L13*-Absorptive & non-absorptive states Flashcards
(23 cards)
Define Absorptive state. another name for the state? and explain the energy metabolism for this state.
-Fed state
-Refers to the pattern of energy metabolism due to high concentration of the nutrients in the blood as a result of absorption of the nutrients in the FED state.
-Some of the nutrients are used to meet immediate energy needs while the excess are stored for energy later.
Define post-absorptive state. Another name for the state. and explain the energy metabolism for this state.
-Fasted state
-A pattern of energy metabolism adopted between meals or during fasting.
-Changes in pattern of energy metabolism depends on the changes in the blood concentration of insulin and other hormones.
Explain the pathway of nutrients in the absorptive state. and give an example of the pathway of a lipid in absorptive state.
-In the absorptive state(fed state), the absorbed nutrients are hexose sugars(glucose, fructose, galactose) and amino acids.
-These nutrients go through the liver into circulation.
-Other nutrients go into adipose tissue, muscles and other tissues.
Lipids > small intestines > lymph (chylomicrons) > venous blood > adipose tissue (not 🧠bc too big)
Explain the control of absorptive state in the activation of insulin from the uptake of glucose.
1.Absorptive state :-
Feeding glucose
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Uptake of glucose
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increase in blood sugar
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Glucose > Enters pancreas > GLUT2 > SGLT1>to mitochondria > glycolysis> Krebs cycle > oxidative phosphorylation > increase in ATP
- Beta-cells in Islets of Langerhans :-
increase in ATP
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causes K+ channels to close
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membrane depolarisation
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increase in Ca2+ intracellular > insulin exocytosis (Bc Ca2+ helps t get insulin to the vesicles)
Give me a example of a disease where glycogen storage does not work as usual to break down to give glucose.
Pompeii disease
-Glycogen is normally synthesised in the liver of 💪s.
-A disorder with glycogen storage cause accumulation of glycogen or change in structure of glycogen.
-An autosomal recessive disorder which affects the functioning of lysosomal acid alpha-glucosidase due to mutation of GAA gene.
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causes cellular damage
-In healthy individuals glycogen accumulates in the cytoplasm of liver and 💪 cells. However patients with Pompeii disease have glycogen accumulated in the lysosome of these cells instead.
Describe the details of insulin relating to its function in the absorptive state.
-Insulin is a hormone secreted by the pancreas.
-Insulin largely influences the pattern of metabolism observed.
-The release of insulin is stimulated by fed state and inhibited by the fasted state.
-In the fed state, the high [glucose]/[amino acids] in the blood stimulates the release of insulin.
-Hormones and NTMs also influence insulin secretion.
What can we convert excess glucose into in adipose tissue ?
Fatty acids and glycerol
Describe the details of insulin relating to its function in the post-absorptive state.
-The 🧠and RBC largely depend on glucose for energy.
-Lack of glucose 👉 brain damage, coma, death
-In the post-absorptive state, plasma levels of glucose is maintained by glucose-supplying and glucose sparing reactions.
-So insulin secretion is impaired (inactivated in the fasted state), the pattern of metabolism = post-absorptive state.
-In this state, glucose can simply get into the tissues(all except 💪&adipose tissues) that ARE NOT insulin dependent tissues.
Name few insulin dependent tissues.
💪 and adipose tissues
How is glucose maintained in short term period of time ?
via glucose supplying reactions
How is glucose maintained in long term period of time ? for days without eating …
Glucose sparing reactions
Describe the steps for ketogenesis.
Adipose tissue break down triglycerides into fatty acids and glycerol.
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That fatty acids then travel to the liver to produce ketone bodies.
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Ketone bodies can act as a source or a precursor source for energy.
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another pathway to produce ATP other than glucose.
***Brain and other tissues use ketone bodies as a source of ATP in those glucose sparing reactions( in long term with starvation).
Explain Starvation
- in famine, starvation is prevalent(common).
-extreme suffering caused by lack of food.
What are the metabolic processes that would have been occurring to enable people to maintain their plasma [glucose] ?
-Depletion of Carbohydrate precursors
-Increased gluconeogenesis (a.a ☞ glucose)
-After 48 hrs, energy is supplied by ketone bodies and free fatty acids
-Prolonged starvation initiates catabolism (organ system dysfunction)
-breaking down muscle proteins to produce amino acids when desperate => catabolism
Describe the 2 types of Diabetes mellitus.
Type 1
-young onset
-loss of Beta cells
-cannot utilise glucose > other fuels
- weight loss
-insulin 💉
-immune system attacks the pancreas âž¡ little to no insulin production
Type 2
-prevalence , 👆 age
-👆 insulin but resistance
-weight loss, ketoacidosis
-Body becomes resistant to insulin
Describe how Diabetes affects the absorptive and post-absorptive state.
For type 1 and 2 Diabetes Mellitus, the insulin receptors are present. However, these receptors are either damaged or not responding to signalling.
Poor management of diabetes affects tissues in the body.
What does the [insulin] in the plasma based on ?
On the level of plasma glucose.
Name few tests for diabetes and how does obese affect this ?
-Glucose tolerance test > used to diagnose diabetic states. The test relies on the metabolic pattern in absorptive state.
-Fasting blood sugar test > used to diagnose diabetic states. The test relies on the metabolic pattern in post-absorptive state.
-Obesity causes slower uptake of glucose > insulin resistance > increase in plasma glucose
Bc of obese issues, what is considered as a more reliable test for the diagnosis and management of diabetes.
Haemoglobin A1C (HbA1C)
Name a agonist used for the management of Type 2 Diabetes Mellitus.
-Glucagon-like peptide-1 (GLP-1) agonists
-GLP-1 is a peptide produced by the cleavage of proglucagon in pancreatic islet alpha-cells.
GLP-1 activates GLP-1 receptors in the pancreas
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increase insulin release(improve insulin release)
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decrease glucagon release
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decrease gastric emptying
Describe glycation
-when sugar molecules attach to proteins without the help of enzymes.
-Maillard reaction ( not enzymatic browning)
-this is y food goes brown when cooking to enhance the flavours.
- makes the food taste good.
- here is alters enzymes / protein function
-glycation reaction leads to the formation of AGEs ( Advanced glycation end products). these trigger the expression of cytokines which leads to cancer and diabetic complications.
Explain the impact of chronic diabetes in the eyes. -retinopathy
-Retinopathy - damage affecting the retina
- growth of poor-quality new blood vessels in the retina.
- Macular oedema
- which can lead to severe vision loss
-Blindness
Explain the impact of chronic diabetes to the nerves or legs - Neuropathy
-Neuropathy - damage affecting the nerves.
-decreased sensation in hands and feet.
-damages blood vessels
-diabetic foot ulcers
-delayed healing > secondary infection > Amputation
