Regulation of plasma glucose Flashcards Preview

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Flashcards in Regulation of plasma glucose Deck (28):
1

What is the normal range of plasma glucose?

100 mg/dL

5.5 mmol/L

2

What is hypoglycemia?

A drop in blood glucose

3

What happens to the body during hypoglycemia?

Different organs have different dependencies on glucose

Brain - requires continuous glucose supply, very sensitive to changes - main source of energy for neural cells

Heart - can produce energy from fatty acids

Liver - hepatocytes have glycogen storage and can catalise metabolites to make ATP - not sensitive to glucose changes

Muscle - glycogen is primary fuel - large storage of glycogen

4

What happens to the brain during hypoglycemia?

A limited amount of glucose can be derived from the glycogen stored in astrocytes - consumed within minutes

cognitive dysfunction -> seizure -> coma

5

What is hyperglycemia?

High blood glucose

Normal if transcient

If prolonged - complications

6

What are the short term complications from hyperglycemia?

Increased urine output

Thirst

Ketoacidosis

7

What are the long term complications from hyperglycemis?

Atherosclerosis

Kidney failure

Eye complications

Diabetic foot ulcer

8

How is glucose in the plasma maintained?

Exchanged between the cytoplasm and the extracellular fluid

9

Can glucose pass through the membrane by diffusion?

NO

10

What facilitates trasfer of glucose into cells?

Carrier proteins

11

What are the different types of carrier proteins found in cells?

GLUT - 1
GLUT - 2
GLUT - 3
GLUT - 4

12

Where is the carrier protein GLUT-1 found?

Brain and RBC

13

Where is the carrier protein GLUT-2 found?

Liver, pancreas and intestine

14

Where is the carrier protein GLUT-3 found?

Brain and kidney

15

Where is the carrier protein GLUT-4 found?

Muscle and adipose tissue

16

What glucose protein carrier is insulin dependent?

GLUT - 4

17

Which hormones enhance the catabolic pathways of glucose metabolism?

Glucagon

Epinephrine

18

Which hormone enhances the anabolic pathways of glucose metabolism?

Insulin

19

What is the cells response to low blood glucose?

1. Activates catabolic pathways at the cell metabolic level

2. Glycogen -> glucose = glycogenolysis

3. Amino acids -> glucose = gluconeogenesis

4. Lipids -> Acetyl CoA = beta oxidation

20

Which amino acids can undergo gluconeogenesis?

Glucogenic amino acids

All but leucine and lysine

From essential proteins

21

What happens to Acetyl-CoA formed by beta oxidation of lipids?

Enters the Krebs cycle to form ATP

Form ketone bodies - byproducts of Acetyl-CoA formation

Can be used as a source of energy

22

What is the cells response to high blood glucose?

1. Activation of anabolic pathways in cells

2. Excess glucose is stored as:

glycogen -> glycogenesis

makes lipids using Acetyl-CoA -> lipogenesis

Make amino acids - assembled to make proteins -> non-essential amino acidss

23

Which sensors detect hypoglycaemia?

Endocrine pancreas

Autonomic nervous system

24

What does the endocrine pancreas release in response to hypoglycaemia?

Makes glucagon

Receptors for glucagon afre found in the liver

Glucagon activates catabolic pathways in hepatocytes to make glucose

25

What does the ANS do in response to hypoglycemia?

Vasoconstriction and activation of sweat glands

Leads to manifestation of hypoglycemia - pale facre and cold sweat

Stimulates the medulla of the adrenal gland to release catecholamines - have receptors on hepatocytes to activate catabolic pathways

Catecholamines also cause tachycardia

26

What sensors detect hyperglycemia?

Endocrine pancreas

27

What does the endocrine pancreas release in response to hyperglycemia?

Insulin

28

What does insulin do in response to hyperglycemia?

1. Increases expression of GLUT-4 receptors on CSM of muscle and adipose tissue

Blood glucose goes down since there are more glucose transporters to transport glucose into the cells

2. Regulates anabolic metabolism in liver, muscle and adipose tissue