Growth and development; calcium homeostasis Flashcards
What is structural growth? (3)
- net protein synthesis
- Lengthening of bones
- Increased number and size of cells
In a human, when is the highest growth rate?
During foetal development and just after birth
What are the 4 factors that effect growth?
- Genetic
- Socioeconomic and nutritional
- Chronic disease and stress
- Endocrine hormones (GH)
What is growth hormones role and where is it made?
Role in growth and metabolism
Synthesised in the anterior pituitary
How is the release of growth hormone controlled? (7)
1. Hypothalamus 2= Growth hormone regulating hormone 2= somatostatin 3. anterior pituitary 4. Growth hormone (metabolism) 5. Liver and other tissues 6. Somatomedins (growth)
What can affect the hypothalamus response?
Stress, sleep, exercise
Decrease in glucose, decrease in FFA, increase in AA
What happens to metabolism when stress affects the hypothalamus? (3)
Increase blood glucose
Increase lipolysis
Increase protein synthesis
How does growth hormone affect the liver?
Increases gluconeogenesis
How does growth hormone affect the muscle? (3)
Increases AA uptake
Increases protein synthesis
Decreases glucose uptake
How does growth hormone affect adipose tissue? (2)
Increase lipolysis
Decrease glucose uptake
What is an indirect consequence of growth hormones?
Promotes growth
What 3 hormones other than GH are important for growth?
Thyroid hormones (CNS) Insulin Sex hormones (muscle, linear and bone)
What are the 3 parts of the bone and how do they stop growing?
Epiphysis — shaft (diaphysis) — epiphyseal growth plate
Sex hormones ossify the epiphyseal plates - can no longer elongate
What does a deficient pituitary disease cause?
Stunted child growth
Deficiency in adulthood
How can you cure a deficient pituitary disease?
recombinant human growth hormone
What does a excess pituitary disease cause? (2)
accelerated growth in children
acromegaly
What are the symptoms of acromegaly? (5)
Coarsening of facial features Enlarged hands or feet Headaches Hypertension Diabetes
How can you treat gigantism and acromegaly? (2)
surgery or radiotherapy
Inhibit GH release
What are the 3 functions and their locations of calcium homeostasis?
- Calcified matrix of bone - extracellular matrix
- Muscle contractions - extracellular fluid
- Second messenger pathways -intracellular
How is the calcium balance regulated? (3)
Parathyroid hormone
Calcitriol - activated vitamin D3
Calcitonin
What is the effect of PTH on the kidney, bone and intestines?
Kidney: Increase Ca2+, decrease PO43-
Bone: Release of Ca2+ & PO43-
Intestines: Ca2+ intake increase
How does PTH effect with calcitriol?
Joins in the kidney after absorbing vitamin D from sun/fish oil/egg and going through the liver
What is the combined effect of PTH and calcitriol?
Cas2+ in plasma increases
What is the combined effect of PTH, calcitriol and calcitonin?
Ca2+ in plasma decreases
What is osteoporosis?
- Fragile bone with an increased fracture susceptibility
- Bone mass decreases
