Nutrition 3 - Physiology of feeding and satiety Flashcards
Energy Homeostasis
Physiological process whereby energy intake is matched to energy expenditure over time
What 2 factors cause obesity?What are the 2 major factors that influence obesity
Accessible, tasty calorie dense foodSedentary lifestyleGeneticsEnvironment
What is metabolic syndrome (syndrome X)?
Central obesity plus 2 of:Blood pressure greater than or equal to 130/85Triglycerides greater than or equal to 1.7 mol/LHDL less than 1.03 in males and 1.29 in females (mol/L)Fasting glucose greater than or equal to 5.6mmol/LDiabetes mellitus
Possible consequences of metabolic syndrome? (4)
CV diseaseDibetes MellitusGallstones CancersMore in list
What is the equation for BMI?
Wegith (kg) / square of height (m)
Categories of BMI?
Up to 25 = thin or normal25-29.9 = overweight30-39.9 = obesegreater than or equal to 40.0 = morbidly obese
What are some of the consequences of obesity (9)
Stroke (hypertension)Respiratory disease (sleep apnoea)Heart disease (lipids, diabetes, hypertension)Gallbladder diseaseOsteoarthritisDementiaNAFLD (fatty liver)DiabetesCancer(Uterus, breast, prostate, colon)Hyperuricemia, gout
Why do we need fat? (3)
Energy storagePrevention of starvationEnergy buffer during prolonged illness
What is one of the reasons why it is difficult to lose weight?
Increased fat alters brain function in order that the brain views the fat as normal and dieting as a threat to body survival
How does the CNS influence energy balance and body weight (3)?
Behaviour - feeding and physical activityANS activity - regulates energy expenditureNeuroendocrine system - secretion of hormones (integration of these determines final output - feeding behaviour)
Where does the CNS influences on energy balance get integrated (in order to produce final behaviour)How do we know this
In the hypothalamus in the brain Lesioning ventromedial hypothalamus causes obesityLesioning lateral hypothalamus causes leaness
What 3 basic concepts underline the control system of energy intake and body weight?
Satiety signallingAdiposity negative feedback signallingFood reward
What is satiation?
Sensation of fullness generated during a meal
What is satiety?
Period of time between termination of one meal and the initiation of the next
What is adiposity?
The state of being obese
What does the satiation and satiety processes regulate?
Meal intimation, termination and inter-meal frequency
When satiation signals increase
During meal to limit meal size
What are the satiation signals? (5)
Cholecystokinin (CCK)Peptide YY (PYY3-36)Glucagon-like peptide 1 (GLP-1)Oxyntomodulin (OXM)Obestatin
Cholecystokinin (CKK)?
Secreted from enteroendocrine cells in duodenum and jejunumReleased in proportion to lipids and proteins in mealSignals via sensory nerves to hindbrain and stimulates hindbrain directly (Nucleus of solitary tract)
Peptide YY (PYY3-36)?
Secreted from endocrine mucosal L-cells of GI tract Levels increase rapidly post-prandiallyInhibits gastric motility, slows emptying and reduces food intake (Hypo)