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Phys. Exam 4 Endocrinology
Endocrinology
43
Physiology
Graduate
12/03/2010

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Term
The islets of Langerhans in the pancreas has outer shell of ___ cells that release ___, and inner shell of ___ cells that release ___. Blood supply comes through the middle and leaves through periphery.
Definition
- alpha cells> glucagon
- beta cells> insulin
Term
Insulin has a and b chains, and gets cleaved at the 30 and 31 to release the __ __. High levels of this peptide may be indicative of an insulin producing tumor.
Definition
c-peptide
Term
Insulin gets cleaved at 30 and 31 amino acids b/c there are ___ amino acids at this cleavage point.
Definition
basic
Term
Insulin release:
Definition
- concentration dependent (50-300 mg/dl)
- biphasic
- amino acids (arginine)
- autonomic
Term
GLUT 2 transporter:
Definition
- on liver, kidneys, hypothalmus
- INDPENDENT of insulin
- Dependent on glucose concentration in extracellular space
Term
GLUT 4 transporter:
Definition
- DEPENDENT on insulin
- on skeletal and fat tissue where action of insulin is important
Term
glucose enters pancreatic beta cell via GLUT 2 transporter> glycolysis> ATP > closes potassium channels> potassium stays inside cell> depolarization> opens voltage gated calcium channels> calcium helps vesicular transport of insulin to cell surface so it can diffuse into fenestrated capillaries
Definition
Term
____ inhibit K+ channels. What does this do?
Definition
- Slufonureas (glyberide)
- By inhibiting the K+ channels, more calcium comes in through voltage gated calcium channels and more insulin is transporter to circulation
Term
Drug helpful for person not making enough insulin?
Definition
Slufonureas (glyberide)
Term
From ___ -___ mg/dl of glucose, insulin release increases. Max insulin release is between 275 and 300 mg/dl, then it levels off. And below 50 you dont releae much insulin, b/c just use that glucose for the brain.
Definition
- 50-300 mg/dl
Term
Insulin release is biphasic, explain:
Definition
- early insulin spike right when glucose raises, spike comes down within 10 minutes
- then slowly rises again for next hour
Term
The spike was already made insulin just sitting in the capillaries ready to go out. The gradual rise is newly synthesized insulin.
Definition
Term
How is the biphasic insulin response changed in Type II Diabetics?
Definition
- early spike is gone
- they have a constant stimulus for insulin production, so always on far right of curve
Term
amino acids can enter into glycolysis or TCA to make energy (arginine)
Definition
Term
Why do you get a higher insulin release when glucose is given po instead of intravenously?
Definition
- glucose interacts with GI tract to stimulate the release of incretins (GLP-1)> go to pancreas and assist glucose in stimulating release of insulin
Term
Incretins are broken down quickly by ____. So you can prolong life of incretins by administering ____ ___, which can improve insulin secretion in response to glucose. Chances of having a hypoglycemic attack are lower with this drug.
Definition
DPP-IV
DPP-IV inhibitors
Term
GLP-1, which is an ___, increases ___ in the pancreatic beta cell, which makes more voltage calcium channels open upon deopolarization, so more insulin is secreted.
Definition
- incretin
- CAMP
Term
Simultaneous Parasympathetics and Sympathetics innervation will have a net affect of ___ insulin release, even though parasympathetics stimulate release.
Definition
inhibiting
Term
Vagus nerve increases ____ insulin release, but sympathetic will trump it and ___ release.
Definition
- increase
- decrease
Term
Insulin increases:
Definition
- anabolism
- glucose transport into muscle and fatty tissues
- glucose utilization
- glycogen, fat, and protein synthesis
- amino acid transport
- fatty acid transport
- potassium transport
Term
High blood glucose without insulin will damage what?
Definition
- insulin independent tissues like kidneys, eyes, RBCs, nerves
- since these tissues are independent of insulin, they still get flooded with glucose in the absence of insulin
- muscle and fat tissues won't really be damaged b/c without insulin, sugar isn't entering these tissues
Term
insulin binding to its receptor causes an upregulation of glucose transpoters to the surface of the cell.
Definition
Term
Insulin's effects on adipose and muscle tissues:
Definition
- increases GLUT-4 receptors except on working muscle
- increases glycogen and protein synthesis in muscle
- increases lipogenesis and inhibits lipolysis
- In the liver increases glycogen synthesis and glucokinase, while inhibiting release of fatty acids
Term
Just a little bit of insulin will result in ____ of release of fatty acids from the liver. This is important for people with __ ___ Diabetes b/c this causes ___.
Definition
- inhibit
- Type I Diabetes
- ketoacidosis
Term
Insulin independent tissues, aka tissues that do not need insulin to access glucose:
Definition
- nervous system
- red blood cells
- renal medulla
- retina
- germinal epithelium
Term
To measure management of Diabetes, what should you measure?
Definition
- glucose attached to Hb aka HbA1c.
Term
Major hormone to prevent hypoglycemia?
Definition
- Glucagon
Term
Triggers for glucagon release?
Definition
- falling blood glucose
- rising amino acids
- autonomics
Term
Factor that causes both insulin and glucagon to increase? Explain.
Definition
- rising amino acids
- drink protein shake> insulin goes up, but not CHOs in it> glucose levels go down> glucagon released
Term
Sympathetic stimulation:
Definition
- inhibits insulin release
- stimulates glucagon release
Term
Insulin from pancreatic beta cells, acts on alpha receptors, which ___ more insulin secretion, and on beta receptors, which ___ insulin secretion. The ___ receptor wins and secretion is ____.
Definition
- inhibit
- stimulate
- alpha
- inhibited
Term
Glucagon from the pancreatic alpha cells acts on alpha receptors which ___ further glucagon secretion and on beta receptors which ___ further glucagon secretion. The ___ receptor wins and glucagon secretion is ___.
Definition
- inhibit
- stimulate
- beta
- stimulated
Term
Glucagon increases:
Definition
- glycogenolysis
- gluconeogenesis
- hormone sensitive lipase
- insulin
- positive inotropic effect on heart
Term
role of hormone sensitive lipase:
Definition
spares glucose for brain by supplying fat for fuel for rest of body
Term
So glucagon stimulates insulin and insulin stimulates glucagon, but not sure how.
Definition
Term
glucagon increases positive inotropic effects on heart. Explain.
Definition
- increased force and speed of heart contractions> increases contractility
Term
During stress, your body wants to ___ ___ ___ so you have ___ insulin, and high ___.
Definition
- make fuel available
- low insulin
- high glucagon
Term
A meal of CHOs will cause:
Definition
- insulin to increase
- glucagon to decrease
Term
A meal of protein will cause:
Definition
- insulin and glucagon to increase
- glucagon protects you from hypoglycemia
Term
Mixed meal of CHOs and protein will cause:
Definition
- increased insulin
- CHO tries to decrease glucagon and protein tries to bring it up, so glucagon doesn't change
Term
Diabetes Mellitus causes:
Definition
- hyperglycemia
- polydypsia
- polyuria
- ketoacidosis and loss of K+
Term
diabetes and hyperosmolar coma:
Definition
- happens in nursing home when pt doesn't drink enough> dehydrated and osmolarity gets high
Term
Metabolic syndrome:
Definition
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