Chapter 19 Metabolic Integration Flashcards
Functions of the pancreas
Secretes insulin in response to rising blood glucose levels
Secretes digestive proteases that degrade dietary protein in the small intestine
- trypsin
- chymotrypsin
- elastase
Functions of the small intestine
- absorbs nutrients
- secretes peptide hormones that control eating behaviors through neuronal signaling in the brain
Functions of the large intestine
- absorb water and electrolytes
What does ghrelin do?
the hunger hormone, stimulates appetite
What does peptide YY do?
hormone that decreases appetite
Functions of the stomach
- prepares food for small intestine by producing chyme, an acidic food slurry
- secretes peptide hormones that control eating behaviors through neuronal signaling in the brain
Functions of the liver
- central processing facility and metabolic hub
- determines the dietary nutrients and metabolic fuels sent to peripheral tissues
- glucose regulator that removes excess glucose from blood when carbohydrate levels are high (controlled by insulin and glucagon signaling)
- portal vein directly delivers nutrients from the small intestine and inactivates toxins from the diet
What are the metabolic fates of Glucose-6-phosphate?
Depends on the metabolic needs of the liver and peripheral tissue
- sent to pentose phosphate pathway
- used in glycogen synthesis
- converted to aceytl-CoA, which can go to lipid synthesis, ketone sythesis, or oxidative phosphorylation
- can be converted to glucose and released into the blood
Functions of skeletal muscle
- uses fatty acids, glucose, or ketone bodies
- used in rapid bursts or endurance activities
- energy source during times of starvation
- stores glycogen
Functions of cardiac muscle
- uses mostly fatty acids and ketone bodies
- uses aerobic respiration for energy
What is creatine kinase?
A reversible enzyme that creates phosphocreatine when cellular ATP levels return to normal during muscle recovery
creatine kinase provides a phosphate from phosphocreatine to regenerate ATP from ADP
Function of adipose tissues
- secretes peptide hormones (adipokines) to regulate metabolic homeostasis
- makes up 15%-25% of an individual’s mass
- fat is stored here
Subcutaneous fat
- located in the thighs, buttocks, arms, and face
Visceral fat
- located in the abdominal fat
- secretes adipokines
- more visceral fat gives rise to a higher risk of cardiovascular disease
Body mass index
provides an estimation of total body fat in an average person
BMI = weight (kg)/height^2
Functions of the brain
- control center of the body
- 20% of O2 consumed by the body is used for oxidative phosphorylation
- generally depends mostly on glucose (60% of body’s glucose is required by the brain)
True or false, fatty acids can cross the blood brain barrier
false (but ketone bodies can)
What is the blood brain barrierI (BBB)?
- BBB limits what molecules traverse into the brain substance
- blocks most molecules less than 500 daltons
- less restrictive at certain places
What is PET imaging?
positron emission topography
uses metabolic radioactive 18F-deoxyglucose to show differences in glucose metabolism in the brain
Function of kidneys
- utilizes gluconeogenesis
- removes concentrated levels of urea, NH4+, ketone bodies, and soluble metabolites
What is hemodialysis?
When blood is filtered from a patient with poor kidneys in order to remove waste products before being returned to them.
What is metabolic homeostasis?
The process of maintaining optimal metabolite concentrations and managing chemical energy reserves in tissues.
Describe the triacylglycerol cycle
- An interorgan process that continually circulates fatty acids and triacylglycerols between adipose tissue and the liver
- maintains energy-rich fatty acids in circulation so that they can be used by peripheral tissues
- two components of that depend on sufficient levels of glycerol-3-phosphate: systemic and intracellular
Describe the functions of insulin
- released by pancreatic beta cells
- stimulates glucose uptake in the liver, skeletal muscle, and adipose tissue
- activates glycogen and fatty acid synthesis
- decreases appetite through neuronal signaling in the brain
