Biosystems 2: Dr. Houseknecht Lecture

Biosystems 2: Dr. Houseknecht


1. What is the most important fuel for the brain?: Glucose
2. Brain glucose uptakes occurs at the rate during absorptive and post-
absorptive periods and is not altered in type II diabetes: same
3. What percentage of islet mass are glucagon (alpha)?: 20% islet mass
4. What percentage of islet mass are insulin cells (beta): 75% islet mass (insulin)
5. The islet of Langerhans has diverse endocrine cell types.. what are they?: -
Glucagon Insulin
Somatostatin
Pancreatic Polypeptide
Ghrelin
6. What is the function of insulin?: ANABOLIC*

Allows cells to take up and store glucose
7. What is the function of glucagon?: CATABOLIC*

Causes cells to release stored nutrients glucose) into the blood
8. What is the function of Amylin?: Slows glucose absorption in dueodenum: suppresses
glucagon secretion
9. What is the function of Ghrelin?: Stimulates appetite, increases food intake and promotes fat
storage
10.What is the function of somatostatin?: Decreases GI activity; suppresses glucagon and
insulin secretion
11.What is the function pancreatic polypetide?: Can inhibit exocrine pancreatic secretion and gall
bladder contraction, however its role in nutrient metabolism is unknown!
12.Which peptide is a secreted biomarker of endogenous insulin release?: C peptide
13.Which peptide chains comprise active insulin?: A & B chains
14.Insulin secretion is phasic: bi
15.When is insulin secretion stimulated?: When beta cells sense high glucose concentrations
16.B cells are , and this is regulates insulin secretion: elec- trically
excitable
17.Which hormones and neurotransmitters negatively impact insulin secre- tion?: Somatostatin
alpha-adrenergic effects of epi/norepi
18.Which hormones and neurotransmitters positively impact insulin secre- tion?: Acetylcholine


1/
11

, Biosystems 2: Dr. Houseknecht


CCK
Glucagon
GLP-1 GIP
19.Each insulin receptor is compromised of an & subunit: alpha,
beta
20.For insulin receptors, the tyrosine kinase domains the intracel-
lular sites: phosphorylates
21.What are the two insulin signaling pathways?: PI3-kinase Translocation of
GLUT 4
22.What is the role of GLUT-1?: Basal glucose uptake
23.What is the role of GLUT-2 in the liver, pancreatic islets, and intestines?: In the liver, removable
of excess from blood, in pancreas, regulation of insulin release
24.What is the role of GLUT-3 in the brain?: Basal glucose uptake
25.What is the role of GLUT-4 in muscle, fat, and heart?: Activity increased by insulin
26.Muscle stimulates glucose uptake: stimulates
27.Adipose tissue glucose reuptake: stimulates
28.Insulin promotes the storage of fat and glucose within : tar-
get cells
29.What is the first organ that insulin reaches through the hepatic portal system?: Liver
30.The liver increases storage of glucose as : glycogen
31.Insulin resets liver to the fed state by reversing what 3 things?: Glycogenol- ysis
Ketogenesis
Gluconeogenesis
32.the liver urea production and protein catabolism: decreases
33.Insulin triglyceride synthesis in thee liver: promotes
34.Insulin potassium and phosphate uptake in the liver: increases
35.Which target tissue promotes protein synthesis by increasing amino acid transport?: muscle
36.What target tissue promotes glycogen synthesis by increasing glucose transport into the
cells?: Muscle
37.Which target tissue reduces circulating free fatty acids and increases the storage of
triglycerides?: Adipose Tissue
38. is produced as a pro-hormone: Glucagon
39.Glucagon mediates it's effects via receptor signaling: GPCR


2/
11