Image
from article Cardiovascular system
Computerized artwork of the human cardiovascular system, including the heart, lungs, and major arteries and veins. (Credit: Science Photo Library RF/Getty Images)
Search Results
Search Results
Refine this search
Search result paging links
8,021 results
Image
from article Cardiovascular system
Diagram of the heart and major vessels of a fetus just before birth. Small arrows within the liver indicate alternative blood routes by way of hepatic sinusoids. (Credit: Based on an original drawing by B. M. Patten; copyright © McGraw-Hill…
Image
from article Cardiovascular system
Single type of circulatory system. (Credit: Based on an original drawing by C. K. Weichert; copyright © McGraw-Hill Education)
Image
from article Cardiovascular system
Double type of circulatory system in a vertebrate having a four-chambered heart (ventral view). (Credit: Based on an original drawing by C. K. Weichert; copyright © McGraw-Hill Education)
Image
from article Cardiovascular system
Illustration of the human cardiovascular system, which involves pulmonary circulation and systemic circulation. Red vessels transport oxygenated blood; blue vessels transport deoxygenated blood; and purple vessels are involved in gas exchange.…
Image
from article Hematologic disorders
Myelophthisic anemia results from a space-occupying lesion in the bone marrow, which hinders hematopoiesis (the process by which the cellular elements of the blood are formed). In this photomicrograph, the bone marrow space is expanded, and the…
Image
from article Hematologic disorders
Scanning electron micrograph of (top) an elongated, flattened sickle cell and (bottom) a normal red blood cell. (Credit: Callista Images/Image Source/Getty Images)
Image
from article Hematologic disorders
Colored scanning electron micrograph of round leukocytes from a patient with leukemia. (Credit: Steve Gschmeissner/Science Photo Library)
Image
from article Allometry
Allometric lines for the mass of some organs across mammal species. (These are best-fit lines: individual species may lie above or below them.) Note that the skeleton is disproportionately heavy in large species (positive allometry), whereas the…
Image
from article Allometry
Three different types of allometry. Each curve shows the growth allometry of organ size in a different species. The adults of each species show static intraspecific allometry. The circles indicate a particular stage of the life history (for example,…
Image
from article Blowpipe
Glassblower blowing into a blowpipe to shape molten glass. (Credit: Hero Images/Getty Images)
Image
from article Tin
Image
from article Tin
Image
from article Electric filter
Image
from article Electric filter
Passive, lumped-element filters. (a) RC low-pass filter. (b) LC band-pass filter.
Image
from article Electric filter
Ladder structure. (a) Overall structure with alternating series and shunt arms. (b) LC circuit whose impedance contains both a finite-frequency pole and a zero. Such circuits are used in the series and shunt arms of the ladder structure.
Image
from article Electric filter
Mechanical filter.
Image
from article Electric filter
Single-amplifier filters. (a) Low-pass Sallen-Key filter. (b) Low-pass, infinite-gain, single-amplifier filter. (c) Cascade of second-order filter realizations.
Image
from article Electric filter
Multiple-amplifier filters. (a) State-variable (KHN) filter. (b) Tow-Thomas filter.
Image
from article Electric filter
Simulated-inductor realization of fifth-order high-pass filter. (a) RLC prototype, normalized for cutoff frequency of 1 rad/s (0.159 Hz). (b) Direct active-RC realization.
Image
from article Satellite television broadcasting
Direct broadcasting television satellite system.
Image
from article Isoelectric point
Titration of alanine with sodium hydroxide (NaOH), showing the course of pH with added fractional equivalents. The four arrows show, from left to right, the pKa [½ cations: NH3+(CH3)COOH, and ½ zwitterions: NH3+(CH3)CHCOO−], the pl (all…
Image
from article Isoelectric point
Course of the charges carried by lysine (pKa = 2.18) molecules in dilute aqueous solution with pH during a titration with alkali. Shown are the net charge, going from +2 at low pH to +1 between pH 4.5 and 6.5, the isoelectric point at pH 9.74, the…
Image
from article Fungi
Porcini mushrooms (Boletus edulis) are members of the Basidiomycota division of Fungi. (Credit: Digoarpi/Shutterstock)
Image
from article Fungi
Spore types (upper illustrations) and structures of parent mycelia (lower illustrations) in fungi.
Image
from article Fungi
Sporangia of saprophytic Rhizopus. (Credit: Richard Gross; copyright © McGraw-Hill Education)
Image
from article Fungi
Sexual mechanisms in fungi: (a) gametic copulation; (b) gametangial copulation; (c) gamete-gametangial copulation; and (d) somatic copulation.
Image
from article Fungi
Colorized scanning electron micrograph of brewer's yeast cells (Saccharomyces cerevisiae). This fungus consists of single vegetative cells, and small daughter cells can be seen budding off from the larger cells. Brewer's yeast is used in the…
Image
from article Medical bacteriology
Microscopic view of bacterial pneumonia, which is a type of pneumonia caused by bacterial infection. (Credit: Stocktrek Images/Corbis)
Image
from article Medical bacteriology
Bacteria culture growth on agar medium in a petri dish. (Credit: Sompraaong0042/Shutterstock)
Image
from article Genetically modified organism (GMO)
Transgenic zebrafish cells. Green fluorescent protein (GFP) is a fluorescent protein first discovered in the jellyfish Aequorea victoria. GFP is commonly used as a reporter of gene expression in other species. Here, GFP is expressed by zebrafish…
Image
from article Genetically modified organism (GMO)
Genome editing technologies. In particular, targeted nucleases are a powerful tool for precise genome editing in GMOs. Among these tools are (a) transcription activator-like effector nucleases (TALENs), (b) zinc-finger proteins (ZFPs), (c) homing…
Image
from article Channelrhodopsin
Three-dimensional (3D) protein crystal structure of channelrhodopsin variant C1C2. (Image courtesy of Protein Data Bank 3UG9, Molecular Modeling Database 96737)
Image
from article Melatonin
Chemical structure of melatonin (C13H16N2O2).
Image
from article Plague
Plague ecology in the United States. The left panel shows how plague occurs in nature among rodents. The right panel shows how plague is spread from rodents to humans and domestic animals. (Credit: Centers for Disease Control and Prevention)
Image
from article Sloan Digital Sky Survey
Sloan Digital Sky Survey (SDSS) 2.5-m (98-in.) telescope at Apache Point Observatory, New Mexico. The secondary mirror is visible in the center of the aperture. The square structure surrounding the primary and secondary mirrors shelters them from…
Image
from article Sloan Digital Sky Survey
Spectrum of a galaxy (image inset) receding at around 6000 km s−1 (3700 mi s−1), or about 2% of the speed of light. The vertical line shows the wavelength at which one expects to observe the emission line Hα for an object at rest (656.3 nm). The…
Image
from article Sloan Digital Sky Survey
Distribution of galaxies within 4° of the celestial equator from the SDSS. In this polar plot, the radius indicates the distance from the Milky Way, and the angle is the right ascension. The diameter shown is 8 × 109 light-years. Blank areas have…
Image
from article Sloan Digital Sky Survey
Map of stars in the SDSS. Grayscale signifies density of stars on the sky. Several streams of stars are noticeable. Areas in background are those unobserved by the survey. (Courtesy of Vasily Belokurov; Sloan Digital Sky Survey)
Image
from article Sloan Digital Sky Survey
Image of Canes Venatici I, a recently discovered satellite of the Milky Way Galaxy. (Photo courtesy of Vasily Belokurov; Sloan Digital Sky Survey)
Image
from article Sloan Digital Sky Survey
Hubble sequence of galaxies, as observed by the SDSS. Elliptical galaxies (types marked E0 and E6) are old, spheroidal, and very massive. Spiral galaxies are on average less massive. While some spiral galaxies (S0 and Sa) tend to have very little…
Image
from article Iridium
Image
from article Nursing
Nursing provides physical and emotional care to ailing individuals. (Credit: Fuse/Getty Images)
Image
from article Binary and multiple asteroids
Asteroid 121 Hermione and its moonlet companion observed with the adaptive optics system mounted on the European Southern Observatory's Very Large Telescope [consisting of four 8.2-m (25-ft) telescopes] at six different times. The satellite revolves…
Image
from article Phospholipases
Sites at which different phospholipases cleave the typical phospholipid phosphatidylcholine. F1 and F2 are long-chain fatty acids esterified at positions 1 and 2 of the glycerol backbone, respectively.
Image
from article Phospholipases
Mechanisms by which activated receptors coupled to phospholipase C (PLC) through heterotrimeric G proteins produce their physiological responses. Terms: PIP2, phosphatidylinositol bisphosphate; DAG, diacylglycerol; PKC, protein kinase C; IP3,…
Image
from article Human-factors engineering
Human-factors engineers design modern computer equipment, including ergonomic keyboards and mouse devices, to accommodate the varied physical contours and dimensions of the human hand. (Credit: JG Photography/Alamy)
Image
from article Human-factors engineering
Human-factors engineering addresses problems related to the design of seats, workplaces, and consoles in terms of a user's physical size, comfort, strength, and visibility. (Copyright © McGraw-Hill Education)
Image
from article Human-factors engineering
Cognitive engineering and the development of new technology applications.
Image
from article Saturn
Saturn viewed on April 25, 2016 by the Cassini orbiter as the planet neared its northern hemisphere's summer solstice. (Credit: NASA/JPL-Caltech/Space Science Institute)
