Intergration 2 Flashcards
Lipid metabolism in adipose tissue after meal (5)
HSL is inhibited
Release of FA into blood is reduced
Insulin stimulates LPL activity (specifically in adipose tissue)
Glucose uptake to adipose tissue increases synthesis of glycerol 3 phosphate
Which stimulates re-esterification of FAs
Lipid metabolism in liver after meal (3)
Increase in FA conc in liver
FA is esterified to form TAG
Increase in cellular TAG stimulates VLDL synthesis and secretion
What contributes to the increase in FA conc in liver (3)
Synthesis from glucose
Uptake within chylomicron remnant
FA escapes into circulation due to action of LPL
Major events in fasted state (6)
No substrates entering the intestine Chylomicrons disappear completely Glucose down to about 5mM Plasma NEFA concentration rise Insulin drops Glucagon and adrenaline increase
Lipid metabolism during fasted state (7)
Increased HSL activity
FA release from adipose tissue in increased
LPL low in adipose tissue
Muscle uses FA as a source of energy
Excess FA taken up by liver
It is then incorporated into TAG and secreted as VLDL
Which is exported to muscle
Carb metabolism in the liver after a meal (5)
Glucose flows into liver
Glucose then phosphorylated
Due to high level of activity of glucokinase
Glycogen phosphorylase is inhibited and glycogen synthase stimulated by insulin
Glycogen storage increase
Excess glycogen may be used for FA synthesis
Role of intestine in energy metabolism (3)
Digestion of energy yielding-nutrients
Absorption of energy-yielding nutrients
Significant site of protein turnover
Role of liver in metabolism (5)
Key role in regulating and coordinating the metabolism of macronutrients Second largest glycogen store Can convert carbs into lipids Produce glucose Formation of ketone bodies
Half of the liver’s energy requirements are produced by glucose and the other half by ______
AAs
Role of adipose tissue in metabolism (5)
Largest store of energy Releases fatty acids in times of need Stores fatty acids in times of excess intake Can convert carbs to lipid May regulate energy intake (leptin)
Role of skeletal muscle in metabolism (4)
Major store of energy in the form of protein
Biggest store of carbs in the form of glycogen
Largest user of energy
Can use both fat and glucose for energy
Brain and metabolism (3)
Normally dependent on glucose as energy substrate
Cannot use FAs
Can adapt to ketone bodies
What are the two levels of metabolism regulation
Substrate supply
Hormones
Gluconeogenic phase (4)
Glycogen stores are depleted
Gluconeogenesis is required to supply tissue with glucose
Main signal is the drop in insulin/glucagon ratio
Increase in the supply of gluconeogenic precursors
What are the main gluconeogenesis AA precursors?(2)
Alanine
Glutamine
How much protein is needed to make a gram of glucose?(2)
1.75g
Because not all AAs can be converted
How much glucose does the brain need daily?
100-120g
Adaptive period (3)
AA used for gluconeogenesis reduces
Ketogenesis increases
Brain adapts to using ketones thus sparing glucose
Adapted phase (3)
Gradual depletion of protein mass
Steady depletion of fat stores
Eventual death if no re-feeding
What happens to thyroid hormone during starvation?(3)
Marked decrease in T3
This reduces metabolic rate
Reduce proteolysis in muscle
During starvation which other organ becomes a major site of gluconeogenesis?
Kidneys
Kidney metabolism during starvation (4)
Increase in hydrogens causes a decrease in pH
Ammonia derived from glutamine and glutamate is formed to excrete excess hydrogen
Renal uptake of glutamine increases
Rest of glutamine molecule can be used to make glucose
What causes an increase in hydrogen ions and a decease in pH?(2)
Increased FAs
Increases ketones
Causes of death in starvation (5)
Antibodies that fight bacteria are degraded to provide AAs Heart failure Dysentery Pneumonia Shock from depletion of blood volume
What is dysentery?(2)
Infection of the digestive tract
Causes diarrhoea and further loss of nutrients
What causes heart failure during starvation?(4)
Infection
Fever
Electrolyte imbalance
Anaemia
What is pneumonia?(4)
Loss of myofibrillar protein from diaphragm and intercostal muscles
Results in inadequate removal of fluid from bronchioles and lunge
Leaves lungs open to induction
Reduced number of antibodies and white blood cells
