Some start up questions:
1. What type of tissue is bone?
2. How are bones classified?
3. What are the different types of bony tissue - differentiate between them histologically.
4. Describe the physiology and histology of muscle contraction.
5. What are the anatomical features of a myofibril?
6. Explain the different parts of a muscle sheath containing many muscle fibres.
7. What muscle groups of the head and neck would you expect to be in the test?
8. What are the major muscles associated with jaw movement
9. Describe the normal function of the TMJ and what occurs when there are abnormalities in the various components of the joint.
10.Discuss the role of prime movers and anatogonists in the musculature of the head and neck
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1) Bone is a kind of connective tissue
ReplyDeleteI think question 4 is the slide filament theory
ReplyDelete1. specialised connective tissue, highly calcified to allow strength and to prevent the diffusion of nutrients.
ReplyDelete2. bones classified by their shape such as long bones (found in arms), short bones (in wrists), flat bones (such as the parietal bone of skull) and irregular in vertebra.
ReplyDelete3. spongy (doesn't contain osteons)and compact (contains lamellae and lucuna) ??
7. muscles of mastication, supra/infra hyoid
8. masseter, medial and lateral Pterygoids and temporalis
9. TMJ is a freely movable joint (diarthroses) bound by synovial tissue. normal functions of the joint, 1. rotational movement + gliding movement. abnormalities include sub-luxation, thinning of the disc (at any age)......?
4) muscle contraction occurs on a microscopic level within the muscle fibres. the process occurs as follows:
ReplyDelete-ACh released from synaptic terminal of motor neuron
-Binds to receptors on end plate
-Depolarises cell
-Action potential propagates into transverse tubule (opens t tubules)
-Calcium is then released from the sarcoplasmic reticulum
-Calcium binds to troponin, unblocking the binding sites on the actin thin filament
-Myosin head binds to actin forming cross bridge between thick and thin filaments
-ATP binds to myosin heads, and provides energy to relax and rotate the head, causing sliding of the filaments.
-This sliding of microfilaments causes muscle cells to contract and thus muscle contraction.
Hey maddie- can we do the muscles of mastication and their origin, insertion and their action (maybe alternitively)
ReplyDelete1. Masseter, has two heads Superficial and Deep. Superficial originates in the anterior 2/3rds of zygomatic arch. Deep originates in the posterior 1/3rd of zygomatic arch. Both insert into the angle of mandible. Action= elevation of mandible.
ReplyDelete6) the connective tissue sheet that covers the whole skeletal muscle is the epimysium. the connective tissue sheath that groups muscle fibres into fasicles is the perimysium. the connective tissue sheath the surrounds each individual muscle fibre is called the endomysium. finally the sheath around bone is called the periosteum. (remember the latin)
ReplyDeleteMASSETER: O - zygomatic arch
ReplyDeleteI - Ramus and Angle of mandible
Action- jaw closure (prime mover)
haha oops
ReplyDeletei think i need to go over it a bit more
http://www.youtube.com/watch?v=RPhCWmOj9ig
ReplyDeletethis is a good resource for TMJ and the muscles of mastication that hannah c found. very useful in explaining your question georgina
I am following your posts with much interest and excitement as I watch you guys unravel the answers.
ReplyDeleteYou are all heading in the right direction. Tom do you think you could just tweak the slide filament theory a little.. add the role of sodium ions and the role of tropomyosin.
Also.. can u guys review what happens to muscles if they are underused such as occurs when a limb has been in plaster.
limbs in plaster leads to little use of the muscle. After an extended period of time without use, there is more connective tissue present..therefore the muscle is nolonger as flexible. is that on the right track sophie?
ReplyDeleteyeaa i think i need to go over it a lot more. thanks guys this is really helpful
ReplyDeleteSure is Maddie... if there is no motor stimulation to a muscle fibre the myofibrils start to breakdown... why people who are immobilised start to wither away.... hence why body builders get bulked up as they get increase in protein - myofibrils, so then the CT sheaths have to build up as well as the blood supply to these cells... hence why they get exaggerated arteries and veins popping out of their skins!
ReplyDeletequestion I cant remember the answer to: which muscle prevents you from placing an x-ray film for a lower periapical?
ReplyDeletei think it is the mylohyoid. if the patient contracts their tongue, the mylohyoid is elevated which i'm guessing would decrease the area available to place the film successfully..thoughts thomas?
ReplyDeleteyeah that sounds good.
ReplyDeleteclarifcation on the action of both medial and lateral pterygoid muscles? and what are the muscles involved in mastication?
yeah its the mylohyoid tom, good work maddie!
ReplyDeletehey why do we have 2 types of bone?
muscles of mast. temporalis, masseter and medial and lateral pterygoid muscles.
ReplyDeletemedial pterygoid elevants mandible and the lateral pterygoid can deviate jaw to other side. so do you think thats is enough to say about the mylohyoid? if we are asked something similar to that..
elevates mandible* no elevants around here.
ReplyDeletemuscles of mastication
ReplyDeletetemporalis - elevation
masseter (prime mover) elevation
medial - elevation
lateral - protrusion, depression and lateral movements
buccinator can assist with guidance in holding food on the occlusal plane and swallowing
obicularis oris can also assist by closing and pursing lips holding food in the mouth
describe the type of joint that forms the TMJ, ligaments involved, and the problems caused by bruxism.
ReplyDeleteoh and realised question 10 hasnt been answered yet... ive got no idea but off the top of my head this is what i think, tell me what to change!
ReplyDelete10)prime movers are the muscles that cause the main muscle movement, and antagonist muscles are the opposite to these muscles and support them during the movement. so suprahyoid muscles serve to elevate the hyoid bone, so the antagonists would be the infrahyoid muscles.
your first question. TMJ= synovial joint, ligaments involved are the temporal mandibular ligament, sphenomandibular ligament and stylomandibular ligament. buxism can lead to pain experienced in the masseter muscle? aswell as occlusal wear of teeth and headaches? not sure if those are the "problems" they are after.. thoughts? also, question 6, need a bit of help..
ReplyDeleteyeah maddie i thought that muscles that would be the most effected by bruxism would be pterygoids, (isnt griding a lateral movement) but headaches and wear facets for sure.
ReplyDelete6) epimysium is the CT sheath that surrounds entire muscle fibre. Perimysium is the CT sheath that surrounds the individual fasicle of myofibrils, endomysium surrounds each muscle fibre
Why do you think that the muscles of mastication and the muscles of facial expression are grouped as they are by anatomists?
ReplyDeleteBecause muscles of mastication attach to bone for chewing etc, where as muscles of facial expression attach to skin to form facial expression eg. wrinkles?
tom, i forgot what you said you thought today..
yeah pretty much it, and then the masticatory muscles join to bone which is a connective tissue, and facial joins to skin which is epithelium.
ReplyDeletewhat are the two types of bone and explain their histological differences? (I know its spongey and dense, but no idea how to explain them histologically)
compact bone is made of closely packed osteons where as spongy bone doesn't contain osteons? not really sure where that is going haha
ReplyDeleteand the lamellae matrix isn't arranged in circles around the blood vessles like in compact bone.
ReplyDeletethe three major groups of neck muscles:
ReplyDeleteposterior triangle
anterior triangle: suprahyoid
anterior triangle: infrahyoid
would you agree with that?
the two types of bone are dense (coticoid) and spongy (cancellous) The dense bone has Lamella (the circle bits) then Lacuna (around the Osteocytes..this is where they sit) then from this the Canalliculus spreads from there..into the Haversian (central) canal..? the horizontal canal is the perforating (volkmans) canal..
ReplyDeleteRE muscles of mastication..i agree with Cath..what she says!!! =)
ReplyDeleterevised slide filament theory:
ReplyDelete-ACh released from motor neuron across synapse
-sodium exchange occurs across endplate, depolarising muscle cell
-action potential propagates across cell, opening transverse tubules
-Ca is released from sarcoplasmic reticulum, travelling through t tububles
- Ca then interacts with tropomysin, which serves as a contraction inhibitor by blocking myosin active sires on actin molecules in thin filaments.
-Ca causes tropymysin to move, exposing myosin active sites
-mysoin heads located on thick filaments then bind to actin molecules forming cross bridges
-atp molecule then binds to myosin head and the subsequent energy change causes bridge to relax and rotate, causing sliding of the filaments
- sliding filaments=contraction
what changes need to be made?
what about the muscle which the perotid gland pierces - im not too sure of that?
ReplyDeletegeorgie,
ReplyDeleteparotid gland pierces buccinator to get to oral cavity.
TMJ = bilateral, synovial joint with fibrous (meniscus) cartilage.
ReplyDeleteNORMAL MOVEMENT = 'glydes' along (forward/backwards) the articular eminence and 'hinges' (rotation) within the mandibular (articular) fossa
with 'synovial' cavity (there are 2 upper and lower) secreting synovial fluid for lubrication and the articular disc providing cushioning/shock absorber.
ABNORMALITIES -
*sub-laxation (partial dislocation) when the condyle glydes beyond the articular eminence
*bruxing
*jaw trauma/fracture
*poor occlusion
cath you are a gun.
ReplyDeletewhich of the masticatory group is involved in the lateral movement of the mandible, and describe the pysiolgy of how this occurs.
lateral mastication
ReplyDeletei would say the buccinator
has 2 origins - alveloar process of mandible and maxilla
and insertion = orbicularis oris
the muscle pulls @ the angle of the mouth laterally and shortens the cheek both vertically and horizontally.
during mastication the buccinator keeps food on the occlusal surface and assists swallowing
in infants - suction for suckling
2 types of bone
ReplyDelete**Compact**
Osteons = Haversian system
rings of Lamellae, seperated by lacunae (which hold osteocytes), amongst 'canaliculi' which are transport and blood supply from haversian canal.
**spongy**
No osteons
Spaced out lamellae form 'trabeculae' with cone shaped 'spicules'
osteocytes found amongst the trabecular lamellae
Blood vessels from haversian canal snake around the spongy bone.
hope this is right and makes sense, its how i am going to try remember it. the diagrams fromt he lecture notes may be worth a sneak peak when decifering my lingo ;)
how would you guys answer
ReplyDeletewhy do we have 2 types of bone????
i think i remember something about spongey bone housing marrow which is important for immunology etc. also dense bone needed for support and structure?
ReplyDeleteEach type of bone serves a different function. eg. compact bones protect everything within it, where as spongy bone protect bone marrow?
ReplyDeleteyeah tom that sounds right....and i like your fillament theory...im still not sure about the two types of bone...and how bone attatches to tendons???
ReplyDeleteand is the buccinator included in the muscles of mastication?? my text only has temporalis, masseter and the medial and lat. pterygoid??
ReplyDeleteyea im still confused with the two types of bones!
ReplyDeleteRachel
There are four paired muscles that facilitate movement of the masticatory apparatus:
Temporalis (temporal)
Masseter
Medial (internal) Pterygoid
Lateral (external) Pterygoid
so i guess the buccinator isnt included?
i think if a masticatory muscle is being asked for that moves jaw laterally it would be the lat pterygoid because the buccinator only moves the mouth laterally.
ReplyDeleterach, sharpeys fibres attach tendons to the periosteum that surrounds bones
ReplyDeleteHi everyone
ReplyDeletegreat to see the Blog so active - a few comments:
The buccinator is not anatomically classed as a muscle of mastication as it doesn't move the mandible, however it is associated with the masticatory process due to it location as the walls of the oral cavity.
Two types of bone - dense (cortical) and cancellous (spongy) - the histology of them is really what they would look like under a microscope. So if can describe the differences in their structure you are on the right track.
The mylohyoid is the muscle which can make placing a film difficult - especially when the mouth is open - can you think why?
The main muscles affected by bruxism would be the major elevators of the mandible as they would be overworking.
All from me..
thats right!!! i forgot ol sharpey and his fibres!! cheers tom..yeah Maddie that makes sense...xx
ReplyDeleteI still dont get how the mylohyoid would make placing a film difficult.
ReplyDeleteand do we need to no the origins and insertions really well.. im finding it so hard to memorise
The mylohyoid would make film placement difficult if the mouth was open as the muscle raises the hyoid bone and helps elevate the tongue...this would make it difficult to place the film.
ReplyDeleteI think that when the mylohyoid contracts it becomes firm and elevates the tongue making the placement difficult and uncomfortable...
ReplyDeleteohh yea makes sense. thanks guys =]
ReplyDeletefunctions:
SCM: tilts the head left and right or up and down?
trapzius: lifts the clavicle and scapula
what about the platysma?
SCM = flexion of head...i think left to right..
ReplyDeletePlatysma = raises skin on neck to form ridges and depressions, also used when a person grimaces (pulls corner of mouth down)
thanks maria =]
ReplyDeleteYour welcome =] umm to answer your question about origins and insertions...i have more of a generalised idea of the...for some of the hyoid ones i know a bit more of but yea...
ReplyDeletewhat bony feature confirms the end of longitudinal bone growth?
ReplyDeleteis it the epiphyseal plate?
ReplyDeleteYep, I'll second that maddie =]
ReplyDeleteoh hey we havent answered question 5)5. What are the anatomical features of a myofibril?
ReplyDeleteis it. myoofilaments are the microscopic proteins which make up muscle fibre. when grouped together they are referred to as myofibrils?
theres gotta be more detail right? =[
ReplyDeletehmmm...i would have said something like myofilaments (thick and thin) make up sarcomere..sarcomere makes up myofibril...??
ReplyDeletemaybe mention how the arrangement of the myofilaments gives the striation appearance on the myofibril...
ReplyDeletedoes anyone know what the 2 main types of CT that comprise the human skeleton are and their advantages?
ReplyDeletesarmad, 2 main types = bone + cartilage
ReplyDeleteadvantages: well bone for strenghth, support, shape, reservoir of minerals etc etc...and cartilage: movement, shock absorber, flexibility, strength, growth (empiphyseal)
that's a stab in the dark.
Ok guys.. all looking good, One clarification on the SFT- calcium interacts with troponin, changing the configuration of the tropomyosin,to expose actin active sites.
ReplyDeleteGood luck tomorrow guys....
See you in the morning.
i agree on bone, but wasn't sure whether blood would be the other one...
ReplyDeletethanks though!
haha yea yea...i wasn't sure which to put down cartilage or blood...guess cartilage will do haha
ReplyDeleteabout to head in..was great to read over this again!!!!! good luck everyone see you soon!!!!! xx
ReplyDeletewow guys - hope the blog platform hasn't gone into meltdown!
ReplyDeleteReading back over the 68 comments is like a complete revision for the exam. For those that participated, well done on your collaboration and support. The blog is perfect for this sort of thing - all in the comfort of your own home.
Good luck this morning - you have certainly prepared well.
I am currently invigilating this exam for you guys.... as Cathy said with this type of preparation you cant go wrong..... c u guys real soon..after the test!
ReplyDelete