#16 Pancreas Physiology presentation ppt

pancreas ppt

1. The Pancreas

2. The Pancreas –an Exocrineand Endocrinegland

3. Functions of the Pancreas
1. Exocrine Gland–Digestive System
Pancreatic Juicesreleased into small intestine
for chemical digestion (catabolism).
Lipase-enzyme that digests lipids.
Amylase(pancreatic) -enzyme that digests starch.
Protease-enzyme that digests proteins.

4. Additional Digestive Enzymes
Trypsinogen trypsin digests protein
(zymogens)
Ribonucleasedigests RNA.
Deoxyribonucleasedigests DNA.
Sodium Bicarbonate -neutralizes HCl.
Also in Pancreatic Juices:

5. Pituitary
Gland
Pineal
Gland
Parathyroid
Gland (posterior)
Thyroid
Gland
Heart
Thymus
Pancreas
Adrenal
Gland
Ovaries
Testes
The EndocrineSystem and Hormones

6. Endocrine
Gland
Hormone binds
to cells with
Receptors
(target tissue)
Hormone
Travels in
bloodstream
Effector Tissue
Releases
Hormone
The Mode of Operation
Lipid
Soluble
Hormone
HormoneInteractions:
Antagonistic–onehormonehavingtheoppositeeffectofanother.
e.g.:Insulinandglucagon;ParathyroidHormoneandCalcitonin.
Synergistic–twoormorehormonesacttogethertohaveagreater
effectthanthesumofthemseparately.
e.g.:TestosteroneandFSH;ProlactinandOxytocin.
Permissive–onehormoneenhancestheeffectofanother
hormonesecretedlater.
e.g.:EstrogenandProgesterone;CortisolandNorepinephrine.

7. SteroidandThyroidHormones:
Thesearehydrophobic(orlipophilic)andreadilypassthroughplasmamembraneand
enterthecytoplasmofthecellsinthetargettissue.
Canalsoenternucleusandbindtochromatin‘receptors’associatedwithDNA,activating
transcriptionofDNA(readinggenes),makingmRNAandgeneratingproteins.
Examples:Prostaglandins,theSexHormones,ThyroxinandCalcitonin.
Peptide and Catecholamine Hormones:
These are watersoluble (hydrophilicor lipophobic) and cannot slip into the cell but
instead bind to receptors on the outer surface of the cell.
Typically activating a G protein, switching cAMPwhich acts as a 2
nd
messengerand
activates other enzymes inside cell.
Examples: Insulin, Glucagon, Epinephrine, Cortisol.

8. Beta-cells
Delta-cells
Alpha-cells
Capillaries
The Islets of Langerhans (Pancreatic Islets)
The Endocrine Gland portion of Pancreas

9. 2. Endocrine Gland–Regulates Metabolism
The islets of Langerhans (Pancreatic islets)
are clusters of endocrine cells in the pancreas.
-cells site of glucagonsynthesis.
-cellssite of insulinsynthesis.
*Ghrelin–also from pancreas (and stomach),
triggers hunger.
delta-cells site of somatostatin synthesis.

10. The Glycemic Index (GI)

11. Insulin and Glucagon
Insulin: Peptide hormone made by cells
If blood glucose rises (e.g. after a meal)
insulin is released.
Insulin causes cells in body to take up
glucose (e.g. ↓blood glucose).
Also causes liver to synthesize glycogen
and other anabolic activities.

12. Glucagon: Peptide hormone made by cells
If blood glucose falls (e.g. in between meals)
glucagon is released.
Causes liver to hydrolyze glycogen(called glycogenolysis)
into glucose (e.g. ↑ blood glucose)
Also causes fats and proteins to be converted into
glucose (called gluconeogenisis) & other catabolic activities.

13. When blood Glucose is high
Insulin is released to make
blood Glucose lower (normal)
Cells in your body
up-take the glucose

14. When blood Glucose is low
Glucagon is released to make
blood Glucose higher (normal)
Liver is key site:
Hepatocytes liberate Glucose stores
(glycogen) and use fats & proteins to
make more glucose *Glycogenolysis*

15. Diabetes Mellitus
•Type I –“Juvenile Onset” (IDDM)
•Type II –“Adult Onset” (NIDDM)

16. Chronic Kidney Disease
& Kidney Failure
Diabetes leading cause
of kidney failure
among Americans.
Heart Disease
Chronically elevated
blood glucose linked
to plaque formation in
coronary arteries
(atherosclerosis).
Diabetics have twice
the risk of heart disease.
Peripheral Arterial Disease
Atherosclerosis in extremities,
causing leg pain, poor
circulation. Gangrene.
Neuropathy
Affects hands and feet;
tingling, burning, numbness
or complete loss of feeling.
Also in organs, can slow
digestion, cause
constipation,
decreased sexual
response.
Eye Problems
Retinopathy:
Blood vessels to retina
leak, bleed, become
blocked; may cause
partial loss of vision
or blindness. increased
Risk cataracts
and glaucoma
Consequences of Chronic Diabetes

17. Neurons can only use glucose!
and they don’t require insulin.
(use Glut-2-transporters)
What if your Glucose becomes too low?
Hypoglycemia, can impair CNS resulting in
dizziness, speech problems and loss of
consciousness.
Unconsciousness => "hypoglycemic coma"
often resulting from "insulin shock ".

18. Insulin
Levels

19. The Glycemic Index (GI)

21. Sucrose EthanolGlucose
2 slices of bread 1 glass of orange juice 1 shot of bourbon
96 Cal used by body
24 Cal hits Liver
Dyslipidemia
24 Cal used by body
96 Cal hits Liver
48 Cal used by body
72 kcal hits Liver
↑ Aldehydes
↑ Uric acid
↑ VLDL+ ↓NO= ↑BP
↑Aldehydes
↑ Acetate
↑ Citrate
↑ VLDL
Makes Glycogen
↑ Insulin
60 Cal glucose + 60 Cal fructoseStarch => glucose
Glucose-6-℗
0.5 Cal used for
de novo Lipogenesis
No effect on Ghrelin
↑Insulin resistance
CNS Depressant
Inhibits Ghrelin
↑ de novo Lipogenesis
↑ de novo Lipogenesis
Glucose-6-℗
120 Cal each

23. Metabolic Syndrome
Numerous metabolic risk factors in one individual, including:
Others Risks -cardiovascular disease, Type 2 diabetes mellitus.
(~50 million Americans have this condition).
Hypothesizedlink to over consumption of HFCS and metabolic syndrome.
1.High Blood Pressure
2.Abdominal Fat
3.High blood Triglyceride levels
4.High Uric Acid levels
5.Insulin resistance
6.State of Chronic Inflammation