Blood  Supply. — The  large  blood-vessels  of  the  pancreas  accompany

the  interlobular  ducts,  but  after  repeated  subdivision  these  vessels  part

company,  and  the  smaller  arteries  pursue  a  separate  course  through  the

Tnterlolniiar  connective  tissue.      Thus   they   reach   all   portions   of  the

26


404


THE  DIGESTIVE  SYSTEM


gland  and  supply  capillaries  to  the  intralobular  connective  tissue  about
the  acini.  Certain  arterial  branches  also  enter -the  islets  and  form  a
specially"rich  plexus  of  broad  capillaries^ ( sinusoids )  within  these  cell
groups.  The  veins  return  the  islet  blood  by  a  similar  course.
The  Lymphatics.
—The  lymphatics  are'
mostlyjconfined  to  the
interlobular  tissue;
where  they  are  in  re-
lation with  the  blood-
ves~sels7"~

The  Nerves.— The
nerves     are     derived
from  the  sympathetic
system,   and  occur  as
small    trunks    within
tnlTlnterlobular    con-
nective   tissue. .     Nu-
merous small  ganglia
occur  in  their  course.
As     in     the     salivary
glands  the  nerves  sup-
ply the  vascular  walls.
About_JJije~secreting
acini  they  form  a  del-
icate   network    of
naked    fibrils,    from
which     end    branches
penetrate    Hre"~~base-
ment    membrane  „  and
terminate     upon,  the
secreting  cells.     Lam-
ellar corpuscles  are  oc-
casionally found  in  the  interlobular  connective  tissue  of  the  pancreas.
Resume. — Finally  the  attention  of  the  student  should  be  specially
directed  to  the  presence  of  the  pancreatic  islets,  the  centro-acinar  cells,
the  very  distinct  inner  granular  and  outer  fibrillar  zones  of  the  secreting
cells,  the  thick  walls  of  the  interlobular  ducts,  the  absence_ofjfl.tralobular
ducts  except  of  the  intercalary  type,  and  the  loose  character  of  the  inter-
lobular tissue  as  the  distinguishing  characteristics  of  the  pancreas.
FIG.  377. — SECTION  OF  A  PANCREATIC  ISLET  FROM
INJECTED  SPECIMEN  OF  CAT'S  PANCREAS  TO  SHOW
THE  PROFUSE  BLOOD  SUPPLY.
