An oscilloscope called an oscillograph, informally known as a scope or o-scope, CRO, or DSO, is a type of electronic test instrument that graphically displays varying signal voltages as a two-dimensional plot of one or more signals as a function of time. Other signals can be displayed. Oscilloscopes display the change of an electrical signal over time, with voltage and time as the Y- and X-axes on a calibrated scale; the waveform can be analyzed for properties such as amplitude, rise time, time interval and others. Modern digital instruments may display these properties directly. Calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument; the oscilloscope can be adjusted so that repetitive signals can be observed as a continuous shape on the screen. A storage oscilloscope can capture a single event and display it continuously, so the user can observe events that would otherwise appear too to see directly. Oscilloscopes are used in the sciences, engineering and the telecommunications industry.
General-purpose instruments are used for maintenance of electronic laboratory work. Special-purpose oscilloscopes may be used for such purposes as analyzing an automotive ignition system or to display the waveform of the heartbeat as an electrocardiogram. Early oscilloscopes used cathode ray tubes as their display element and linear amplifiers for signal processing. Storage oscilloscopes used special storage CRTs to maintain a steady display of a single brief signal. CROs were largely superseded by digital storage oscilloscopes with thin panel displays, fast analog-to-digital converters and digital signal processors. DSOs without integrated displays are available at lower cost and use a general-purpose digital computer to process and display waveforms; the basic oscilloscope, as shown in the illustration, is divided into four sections: the display, vertical controls, horizontal controls and trigger controls. The display is a CRT or LCD panel laid out with horizontal and vertical reference lines called the graticule.
CRT displays have controls for focus and beam finder. The vertical section controls the amplitude of the displayed signal; this section has a volts-per-division selector knob, an AC/DC/Ground selector switch, the vertical input for the instrument. Additionally, this section is equipped with the vertical beam position knob; the horizontal section controls the time base or "sweep" of the instrument. The primary control is the Seconds-per-Division selector switch. Included is a horizontal input for plotting dual X-Y axis signals; the horizontal beam position knob is located in this section. The trigger section controls the start event of the sweep; the trigger can be set to automatically restart after each sweep, or can be configured to respond to an internal or external event. The principal controls of this section are the source and coupling selector switches, an external trigger input and level adjustment. In addition to the basic instrument, most oscilloscopes are supplied with a probe; the probe connects to any input on the instrument and has a resistor of ten times the oscilloscope's input impedance.
This results in a.1 attenuation factor. Some probes have a switch allowing the operator to bypass the resistor. Most modern oscilloscopes are lightweight, portable instruments compact enough for a single person to carry. In addition to portable units, the market offers a number of miniature battery-powered instruments for field service applications. Laboratory grade oscilloscopes older units that use vacuum tubes, are bench-top devices or are mounted on dedicated carts. Special-purpose oscilloscopes may be rack-mounted or permanently mounted into a custom instrument housing; the signal to measure is fed to one of the input connectors, a coaxial connector such as a BNC or UHF type. Binding posts or banana plugs may be used for lower frequencies. If the signal source has its own coaxial connector a simple coaxial cable is used. In general, for routine use, an open wire test lead for connecting to the point being observed is not satisfactory, a probe is necessary. General-purpose oscilloscopes present an input impedance of 1 megohm in parallel with a small but known capacitance such as 20 picofarads.
This allows the use of standard oscilloscope probes. Scopes for use with high frequencies may have 50‑ohm inputs; these must be either used with Z0 or active probes. Less-frequently-used inputs include one for triggering the sweep, horizontal deflection for X‑Y mode displays, trace brightening/darkening, sometimes called z'‑axis inputs. Open wire test leads are to pick up interference, so they are not suitable for low level signals. Furthermore, the leads have a high inductance. Using a shielded cable is better for low level signals. Coaxial cable has lower inductance, but it has higher capacitance: a typical 50 ohm cable has about 90 pF per meter. A one-mete
In human anatomy, the groin is the junctional area between the abdomen and the thigh on either side of the pubic bone. This is known as the medial compartment of the thigh that consists of the adductor muscles of the hip or the groin muscles. A pulled groin muscle refers to a painful injury sustained by straining the hip adductor muscles; these hip adductor muscles that make up the groin consist of the adductor brevis, adductor longus, adductor magnus and pectineus. These groin muscles adduct the thigh; the groin is innervated by the obturator nerve, with two exceptions: the pectineus muscle is innervated by the femoral nerve, the hamstring portion of adductor magnus is innervated by the tibial nerve. In the groin, underneath the skin, there are three to five deep inguinal lymph nodes that play a role in the immune system; these can be swollen due to certain diseases, the most common one being a simple infection, less from cancer. A chain of superficial inguinal lymph nodes drain to the deep nodes.
In a venography procedure, the groin is the preferred site for incisions to enter a catheter into the vascular system. The inguinal ligament runs from the pubic tubercle to the anterior superior iliac spine and its anatomy is important for hernia operations. Like other flexion surfaces of large joints, it is an area where blood vessels and nerves pass superficially, with an increased amount of lymph nodes. In a venography procedure, the groin is the preferred site for incisions to enter a catheter into the vascular system. Loin Athletic pubalgia
The somatosensory system is a part of the sensory nervous system. The somatosensory system is a complex system of sensory neurons and pathways that responds to changes at the surface or inside the body; the axons of sensory neurons connect with, or respond to, various receptor cells. These sensory receptor cells are activated by different stimuli such as heat and nociception, giving a functional name to the responding sensory neuron, such as a thermoreceptor which carries information about temperature changes. Other types include mechanoreceptors and nociceptors which send signals along a sensory nerve to the spinal cord where they may be processed by other sensory neurons and relayed to the brain for further processing. Sensory receptors are found all over the body including the skin, epithelial tissues, muscles and joints, internal organs, the cardiovascular system. Somatic senses are sometimes referred to as somesthetic senses, with the understanding that somesthesis includes the sense of touch and haptic perception.
The mapping of the body surfaces in the brain is called somatotopy. In the cortex, it is referred to as the cortical homunculus; this brain-surface map is not immutable, however. Dramatic shifts can occur in response to injury; the four mechanoreceptors in the skin each respond to different stimuli for long periods. Merkel cell nerve endings are found in hair follicles. Due to having a small receptive field, they are used in areas like fingertips the most. Tactile corpuscles react to moderate light touch, they are located in the dermal papillae. They respond unlike Merkel nerve endings, they are responsible for the ability to feel gentle stimuli. Lamellar corpuscles distinguish rough and soft substances, they react in quick action potentials to vibrations around 250 Hz. They have large receptor fields. Pacinian reacts only to sudden stimuli so pressures like clothes that are always compressing their shape are ignored. Bulbous corpuscles react and respond to sustained skin stretch, they are responsible for the feeling of object slippage and play a major role in the kinesthetic sense and control of finger position and movement.
Merkel and bulbous cells - slow-response - are myelinated. All of these receptors are activated upon pressures that squish their shape causing an action potential. All afferent touch/vibration info ascends the spinal cord via the posterior column-medial lemniscus pathway via gracilis or cuneatus. Cuneatus sends signals to the cochlear nucleus indirectly via spinal grey matter, this info is used in determining if a perceived sound is just villi noise/irritation. All fibers cross in the medulla; the postcentral gyrus includes the primary somatosensory cortex collectively referred to as S1. BA3 receives the densest projections from the thalamus. BA3a is involved with the sense of relative position of neighboring body parts and amount of effort being used during movement. BA3b is responsible for distributing somato info, it projects texture info to BA1 and shape + size info to BA2. Region S2 divides into parietal ventral area. Area S2 is involved with specific touch perception and is thus integrally linked with the amygdala and hippocampus to encode and reinforce memories.
Parietal ventral area is the somatosensory relay to the premotor cortex and somatosensory memory hub, BA5. BA5 is association area. BA1 processes texture info. Area S2 processes light touch, visceral sensation, tactile attention. S1 processes the remaining info. BA7 integrates visual and proprioceptive info to locate objects in space; the insular cortex plays a role in the sense of bodily-ownership, bodily self-awareness, perception. Insula plays a role in conveying info about sensual touch, temperature and local oxygen status. Insula is a connected relay and thus is involved in numerous functions; the somatosensory system is spread through all major parts of the vertebrate body. It consists both of sensory receptors and afferent neurons in the periphery, to deeper neurons within the central nervous system. A somatosensory pathway will have three long neurons: primary and tertiary; the first neuron always has its cell body in the dorsal root ganglion of the spinal nerve. The second neuron has its cell body either in the brainstem.
This neuron's ascending axons will cross to the opposite side either in the spinal cord or in the brainstem. In the case of touch and certain types of pain, the third neuron has its cell body in the VPN of the thalamus and ends in the postcentral gyrus of the parietal lobe. Photoreceptors, similar to those found in the retina of the eye, detect damaging ultraviolet radiation (
The lancelets known as amphioxi, consist of about 30-35 species of "fish-like" benthic filter feeding chordates in the order Amphioxiformes. They are the modern representatives of the subphylum Cephalochordata, their main interest in zoology is that they provide evolutionary insight on the origins of vertebrates. Their genomes hold clues about evolution how vertebrates have employed old genes for new functions, providing the opportunity to improve our knowledge of amphioxus genome structure and evolution; the genome of a few species in the genus Branchiostoma have been sequenced: B. floridae, B. belcheri, B. lanceolatum. In Asia, lancelets are harvested commercially as food for domesticated animals. In Japan, amphioxus has been listed in the registry of “Endangered Animals of Japanese Marine and Fresh Water Organisms”. Lancelets are distributed in shallow subtidal sand flats in temperate and tropical seas around the world; the only exception is Asymmetron inferum, a species known from the vicinity of whale falls at a depth of about 225 m.
Although they are able to swim, adult amphioxi are benthic. They live in sandy bottoms whose granulometry depends on the species and the site, they are found half-buried in sand; when disturbed, they leave their burrow and will swim a short distance, rapidly burrow again, posterior end first, into the sand. Adults can tolerate salinities as low as 6‰ and temperatures from 3 to 37°C, their habitat preference reflects their feeding method: they only expose the front end to the water and filter-feed on plankton by means of a branchial ciliary current that passes water through a mucous sheet. Branchiostoma floridae is capable of trapping particles from microbial to small phytoplankton size, while B. lanceolatum preferentially traps bigger particles. Lancelets are gonochoric animals, they only reproduce during their spawning season, which varies between species - corresponding to spring and summer months. All lancelets species spawn shortly synchronously or asynchronously. Nicholas and Linda Holland were the first researchers to describe a method of obtaining amphioxus embryos by induction of spawning in captivity and in vitro fertilization.
Spawning can be artificially induced in the lab by thermal shock. The first representative organism of the group to be described was Branchiostoma lanceolatum, it was described by Peter Simon Pallas in 1774 as molluscan slugs in the genus Limax. It was not until 1834 that Gabriel Costa brought the phylogenetic position of the group closer to the agnathan vertebrates, including it in the new genus Branchiostoma. In 1836, Yarrel renamed the genus as Amphioxus, now considered an obsolete synonym of the genus Branchiostoma. Today, the term "amphioxus" is still used as a common name for the Amphioxiformes, along with "lancelet" in the English language. Observations of amphioxus anatomy began in the middle of the 19th century. First, the adult the embryonic anatomy were described. Alexander Kowalevsky first described the key anatomical features of the adult amphioxus. De Quatrefages first described the nervous system of amphioxus. Other important contributions to amphioxus adult anatomy were given by Heinrich Rathke and John Goodsir.
Kowalevsky released the first complete description of amphioxus embyos, while Schultze and Leuckart were the first describing the larvae. Other important contributions to amphioxus embyonic anatomy were given by Hatschek, Conklin and by Tung. Depending on the exact species involved, the maximum length of lancelets is 2.5 to 8 cm. Branchiostoma belcheri and B. lanceolatum are among the largest. Except for the size, the species are similar in general appearance, differing in the number of myotomes and the pigmentation of their larvae, they without any paired fins or other limbs. A poorly developed tail fin is present, so they are not good swimmers. While they do possess some cartilage-like material stiffening the gill slits and tail, they have no true skeleton. In common with vertebrates, lancelets have a hollow nerve cord running along the back, pharyngeal slits and a tail that runs past the anus. Like vertebrates, the muscles are arranged in blocks called myomeres. Unlike vertebrates, the dorsal nerve cord is not protected by bone but by a simpler notochord made up of a cylinder of cells that are packed to form a toughened rod.
The lancelet notochord, unlike the vertebrate spine, extends into the head. This gives the subphylum its name; the nerve cord is only larger in the head region than in the rest of the body, so that lancelets do not appear to possess a true brain. However, developmental gene expression and transmission electron microscopy indicate the presence of a diencephalic forebrain, a possible midbrain, a hindbrain but recent studies involving a comparison with vertebrates indicates that the vertebrate thalamus and midbrain domains jointly correspond to a single amphioxus region, termed Di-Mesencephalic primordium Lancelets have four known kinds of light-sensing structures: Joseph cells, Hesse organs, an unpair
Deep palmar arch
The deep palmar arch is an arterial network found in the palm. It is formed from the terminal part of the radial artery, with the ulnar artery contributing via its deep palmar branch, by an anastomosis; this is in contrast to the superficial palmar arch, formed predominantly by the ulnar artery. The deep palmar arch lies upon the bases of the metacarpal bones and on the interossei of the hand, being covered by the oblique head of the adductor pollicis muscle, the flexor tendons of the fingers, the lumbricals of the hand. Alongside of it, but running in the opposite direction—toward the radial side of the hand—is the deep branch of the ulnar nerve; the superficial palmar arch is more distally located than the deep palmar arch. If one were to extend the thumb and draw a line from the distal border of the thumb across the palm, this would be the level of the superficial palmar arch; the deep palmar arch is about a finger width proximal to this. The connection between the deep and superficial palmar arterial arches is an example of anastomosis, can be tested for using Allen's test.
From the deep palmar arch emerge palmar metacarpal arteries. Superficial palmar arch Palmar carpal arch Dorsal carpal arch This article incorporates text in the public domain from page 595 of the 20th edition of Gray's Anatomy lesson5artofhand at The Anatomy Lesson by Wesley Norman Atlas image: hand_blood2 at the University of Michigan Health System
A transducer is a device that converts energy from one form to another. A transducer converts a signal in one form of energy to a signal in another. Transducers are employed at the boundaries of automation and control systems, where electrical signals are converted to and from other physical quantities; the process of converting one form of energy to another is known as transduction. Transducers that convert physical quantities into mechanical ones are called mechanical transducers. Examples are a thermocouple that changes temperature differences into a small voltage, or a Linear variable differential transformer used to measure displacement. Transducers can be categorized by which direction information passes through them: A sensor is a transducer that receives and responds to a signal or stimulus from a physical system, it produces a signal, which represents information about the system, used by some type of telemetry, information or control system. An actuator is a device, responsible for moving or controlling a mechanism or system.
It is controlled by a signal from a control manual control. It is operated by a source of energy, which can be mechanical force, electrical current, hydraulic fluid pressure, or pneumatic pressure, converts that energy into motion. An actuator is the mechanism; the control system can be software-based, a human, or any other input. Bidirectional transducers convert physical phenomena to electrical signals and convert electrical signals into physical phenomena. An example of an inherently bidirectional transducer is an antenna, which can convert radio waves into an electrical signal to be processed by a radio receiver, or translate an electrical signal from a transmitter into radio waves. Another example is voice coils, which are used in loudspeakers to translate an electrical audio signal into sound and in dynamic microphones to translate sound waves into an audio signal. Active sensors require an external power source to operate, called an excitation signal; the signal is modulated by the sensor to produce an output signal.
For example, a thermistor does not generate any electrical signal, but by passing an electric current through it, its resistance can be measured by detecting variations in the current or voltage across the thermistor. Passive sensors, in contrast, generate an electric current in response to an external stimulus which serves as the output signal without the need of an additional energy source; such examples are a photodiode, a piezoelectric sensor, thermocouple. Some specifications that are used to rate transducers Dynamic range: This is the ratio between the largest amplitude signal and the smallest amplitude signal the transducer can translate. Transducers with larger dynamic range are more "sensitive" and precise. Repeatability: This is the ability of the transducer to produce an identical output when stimulated by the same input. Noise: All transducers add some random noise to their output. In electrical transducers this may be electrical noise due to thermal motion of charges in circuits.
Noise corrupts small signals more than large ones. Hysteresis: This is a property in which the output of the transducer depends on not only its current input but its past input. For example, an actuator which uses a gear train may have some backlash, which means that if the direction of motion of the actuator reverses, there will be a dead zone before the output of the actuator reverses, caused by play between the gear teeth. Electromagnetic: Antennae – converts propagating electromagnetic waves to and from conducted electrical signals magnetic cartridges – converts relative physical motion to and from electrical signals Tape head, disk read-and-write heads – converts magnetic fields on a magnetic medium to and from electrical signals Hall effect sensors – converts a magnetic field level into an electrical signal Electrochemical: pH probes Electro-galvanic oxygen sensors Hydrogen sensors Electromechanical: Accelerometers Air flow sensors Electroactive polymers Rotary motors, linear motors Galvanometers Linear variable differential transformers or rotary variably differential transformers Load cells – converts force to mV/V electrical signal using strain gauges Microelectromechanical systems Potentiometers Pressure sensors String potentiometers Tactile sensors Vibration powered generators Vibrating structure gyroscopes Electroacoustic: Loudspeakers, earphones – converts electrical signals into sound Microphones – converts sound into an electrical signal Pickup – converts motion of metal strings into an electrical signal Tactile transducers – converts electrical signal into vibration Piezoelectric crystals – converts deformations of solid-state crystals to and from electrical signals Geophones – converts a ground movement into voltage Gramophone pickups – Hydrophones – converts changes in water pressure into an electrical signal Sonar transponders Ultrasonic transceivers, transmitt
Intensive care medicine
Intensive care medicine, or critical care medicine, is a branch of medicine concerned with the diagnosis and management of life-threatening conditions that may require sophisticated life support and intensive monitoring. Patients requiring intensive care may require support for cardiovascular instability lethal cardiac arrhythmias, airway or respiratory compromise, acute renal failure, or the cumulative effects of multiple organ failure, more referred to now as multiple organ dysfunction syndrome, they may be admitted for intensive/invasive monitoring, such as the crucial hours after major surgery when deemed too unstable to transfer to a less intensively monitored unit. Medical studies suggest a relation between ICU volume and quality of care for mechanically ventilated patients. After adjustment for severity of illness, demographic variables, characteristics of the ICUs, higher ICU volume was associated with lower ICU and hospital mortality rates. For example, adjusted ICU mortality was 21.2% in hospitals with 87 to 150 mechanically ventilated patients annually, 14.5% in hospitals with 401 to 617 mechanically ventilated patients annually.
Hospitals with intermediate numbers of patients had outcomes between these extremes. ICU delirium and inaccurately referred to as ICU psychosis, is a syndrome common in intensive care and cardiac units where patients who are in unfamiliar, monotonous surroundings develop symptoms of delirium; this may include interpreting machine noises as human voices, seeing walls quiver, or hallucinating that someone is tapping them on the shoulder. There exists systematic reviews in which interventions of sleep promotion related outcomes in the ICU have proven impactful in the overall health of patients in the ICU. In general, it is the most expensive, technologically advanced and resource-intensive area of medical care. In the United States, estimates of the 2000 expenditure for critical care medicine ranged from US$15–55 billion. During that year, critical care medicine accounted for 0.56% of GDP, 4.2% of national health expenditure and about 13% of hospital costs. In 2011, hospital stays with ICU services accounted for just over one-quarter of all discharges but nearly one-half of aggregate total hospital charges in the United States.
The mean hospital charge was 2.5 times higher for discharges with ICU services than for those without. Intensive care takes a system-by-system approach to treatment; as such, the nine key systems are each considered on an observation-intervention-impression basis to produce a daily plan. In addition to the key systems, intensive care treatment raises other issues including psychological health, pressure points and physiotherapy, secondary infections. In alphabetical order, the nine key systems considered in the intensive care setting are: cardiovascular system, central nervous system, endocrine system, gastro-intestinal tract, integumentary system, microbiology and respiratory system. Intensive care is provided in a specialized unit of a hospital called the intensive care unit or critical care unit. Many hospitals have designated intensive care areas for certain specialities of medicine, such as the coronary intensive care unit for heart disease, medical intensive care unit, surgical intensive care unit, pediatric intensive care unit, neuroscience critical care unit, overnight intensive-recovery, shock/trauma intensive-care unit, neonatal intensive care unit, other units as dictated by the needs and available resources of each hospital.
The naming is not rigidly standardized. For a time in the early 1960s, it was not clear that specialized intensive care units were needed, so intensive care resources were brought to the room of the patient that needed the additional monitoring and resources, it became evident, that a fixed location where intensive care resources and dedicated personnel were available provided better care than ad hoc provision of intensive care services spread throughout a hospital. Common equipment in an intensive care unit includes mechanical ventilation to assist breathing through an endotracheal tube or a tracheotomy. Critical care medicine is an important medical specialty. Physicians with training in critical care medicine are referred to as intensivists. In the United States, the specialty requires additional fellowship training for physicians having completed their primary residency training in internal medicine, anesthesiology, surgery or emergency medicine. US board certification in critical care medicine is available through all five specialty boards.
Intensivists with a primary training in internal medicine sometimes pursue combined fellowship training in another subspecialty such as pulmonary medicine, infectious disease, or nephrology. The American Society of Critical Care Medicine is a well-established multiprofessional society for practitioners working in the ICU including nurses, respiratory therapists, physicians. Most medical research has demonstrated that ICU care provided by intensivists produces better outcomes and more cost-effective care; this has led the Leapfrog Group