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Heart-Rate Monitor

This project uses a sensitive light-detecting resistor to detect small changes in the light beaming through your finger as your blood pumps through tiny arteries in the finger. This device is not the same as the heart-rate monitors typically used in…

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from article Allosteric enzyme

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Model of an allosteric enzyme composed of two subunit monomers. Regulatory effects are obtained by shifting back and forth between the two states—relaxed (R state) and taut (T state). In the R state, the enzyme reacts with substrate and activators;…

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from article Heart (invertebrate)

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Invertebrate hearts range from (left) the centralized hearts and open circulatory systems of grasshoppers to (right) the distributed hearts and closed circulatory systems of segmented worms. (Copyright © McGraw-Hill Education)

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from article Heart (invertebrate)

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Circulatory system in a marine snail (Aplysia). Arrows indicate the normal direction of blood flow. (Credit: E. Mayeri, J. Koester, I. Kupfermann, G. Liebeswar, and E. R. Kandel)

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from article Heart (invertebrate)

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Cardiac ganglion of a lobster (Homarus): (a) nerves on the inner dorsal surface of the heart; (b) cell body position of all nine intrinsic neurons. (Credit: D. K. Hartline)

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from article Heart (invertebrate)

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Cross section of a leech (Hirudo), showing its major organs and muscles, including its ventral nerve cord and the four longitudinal coelomic sinuses, which are the main vessels of its circulatory system. The nerve cord is enclosed in the ventral…

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from article Amino acid

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Structural formula for an amino acid. (Copyright © McGraw Hill)

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from article Amino acid

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The 20 amino acids that serve as the building blocks for proteins. These amino acids (shown with their respective three-letter abbreviations) can be divided into nonpolar, polar, and electrically charged groups. (Copyright © McGraw Hill)

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from article Amino acid

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Synthesis of a dipeptide. When an amino group of one amino acid is linked to the carboxyl group of another amino acid, a peptide bond linkage is formed. A molecule of water (H2O) is split out when a peptide bond is formed. (Copyright © McGraw Hill)

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from article Amino acid

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Two-dimensional chromatogram of a protein. (Credit: R. J. Block, E. L. Durrum, and G. Zweig)

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from article Mitochondrial replacement therapy

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Spindle transfer involves the excision of the metaphase II spindle from a donor egg and replacing it with the metaphase II spindle from the affected egg. The metaphase II spindle contains the condensed chromosomes of the egg's haploid genome. Terms:…

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from article Mitochondrial replacement therapy

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Cytoplasmic transplantation involves the addition of a donor's ooplasm (cytoplasm in an oocyte) to the recipient oocyte prior to fertilization. Terms: ICSI, intracytoplasmic sperm injection; mtDNA, mitochondrial DNA; nDNA, nuclear DNA. (Credit:…

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from article Mitochondrial replacement therapy

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Pronuclear transfer requires that both the donor and affected eggs be fertilized by the father's sperm simultaneously in vitro. Following fertilization and once pronuclei are visible by microscopy, the two pronuclei from the donor egg are removed,…

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from article Glucose

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Steps involved in the regulation of blood glucose. The pancreas acts as both the sensor and effector organ. (Copyright © McGraw-Hill Education)

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from article Glucose

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Breakdown (catabolism) of glucose. Glucose is catabolized in three steps: glycolysis, Krebs cycle, and oxidative phosphorylation. The final product is ATP (adenosine triphosphate), which is an organic molecule that cells use as a source of energy to…

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from article Glucose

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Glucose and insulin uptake in normal individuals and those with type 1 or type 2 diabetes. (Copyright © McGraw-Hill Education)

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from article Camel

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Bactrian camel (Camelus bactrianus). (Photo courtesy of Brent Huffman, Ultimate Ungulate Images)

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from article Tuberculosis

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Tuberculosis is caused by the tubercle bacillus Mycobacterium tuberculosis. (Left) Colorized scanning electron micrograph (SEM) depicting some of the ultrastructural details seen in the cell wall configuration of a number of Gram-positive…

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from article Tuberculosis

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Annual number of tuberculosis (TB) cases in the United States from 1992 to 2017. During this time period, there has been a decline in the prevalence of tuberculosis. However, the progression of decline has slowed since 2013 (indicated by the purple…

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from article Tuberculosis

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Skin testing for tuberculosis, using the Mantoux test. (a) Tuberculin PPD (purified protein derivative) is injected into the dermis. A small bleb develops, but is absorbed within a short time. (b) After 48–72 h, the skin reaction is read and given a…

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from article Tuberculosis

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Chest radiograph (posteroanterior view) showing extensive tuberculosis with cavitation in the right lung. (Copyright © McGraw-Hill Education)

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from article Radioimmunoassay

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Competing reactions that form the basis of radioimmunoassay. Dagger indicates antigen in known standard solutions or unknown samples. B indicates bound antigen; F, free antigen.

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from article Radioimmunoassay

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Standard curve for radioimmunoassay of gastrin. Hormone concentration in unknown plasma sample is determined as shown.

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from article Tendon

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Anatomical illustration of a human arm, including the tendons of the biceps muscle (biceps brachii). (Copyright © McGraw Hill)

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from article Tendon

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Colored scanning electron micrograph of tendon fibers, which are made from collagen and aligned in a parallel fashion. Some fibers have been teased apart. (Credit: Steve Gschmeissner/Alamy)

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