Energy Metabolism Flashcards
Define energy (fuel) metabolism. Name the 3 energy fuels
Process of storage & utilisation of fuels.
Glucose, amino acids, fatty acids
Biomolecules in excess are?
energy storage molecules
What is glycogen?
main storage form of glucose
What is metabolic rate? How is it measured?
the speed at which we use energy.
“Rate at which E is expended during internal & external work”.
Measured kilojoules/hour
Whats factors influence metabolic rate?
age, gender, muscular activity, size (SA), environmental temp.
What is basal metabolic rate?
animal’s RESTING metabolic rate
As mass increases…?
MR increases
Name the 3 possible states of energy balance (EB) & explain
- Neutral EB (energy input=output)
- Positive EB (energy input>output) =>gaining weight
- Negative EB (energy input losing weight
Seasonal fluctuating of EB in animals is good. Why?
Alternating seasons of good/bad food quantity/quality ensures energy reserves are mobilised. Essential part of long-term feeding strategy (hibernation)
What is glycogenesis?
Breakdown of glucose to glycogen
What is glycogenolysis?
glycogen=>glucose
What is gluconeogenesis?
amino acids/lactic acids=>glucose
What is protein synthesis?
amino acids=>protein
What is protein degredation?
protein=>amino acids
What is lipogenesis?
(synthesis)
fatty acids & glycerol=> triglycerides (fat)
What is lipolysis?
triglycerides (fat)=> fatty acids & glycerol
Name the endocrine portion of the pancreas
pancreatic islets
Name the 4 cell types found in pancreatic islets and what they secrete
Alpha -secrete glucagon
Beta -secrete insulin
Delta -somatostatin
F cells -pancreatic polypeptide (not a hormone)
What is the principle action of glucagon?
to increase blood glucose concentration when it falls below normal
What is the principle action of insulin?
helps lower blood glucose concentration when it is too high
What does blood glucose concentration control?
secretion of glucagon & insulin via - feedback
Explain the physiology of low blood glucose concentration
Low [BG] stimulates secretion of glucagon.
Gluca. acts on liver cells to speed up conversion of glycogen to glucose (glycogenolysis), & to promote formation of glucose from lactic acid (gluconeogenesis).
As result, liver cells release glucose into blood more rapidly [] ^
Explain the physiology of high BG concentration
High [BG] stimulates secretion of insulin.
Insulin:
speeds up facilitated diff. of glucose into cells
increase glycogenesis
increase lipogenesis
slow glycogenolysis
slow gluconeogenesis
.’. [BG] decreases
Anterior pituitary secretes
hormones (GH) that regulate a wide range of bodily activities, from growth to repro.
The anterior pituitary cells, somatotrophs, secrete …? thyrotrophs secrete…?
soma- Growth Hormone (GH) aka somatotropin
thyro -thyroid-stimulating hormone (TSH)
What does GH stimulate?
secretion of insulin-like growth factors (IGF’s), hormones that stimulate general body growth & regulate aspects of metabolism
GH (somatotropin) production is regulated by?
GH releasing hormone (GHRH)
GH inhibiting hormone (GHIH)
Hypoglycaemia (low blood sugar) stimulates?
hypothalamus to secrete GHRH=>reaches pituitary stimulates somatotrophs to release GH=>GH stimulates secretion of IGF, which speed up glycogenolysis=>glucose enters blood more rapidly, raising BS.
Hyperglycaemia (high BS) stimulates?
hypothalamus to secrete GHIH=>reaches pituitary & inhibits secretion of GH by somatotrophs=>low [] of GH & IGF’s slows glycogenolysis=>glucose enters blood more slowly, lowering BS.
Follicular cells in thyroid gland produce which two hormones? And is the only gland that does what?
Thyroxine (T4)
Triiodothyronine (T3)
only endocrine gland that stores its secretory products in large quantities.
Two basic ingredients for thyroid hormone synthesis
Tyrosine & iodine
A bit about conversion of T4 to T3
90% of secretion in mammals is T4
Most T4 is stored, then activated & converted to T3 (80%)
Primary action of thyroid hormones (T3 & T4) is?
to increase basal metabolic rate
increase fat & carbohydrate metabolism (glycolysis, glycogenolysis, lipolysis)
increase number/activity of mitochondria
Adrenal glands produce?
catecholamines (adrenaline & noradrenaline)
what are the biological effects of catecholamines
increased HR, Bp
Dilation of pupils, airways, blood vessels
increased gluconeogenesis, glycogenolysis, cellular O2 consumption
Describe what a tertiary endocrine disorder is
problem originates in hypothalamus
describe what a secondary endocrine disorder is
initial disorder is in pituitary gland
describe what a primary endocrine disorder is
the specific endocrine gland is dysfunctional
