The numerous mitochodnrial variations (in total shape as well as cristae shape) seen with different species, tissues, strains, experimental manipulations can sometimes lead to interesting speculations about which mitochondrial membrane proteins might be present or absent or changed. Electron tomography as well as routine transmission electron microscopy can allow speculation about mitochondrial performance.

Isolated mitochondrial supply an easy example of changes in cristae junctions where under some conditions they are non-functional (missing).

In vivo, mitochondria are surrounded by areas of cytoplasm which can have cytoskeletal elements closely approximated, and/or linked to mitochondria (e,g, nerve terminals – called mitochondrial associated adherens complexes) , with desmosomes (sometimes called mitochondrial tethers–of which there are dozens of samples in many species on this website), nuclear pores (i don’t believe these have been named–of which there are also dozens of samples in many species on this website), and sometimes other organelles, such as RER and secretion granules).

Positions of cristae, arrangement  (perpendicular, parallel, etc) and number of cristae and cristae junctions are variable features depending upon which cytoplasmic elements are adjacent to that particular side (site) on the outer mitochondrial membrane. Some morphometric work was done on neural tissue by Perkins et al, Journal of Neuroscience January 20, 2010, 30(3):1015–1026, and they state that the number of cristae junctions is greater on the side of the mitochondrion which is involved in what they call “mitochondrion-associated adherens complex”  –maybe an unfortunate use of the word adherens…. owing to its immediate confusion with adherens junctions… maybe deliberate use of the word adherens because of the presence of what they term cytoskeletal structures).

estimates:

crista junction 15nm diameter
OMM thickness 20nm
omm+imm contact distance 14nm
tubular cristae (hepatochte mitochondria) 30-40nm diameter
about 90 degree angle (perpendicular) cristae to junctions
junctions at higher numberical density on sides where contact with plasmalemma is (specialized areas)
intermediate filaments and microtubules aligned with the long axis of mitochondrion (what does this mean? parallel?)
struts (perpendicular to mitochondrion, filaments a little thicker than intermediate filaments?) (a ring?)
filaments and microtubules define a “vesicle” free area as the M-associated adherens complex.
possible vesicle tethers beside the m-associated adherens complex about 8 nm apart