Post absorptive mechanisms and energy balance Flashcards
Examples of metabolic diseases
diabetes
increased bmi
high cholesterol
malnutrition or absorption problems
Where does glucose travel in the body once absorbed?
In intestine
Absorbed into blood travels to the liver
Ends up in muscle, brain, erythrocytes, adipocytes
What does glucose do in the liver?
Insulin promotes uptake of glucose into the cells
Glucose is stored as glycogen - glycolysis
some glucose is used in metabolism
some glucoses converted to triglycerides - these are combined with a protein to be water soluble, transported around body as VLDL
What is a VLDL?
very low density lipoprotein - triglycerides are transported around the body as this when combined with a protein
Glucose in the muscles?
insulin promotes uptake of glucose
stored as glycogen - glycolysis
Glucose in the brain?
Constant supply of glucose needed
It is converted into acetyl CoA for metabolism
Glucose in red blood cells?
They can’t produce their own ATP - no mitochondria, so anaerobic respiration occurs and lactate is produced
Glucose in adipocytes?
Glucose used in respiration
Or insulin promotes uptake of glucose
Glucose stored as triglycerides
Where are amino acids used after digestion?
Amino acids built up into proteins, proteins broken down into peptides/AAs
used in various compounds e.g. peptide hormones
can be used to produce ATP
Triglycerides to adipose?
CHYLOMICRONS
Triglycerides and specific proteins are combined to form a chylomicron.
Chylomicrons travel through the lymph system
Triglycerides stored in the adipose tissue
What happens during the short fast between meals? (few hours of fast)
Glycogen in the liver or muscle is broken down and released into bloodstream
Glucagon hormone - promotes glycogenolysis in the liver (and muscles?)
glucose goes to the brain and erythrocytes
What happens during a longer-than-a-few-hours fast?
Glycogen stores used up (liver/muscle)
amino acids and lactate(rbc) and glycerol (used for ATP production)
Converted to glucose - gluconeogenesis
Glucose used to supply energy to the brain and RBC
Fats during fasting
Release of glucagon
Broken down into glycerol and fatty acids
Glycerol - goes to liver - gluconeogenesis
Fatty acids - can be used into the kidney or muscles OR travel to the liver and used in the production of ketones
Lipolysis
lipids/fats being broken down
glucagon promotes breakdown
Extremely long fast (starvation nearly)
Decreased gluconeogenesis
Less proteins used for glucose
Fatty acids - energy source in the muscles
- converted to ketones in the liver (ketogenesis)
Ketones supply brain instead of glucose
Muscle uses less ketones
In prolonged fasting(severe lack of glucose) where does any glucose go?
Brain using ketones
Any remaining glucose used in red blood cells - they can’t use ketones
What substances can be measured in the bloodstream to aid in diagnosis of issues with metabolism?
glucose
ketones
insulin
lactate
triglycerides
Hormones affecting metabolism
- cortisol - produced in adrenals - stress
- adrenaline/noradrenaline - adrenals - fight or
flight - promote energy release when need to run away - thyroxine
- growth hormone somatostatin
- insulin and glucagon
Is insulin anabolic or catabolic?
anabolic
- protein synthesis
- glucose and fat storage
Is glucagon anabolic or catabolic?
Catabolic
- glycogenolysis
- gluconeogenesis
- ketogenesis
What is DIT?
Diet Induced Thermogenesis - energy used in processing diet
What uses up energy from food in order to maintain an energy balance?
BMR
DIT
activity
Which hormones control appetite?
ghrelin
leptin
What is leptin? What happens in an overweight person?
A hormone that in normal weight suppresses appetite
Too much fat (in obesity) - constantly high levels - can become immune
