vitamins 4 Flashcards
what is the calcium level that needs to be maintained in the blood
9-11mg/dl
what is the importance of calcium
- extracellular fluid - CA2+ essential
- nerve cells
- muscle cells - too high cardiac arrest, too low respiratory arrest
where is the major store of calcium
99% bones
what happens to osteoblast and osteoclast activity at different calcium levels
too low - osteoclast activity releases calcium
too high - osteoblast activity stores calcium
what is the uncalcified bone matrix called
osteoid
what is the characteristics of a osteoclast cell
- release calcium
- multinucleate cell
- secretes acid - dissolves bone marrow
what is the characteristics of a osteoblast cell
- store calcium
- line bone surface
- secrete bone matrix - osteoid
- embedded as osteocytes
what does the parathyroid hormone do - PTH
- 84 aa peptide hormone
- low calcium - parathyroid hormone secreted, acts on calcium sensing receptor and cAMP
promotes: - osteoclast activity - release calcium
- kidneys - decrease calcium loss and calcitriol formation
what is the function of calcitriol
- made in kidney by vitamin D
promotes: - uptake of calcium from gut
- decreases calcium loss by kidneys
- osteoclast activity to release calcium
what does calcitonin do
- secreated from thyroid gland at high calcium levels
- inhibits osteoclasts
- inhibits kidney calcium reabsorption
what are the % of calcium absorbed in the kidney
proximal tubule - 70%
distil tubule - - 9%
thick ascending limb - 20%
collecting duct - 1%
what is the bmi formula
BMI = weight (kg) / hight (m2)
what is the increased risks associated with obesity
- type 2 diabetes
- coronary heart disease
- some cancers - breast and bowel
- strokes
- reduced quality of life - psychological problems
what are the causes of obesity
- consuming calories - increases the well fed state, fatty and sugary foods, cheap and high calorie food
- lack of exercise
- hormonal/ genetic
what does lipoprotein lipase secretion do
- lipolysis of chylomicron —> free fatty acids and chylomicron remnant
what does triglycerides contain in the digestive pathway
perilipins
what does excess fat lead to
- enlarged adipose
- cell proliferation - de novo adipogenesis
what is the evolution of adipose tissue
- store for times of need
- reduce heat loss
- immune response
- buoyancy
what is the characteristics of healthy adipose tissue
- insulin sensitive
- functional mitochondria
- beige fat biogenesis - cold exposure
- angiogenesis
- anti-inflammatory
what happens to malfunctioning adipose tissue
- decreased insulin sensitivity
- decreased mitochondrial function
- decreased fat biogenesis
- decreased angiogenesis
- increased inflammation
- increased fibrosis
- altered lipid profile - increase
what happens in the under fed state
- metabolism decreases and huger increases
- eat and reach homeostasis
- if you over eat you may reach nutrient overload state - well fed state
what happens in the well fed state
- metabolism increases and hunger decreases
- body then reaches homeostasis
- body then begins to reach a nutrient deprived state - under fed state
what is the afferent system
carries signals towards the central nervous system
what is the efferent system
carries signals from the central nervous system
what are the anabolic circuits
- promotes foot intake and rest
- synthesis of complex molecules from simpler ones
what are the catabolic circuits
- reduce eating and increase energy expenditure
- promotes breakdown of complex molecules into simpler ones
what is leptin
- protein hormone
- produced in adipose and small intestine enterocytes
- too little leads to obesity
what does leptin repress
- neuropeptide Y
- agouti-related proteins - AGRP
- leads to decreased food intake and increases energy expenditure
what does leptin stimulate
- pro-opinomelanocortin (POMC) —> α-melanocyte–stimulating hormone (α-MSH)
- Cocaine-amphetamine–regulated transcript (CART) —> decreased food intake
what does oestrogen stimulate and where is it produced
- beige fat biogenesis
- adrenal gland
what does androgens stimulate and where is it made
- angiogenesis
- lipolysis
- intermost adrenal cortex
what does growth hormone do and where is it made
- reduce insulin signalling increasing lipolysis
- made in the pituitary gland
what does ghrelin do and where is it found
- increased appetite
- fat storage and stimulates growth hormone
- found in stomach cells
what happens if you were previously overweight
- low resting metabolic rate
- need fewer calories to maintain weight —> difficulty keeping weight off
what is the treatments for obesity
- diet - loose 0.5-1kg per week, fruit and veg
- exercise - minimum 150 minutes of moderate
- medication - orlistant - inhibits lipases and alli, BMI over 28
surgery - severely obese, BMI over 50
