loop of Henle

(noun)

A structure in a kidney's nephron that connects the proximal convoluted tubule to the distal convoluted tubule.

Related Terms

Examples of loop of Henle in the following topics:

  • Kidney Function and Physiology

    • In the loop of Henle, the permeability of the membrane changes.
    • Additionally, the loop of Henle invades the renal medulla, which is naturally high in salt concentration.
    • Because two sides of the loop of Henle perform opposing functions, it acts as a countercurrent multiplier .
    • The vasa recta around the loop of Henle acts as the countercurrent exchanger.
    • The loop of Henle acts as a countercurrent multiplier that uses energy to create concentration gradients.

  • Nephron: The Functional Unit of the Kidney

    • The second part is called the loop of Henle, or nephritic loop, because it forms a loop (with descending and ascending limbs) that goes through the renal medulla.
    • As urine travels down the collecting duct system, it passes by the medullary interstitium, which has a high sodium concentration as a result of the loop of Henle's countercurrent multiplier system.
    • The nephron is the functional unit of the kidney.
    • The glomerulus and convoluted tubules of the nephron are located in the cortex of the kidney, while the collecting ducts are located in the pyramids of the kidney's medulla.
    • Explain the role of the nephron as the functional unit of the kidney

  • Characteristics of Mammals

    • The presence of hair is one of the most obvious traits of a mammal.
    • The lower jaw of mammals consists of only one bone, the dentary.
    • The jaws of other vertebrates are composed of more than one bone.
    • The kidneys of mammals have a portion of the nephron called the loop of Henle or nephritic loop, which allows mammals to produce urine with a high concentration of solutes; higher than that of the blood.
    • Bones of the mammalian inner ear are modified from bones of the jaw and skull.

  • Control of Homeostasis

    • In contrast, positive feedback loops push the organism further out of homeostasis, but may be necessary for life to occur.
    • Any homeostatic process that changes the direction of the stimulus is a negative feedback loop.
    • This is still a negative feedback loop, but not in the direction expected by the use of the term "negative."
    • Another example of an increase as a result of a feedback loop is the control of blood calcium.
    • A positive feedback loop maintains the direction of the stimulus and possibly accelerates it.

  • Humoral, Hormonal, and Neural Stimuli

    • The release of hormones can be triggered by changes in the blood ("humor"), by the actions of other hormones, or by neurological stimuli.
    • This is an example of a negative feedback loop.
    • Hormonal stimuli refers to the release of a hormone in response to another hormone.
    • As blood concentrations of T3 and T4 rise, they inhibit both the pituitary and the hypothalamus in a negative feedback loop.
    • This in turn causes the release of the hormones T3 and T4.

  • The Protein Synthesis Machinery

    • All tRNAs fold into very similar cloverleaf structures of four major stems and three major loops.
    • Each tRNA has a sequence of three nucleotides located in a loop at one end of the molecule that can basepair with an mRNA codon.
    • The anticodon-containing loop is at one end of the molecule (in grey here) and the amino acid acceptor arm is at the other end of the molecule (in yellow here) past the bend of the "L".
    • All tRNAs, regardless of the species they come from or the amino acid they carry, self-basepair to produce a cloverleaf structure of four main stems and three main loops.
    • The opposite end of the folded tRNA has the anticodon loop where the tRNA will basepair to the mRNA codon.

  • Hormonal Regulation of the Reproductive System

    • An increase in gonad hormone levels inhibits GnRH production through a negative feedback loop .
    • LH stimulates production of the sex hormones (androgens) by the Leydig cells of the testes.
    • LH also plays a role in the development of ova, induction of ovulation, and stimulation of estradiol and progesterone production by the ovaries .
    • These hormones encourage the development of sperm cells within the testicles, which then produce inhibin and inhibit the production of GnRH, FSH and LH in a negative feedback loop.
    • GnRH secreted by the hypothalamus stimulates the release of FSH, which stimulates the growth of egg cells, and LH, which signals for the the ovulation of an egg from its follicle.

  • Chromosomal Structural Rearrangements

    • A chromosome inversion is the detachment, 180° rotation, and reinsertion of part of a chromosome.
    • Inversions may occur in nature as a result of mechanical shear, or from the action of transposable elements (special DNA sequences capable of facilitating the rearrangement of chromosome segments with the help of enzymes that cut and paste DNA sequences).
    • To maintain point-for-point synapsis during meiosis, one homolog must form a loop, and the other homolog must mold around it.
    • When one chromosome undergoes an inversion, but the other does not, one chromosome must form an inverted loop to retain point-for-point interaction during synapsis.
    • Describe the various types of structural rearrangements of chromosomes and how they can impact an organism

  • Genomic DNA and Chromosomes

    • The genome of an organism consists of its entire complement of DNA, which encodes the genes that control the organism's characteristics.
    • In prokaryotes, the genome is composed of a single, double-stranded DNA molecule in the form of a loop or circle .
    • Some prokaryotes also have smaller loops of DNA called plasmids that are not essential for normal growth.
    • Each species of eukaryotes has a characteristic number of chromosomes in the nuclei of its cells.
    • The variation of individuals within a species is due to the specific combination of the genes inherited from both parents.

  • Open and Closed Circulatory Systems

    • The circulatory system is effectively a network of cylindrical vessels (the arteries, veins, and capillaries) that emanate from a pump (the heart).
    • In all vertebrate organisms, as well as some invertebrates, this is a closed-loop system in which the blood is not moving freely in a cavity.
    • An open circulatory system does not use as much energy to operate and maintain as a closed system; however, there is a trade-off with the amount of blood that can be moved to metabolically-active organs and tissues that require high levels of oxygen.
    • In fact, one reason that insects with wing spans of up to two feet wide (70 cm) are not around today is probably because they were outmatched by the arrival of birds 150 million years ago.
    • (a) In closed circulatory systems, the heart pumps blood through vessels that are separate from the interstitial fluid of the body.