Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Support and Movement > Week 2 > Flashcards

Week 2 Flashcards

1
Q

what are the components of ECM

A
  • collagens
  • glycosaminoglycans and proteoglycans
  • elastin
  • structural glycoproteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the molecules involved in ECM function

A
  • integrins
  • metalloproteinases
  • growth factors and cytokines
  • transcription factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are fibrillar collagens

A

form from cross-striated linear fibrils and are major structural components of CT; made of alpha chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are non-fibrillar collagens

A

form non-linear aggregates, and are further classified based on the type of network they make in the ECM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the triple helical domain formula

A

(GLY- X-Y)n
(glycine is smallest amino acid- no side chain; center of helix; X & Y often proline and hydroxyproline face outward)
- fibrillar: few or no interruptions; n = ~333 repeats
- non-fibrillar: interruptions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

_ collagen alpha chains are coiled around each other into a ____ to form a rigid rope like structure

A

3; triple-helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the triple helix structure and stability depends on:

A

proline, hydroxyproline, lysine, hydroxylysine

  • large, rigid, cyclic amino acids, unique hydroxylation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are hydroxyprolines essential for

A

thermal stability - form water-bridged hydrogen bonds that stabilize triple helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are hydroxylysines essential for

A

intra-and intermolecular cross-links that stabilize lateral associations of collagen molecules in fibrils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the enzymes called that hydroxylate proline or lysine

A

prolyl or lysyl hydroxylases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are essential cofactors in the hydroxylation of proline and lysine residues

A

ascorbate (vitamin C) and ferrous iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what happens in the absence of vitamin C

A

scurvy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the steps to remember in collagen biosynthesis

A
  • hydroxylation
  • chain association
  • trimerization
  • secretion into ECM
  • Cleavage of amino (NT) and carboxyl (CT) domains
  • Covalent crosslinks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is dermatosporaxis

A
  • genetic defect in cattle and sheep causing extremely fragile skin and death shortly after birth
  • deficiency in N-protease in skin, resulting in persistence of NT domain
  • twisted collages prevent packing of collagen molecules into cylindrical fibrils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are lateral associations of collagen molecules into fibrils stabilized by

A

intra and intermolecular crosslinks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what does lysyl oxidase form and what is it

A
  • cross links between Lys and/or HydroxyLys residues near CT and NT domains
  • Cu +2 dependent enzyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does interference with lysyl oxidase lead to

A

connective tissue defect called lathyrism
- due to lack of cross-linking and decreased fibril stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the possible ways lathyrism can occur

A
  • defect in copper metabolism
  • mutations in lysyl oxidase gene
  • sweet peas, clover (BAPN) -> competitive inhibitor of lysyl oxidase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is type 1 collagen

A
  • major protein of ECM
  • found in bones, teeth, tendons, blood vessels
  • heterotrimer 2 alpha1 chains, 1 alpha2 chains
  • chains associate at carboxyl domain and fold into triple-helical molecules
  • self-assemble into fibrils - strength and template
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is osteogenesis imperfecta

A
  • genetic disease
  • extreme brittleness of bones
  • poor mineralized osteoporosis, joint laxity, blood vessel rupture, blue sclera
  • variability in phenotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is OI caused by

A

mutations in either 2 collage type 1 genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

where are the mutations most severe with OI

A

TH domain - will be lethal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is Ehlers-Danlos Syndrome

A
  • heterogenous group of connective tissue disorders characterized by:
  • joint hypermobility
  • skin elasticity and fragility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why do mutations in the TH domain cause most severe phenotype? What is the importance of Gly residues and Gly-X-Y formula?

A
  • gly (smallest aa): important to form tightly wound triple helix; if disrupted then the trimer is loosened and affects every other structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the function of CT? why less severe than TH domain?

A
  • CT domain is important for forming disulfide bonds that stabilize 3 chains together before trimerization
  • if some chains have mutations in CT domain, these mutant chains won’t participate, but ones that are normal will participate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens to the NT domain? why mildest phenotype?

A
  • if right at cleavage junction it affects the CT - hyperflexibility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is haploinsufficiency

A
  • ex: mutation in the CT domain
  • CT is needed for alignment and association of 3 alpha chains prior to trimerization
  • if mutant alpha chain is unable to participate in chain association, this scenario would result in 50% reduction of trimeric collagens produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is dominant interferance

A
  • ex: mutation in TH domain
  • mutant partially-functional collagen alpha chains still able to compete with normal chains for binding to CT domain
  • hybrid molecules can’t form stable trimers -> all 3 chains likely degraded via protein suicide
  • also 3 mutant chains could trimerize and be secreted in ECM -> interfere with aggregate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are glycosaminoglycans?

A
  • unbranched polysaccharide chains or repeating disaccharide units
  • one sugar is amino sugar and other is uronic acid
  • highly negatively charged b/c carboxyl and sulfate groups
  • found in ECM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how are 6 gag groups distinguished

A
  • sugar residues
  • type of linkage
  • number and location of sulfate groups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

all but ___ are covalently linked to a protein core to form _______

A

HA; proteoglycans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is hyaluronic acid (HA)

A
  • simplest GAG
  • least neg charge
  • highest molecular weight
  • not made on protein core
  • serves as backbone for cartilage PG aggrecan
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is chondroitin sulfate (CS) and keratan sulfate (KS)

A
  • highly neg charge
  • components of cartilage PG aggregcan
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is dermatan sulfate (DS)

A
  • component of 2 bone PG, biglycan and decorin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what is heparin (HN)

A
  • most neg charge
  • found in mast cells
  • has anticoagulant and antiproliferative properties
  • commonly a component of the PG serglycin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what in Heparan Sulfate (HS)

A
  • found on cell surfaces in PGs
  • regulate cytokine-mediated cell interactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how does a GAG get linked to its core protein

A
  • a link tetrasaccharide is assembled on serine residue
  • rest of GAG chain, with repeating disaccharide units is synthesize -> one sugar residue at a time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are the most important 4 PG

A

aggrecan, decorin, serglycin, syndecan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is aggrecan

A
  • largest PG
  • highly neg charge
  • major component of cartilage
  • forms supramolecular aggregates on HA GAG backbone
  • made of chondroitin sulfate and keratin sulfate GAGs
  • enables cartilage to withstand compressive force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is decorin

A
  • smallest PG
  • constituent of bone
  • made of dermatan sulfate GAG
  • “decorates” type 1 collagen fibers
  • maintains inter-fibrillar space to allow mineralization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what is serglycin

A
  • high neg charge
  • made by mast cells
  • made of heparin GAG
  • important anticoagulant and antiproliferative properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what is syndecan

A
  • cell surface PG
  • comprised of heparan sulfate GAG
  • regulates cytokine-mediated cell interactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what are the steps in aggrecan biosynthesis

A
  • aggrecan protein core made on RER
  • transported from RER to golgi
  • in golgi, GAG chains are added to protein core one sugar at a time
  • molecules transported via secretory vesicles to ECM
  • hyaluronan is made on plasma membrane
  • in ECM, aggrecan, link protein, and hyaluronan come together to form PG aggregates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what percent of calcium exists in the serum? and how is it partioned?

A

1%
- partitioned into 3 sections (ionized, complexed, proetin-bound)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

why would serum spontaneously precipitate

A
  • contains more than the minimal concentration of calcium nad phosphate ions needed
  • in inhibitor-free permissive environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

mineral is deposited in the form of ____

A

hydroxyapatite

Ca10(PO4)6(OH)6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

for mineralization to occur, 2 conditions must be present:

A
  1. permissive environment (nucleation site)
  2. lack of inhibitors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

mineralization can happen anywhere if the environment is ____

A

permissive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is an example of mineralization inhibitors

A

matrix Gla proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

why doesn’t cartilage mineralize

(hyaline)

A

sulfated GAG

- bind Ca -> they are inhibitors to mineralization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

how does hypertrophic cartilage mineralize

A
  • during EO, hypertrophic cartilage aquires ability to mineralize and be vascularized b/c the ECM components change
  • late hypertrophic cartilage chondrocytes release matrix vesicles (MVs) from their plasma membrane into ECM
  • MVs provide nucleation sites where mineralization first occurs by concentrating Ca and PO4 in MVs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what type of collagen is hypertrophic cartilage

A

Type X

type 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what are the 4 molecules that matrix vesicles contain that allow mineralization?

A
  • alkaline phosphatase
  • annexin
  • calbindin
  • metalloproteinases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what dose alkaline phosphatase do

A

increases phosphate concentration near MV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what does annexin do

A

forms membrane channels for calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what is calbindin

A

calcium binding protein inside MVs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what does matalloproteinases do

A

degrade ECM and inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

why does bone ECM permit mineralization

A

contains calcium binding proteins

in organic phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what is an osteocyte

A

master regulator cell of bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

bone is mineralized ~50-75% of its volume - this enables bone to serve as a ____-____ ____

A

weight-bearing organ

deposited directly proportional to compressional load that it carries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

what does bone need to undergo in order to adapt to changes in mechnical pressure

A

remodeling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

during remodeling, mineral, organic matrix and cells are replaced, this tightly regulated process results from a:

A

balanced action of osteoblasts and osteoclasts

monitored by osteocytes

63
Q

how is remodeling locally controlled

A

by cytokines and growth factors

64
Q

how is remodeling systemically controlled

A

by hormones PTH, VD, and calcitonin

65
Q

what is mechanotransduction

A
  • bone adapts to mechanical pressure
  • osteocytes sense changes in pressure and Ca concentrations in bone fluid and respond by secreting cytokines that activate OBs or OCLs
66
Q

what is Wolff’s law

A

normal healthy bone will adapt to the loads under which it is placed

boned of athletes stronger than non-athlete

67
Q

what are the 3 local coupling factors that regulate remodeling

A
  1. TGFB - transforming growth factor-beta
  2. PGE2 - Prostaglandin E.
  3. N2O - Nitrous oxide
68
Q

what does FGFB do

A

tells osteoblasts to make more bone

it is a cytokine (protein)

69
Q

what does PGE2 do

A

secreted by OB - activates osteoclasts to begin resorbing bone

lipid

70
Q

what does N2O do

A

synthesized by OB - tells OCLs to stop resorbing bone

gas

71
Q

what is osteoclastogenesis

A

osteoclast formation

local and systemic

72
Q

what are the two ways the rate of bone resorption is regulated by

A
  1. controlling ostepclast number
  2. regulating osteoclast activity
73
Q

what are the local factors of osteoclastogenesis

A
  • local coupling factors (TFGB, PGE2, N2O) and cytokines are produced by OBs
  • cytokines bind receptors of pre-OCLs and promote or inhibit their differentiation into mononuclear OCLs
74
Q

what are the systemic (hormonal) factors of osteoclastogenesis

A
  • PTH and VD activate resorption by stimulating OBs to secrete cytokines and increase # of pre-OCLs
  • Calcitonin binds receptors on OCLs and inhibits their activity
  • Estradiol inhibits OCLs formation by inhibiting cytokines
75
Q

what happens in post-menopausal women

A

osteoporosis
- b/c decreased estrogen secretion results in increase pre-OCLs and elevation in bone resorption

76
Q

what are general steps of local and systemic control of bone remodeling

A
  1. systemic signal affect OB to tell it to stop making bone
  2. OB secrete facots that act to bring in OCLs/ activate OCLs
  3. OCLs secrete hydrochloric acid that degrades mineral
  4. stimulates release of factors that tell OB that bone is being resorbed
  5. OB secrete other facts that tell OCLs to go away
77
Q

what is osteoporosis

A
  • when resorption is greater that formation
  • varied causes
  • characterized by osteopenia (reduced bone mass)
  • radiographic retection not possible until 30-40% bone loss
  • with age bone is lost from everywhere
  • postmenopausal women
78
Q

how to prevent osteoporosis

A
  • exercise to increase bone mass
  • ingest approprate Ca when young
  • ability to take up Ca will decrease with age
  • humans need 1 gm Ca/day till 65; then ~2.5 gm/day
79
Q

what is osteopetrosis

A
  • rate of bone formation greater than resorption
  • rare heredity disorders -> osteoclast dysfunction
  • bones are dense and brittle
  • marrow is affected -> hematopoiesis can occur in liver and spleen
  • anemia common
  • Tx: marrow transplant
80
Q

serum calcium is under strict homeostatic control @ ____

A

10mg/dl; 2-3mM

81
Q

Ca is an essential ____ for many key biological processes

82
Q

Serum Ca2+ concentrations are maintained on a minute-to-minute basis by:

A
  • PTH
  • VD
  • Calcitonin
  • Dietary intake
  • Excretion
83
Q

cystolic calcium concentration is in the ____ range

A

micromolar

84
Q

what does the calcium-ATPase pump do

A

uses energy to pump Ca++ out of cytosol to the cell exterior or into the ER lumen

85
Q

what does the sodium-driven calcium antiport do

A

exchanges sodium for Ca++ as Ca++ is being extruded from cell

86
Q

what do calcium pumps in mitochondria do

A
  • not very efficient
  • pump Ca++ out of the cytosol when Ca2+ levels are high
87
Q

what do calcium-binding proteins (CaBP) do

A
  • in cell, Ca++ is bound by CaBP (calsequestrin or calmodulin)
  • help escort Ca++ out of cell
88
Q

dietary Ca2+ absorption takes place in the small intestine and is about ___% effective

89
Q

the amount of Ca ingested should ___ the amont lost through feces, urine, and sweat

90
Q

what increases Ca absorption in the intestine

A

1-25-(OH)2-vitamin D

91
Q

what does VD do

A
  • facilitates Ca absorption by activating transcription of a Ca binding protein (calbindin) in intestine
92
Q

what does calbindin do

A

escorts Ca across the cell and into circulation

93
Q

what is acute hypocalcemia and how is it caused and treated

A
  • severe drop in Ca++ (below 5-6 mg/dl)
  • lack of Ca++ in nerve impulse transmission and muscle contraction
  • death from failure of cardiac muscle contraction
  • tx: IV calcium chloride or calcium lactate

human - tetany in hand
cow - milk fever

94
Q

what is chronic calcium deficiency

A

rickets - young animals
osteomalacia - older animals

95
Q

what is rickets

A
  • Ca deficiency during skeletal growth
  • ex: chick embryo grown in shell-less culture
96
Q

what is osteomalacia

A

chronic Ca deficiency in adulthood leads to lameness and spontaneous fractures

97
Q

what is hypercalcemia, an example, and tx

A
  • osteopetrosis
  • increase in threshold for nerve and muscle activation
  • clinical symptoms: brittle bones, weakness, lethargy
  • ex: dairy bulls kept on high Ca diet meant for cows
  • tx: IV chloride or lactate

elevation in serum Ca++ (above 10mg/dl)

98
Q

what is hyperphospatemia

A
  • too much phosphate, not enough Ca
  • Ca:P ratio should be 2:1
  • deficiency of Ca in presence of access P leads to bone resorption and skeletal defects

big head disease - horses
twisted snout - pigs

99
Q

explain VD synthesis and metabolism

A
  • made in skin (VD3) and ingestin in diet (VD2)
  • undergoes hydroxylations by 1-a-hydroxylase in liver, kidney to form active 1,25(OH)2-VD
  • production of active form is dependent on PTH which is released when serum Ca are low
100
Q

what kind of hormone is VD

A

a steroid hormone

101
Q

what is the mechanism of VD action

A
  • diffuses into cell and binds to VD receptor
  • results in conformational change of VDR
  • enables VD/VDR complex to bind specific VD regulatory elements in target DNA
  • gene transcription and protein synthesis stimulated or repressed
102
Q

what are the 3 target sites of VD and what are the results

A
  1. intestine -> increases CaBP (calbindin) -> increase absorption
  2. kidney -> increases CaBP -> increases re-absorption
  3. bone -> decreases OB -> increase OCL -> resorbtion

end result: serum Ca level increases

103
Q

what is PTH

A
  • peptide hormone
  • made by parathyroid
  • undergoes cleavage
  • 84aa active form
  • secreted when Iow Ca
  • half-life 2-5 min
  • receptors on kidney and OB
104
Q

what are two target sites of PTH and what is result

A
  1. kiney -> 1-a-hydroxylase -> VD
  2. bone -> decrease OB -> increase OCL -> increase resorption
105
Q

what is calcitonin

A
  • single peptide of 32aa
  • secreted as prehormone by C cells in thyroid in response to hypercalcemia
  • lowers Ca2+ levels by acting directly on OCL and inhibiting resorption
106
Q

what is PTH-related peptide (PTHrP)

A
  • hormone produced by tumors and by lactating breast
  • functions to elevate the blood Ca2+
  • competes with PTH for receptor binding
107
Q

explain systemic regulation of Ca

A
  • drop in Ca -> PT gland secretes PTH
  • kidney: PTH stimulates production of 1-a-hydroxylase - allows hydroxylation of active form of VD, 1-25-(OH)2D3, Calcitriol
  • kidney: 1-25VD stimulates CaBP production and increases re-absorption of Ca2+ from urine
  • bone:1-25VD and PTH act on OB; OB signal to OCL to start resorbing bone
  • intestine: 1-25VD stimulates CaBP and increases absorption of Ca2+
  • result = raise in serum Ca2+
  • increase in serum Ca2+ detected by C cells in thyroid, leads to release of calcitonin (CT)
  • CT inhibits resorption of bone by acting on OCL
108
Q

what are the causes of osteodystrophies

A
  • temporal imbalances (nutritional, endocrine/hormonal, toxic origins/drugs)
  • GI/renal/hepatobiliary dysfunction
109
Q

what can osteodrystrophies affect

A
  • skeletally immature animals during EO and IO (growth)
  • during remodeling processes at any age -> specific lesios not specific causes

diffferent types of metabolic bone disease can manifest in same animal

110
Q

what is the most critical local activator of OCLs

111
Q

what is the most critical systemic activator of OCLs

A

PTH and Calcitonin

112
Q

what are the endocrine clads that produce 2 hormonal regulators (activator and inhibitor) of OCL

A

Parathyroid - PTH
Thryroid - Calcitonin

113
Q

what are the two most important nutriend minerals and one critical nutrient/hormone regulating skeletal remodeling

activated by kidney

A
  1. Ca2+ and PO4-
  2. active Vit D3

activated by kidney

114
Q

what is bone modeling

A
  • adaptive process
  • architectural change
  • growth
  • increase in bone length and diameter
  • pathologic states (fracture healing, infection, neoplasia)
  • bone repair/replacement

EO

115
Q

what is bone remodeling

think IO

A
  • contant, throughout life
  • physiologic maintenance of skeleton
  • replacement of old bone -> new bone
  • maintain bone mass
  • replace old bone/repair microfractures
  • respond to metabolic/nutritional changes
116
Q

what are the 3 most common metabolic osteodystrophies

A
  • osteopenia/osteoporosis
  • rickets (immature)/osteomalacia (mature)
  • fibrous ostrodystrophies (primary hyperparathyroidism, secondary hyperparathyroidism - renal, nutritonal)
117
Q

osteopenia/osteoporosis

A
  • osteopenia = decreased bone density or mass
  • osteoporosis = clinical syndrome of reduced bone mass manifested by bone pain and pathologic fractures
  • bone shape normal but reduced amont of trabecular bone
118
Q

what are the causes of osteoporosis

A

nutritional
- protein calorie malnutrition
- calcium deficiency
- copper deficiency

physical inactivity (disuse/immobilization)

119
Q

lesions of osteoporosis

A
  • decreased OB activity
  • decrease trabecular bone -> decreased compact bone (decreased bone density & increased porosity)
  • pathologic fractures & infractions
120
Q

rickets and osteomalacia

A
  • defective mineralization
  • affect bone and growth cartilage
  • rickets = softening of both bones and growth cartilage
  • osteomalacia = softening of bones
121
Q

what are the causes of rickets/osteomalacia

A
  • Vit D deficiency
  • phosphorous deficiency (herbivores on phosphorous deficient diet)
122
Q

what are the two phases of bone formation

A
  1. osteoid formation
  2. mineral deposition

in rickets and osteomalacia - osteoid mineralization does not occur

123
Q

rickets and osteomalacia pathogenesis

A
  • reduced mineralization - deposition of large seams of osteoids
  • decreased OCL resorption
  • growth plate deformities in young animals
124
Q

rickets - lesions

A
  • thickend & nodular physes
125
Q

rickets and osteomalacia lesions

A
  • trabecular bone lined by large seams of osteoid
  • cortical bone (deofrmed/bowed, endpstea; surfaces lined by thick seams of osteoid, pathologic fractures -> catastrophic fractures)
126
Q

fibrous ostrodystrophy

A

pathogenesis
- persistend and extreme increase in PTH
- primary hyperparathyroidism

rubber jaw, big head/bran dz

127
Q

what are the causes of secondary hyperparathyroidism

A

chronic renal insufficiency/failure
- super, constituently high PTH

high phosphorous diets

128
Q

pathogenesis of renal secondary hyperparathyroidism

A
  • decreased GFR -> increased PO4
  • CaPO4 crystallization -> decreased iCa
  • decreased iCa -> increased PTH release
  • decreased bone formation
  • increased OCL differentiation/activation
  • increased FB differentiation > OB differentiation
  • OCL bone resorption with replacement fibrosis

squishy bones

129
Q

what is the function of joints

A
  • locomotion
  • stability (bone)
  • motion of bone
130
Q

what are the key features of joints

A
  • robust to withstand forces
  • smooth, frictionless motion of bony ends
  • dampen vibration during impact
131
Q

fibrous joints

A

articulation between vertebral bodies

132
Q

cartilaginous joints

A
  • hyaline/fibrous cartilage interface
  • pubic symphysis
133
Q

synovial joints

A
  • both bone ends articulate via hyaline cartilage
  • contained in joint capsule
  • synovial fluid
133
Q

synovial joints

A
  • both bone ends articulate via hyaline cartilage
  • contained in joint capsule
  • synovial fluid
134
Q

what is the structure of a joint

A
  • articular (hyaline) cartilage
  • subchondral bone
  • synovium/synovial fluid
  • joint cpasule
  • meniscus
  • intra and extra-capsular ligaments (collateral, patellar)
135
Q

what is the function of articular cartilage

A
  • low friction gliding surface
  • transmits weight bearing forces to underlying bone
  • can withstand high cyclic loads
136
Q

what is the function of subcondral bone

A
  • adaptation to stress (wolffs law, thickening of compact bone of increased stress, alterationto configuration of trabecular bone)
  • attenuation of force (compact bone - rigid suport; trabecular bone - elasticity; deformable - changes in rigidity have repercussions)
137
Q

what is the function of the outer layer of the joint capsule

A
  • mechanical stability
  • innervation (proprioceptive info)
  • produce synovial fluid
138
Q

what are the 2 layers of the synovium and synovial fluid

A
  • subintimal layer
  • intimal layer
139
Q

what are the components of the intimal layer of the synovium

A
  • lacks basal membrane
  • synoviocytes (Type A - macrophage and B - fibroblast)
140
Q

what is the composition of synovial fluid

A
  • blood plasma
  • hyaluronic acid - viscous
  • lubricin
  • cells
141
Q

what is the function of synovial fluid

A
  • lubrication
  • delivery of nutrients to cartilage
  • removal of waste from cartilage
  • joint homeostasis (cytokines, growth factors, enzymes)
142
Q

what is the functuon of the meniscus

A
  • improve joint geometry for even more loading
  • mechanical stability
143
Q

what is the function of peri-articular structures (ligaments)

A

joint stability

144
Q

what is osteoarthritis

A
  • results in articular cartilahe damage and degeneration
  • can start with injury to any pf the parts of joint
  • results in injury to all other parts of joint
145
Q

joint acute injury

A
  • unusual
  • mis-step or fall
  • osteochondral damage
  • meniscal damage
  • ligament injury
  • joint capsule
146
Q

what is chronic joint injury

A
  • most common
  • cyclic loading (microdamage, response to loading results in weak areas)
  • osteochondral damage
  • meniscal damage
  • ligament injury
  • joint capsule
147
Q

what is the influence of subchondral bone

A

mechanical
- increase bone remodeling -> increase bone density -> changes deformability

biochemical
- releases inflammatory cytokines

pain
-well inervated

148
Q

influence of synovitis

A
  • inflammation of inner lining of joint capsule

biochemical
* produces inflammatory mediators; cytokines

pain
* well innervated
* effusion
* inflammation of nerve endings

149
Q

what is the influence of soft tissue structures

meniscus, ligaments

A

damage
* mechanical instability - stress of articular surface
* produce inflammatory cytokines - cartilage breakdown
* pain - innervated

150
Q

what is subluxation

A
  • incomplete or partial dislocation of a bone in a joint
  • results in malalignment of nomral bone or limb axis
  • results from severe soft tissue trauma and disruption of ligaments and joint capsule
151
Q

how does osteoarthritis occur and what does it result in

A
  • occurs from injury to any part of joint
  • results in secondary damage to other parts of joint
152
Q

what are the clinical manifestations of osteoarthritis

A

joint effusion
* increased synovial fluid due to inflammation

pain (lameness)
* highly innervated structures (synovium, subchondral bone, intra and extra-capsular soft tissue)

decreased joint range of motion
* body attemps to stabilize joint (fibrosis, osteophytosis - proliferation of joint edges)

Support and Movement (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions