Case 8 Flashcards
to have a wee
The main hormone responsible for calcium homeostasis
PTH
PTH In the bones it binds to osteoblasts and stimulates them to increase their expression of
RANKL
what do the kidneys upregulate the hydroxylation of
Vitamin D
What does vitamin D inhibit on the parathyroid cells
Transcription of PTH gene thus negative feedback
what are the 3 things that regulated the conc of calcium in the blood
PTH, Calcitonin and Vit D
How many bones in the human skeleton
206
what are the type of bones in the body
Long bones Short bones Flat bones Irregular bones Sesamoid bones
what are the 3 things a long bone consists of
Diaphysis
Epiphysis
Metaphysis
What is the basic functional unit of a compact bone
osteon
Where is red bone marrow found
between trabeculae of spongy bone
What is red bone marrow responsible for
blood cell formation
What is the periosteum
layer over compact bone that covers all surface and protects the bone
where is the endosteum found
lines the marrow cavity
what do the collagen fibres provide
an organic framework on which hydroxyapatite crystals can form
what are the 4 cells of the bone
Osteoblasts
Oestoclasts
Osteocytes
osteoprogenitor cells
what do osteoclasts do
bone resorption
how do osteoclasts do their thing and what is the process called
osteoclast membrane secretes enzymes and acids which dissolve the matrix and release the stored minerals into the blood stream
Osteolysis
how are osteoclasts activated
RANK receptors on the surface membrane
RANKL binds to the RANK
this creates intracellular signalling and makes them differentiate
Where does RANKL come from
osteoblasts
what does over expression of RANKL cause
osteoporosis
Who does the RANKL travel (what through)
canailcuils
what do osteoblasts secrete in an unmineralised bone matrix
IGF-1 and TGF-B(beata)
What is formed in a bone fracture
Haematoma formation
What is a Haematoma
large blood clot
What are the 4 steps of a fracture in healing
1) Haematoma Formation
2) Fibrocartilaginous callus
3) Bony Callus formation
4) Bone remodelling
what are the 3 phases of wound healing
1) inflammatory phase
2) Proliferation phase
3) Maturation phase
what cell rebuilds skin
fibroblast
what is S.aureus
gram positive bacterium
what colour do Gram positive bacterium go and why
Violet due to the thick layer of peptidoglycan
what colour do gram negative go and why
red as the thin peptidoglycan layer doesn’t retain the Cristal violet stain
what is the hayflick limit
cells wear out with age
what is there a very high level of and why
FSH and due to the decreased levels in oestrogen
T and Z score explain
T score is the patients BMD compared to a young healthy control
Z score is the patients BMD compared to an age-matched control
what is osteogenesis
Type III collagen to type I
what does oestrogen do to osteoclasts and osteoblasts
Osteoblasts increases osteogenesis and stimulates the release of the growth factors IGF-1 and TGFB(beta)
In osteoclasts it increases apoptosis
what does a glucocorticoid induced osteoporosis have on osteoclasts and blasts
Osteoblasts increases apoptosis
Osteoclasts it increases RANKL expression
what percentage of calcium is in the skeleton
99%
function of calcium
structure of bones
muscular contraction Ca2+
what is Bendrofluazide do
reduces the uptake of water by blocking Na?K pumps in the ascending loop of henle and used to treat hypertension by remedying the amount of water the heart has to pump
