c=J pars intermedia
I;::; \:1 primar y capillary net
Ig~gg81 secondary capillary net
Cyclostome
~ direction of blood flow
lIIIIIIlIIJJlII vascutar plexus
•
portal vessels
oc
Necl urus
Typical Urodela
Teleostei
Elasmobranc hii
ah
Anura
Ophidia or Lacertilia
Fig. 2.3 Vascular relationships between the brain and pituitary in cold-blooded vertebrates,
according to J.D. GREEN, illustrating the trend toward evolution of a hypophysial portal
system. Abbreviations: ah Adenohypophysis; me Median eminence; nh Neurohypophysis;
nl Pars nervosa; DC Optic chiasma; pd Pars distalis ; pi Pars inrerrnedia: pt Pars tuberalis ;
sv Saccus vasculosus ; vi Ventral lobe. (From GORBMAN and BERN, 1962 as modified from
GREEN, 1951).
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