Top videos
• Define and use related medical terminology.
• Describe and demonstrate techniques for imaging the thyroid gland.
• Discuss functional abnormalities of the thyroid gland.
• Correlate laboratory data relevant to the thyroid and parathyroid glands.
• Describe, and recognize on images, pathologies of the thyroid gland.
• Identify the anatomy of the parathyroid glands on diagrams and sonograms.
• Describe and demonstrate techniques for imaging the parathyroid glands.
• Describe, and recognize on images, pathologies of the parathyroid glands.
• List and describe other neck masses.
• Follow relevant protocols when scanning.
• Differentiate the sonographic appearances of the female reproductive organs in relation to the menstrual cycle, the use of contraceptives and hormone replacement, and following chemotherapy.
• Explain the Patient Privacy Rule (HIPAA) and Patient Safety Act (see reference).
Identify the anatomy and explain the physiology of the breast on diagrams and sonograms.
Describe and demonstrate the protocol for sonographic scanning of the breast, including the clock and quadrant methods, and targeted examinations based on mammographic findings.
Describe the various diagnostic pathways that may lead to a sonographic breast examination, and explain how the ultrasound findings are correlated with other imaging modalities.
Identify and describe sonographic images of benign and malignant features and common breast pathologies.
Explain biopsy techniques for breast tumors.
Define and use related medical terminology.
Explain the Patient Privacy Rule (HIPAA) and Patient Safety Act (see reference
Neurotransmitter 3D Animation
on Tuesday, December 21, 2010
Neurotransmitters are endogenous chemicals which transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of the synapse. Release of neurotransmitters usually follows arrival of an action potential at the synapse, but may also follow graded electrical potentials. Low level "baseline" release also occurs without electrical stimulation. Neurotransmitters are synthesized from plentiful and simple precursors, such as amino acids, which are readily available from the diet and which require only a small number of biosynthetic steps to convert. The chemical identity of neurotransmitters is often difficult to determine experimentally. For example, it is easy using an electron microscope to recognize vesicles on the presynaptic side of a synapse, but it may not be easy to determine directly what chemical is packed into them. The difficulties led to many historical controversies over whether a given chemical was or was not clearly established as a transmitter. In an effort to give some structure to the arguments, neurochemists worked out a set of experimentally tractable rules. According to the prevailing beliefs of the 1960s, a chemical can be classified as a neurotransmitter if it meets the following conditions: * There are precursors and/or synthesis enzymes located in the presynaptic side of the synapse. * The chemical is present in the presynaptic element. * It is available in sufficient quantity in the presynaptic neuron to affect the postsynaptic neuron; * There are postsynaptic receptors and the chemical is able to bind to them. * A biochemical mechanism for inactivation is present. There are many different ways to classify neurotransmitters. Dividing them into amino acids, peptides, and monoamines is sufficient for some classification purposes. Major neurotransmitters: * Amino acids: glutamate, aspartate, D-serine, γ-aminobutyric acid (GABA), glycine * Monoamines and other biogenic amines: dopamine (DA), norepinephrine (noradrenaline; NE, NA), epinephrine (adrenaline), histamine, serotonin (SE, 5-HT), melatonin * Others: acetylcholine (ACh), adenosine, anandamide, nitric oxide, etc. In addition, over 50 neuroactive peptides have been found, and new ones are discovered regularly. Many of these are "co-released" along with a small-molecule transmitter, but in some cases a peptide is the primary transmitter at a synapse. β-endorphin is a relatively well known example of a peptide neurotransmitter; it engages in highly specific interactions with opioid receptors in the central nervous system. Single ions, such as synaptically released zinc, are also considered neurotransmitters by some[by whom?], as are some gaseous molecules such as nitric oxide (NO) and carbon monoxide (CO). These are not classical neurotransmitters by the strictest definition, however, because although they have all been shown experimentally to be released by presynaptic terminals in an activity-dependent way, they are not packaged into vesicles. By far the most prevalent transmitter is glutamate, which is excitatory at well over 90% of the synapses in the human brain. The next most prevalent is GABA, which is inhibitory at more than 90% of the synapses that do not use glutamate. Even though other transmitters are used in far fewer synapses, they may be very important functionally—the great majority of psychoactive drugs exert their effects by altering the actions of some neurotransmitter systems, often acting through transmitters other than glutamate or GABA. Addictive drugs such as cocaine and amphetamine exert their effects primarily on the dop
Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus. The process of normal human childbirth is categorized in three stages of labour: the shortening and dilation of the cervix, descent and birth of the infant, and birth of the placenta. In many cases, with increasing frequency, childbirth is achieved through caesarean section, the removal of the neonate through a surgical incision in the abdomen, rather than through vaginal birth. In the U.S. and Canada it represents nearly 1 in 3 (31.8%) and 1 in 4 (22.5%) of all childbirths, respectively.
Over one million Americans have the sexually transmitted virus, HIV, which can lead to the deadly disease known as AIDS.
HIV can be transmitted in the sexual fluids, blood or breast milk of an infected person. HIV prevention therefore involves a wide range of activities including prevention of mother-to-child transmission, needle exchanges and harm reduction for injecting drug users, and precautions for health care workers.
A drug allergy is the abnormal reaction of your immune system to a medication. Any medication — over-the-counter, prescription or herbal — is capable of inducing a drug allergy. However, a drug allergy is more likely with certain medications. The most common signs and symptoms of drug allergy are hives, rash or fever. A drug allergy may cause serious reactions, including anaphylaxis, a life-threatening condition that affects multiple body systems. A drug allergy is not the same as drug side effects, the known possible reactions that are listed on a drug label. A drug allergy is also distinct from drug toxicity caused by an overdose of medication.
Atrial fibrillation (also called AFib or AF) is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications. Some people refer to AF as a quivering heart. An estimated 2.7 million Americans are living with AF.
Atrial flutter is a type of abnormal heart rate, or arrhythmia. It occurs when the upper chambers of your heart beat too fast. When the chambers in the top of your heart (atria) beat faster than the bottom ones (ventricles), it complicates your heart rhythm