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BIOD27H3 Lecture Notes - Menopause, Prolactin, Exocytosis

Biological Sciences
Course Code
Ingrid L.Stefanovic

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BGYB30H3 Lecture 21 Notes
-normal growth requires
x Sex hormones
x Insulin and insulin growth factors
x Growth hormones
x thyroid hormone
x diet (nutrients such as calcium)
x genetics
-cortisol has catabolic effects on growth by increased calcium in the blood
-peak growth occurs during teenage years
-nutrients, circadian rhythms and other hormones stimulate growth hormone
-growth hormone that binds to binding protein in the blood increases its half life in the blood to
prevent excretion in urine
-growth rate is determined by amount of GH binding protein in the blood
-growth hormone stimulates release of insulin like growth factors from the liver, which
negatively feedback on GH
-IGF and GH cause
x bone and soft tissue growth
x increased protein synthesis
x cartilage growth
x breakdown of glycogen and triglycerides
-dwarfism is less common now due to medications and is caused by inhibiting of bone growth
-giantism is caused by excess bone growth
-acromegaly is caused by excess soft tissue and cartilage growth in adults and is progressive
-growth hormone causes both hyperplasia (cell division increase) and hypertrophy (increased
cell size)
-bone growth requires sex hormones, IGFs, GH, TH and calcium
-calcium is stored as a calcium phosphate crystal
-the bone is dynamic in that it is constantly being formed and broken down even after bone
lengthening ceases
-bone contains compact bone layer for strength and spongy trabecular bone layer that is less
-osteoblasts are bone forming cells that produce enzymes and osteoids
-osteoclasts dissolve bone to release calcium by releasing acid and enzymes
-epiphysis is the end of the bone while the shaft of the bone is the diaphysis
-epiphysial plate is where bone growth occurs because osteoblasts are found there
-diaphysis is where bone diameter increases
-chondrocytes are found under the compact bone of the epiphysis and osteoblasts are found
under chondrocytes
-chondrocytes divide to add length to the bone as well as cartilage
-osteoblasts lay down bone on top of the cartilage to replace dead chondrocytes
-following puberty, sex hormones inactive the epiphysial plate to cause bone growth to stop
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