摘要:

The cells of twelve arterioles have been reconstructed from serial Araldite sections of 0.5 µm thickness stained with toluidine blue. Each arteriole had a single layer of smooth muscle cells. Each cell was spindle-shaped, contained one nucleus and was wound around part of the circumference of the arteriole. A 30-µm length of arteriole contained 19.1 ± SEM 2.2 nuclei, and therefore the same number of smooth muscle cells. This number did not vary with ãrteriolar internal diameters in the range 11–31 µm. The maximal axial width of the cells was found by inspection to be 4.2 ± 0.2 µm and this too was independent of the ãrteriolar diameter. From the number and width of the cells and the surface area of the arteriole, the length of the cells was calculated to be 47 ± 6 µm. The length was greater in the large arterioles and was 90% of the circumference on average. The thickness of the smooth muscle cells in the radial direction was 3.3 ± 0.2 µm. The helical pitch of the cellular axes to the axis of the arteriole was 81.3 ± 1.5 °. These results are discussed in relation to the tension developed in ãrteriolar walls and in relation to the electrotonic spread of current from cell to cell along an arteriole that has been measured with intracel

ISSN:1422-6405    

DOI:10.1159/000145246

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

The infratemporal fossa grows allomorphically in primates at a faster rate than general cranial and inferred body size. The coefficient of allometry approximates 1.5 across most primate groups, suggesting direct scaling of the musculus temporalis cross-sectional area to body mass. This coefficient is larger than 1.5 in Lorisoidea and Ceboidea. Medio-lateral relative growth of the infratemporal passage that accommodates m. temporalis rather than antero-posterior growth absorbs a disproportionate amount of this expansion. Likewise, infratemporal fossa breatdh is positively allometric to tooth size, especially in insectivorous, frugivorous and folivorous primate samples that are homogeneous with respect to diet. The seemingly growth-related positive relation between tooth size and distal placement of the zygomatic root that is consistent over the cumulative sample is erased by controlling for diet. Increased relative amounts of m. temporalis per unit of dental occlusal area is indicated in larger-bodied forms; increasing crown height may be a mechanism to adjust for this.

ISSN:1422-6405    

DOI:10.1159/000145247

出版商:S. Karger AG    

年代:1980

数据来源: Karger

摘要:

A simple morphological method is described whereby the numbers of nuclei in different types of skeletal muscle fibre may be determined. The method allows for the anisotropy of skeletal muscle fibres and the non-random distribution of their nuclei. The advantages in the use of a morphological (rather than a biochemical) method are discussed, together with possible applications of the method in the study of changes which occur in skeletal muscle in adaptation to stress and in disease.

ISSN:1422-6405    

DOI:10.1159/000145248

出版商:S. Karger AG    

年代:1980

数据来源: Karger