LOCO SSS2 Flashcards
at what stage does femoral artery –> popliteal artery? [1]
adductor hiatus
inverterbral disc structure:
what is annulus comprised of ? [1]
what is nucleus pulposus comprised of? [3]
inverterbral disc structure:
what is annulus comprised of ? [1]
15/20 type 1 collagenous laminae, run obliquely
what is nucleus pulposus comprised of? [3]
type II collagen
water
proteoglycans
around 85% water !!
purple structure?
role? [3]
ligamentum flavum !
- Extends from lamina above to lamina below of adjacent vertebra
- Resists separation of the lamina
- Stops abrupt flexion
- High elastic content so assists with straightening after flexion
what is the enthesis? [1]
bone / tendon insertion: tendon to fibrocartilage to calficified fibrocartilage
what is A?
A = secondary ossification centre
what does the deltoid ligament attach to? [3]
medial malleoulus
calcaneus
navicular
which 3 ligaments make the the lateral ligament? [3]
which are they clinically significant? [1]
which 3 ligaments make the the lateral ligament? [3]
anterior talofibular
posterior talofibular
calcaneofibular
which are they clinically significant? [1]
because theyre seperate structures - really likely to tear: lateral collateral ligament tear
which muscles of leg cause foot inversion? [2]
- *tibialis posterior -** deep posterior compatment
- *tibialis anterior** - anterior comparment
what maintains the longitduinal arches? [2]
- *dynamic support**
- muscle contracts as when required
- muscle tendons insert into apex of arches - when muscles contracts, pulls apex up & counteract body weight
- includes intrinsic muscles
- *passive support**
- constant & ongoing support
- due to shape of bones: allows them to interlock
explain the arches of the foot? [3]
- *medial longitudinal arch:**
- open footprin side: middle of foot isnt it
- contact with ground: big toe & calcaneous
- resilient due to large no. of bones
- *lateral longitudinal arch:**
- flatter
- less bones
- talus transmits body weight through it - weight not central though - either goes forward or backwards
transverse arch:
not a true arch - maintained by some mscles and ligaments as longuitnial arches
- bony fit is particularly good
which structures pass under the flxor retincula? [2]
which structures pass under the extensor retincula? [2]
which structures pass under the flxor retincula? [2]
tibial nerve
posterior tibial artery
which structures pass under the extensor retincula? [2]
deep peroneal nerve (fibular nerve)
anterior tibial artery
explain the arches of the foot? [3]
- *medial longitudinal arch:**
- open footprin side: middle of foot isnt it
- contact with ground: big toe & calcaneous
- resilient due to large no. of bones
- *lateral longitudinal arch:**
- flatter
- less bones
- talus transmits body weight through it - weight not central though - either goes forward or backwards
transverse arch:
not a true arch - maintained by some mscles and ligaments as longuitnial arches
- bony fit is particularly good
explain mechanism of docking at NMJ and release of Ach occurs at presynaptic vesicle
vesicles docks by:
- synaptobrevin interacts with syntaxin and SNAP25: holds the vesicle close to pre-synaptic membrane (but doesnt fuse) = docking.
- Ca2+ binds to synaptotagmin: interacts with SNAP25/ syntaxin complex and tightens interaction between the vesicle and presynaptic membrane complexs & causes it to merge & release of Ach = confirmational change occurs.
what is scissor gait:
•Thigh swings across body during swing phase
•Difficulty in putting heel on ground
–Toe walking
–Unstable
at what point does an AP occur in muscle? [1]
at what point does an AP occur in muscle? [1]
- depolarisation occurs at 40mV
what are the two types of NMJ blockers [2] explain them
What are the two types of NMJ blockers [2]:
1. D tubocuraine: non-depolarising muscle relaxant
blocks the nicotonic Ach-R & prevents AP occuring
- Acetylcholinesterase inhibitor works as an antidote to it
- *2. depolarisng muscle relaxant**
- stimulate Ach-R like Ach and activate muscle (muscle twitch)
- but **do not detach: no more Ach can bind (paralysis)
- even if membrane is repolarised (from Na channels / NaKATPase), the drug causes it to bedesensitised**
- but breaks down after a while, so not perm. paraylses
which is this muscle?
innervation?
movement [2]
which is this muscle: sartorius
innervation: femoral nerve
movement [2]: flexes hip AND knee
what does quantal release of Ach mean? [1]
every vesicle contains same amount of ACh: same amount of NM is released with each AP. get a 1:1 transmission of nerve & muscle.
what is the order of neurovasculature of femoral things? [3]
femoral artery = pulsating just belowing midinguinal point
femoral nerve = lateral to artery
femoral vein = medial
VAN
what are the 3 different muscles that insert at the medial aspect of the knee? [3]
which compartment are they all originally from? [3]
what is name for this meetin of three muscles? [3]
- Sartorius - anterior
- Gracilis - medial
- Semitendinosus - posterior
= pes anserinus !!
lower motor neurons innervate skeletal muslces (alpha-motor neurones)
where do you find the cell body of the motor unit of the NMJ? [1]
one alpha motor neuron innervates: [1]
- one muscle fibre
- a number of muscle fibres
where do you find the cell body of the motor unit of the NMJ? [1]
ventral (anterior) horn of the spinal cord
one alpha motor neuron innervates: [1]
- one muscle fibre
- *- a number of muscle fibres:** forms the motor end plate (presynaptic NMJ)
nerve roots of patella reflex? [1]
what does it cause to occu? [1]
causes contraction of quads
L2-4 nerve
Myotome: L3-L4
what is the Q line?
where is at a line between? [2]
what s the angle in men? (compared to vertical) [1]
whats the angle in women? (compared to vertical) [1]
Q line: asis –> centre of patella
what s the angle in men: 14 degress
whats the angle in women: 17 degrees
Where do you find:
L type calcium channels [2]
N type calcium channels [1]
L type calcium channels [2]
heart
vascular smooth muscle
N type calcium channels [1]
pre-synaptic terminals - very close to the vesicles
Where is T1 dermatome? [1]
where is T2 dermatome? [1]
Where is T1 dermatome? [1]
medial forearm
where is T2 dermatome? [1]
axillary forearm
what is staccator gait like?
- plantaflexor paraylsis - no forward thrust
- unaffected limb never advances beyond affected limb. just the knee flexors & hip flexors lift it up and swing it forwa
what is the medial menisci attached to [2] (anteriorly / posteriorly)
what is the lateral menisici attached to? [1]
what is the medial menisci attached to [2]
- *anteriorly: ACL
posteriorly: tibial collateral ligament**
what is the lateral menisici attached to? [1]
pcl
NOT ATTACHED TO LATERAL COLLATERAL LIGAMENT
which structures make up the unhappy triad? [3]
- Medial meniscus
- ACL
- Tibial collateral ligament
what is the name of the inorganic substance that is precipitated over collagen fibres to calcify it? [1]
what is structure of ^ like on collagen fibres? [1]
what is the name of the inorganic substance that is precipitated over collagen fibres to calcify it? [1]
95% calcium hydroxyapatite
what is structure of ^ like on collagen fibres? [1]
- as crystals
what are the internal [1] and external signals [2] for bone remodelling?
what are the internal and external signals for bone remodelling?
- *internal factors**
- osteocytes processes extend in canaliculi & touch their neighbours
- osteocytes produce sclerostin to indicate bone health ! - stops osteoblasts coming
- when osteocytes stop producing sclerostin: indicates bad bone health
- *external factors**
- serum calcium level: low serum calcium causes the release of parathyroid hormone - causes osteoblasts to make RANK L
- pro-inflam cytokines: IL1, IL6, IL17 & TNF
what substance causes increases of calcium absorbtion from gut? [1]
1,25 dihydroxyvitamin D
how does PTH cause Ca2+ reabsorbtion from bones via the increase of activity and no. osteoclasts? [3]
Ca2+ reabsorbtion from bones - increases activity and no. osteoclasts
PTH binds to osteoblasts
osteoblasts produce RANKL
osteoclasts have RANKL receptor
activates osteoclasts
which substance, released from C cells in thyroid gland causes decrease in Ca2+ reabsorbtion? [1]
calcitonin
explain how intramembranous ossificatin occurs xo
- ossification centre appears in fibrous connective tissue membrane: here mesenchymal cells condense and differentiate as osteogenic cells: osteoblasts
- Osteoblasts secrete bone matrix (osteoid) & matrix becomes calcified with calcium hydroxyapatite
- trapped osteoblasts become osteocytes
- Mesenchyme on outside condenses: periosteum
- blood vessels growing to supply the bone with nutrients will bring in osteoclasts, which can then remodel the bone into compact/cortical bone on the outside and trabecular bone on the inside.
how does appositional growth of bone occur? (to the side)
- osteoprogenitors in periosteum differentiate as osteoblasts – secrete new bone matrix to form compact, cortical bone (osteons) and grow on either side of a blood vessel.
- these ridges get bigger and eventually form a tunnel with a blood vessel right in the centre.
- Inside tunnel: Former periosteum becomes endosteum due to being enclosed inside the bone due to bone growth. It still has progenitor cells
- Osteoblasts make new bone lamellae filling tunnel
which cell signals bone remodelling? [1]
what hormone does ^ cell secrete? [1]
how does the process occur? [2] (basic)
which cell signals bone remodelling? [1]
-osteocytes
what hormone does ^ cell secrete? [1]
sclerostin
how does the process occur? [2]
- *-sclerostin** secreted: causes inhibition of osteoblast action
- cellular process extend in canaliculi and touch their neighbours
supinator
how does endochondral ossification occur?
- Mesenchymal cells condense and differentiates into chondroblasts to produce hyaline cartilage model extracellular matrix (so they use collagen type 2 rather than collagen type 1).
- the perichondrium forms around cartilage model and holds all the mesenchymal cells next to the condensing bone
- To begin with, ECM is made more from collagen type 2, more proteoglycans: causes cartilage to grow in legnth and width (into the shape of the bone): causes to be further away from nutrient source
- chondrocytes now in the middle will begin to deteriorate as there is no blood supply into this cartilage
- this creates cavities, right in the centre, where the cartilage used to be. When they die, this triggers calcification as it triggers a Ph change: It releases vesicles in the chondrocytes with enzyme like alkaline phosphatase which changes the ph and encourages calcification of the matrix.
At this time, a blood vessel known as the nutrient artery can penetrate the perichondrium and begin to bring in osteoclasts from the haemopoietic cells to start remodelling: break down some of the spongy bone to create a marrow, or medullary, cavity in the centre.
Bone on the inside and bone on the outside grow towards each other to completely replace the cartilage.
