactions, and a reactant in hydrolysis reactions. Homeostatic control mechanisms important for keeping blood in a healthy pH range include chemicals called buffers, weak acids and weak bases released when the pH of blood or other body fluids fluctuates in either direction outside of this normal range. Carbon atoms in organic compounds readily share electrons with hydrogen and other atoms, usually oxygen, and sometimes nitrogen. Carbon atoms also may bond with one or more functional groups such as carboxyls, hydroxyls, aminos, or phosphates. Their structural forms include monosaccharides such as glucose, disaccharides such as lactose, and polysaccharides, including starches (polymers of glucose), glycogen (the storage form of glucose), and fiber. Lipids are hydrophobic compounds that provide body fuel and are important components of many biological compounds. Triglycerides are the most abundant lipid in the body, and are composed of a glycerol backbone attached to three fatty acid chains. Phospholipids are compounds composed of a diglyceride with a phosphate group attached at the molecule’s head. Nucleotides are compounds with three building blocks: one or more phosphate groups, a pentose sugar, and a nitrogen- containing base. In the periodic table of the electenergy) to learn about electrical energy and the elements, elements in a single column have the same attraction/repulsion of charges.
Typically patients are started on injectable medications initially owing to their lower expense generic 20 gm cleocin gel otc acne 10, better side effect profile, and need for less frequent and less intensive monitoring. Non- diabetic patients with high blood sugars on steroids may warrant diabetes consultation (they may need insulin at home while on steroids). Take a good history, ask about tinnitus, do the Dix-Hallpike maneuver for at least a minute in each position (have an emesis bucket handy! No test perfectly distinguishes central and peripheral vertigo, but searching for neighborhood signs that localize the lesion to the brainstem is paramount. Any one of the following is concerning for a central lesion: negative head impulse, nystagmus that is vertical or variable in its direction and skew (vertical misalignment) on cross cover fixation testing. Patients with peripheral vertigo may complain of “double vision” from nystagmus, but they should not have true diplopia or disconjugate eye movements on formal testing. Common Empiric Antibiotic Dosing for Meningitis in Adults Drug Dose Notes Vancomycin 15 mg/kg Modify dosage based on renal (actual dysfunction and age (see weight) q12 Toolbook). Cefepime 2 g q8 hrs Modify dosage in patients with renal dysfunction Ampicillin 2 g q4 hrs Modify dosage in patients with renal dysfunction. If sensation is intact to cotton wisp, it is probably not “numb” - Most patients with mild isolated facial paresthesias have no acute brainstem pathology if no neighborhood findings are present - Most patients with mild isolated limb paresthesias have an entrapment or radicular lesion if no weakness is present - Bilateral arm paresthesias may signify central cord syndrome, always image the C-spine - Hugging sensations may signify a transverse myelitis - Splitting the midline with vibration can be supportive of functional overlay, but does not rule out neurological disease Pseudoseizures - Always respond to the patients with concern, but do not give Ativan if it’s not a seizure - A reasonable number of true epileptics also have pseudoseizures. The consultation is usually for assistance with determining neurologic prognosis, or to rule out seizure. It is helpful to clarify with the primary team exactly what their question is at the time the consult is called, and if neurology remains on board for any length of time, continue to have discussions with the primary team about the role of the consulting neurology team. Myoclonus and other “jerks” in Hypoxic Ischemic Injury These patients frequently develop myoclonic jerking post-arrest and non- neurologists often interpret it as seizure. We do not treat it unless it is interfering with the patient’s care or is disturbing to the patient’s family. You can use benzodiazepines for treatment; alternatively, Keppra and valproic acid have some utility for myoclonic jerking. Post-arrest patients can also develop Lance—Adams syndrome, which causes myoclonic jerks but has a much better prognosis. Significance of physical findings in coma following cardiac arrest Patients with less chance of regaining independence Initial exam No pupillary light reflex One day Motor response no better than flexor and spontaneous eye movements neither orienting nor roving conjugate Motor response no better than flexor, no spontaneous eye Three days opening Motor response not obeying commands and spontaneous eye One week movements neither orienting nor roving conjugate. Oculocephalic response not normal, not obeying commands, Two weeks no spontaneous eye opening, eye opening not improved at least 2 grades from initial examination Patients with best chance of regaining independence Pupillary light reflexes present and motor response flexor or Initial exam extensor. Remember that the guidelines for prognosis derived from the Levy criteria do not always apply to patients who are were treated with therapeutic hypothermia or patients with major metabolic or infectious aberrations. If major derangements exist, these must be corrected before any statements about prognosis can be made. Blondin et al, 2011’s review on prognosis after hypothermia suggests that loss of pupils or corneals at 72 hours is still the best predictor of poor prognosis.
There are three stages of villi development: Primary Villi - cytotrophoblast Secondary Villi - cytotrophoblast + extraembryonic mesoderm Tertiary Villi - cytotrophoblast + extraembryonic mesoderm+ blood vessels There are two main types of early villi: Anchoring villi - attached to decidua Floating villi - not attached to decidua buy 20gm cleocin gel free shipping acne zinc, floating in maternal lacunae. The epiblast layer, consisting of totipotential cells, derives all 3 embryo layers: endoderm, mesoderm and ectoderm. The primitive streak is the visible feature which represents the site of cell migration to form the additional layers. Historically, gastrulation was one of the earliest observable morphological event occurring in the frog embryo. Currently, the molecular and physical Embryonic Disc showing mechanisms that regulate patterning and migration during this key event primitive streak are being investigated in several different animal models. In humans, it is proposed that similar mechanisms regulate gastrulation to those found in other vertebrates. Mesenchymal cells have an embryonic connective tissue-like cellular arrangement, that have undergone this process may at a later time and under specific signaling conditions undergo the opposite process, mesenchyme to epithelia. This process occurs at the primitive streak where epiblast cells undergo an epithelial to mesenchymal transition in order to delaminate and migrate. This signaling role patterns many different tissues (neural plate, neural tube, somites, endodermal organs). It has its own sequence of development from a primitive axial process and is a developmental feature not present in the adult anatomy. Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002 - Fertilization (http://www. In the third to fourth week we will now follow the development of the trilaminar embryo as each layer begins to differentiate into the primordia of different tissues within the embryo. From this point onward the lectures will not be in a strict timeline format as we will have to follow each layer (ectoderm, mesoderm, endoderm) forward through its early development, and then jump back to discuss the next layer. Carnegie stage 9 showing somite formation Mesoderm means the "middle layer" and it is from this layer that nearly all the bodies connective tissues are derived. In early mesoderm development a number of transient structures will form and then be lost as tissue structure is patterned and organised. Humans are vertebrates, with a "backbone", and the first mesoderm structure we will see form after the notochord will be somites. Coelom, meaning "cavity", and major fluid-filled cavities can be seen to form both within the embryo (intraembryonic coelom) and outside the embryo (extraembryonic coelom). The intraembryonic coelom is the single primitive cavity that lies within the mesoderm layer that will eventually form the 3 major anatomical body cavities (pericardial, pleural, peritoneal). Somites are developmental structures that contribute the following adult structures : vertebra, notochord, dermis, skeletal muscle vertebra, intervertebral discs, dermis, skeletal muscle kidney, body wall connective tissue, sensory ganglia kidney, gastrointestinal tract smooth muscle, mesentry Submit References Textbooks The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Francis-West - Mesoderm Ch11 p311-339 Body Cavities Ch6 p127-146 Additional Textbooks Before We Are Born (5th ed. Carlson Ch9,10: p173-193, 209-222 Body Cavities Ch5 p29-32, Ch7 p47,48 Online Textbooks Developmental Biology by Gilbert, Scott F. Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York and London: Garland Science; c2002 - Figure 21-78.
The Five Major Peritoneal Folds Fold Description Greater Apron-like structure that lies superficial to the small intestine and transverse colon quality cleocin gel 20 gm acne breakout causes; a site of fat omentum deposition in people who are overweight Table 23. Note the route of non-fat nutrients from the small intestine to their release as nutrients to the body. Functions of the Digestive Organs Organ Major functions Other functions Ingests food Moistens and dissolves food, allowing you to Chews and mixes food taste it Mouth Begins chemical breakdown of carbohydrates Cleans and lubricates the teeth and oral cavity Moves food into the pharynx Has some antimicrobial activity Begins breakdown of lipids via lingual lipase Propels food from the oral cavity to the Pharynx Lubricates food and passageways esophagus Esophagus Propels food to the stomach Lubricates food and passageways Mixes and churns food with gastric juices to form chyme Begins chemical breakdown of proteins Stimulates protein-digesting enzymes Stomach Releases food into the duodenum as chyme Secretes intrinsic factor required for vitamin Absorbs some fat-soluble substances (for B12 absorption in small intestine example, alcohol, aspirin) Possesses antimicrobial functions Mixes chyme with digestive juices Propels food at a rate slow enough for digestion and absorption Small Provides optimal medium for enzymatic activity Absorbs breakdown products of carbohydrates, intestine proteins, lipids, and nucleic acids, along with vitamins, minerals, and water Performs physical digestion via segmentation Table 23. The first of these processes, ingestion, refers to the entry of food into the alimentary canal through the mouth. There, the food is chewed and mixed with saliva, which contains enzymes that begin breaking down the carbohydrates in the food plus some lipid digestion via lingual lipase. Chewing increases the surface area of the food and allows an appropriately sized bolus to be produced. This act of swallowing, the last voluntary act until defecation, is an example of propulsion, which refers to the movement of food through the digestive tract. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which act to propel food along (Figure 23. Peristalsis is so powerful that foods and liquids you swallow enter your stomach even if you are standing on your head. Mechanical digestion is a purely physical process that does not change the chemical nature of the food. It includes mastication, or chewing, as well as tongue movements that help break food into smaller bits and mix food with This OpenStax book is available for free at http://cnx. Although there may be a tendency to think that mechanical digestion is limited to the first steps of the digestive process, it occurs after the food leaves the mouth, as well. The mechanical churning of food in the stomach serves to further break it apart and expose more of its surface area to digestive juices, creating an acidic “soup” called chyme. Segmentation, which occurs mainly in the small intestine, consists of localized contractions of circular muscle of the muscularis layer of the alimentary canal. These contractions isolate small sections of the intestine, moving their contents back and forth while continuously subdividing, breaking up, and mixing the contents. By moving food back and forth in the intestinal lumen, segmentation mixes food with digestive juices and facilitates absorption. In chemical digestion, starting in the mouth, digestive secretions break down complex food molecules into their chemical building blocks (for example, proteins into separate amino acids). Food that has been broken down is of no value to the body unless it enters the bloodstream and its nutrients are put to work. This occurs through the process of absorption, which takes place primarily within the small intestine.
In ad- dition generic 20gm cleocin gel amex acne 9 month old, zanamivir has been shown to be effective in patients at risk of developing influenza-related complications such as age ≥ 65 years and the presence of under- lying chronic disease including asthma, chronic obstructive pulmonary disease, cardiovascular disease, diabetes mellitus, and immunocompromise (Lalezari 2001). Influenza infections may lead to respiratory tract complications that result in antibi- otic treatment. A meta-analysis of 7 clinical trials reported that 17 % of placebo recipients developed a respiratory event leading to antibiotic use, mainly for acute bronchitis or acute sinusitis, whereas among zanamivir-treated patients the inci- dence of respiratory events leading to the use of antimicrobials was 11 % (Kaiser 2000b). In the setting of a large managed care plan (> 2,300 patients treated), the patterns of influenza compli- cations were found to be similar in zanamivir-treated and untreated patients (Cole 2002). Prophylaxis A series of randomised trials have proven the efficacy of zanamivir in the preven- tion of influenza. In a study involving healthy adults, 10 mg once a day or placebo was administered by oral inhalation at the start of the influenza outbreak. Zanamivir was 67 % efficacious in preventing clinical influenza (6 % [34/554] clinical influenza in the placebo group vs. Another clinical trial enrolled families with two to five members and at least one child who was five years of age or older. As soon as an influenza-like illness devel- oped in one family member, the family received either zanamivir (10 mg zanamivir inhaled once daily for 10 days) or placebo. In the zanamivir families, 4 % of fami- lies had at least one new influenza case, compared with 19 % in the placebo fami- Zanamivir 217 lies. A similar risk reduction was shown in a study where zanamivir was administered after close contact with an index case of influenza-like illness (Kaiser 2000). In a study of inhaled zanamivir for the prevention of influenza in families, 4 % of zanamivir versus 19 % of placebo households had at least 1 contact who developed symptomatic, laboratory-confirmed influenza (81 % protective efficacy). The pro- tective efficacy was similarly high for individuals (82 %) and against both influenza types A and B (78 % and 85 %, respectively, for households) (Monto 2002). Children In a trial on children aged five to twelve years, zanamivir reduced the median time to symptom alleviation by 1. Zanamivir-treated patients returned to normal activities significantly faster and took significantly fewer relief medications than placebo-treated patients (Hedrick 2000). Children, especially those under 8 years old, are usually unable to use the delivery system for inhaled zanamivir appropriately (not producing measurable inspiratory flow through the diskhaler or producing peak inspiratory flow rates below the 60 l/min considered optimal for the device). As a lack of measurable flow rate is related to inadequate or frankly undetectable serum concentrations, prescribers should carefully evaluate the ability of young children to use the delivery system when considering prescription of zanamivir. When zanamivir is prescribed for children, it should be used only under adult supervision and with attention to proper use of the delivery system (Relenza 2003). Special Situations Special settings in which zanamivir has been used include acute lymphoblastic leu- kemia (Maeda 2002) and allogeneic stem cell transplantation (Johny 2002). The second report found no toxicity attributable to zanamivir and rapid resolution of influenza symptoms. Avian Influenza Strains In a study performed on mice in 2000, zanamivir was shown to be efficacious in treating avian influenza viruses H9N2, H6N1, and H5N1 transmissible to mammals (Leneva 2001).
Shaken baby syndrome permeates all socio-economic and educational classes in society (American Academy of Ophthalmology discount cleocin gel 20 gm without a prescription acne varioliformis, 2002; Dias & Barthauer, 2001; Health Canada, 2001; Lancon et al. Biological fathers and stepfathers are the most common perpetrators (56% of cases), followed by boyfriends (16%), biological mothers (15%), and babysitters (14%) (Newton & Vandeven, 2005). In all, parents and paramours comprise approximately three-quarters of all perpetrators (Lazoritz & Palusci, 2001). Race has not been found to correlate with the incidence of shaken baby syndrome (Sinal & Petree, 2000). Factors such as unemployment, poverty, young parental age, substance abuse, and behavioural problems in the parent or child do contribute to the incidence of shaken baby syndrome (Fulton, 2000; Kemp & Coles, 2003; Starling et al. Parent education level and single parent status may also be important (Goldstein, Kelly, Bruton, & Cox, 1993). Parents that harbor unrealistic expectations for the child to fulfill the parents’ personal needs, or to behave beyond their age, are also at a higher risk of harming their children (Fulton, 2000; Showers, 1989). Because the prevalence of shaken baby syndrome is relatively low in the population, the predictive value of social characteristics is limited (Kemp & Coles, 2003). Studies have shown that shaken baby syndrome is more likely to be missed in families where the parents are married, Caucasian, and of higher socioeconomic status, due to health care provider bias (Ricci, Giantris, Merriam, Hodge, & Doyle, 2003; Sanders, Cobley, Coles, & Kemp, 2003). It is therefore prudent for health care workers to maintain a uniform index of suspicion in all cases of infants with traumatic brain injury. This is significant for the prevention of shaken baby syndrome, since 15 to 25% of healthy infants spend up to 50% of their waking hours crying inconsolably (Papousek & von Hofacker, 1998). Perpetrators classically describe, in hindsight, how an infant’s relentless, inconsolable crying, compounded by various life stressors, caused them to violently and impulsively shake an infant in their care (American Academy of Ophthalmology, 2002; Fulton, 2000; Levin, 1998). Infant colic is defined in the medical literature as persistent, excessive crying in an otherwise healthy infant, and is relatively poorly understood (Deshpande, 2005). Various theories as to the cause of colic have included gastrointestinal discomfort from lactose intolerance, difficulty adjusting to a diet of breast milk, self-regulatory dysfunction of behavioural-emotional states, and an immature infant sleep-wake organization (Papousek & von Hofacker, 1998). Barr, a pediatrician with a research interest in shaken baby syndrome, has identified a ‘crying curve’ that represents a universal pattern of infant crying. Barr contends that all infants follow this pattern, and that infants with ‘colic’ are merely at the end of a spectrum of normal crying behaviour (Barr, 1990). In a German study examining the link between persistent infant crying and the mother-infant relationship, Papousek and von Hofacker found that mothers of persistent criers scored markedly higher on scales for depressed mood, exhaustion, frustration/anger, and anxious overprotection (Papousek & von Hofacker, 1998). As well, Stifter and Bono found that mothers of colicky babies reported feeling less competent as mothers (Stifter & Bono, 1998). Clearly, incessant infant crying takes its toll on caregivers and predisposes infants to the risk of violent shaking. Accurate assessment of the true incidence of shaken baby syndrome presents an exceedingly difficult challenge. Some infants may not be brought to medical attention at the time of injury but later manifest unexplained developmental delays, neurological impairments, and learning difficulties (American Academy of Pediatrics, 2001; Duhaime et al. Consequently, experts suspect that documented cases of shaken baby syndrome represent a mere fraction of the total number of shaken infants per year.
It may arise from a variety of causes buy cheap cleocin gel 20 gm online acne 37 weeks pregnant, and treatments almost always involve fluid replacement and medications, called inotropic or pressor agents, which restore tone to the muscles of the vessels. In addition, eliminating or at least alleviating the underlying 922 Chapter 20 | The Cardiovascular System: Blood Vessels and Circulation cause of the condition is required. This might include antibiotics and antihistamines, or select steroids, which may aid in the repair of nerve damage. A common cause is sepsis (or septicemia), also called “blood poisoning,” which is a widespread bacterial infection that results in an organismal-level inflammatory response known as septic shock. Neurogenic shock is a form of vascular shock that occurs with cranial or spinal injuries that damage the cardiovascular centers in the medulla oblongata or the nervous fibers originating from this region. Anaphylactic shock is a severe allergic response that causes the widespread release of histamines, triggering vasodilation throughout the body. It is not always recognized as a distinct condition and may be grouped with cardiogenic shock, including pulmonary embolism and cardiac tamponade. Treatments depend upon the underlying cause and, in addition to administering fluids intravenously, often include the administration of anticoagulants, removal of fluid from the pericardial cavity, or air from the thoracic cavity, and surgery as required. The most common cause is a pulmonary embolism, a clot that lodges in the pulmonary vessels and interrupts blood flow. Other causes include stenosis of the aortic valve; cardiac tamponade, in which excess fluid in the pericardial cavity interferes with the ability of the heart to fully relax and fill with blood (resulting in decreased preload); and a pneumothorax, in which an excessive amount of air is present in the thoracic cavity, outside of the lungs, which interferes with venous return, pulmonary function, and delivery of oxygen to the tissues. This includes the generalized and more specialized functions of transport of materials, capillary exchange, maintaining health by transporting white blood cells and various immunoglobulins (antibodies), hemostasis, regulation of body temperature, and helping to maintain acid-base balance. In addition to these shared functions, many systems enjoy a unique relationship with the circulatory system. For example, you will find a pair of femoral arteries and a pair of femoral veins, with one vessel on each side of the body. Moreover, some superficial veins, such as the great saphenous vein in the femoral region, have no arterial counterpart. Another phenomenon that can make the study of vessels challenging is that names of vessels can change with location. Like a street that changes name as it passes through an intersection, an artery or vein can change names as it passes an anatomical landmark. For example, the left subclavian artery becomes the axillary artery as it passes through the body wall and into the axillary region, and then becomes the brachial artery as it flows from the axillary region into the upper arm (or brachium). You will also find examples of anastomoses where two blood vessels that previously branched reconnect. Anastomoses are especially common in veins, where they help maintain blood flow even when one vessel is blocked or narrowed, although there are some important ones in the arteries supplying the brain. As you study this section, imagine you are on a “Voyage of Discovery” similar to Lewis and Clark’s expedition in 1804–1806, which followed rivers and streams through unfamiliar territory, seeking a water route from the Atlantic to the Pacific Ocean. You might envision being inside a miniature boat, exploring the various branches of the circulatory system.