Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neurochemistry 2 > Hypoglycemia > Flashcards

Hypoglycemia Flashcards

1
Q

What is diabetes?

A

Chronic metabolic disease characterised by elevated levels of blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How many people are affected by diabetes worldwide?

A

425 million people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is hypoglycemia defined?

A

Plasma glucose level ≤ 70mg/dL or ≤ 3.9mmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the standard concentration of glucose in plasma?

A

60 to 100 mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What two hormones are involved in the regulation of blood glucose levels?

A

Insulin and glucagon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is glycogen?

A

A polysaccharide that is made and stored in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the physiological role of glycogen?

A

It is an energy reserve that can be quickly mobilised if there is a sudden need for glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What occurs in the body when blood glucose levels rise?

A

Insulin secretion from beta cells in the pancreas increases, glucagon production in the liver is inhibited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is glycogen synthesised?

A

Glucose enters liver cells from the blood stream and stimulate enzymes to convert glucose to chains of glycogen (glycogenesis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the symptoms of hypoglycemia?

A

Tremor, tachycardia, hyperphagia, diaphoresis, disorientation, delirium,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

At what blood glucose concentration is decreased insulin secretion seen?

A

~80mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

At what blood glucose concentration is increased glucagon and epinephrine secretion seen?

A

~70mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

At what blood glucose concentration do symptoms of hypoglycemia tend to be seen?

A

~55mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

At what blood glucose concentration is functional brain failure seen?

A

Less than 50mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is meant by functional brain failure in hypoglycemia?

A

Decreased cognition, aberrant behavior, seizure, coma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

At what blood glucose concentration is neuronal death seen?

A

Below 20mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What neurodegenerative condition is associated with diabetes due to episodes of severe hypoglycemia?

A

Dementia - Alzheimer’s and vascular

18
Q

What is meant by the term neuroglycopenia?

A

Low blood glucose levels in the brain

19
Q

What pathophysiological process occurs with the hypoglycemic cognitive deficit in diabetic rat models?

A

Oxidative stress

20
Q

What is a common rat model of type 1 diabetes and how is it induced?

A

Streptozotocin - drug mediated depletion of beta cells (necrotic death) followed by insulin injections to induce hypoglycemia

21
Q

Which brain regions were shown to have an increase in oxidative stress in a rat model of T1D?

A

Hippocampus, cortex

22
Q

What rescues the oxidative damage in the hippocampus seen in recurrent moderate hypoglycemic rats?

A

NOX2 inhibition

23
Q

What changes to glucose transporters are observed due to hypoglycemia?

A

Increased GLTU1 mRNA and protein in brain and capillaries/BBB (to increase glucose trafficking to the brain)

Upregulation of GLUT3 (neuronal transporter) and MCT2

24
Q

What is the typical response to hypoglycemia in healthy individuals?

A

Initial decrease in cerebral glucose consumption which is more prominent in regions of the brain that is active. Glucose transporters are upregulated. Further hypoglycemic events result in adaptive glucose uptake

25
Q

How do patients with uncontrolled T1D respond to recurrent hypoglycemic events?

A

Impaired simulation of hyperinsulinemic hypoglycemia-induced glucose oxidation, poor glucose uptake

26
Q

How does hypoglycemia impact glycolysis in murine models?

A

Fasting decreases glucose metabolism and malonyl-coenzyme A production in hypothalamus and cortex which reprograms substrate utilisation from glycolysis to lipid oxidation

27
Q

What changes to glycolytic enzymes are observed due to hypoglycemia?

A

Decreased levels of rate-limiting enzymes in the brain

28
Q

How does hypoglycemia impact the TCA cycle in T1D patients compared to healthy individuals?

A

Increase in TCA cycle flux

29
Q

What changes in mitochondrial respiration are induced by hypoglycemia?

A

Impairment of electron transport chain

Decreases respiratory control ration

30
Q

What are alternate sources of energy for brain during hypoglycemia?

A

Lactate and ketone bodies

31
Q

What are the benefits of utilising alternative fuels during hypoglycemia?

A

Increase oxidative metabolism

Decrease autonomic and neuroglycopenic symptoms

Enhance glucose counter regulatory mechanisms

32
Q

What are the energy sources in the initial phases of hypoglycemia?

A

Lactate initially, then glutamate and glutamine, then aspartate

33
Q

What are ketone bodies the products of?

A

Fatty acid metabolism

34
Q

How do ketone bodies feed into the TCA cycle?

A

Metabolised into acetyl-CoA

35
Q

What are the main two ketone bodies used as energy sources?

A

3-b-hydroxybutyrate and acetone

36
Q

b-hydroxybutyric acid contributes to the neuronal synthesis of which amino acids?

A

Glutamate and glutamine

37
Q

What is glycogen?

A

Reserve respiratory substrate for the brain during metabolic stress

38
Q

Where is glycogen stored?

A

In astrocytes adjacent to synthesis and degradation enzymes

39
Q

How is glycogen mobilised during hypoglycemia?

A

Acted upon by glycogen phosphorylase in astrocytes and converted to glucose-1-phosphate and glucose-6-phosphate to feed glycolysis

40
Q

What is the glycogen supercompensation phenomenon?

A

Glycogen levels exceeding pre-hypoglycemia levels for a few hours following restoration of euglycemia after hypoglycemia

Neurochemistry 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions