| sural region | The muscular swelling of the back of the leg below the knee, formed chiefly by the bellies of the gastrocnemius and soleus muscles. Synonym: regio suralis, sura, calf. (05 Mar 2000) |
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| deltoid region | The lateral aspect of the shoulder demarcated by the outlines of the deltoid muscle. Synonym: regio deltoidea. (05 Mar 2000) |
| switch region | <molecular biology> The nucleotide sequences in heavy chain immunoglobulin genes located in the introns at the 5' end of each CH locus concerned with DNA recombination events that lead to changes in the type of heavy chain produced by a B-cell, for example IgM to IgG switching. These regions are highly conserved sequences. See: isotype switching. (19 Jan 1998) |
| dorsal hypothalamic region | The portion of the hypothalamus located immediately ventral to the hypothalamic sulcus; contains small nuclei, some of which are associated with the ansa lenticularis and the entopeduncular nucleus. (05 Mar 2000) |
| iliac region | The topographical area of the inferior abdomen related to the inguinal canal, lateral to the pubic region. Synonym: regio inguinalis, groin, iliac region, inguen. (05 Mar 2000) |
| immunoglobulin constant region | That region of the immunoglobulin (antibody) molecule that is invariable in its amino acid sequence within any class of immunoglobulins. It confers the biological specificity to the ig and is grossly species specific. It comprises the c-terminus half of the light chains and three quarters or more of the heavy chains, all of the fc fragment, and the c-terminus half of the fab fragment. (12 Dec 1998) |
| immunoglobulin joining region | Segment of light and heavy chains of mouse and human immunoglobulins where the genes for the variable region upstream join those of the constant region downstream (an important part of the antibody diversity mechanism). In the joining region of the light chain are the genes coding for amino acids 96 to 107. (12 Dec 1998) |
| immunoglobulin switch region | Site on a segment of a B-cell immunoglobulin heavy-chain gene where recombination or rearrangement can occur, expressed as isotype or allotype switching, maturation of immune response, or recombination of DNA molecules. It is found on genes encoding all five immunoglobulin heavy chains. (12 Dec 1998) |
| immunoglobulin variable region | That region of the immunoglobulin (antibody) molecule that varies in its amino acid sequence and composition, confers the antigenic specificity, and is thought to comprise the binding site for the antigen. It is located at the n-terminus of the fab fragment of the immunoglobulin. It includes hypervariable and framework regions, vh family subgroups, and the complementarity-determining region. (12 Dec 1998) |
| inframammary region | The region of the chest inferior to the mammary gland. Synonym: regio inframammaria. (05 Mar 2000) |
| infraorbital region | The region of the face below the orbit and alongside the nose on each side. Synonym: regio infraorbitalis. (05 Mar 2000) |
| infrascapular region | The region of the back lateral to the vertebral region and below the scapula. Synonym: regio infrascapularis. (05 Mar 2000) |
| inguinal region | The topographical area of the inferior abdomen related to the inguinal canal, lateral to the pubic region. Synonym: regio inguinalis, groin, iliac region, inguen. (05 Mar 2000) |
| intergenic region | <molecular biology> DNA sequences located between genes that comprise a large percentage of the human genome with no known function. (09 Oct 1997) |
| intermediate hypothalamic region | The infundibular portion of the hypothalamus, includes the medial tuberal nuclei and portions of the dorsomedial, ventromedial, arcuate (infundibular), posterior and lateral hypothalamic nuclei; located internally in the general area of the infundibulum. (05 Mar 2000) |