ZOOGCC33TH Topic Structure and function of Pancreas By Pritha Gupta Dept of Zoology Pancreas It is the second largest gland of the human body Consists of both exocrine and endocrine parts and hence called as ID: 913794
Download Presentation The PPT/PDF document "CORE COURSE 3 - PHYSIOLOGY AND BIOCHEM..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
CORE COURSE 3- PHYSIOLOGY AND BIOCHEMISTRYZOOG-CC3-3-TH
Topic:
Structure and function of
Pancreas
By
Pritha
Gupta
Dept . of. Zoology
Slide2PancreasIt is the second largest gland of the human body . Consists of both exocrine and endocrine parts and hence called as
‘mixed gland’
It develops as outgrowths arising close to the hepatic
diverticulum
.
It is located on the posterior wall of abdominal cavity.
Human pancreas is differentiated into
head,body
and tail. The head is located close to the duodenal cavity while the body and tail extends across the posterior wall of abdomen
upto
the
hilus
of spleen.
Slide3Histology of PancreasMajor part of the pancreas consists of acini or exocrine part .The
acini
are spherical lobule consisting of 40-50 pyramidal cells around a narrow lumen
.
Cytoplasm contains granular ER, prominent
nucleus,golgi complex and numarous zymogen granules
Fig : Section of mammalian pancreas
Fig:
Acinar
part of Pancreas
Slide4Islets of Langerhans
CELL
TYPE
QUANTITY
POSITION
HORMONE PRODUCEDα
cell or A cell20%
Peripheral partGlucagon
β cell or B cell
70%
Central
partInsulinδ cell or D cell < 5%VariableSomatostatinF cellVery fewVariablePancreatic Polypeptide
Fig : Pancreatic Islet
Human pancreas contains about 1million islets which comprise about 1-2% of the volume of the gland.
Each islet consists of 2000-3000
cells,arranged
in irregular cords separated by sinusoids.
Islets of
Langernans
contain mainly 4 types of cells –
α
cells,
β
cells,
δ
cells and F cells.
A considerable quantity of
stroma
is found in between pancreatic islets and
acini
.
Slide5Functions of GlucagonIt is secreted from the α- cells and known as ‘
hyperglycaemic
factor’ since it increases blood sugar level by the following ways:
It stimulates
glycogenolysis
It stimulates
lipolysis
It increases glycogen breakdown and prevents recycling of glucose to glycogen
Stimulates neoglucogenesis
Slide6Functions of InsulinIt is secreted from the β- cells and known as ‘
hypoglycaemic
factor’ since it reduces blood sugar level by the following ways:
Effects on carbohydrate metabolism :
Increases glucose transport from extracellular fluid into muscles,
adiposetissues
and other
extrahepatic cells.
Inhibits glycogenolysis
Prevents
gluconeogenesis
Stimulates glycogenesis
Slide7Insulin contd……Effect on protein metabolism
:
Enhances amino acid uptake
Decreases protein
breakdown,amino
acid catabolismEffect on lipid metabolism :1.Lowers circulating levels of fatty acids2. Enhances synthesis of lipids from carbohydrates
Effect on tissue growth :It stimulates proliferation of and growth of tissues like
liver,skin, connective tissue etc.
Slide8δ-cells produce somatostatin , a polypeptide hormone. It decreases gastric acid and gastrin production .
What is Diabetes Mellitus ?
Hyposecretion
of
β
– cells of the islets is very common and this may lead to a metabolic disorder Diabetes Mellitus .Symptoms include
polyphagia
,
polydipsia , high blood sugar and inability to
utilise
glucose.