Class notes
L19 Liver - Glucose Homeostasis
- Course
- Institution
Lecture on liver function, glucose homeostasis / gluconeogenesis by Despo Papachristodoulou
[Show more]
Seller
Follow
aurelianatasyaa
Content preview
L19 – Liver in Metabolism: Glucose HomeostasisSlide 2
• Location of pancreatic islets reflects their functional role
Explain why glucose is an important metabolic fuel
Slide 3 – The requirement for glucose is continuous
• Glucose is the preferred fuel source for all tissues
• Some tissues have a continuous dependence on glucose
- Erythrocytes can only get glucose because they have no mitochondria
Slides 4-5 – Blood glucose concentration
• Physiological circulating glucose concentration: 3.9-6.2 mM
• Average fasting (for most adults): 4.4-5 mM
• If it drops to 2.5 or less, coma and death can result
• If it rises for an extended time, dehydration, wasting of body tissue and eventually death
will result
- Kidney can reabsorb glucose up to a point
- Draws water from extracellular fluid and other fluid, hence you will get dehydrated
Slides 6-8 – The roles of glucose
• Source of energy
- Glucose --> pyruvate gives 2 ATP
- Glucose --> CO2 + H2O gives 31 ATP
• Source of NADPH
- Useful for tissues that are synthesised in fat (in the liver)
, - Useful for integrity of the erythrocyte membrane which is subject to damage (has high
pentose phosphate pathway, produces NADPH)
- Needed for synthetic reactions (fatty acids, steroids) and drug metabolism
• Source of pentose sugars for synthetic reactions (nucleotides, DNA)
• Source of carbon for other sugars and glycoconjugates (mannose, galactose, glucuronic
acid)
• Erythrocytes reoxidise NAD by producing lactate as it cannot store it due to its lack of
mitochondria
Slide 7 – Advantages of glucose as a metabolic fuel
• Water soluble, does not require carrier in the circulation
• Can cross blood-brain barrier
• Can be oxidised anaerobically
Slide 8 – Disadvantages
• Relatively low yield of ATP per mole compared to fatty acids
• Osmotically active
• In high concentrations, can directly damage cells or lead to accumulation of toxic by-
products (fructose, sorbitol)
Slide 9 – Pathways involving glucose
• Predominant pathways involving glucose are different in different tissues
• On the whole, all tissues use glucose
• The liver can provide glucose for other tissues
Slide 10 – Role of glucose in skeletal muscle
• Glycogen used in the muscle is used in the muscle and not released anywhere
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller aurelianatasyaa. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.87. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67096 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now