David Dixon Flashcards
What type of muscles are muscles of mastication
Skeletal
What are the muscles of mastication
4
Masseter
Temporalis
Lateral pterygoid
Medial pterygoid
What are the origin and inserstions of massater
Origin
Superficial head- zygomatic process of maxilla, anterior zygomatic arch
Deep head- posterior zygomatic arch
Insertion
Superficial head- angle on lateral surface of mandible
Deep head- upper half of ramus
What is the function of the massater
Elevates mandible
Which nerve supplies massater
Mandibular branch of trigeminal nerve
Where does temporalis originate and insert
Originate at temporal gods and deep surface of temporal fascia
Inserts onto coronoid process
What is the function of temporalis
Elevates and retrudes mandible
What nerve innervates temporalis
Mandibular branch of trigeminal nerve
What are the origins and insertions of lateral pterygoid muscle
Origin
Superior head- greater wing of sphenoid
Inferior head- lateral surface of lateral pterygoid plates
Insertion
Pterygoid fovea of condyle
What is the function of the lateral pterygoid
Depress mandible
What innervates lateral pterygoid muscle
Mandibular branch of trigeminal nerve
What is the origin and insertion of medial pterygoid
Origin
Deep head- medial surface of lateral pterygoid plate
Superficial head- maxillary tuberosity and pyrimidal process
Insertion
Medial surface of ramus and angle of mandible
What is the function of medial pterygoid muscle
Elevates mandible
Protrudes mandible
Side to side movement
What innervates medial pterygoid muscle
Mandibular branch of trigeminal nerve
What are the four supra hyoid muscles involved in depression of mandible
Digastric- depresses mandible
Stylohyoid- elevates hyoid bone
Mylohyoid- forms floor of mouth
Geniohyoid- protracts and elevates hyoid bone or depresses mandible
What’s are the types of oral mucosa
3
Lining
Masticatory
Specialised
What are the layers of oral mucosa
Oral epithelium
Basement membrane
Lamina propria (papillary and reticular layer)
Submucosa
What are the layers of skin
Epidermis
Basement membrane
Dermis (papillary layer and reticular layer)
Hypodermis
What are the zones of oral mucosa epithelium as they differentiate
4
Basal layer
Stratum spinosum/prickle layer
Stratum granulosum
Keratinised layer
What shape are the cells of oral mucosa from proliferation to differentiation
Cuboidal to squamous
What is the difference between ortho and parakeratinised epithelium
Ortho keratinised have complete keratinisation
Parakeratinised are in an intermediate stage of keratinisation
What percentage of mucosa is lining mucosa
60%
What percentage of mucosa is masticatory mucosa
25%
What are epithelial cytokeratins
How many cytokeratins do each epithelial cell contain
Keratin proteins found in the intracytoplasmic cytoskeleton of epithelial tissues
At least 2, one from each family
What substance is used in histopathology to characterise epithelial tissues
Pan cytokeratin antibodies
What are desmosomes
Inter epithelial cell adhesion sites
What are desmosomes made of
Cell adhesion molecules with linking proteins attaching them to cytoskeleton
What are hemidesmosomes
Sites connecting basal epithelial cells to basement membrane
Where can keratinised lining mucosa be found
1
Vermillion
Where is non keratinised lining mucosa found
6
Soft palate Ventral tongue Floor of mouth Alveolar mucosa Labial mucosa Buccaneers mucosa
Where is keratinised masticatory mucosa found
2
Gingivae
Hard palate
Where is keratinised specialised mucosa found
1
Dorsum of tongue
Where can non keratinised specialised mucosa be found
2
Junctional epithelium
Saliva duct lining
Name the types of gustatory epithelium
4
Circumvalate
Fungiform
Filiform
Foliate
Where are melanocytes found and what is there function
Basal layer
Synthesis of melanin and transfer to keratinocytes
Where are langerhans cells located and what is their function
Suprabasal layers
Traps and processes antigens
Where are merkel cells located and what is it’s function
Basal layer
Tactile sense
Where are lymphocytes found in the epithelial layer and what is it’s function
Variable location
Inflammation response
Define acute inflammation
The initial response taking place minutes to hours following injuries
Define chronic inflammation
Persistent inflammation alongside attempts at healing which can go on months to years
Functions of acute inflammation
3
Carries proteins, fluid and cells from local blood vessel to damaged area
Destroys causative agent of inflammation
Removes damaged tissue
What are the cardinal signs of inflammation
5
Heat Redness Swelling Pain Loss of function
What are the stages of accuse inflammation
4
Tissue damage
Release of inflammatory mediators
Vascular changes
Exudate formation
What vascular changes do inflammatory mediators cause
Shorten diameter of endothelial cells creating gaps and cause CAM expression increasing permeability
What do cell adhesion molecules facilitate
Margination
After leukocytes migrate out of vessels between endothelial cells how are they attracted to inflammation site
Chemotaxis
What cell adhesion molecules are part of the immunoglobulin supergene family and where are they found
3
Intercellular adhesion molecule 1-endothelial cells
Intercellular adhesion molecule 2-endothelial cells
Vascular cell adhesion molecule 1- endothelial cells
What cell adhesion molecules are part of the selectin family and where are they found
3
E selectin- endothelial cells
P selectin- endothelial cells
L selectin- leukocytes
Which cell adhesion molecules are part of the integrin family and where are they found
1
Alpha 2 integrins- leukocytes
What is inflammatory exudate made up of
3
Cells
Proteins
Serum
What type of cells are found in inflammatory exudate in acute and chronic inflammation
Accute- neutrophils
Chronic- monocytes, macrophages, lymphocytes
Occasionally erythrocytes
Define respiratory burst
A rapid release of oxygen species by neutrophils and monocytes on contact with pathogens, to aid degredation of bacteria, fungi and other matter
What serum proteins can be found in inflammatory exudate
4
Albumin
Fibrinogen
Immunoglobulin
Complement proteins
What is pus
An inflammatory exudate rich in neutrophils, some of which are dying through auto digestion of their own enzymes alongside bacterial debris
What does the left coronary artery divide into
Circumflex coronary artery
Left anterior descending coronary artery
Define cardiac output
What is the average cardiac output
Total amount of blood pumped from one ventricle per minute
5000ml per min
Define stroke volume
What is the average stroke volume
Volume of blood pumped out of one ventricle during one systole
70-80ml per beat
What is the equation for cardiac output
CO = SV x HR
Define compliance
A description of how easily a chamber of the heart or lumen of blood vessel expands when it is filled with a volume of blood
What is the equation for compliance
🔼V (change in vol) / 🔼P (change in pressure)
What is preload
What is afterload
Preload is amount of stretch of cardiomyocytes during diastole
Afterload is amount of resistance heart must pump against when ejecting blood during systole
What is the action of the baroreceptor reflex when blood pressure increases
Detected by baroreceptors in carotid sinuses and aortic arch, relayed to cardiac centre in medulla oblongata
Increases parasympathetic and decreases sympathetic stimulation to decrease heart rate and stroke volume
Vasomotor center decreases sympathetic stimulation of blood vessel causing vasodilation to decrease peripheral resistance
What is the action of the baroreceptor reflex when blood pressure decreases
Detected by baroreceptors in carotid sinuses and arch of aorta and relayed to cardiac center to inhibit baroreceptor reflex
Increase in sympathetic stimulation and decreases parasympathetic stimulation to increase heart rate and stroke volume
Vasomotor centre increases sympathetic stimulation to cause vasoconstriction of blood vessels which increases peripheral resistance
What is chronotrophy
Alterations in heart rate
What is ionotrophy
Alterations in force of contraction
What happens when B1 adrenoceptors stimulated
Where are they located
Increases heart rate via SAN
Increases force of contraction
Found on cardiac muscle
What happens when B2 adrenoceptors stimulated
Where are they located
Arteriolar relaxation
Increases blood flow
Found on arterioles of coronary circulation
What happens when a1 receptors stimulated
Arteriolar construction
Increased resistance
What happens when M2 mACh receptors stimulated
Where are they located
Decrease heart rate via AVN
Found on cardiac muscle
What is starlings law
The more the heart fills the stronger the force of contraction based on the length tension relationship of ventricular cardiac muscle as preload is increased so cardiac output is overall increased
What is the length of cardiac cycle in normal adult
O.7-0.8 seconds
What does a phonocardiogram show
Valves opening and closing
What are the three heart sounds and what causes them
S1 = lub: closing of atrioventricular valve
S2 = dub: closing of semilunar valves
S3 = sound of blood flowing into aorta or sloshing back and forth in ventricle
How many action potentials are produced by SAN per minute
60-100
What are the phases of cardiac action potential
4
Depolarisation
Plateau
Repolarisation
Resting
What occurs during depolarisation of cardiac action potential
Voltage gated sodium channels open and some voltage gated calcium channels open
What happens during plateau of cardiac action potential
Voltage gated sodium channels close and voltage gated calcium channels open
What happens during repolarisation of cardiac action potential
Voltage gated potassium channels open and voltage gated calcium channels close
What happens during resting phase of cardiac action potential
Voltage gated sodium channels and voltage gated calcium channels closed and voltage gated potassium channels open
What are the stages of electrical conduction in heart
SAN generates action potential
Action potential spreads through Atria to AVN
Action potential delayed at AVN allowing atrial contraction and ventricular filling
Impulse from AVN travels down ventricular septum via bundle of his
Impulse dispersed through myocardium via purkinje fibres
Remaining ventricular cells contract due to spread of impulse via cell gap junctions
What does the p wave of ECG show
Atrial depolarisation and contraction
What does PR interval represent
Impulse in AVN node spanning from onset of atrial contraction to beginning of ventricular contraction
What does QRS complex of ECG show
Ventricular depolarisation and contraction
What does ST segment of ECG represent
Entire ventricle depolarisation
What does the Twave of ECG show
Ventricular repolarisation and relaxation
How much ventricular filling does atrial contraction cause
10-30%
What is end diastolic volume
Volume of blood in ventricles at end of diastole
Why does volume of ventricles not change at beginning of ventricular systole
What does isovolumetric mean in relation to this
Both atrioventricular and semilunar valves closed
Ventricles contracts with no corresponding volume change
What is end systolic volume
Blood remaining in ventricle after systole
What is an arrhythmia
Irregularities of heart beat
What causes atrial fibrillation
How common is atrial fibrillation
How does atrial fibrillation preset clinically
Electric impulses from SAN overwhelmed by other disorganised electrical impulses
Present in 1% population
Palpitations, fainting, chest pain, thrombus formation
What causes ventricular fibrillation and what does this result in
Hypoxic myocardium creates irritable myocardial cells that act as additional pacemakers causing muscles to twitch instead of pump
Ventricular contraction uncoordinated so blood pumped inefficiently leading to cardiac arrest
What are the pressures in the heart chambers
Vena cava - 13/8 RA- 13/8 RV- 30/8 Pulmonary artery- 30/17 Pulmonary vein- 18/12 LA- 17/12 LV- 120/10 Aorta - 120/70
What is a ligand
A molecule that binds onto a receptor to transmit signal within or between cells
Define phosphorylation
Addition of phosphate group to switch mechanisms on or off
What is kinase
An enzyme that catalysed phosphorylation
What is a cytokine
Any cell signaling molecule of the immune system
What are autocrine hormones
Hormones that have effect on the cell by which it is secreted
What are paracrine hormones
Hormones that only effect cells nearby to the gland secreting it
What are the domains of receptors called
3
Extra cellular/ligand binding domain
Trans membrane spanning domain
Intercellular domain
What is the intercellular signalling cascade
The sequential activation of proteins inside cell until message reaches its final destination leading to response
What are the 4receptor families
Ion channel
G protein coupled receptors
Enzyme linked receptors
Intracellular receptors
What is the G protein and what does it do
Guanosine di phosphate
Activates enzyme subunit
Which receptors detect tastants
What receptor family are they from
Taste receptors on taste cells in taste buds
Ion channels
G protein coupled receptors
What type of receptors detect pain ( noxious stimuli and pressure)
What receptor family are these from
Pressure and proprioception receptors
Ion channel
G protein coupled receptors
What are the concentrations of potassium and sodium across membrane at resting potential
Potassium 20 times more concentrated in cytosol
Sodium 10 times more concentrated in extra cellular fluid
What value is resting potential
-70mV
How many sodium’s and potassium’s does the sodium potassium pump transport
3 sodium’s out for every 2 potassium’s in
What happens during the initial phase of depolarisation
Resting potential to +40mV as vaultage gated sodium channels open
What happens during repolarisation
Charge returns to resting potential as sodium channels close and potassium channels open and potassium moves out
What happens during hyperpolarisation
Slowly recovering overshoot of resting potential by sodium potassium pump
How long from stimulus to AP
How long from Stimulus to resting state
Less than 1ms
5ms
What effect does pulpal inflammation have on neurones
Increases excitability of primary afferent neurones
Increases sodium ion channels
What are the teeth fibre types and what do the detect
3
A beta fibres - sharp pain
A delta fibres - sharp pain
C fibres - dull pain
Compare size and mylination of the teeth fibre types
A beta
5-12 micrometers, myelinated
A delta
2-5 micrometers, mylinated
C fibres
0.3-1.2 micrometers, unmyelinated
What is the clinical name of local anaesthetic used by dentists and how does it act
Lidocaine
Inhibits influx of sodium ions through voltage gated sodium ion channels so AP not generated and propagation inhibited
What is the granular layer of tomes
A narrow layer of granular/inter globular unmineralised dentine found in root dentine Adjacent to cementum
What is the mineral inorganic component of dentine
Hydroxyapatite
What does the organic matrix component of dentine consist of
2
Collagen- primarily type 1
Non collagenous proteins
What is the cellular component of dentine
Odontoblasts
What is predentine
How thick is it
Where is it thickest
An unmineralised layer of dentine containing collagen, glycoproteins and proteoglycans which is 10-50 micrometers thick
Thickest where dentinogenisis occurring
What percentage mineralised is dentine
70%
How thick are dentine tubules from pulp to amelodentine junction
2.5 to 0.9 micrometers
What are lines of Owen
Changes in colour of dentine representing changes in mineralisation through development of tooth
What type of tissue is pulp
Soft connective tissue
What are odontoblasts joined by
Gap junctions
What are dentine tubules lined by
An organic sheath Called lamina limitans
What are the components of dentines organic matrix
4
Collagen
Non collagenous proteins
Lipids
Proteoglycans
What percentage of dentines organic matrix is collagen, what type
90% type 1 primarily
What percentage of dentines organic matrix is non collagenous proteins
Give examples of non collagenous proteins in dentine
2
10%
Dentine phosphoprotein
Dentine sialoprotein
What is the difference between hydroxyapatite Cristals found in dentine and enamel
Crystals smaller in dentine and found on and between collagen fibrils of organic matrix rather than in prisms
What are the pulp zones moving inward
4
Odontoblast zone
Cell free zone of Weil
Cell rich zone
Pulp core
What is pulp composed of with percentages
3
75% water
25% organic matrix
1% inorganic material
What is in the organic matrix of pulp
3
Collagen type 1 and 3 Fibronectin Ground substance (proteoglycans and glycosaminoclycans)
What are the most common pulp cells
Where are they located
What is their function
Fibroblasts
Found in cell rich zone of coronal portion
Form and maintain pulp matrix and synthesise cytokines
How does blood enter pulp
Apical foremen
Where do arteries terminate in pulp
Sub odontoblastic capillary plexus in cell free zone
Where are cell bodies of pulp neurones located and where do pulp neurones terminate
Trigeminal ganglion
Dorsal horn of medulla
What to branching afferent axons of pulp form and where is this structure located
Branching afferent axons form subodontoblastic plexus of Roshkow in cell free zone
What percentage of axons terminate in coronal and radicular pulp
90% terminate in coronal pulp
10% terminate in radicular pulp
What percentage of nerve fibres in pulp are A delta, A beta and c fibres
A delta = 22%
A beta = 4%
C fibres = 75%
What makes up the gingival attachment appuratus
3
Cementum
Periodontal ligament
Alveolar bone
What is the appearance of bundle bone and what is it capable of
Linear appearance
Capable of turning over and remodelling
What are the functions of periodontal ligament
4
Support
Remideling
Sensory
Nutritive
What are the types of cementum and where are they located
4
Acellular located at cervical 1/3
Cellular located at apical1/3 and furcations
Mixed found at apical 1/3 and furcations
Acellular afibrillar found close to CEJ
What fibre type is acellular cementum and what is it’s function
Extrinsic
Anchorage
What fibre type is cellular cementum and what is it’s function
Intrinsic
Functional adaptation and repair
What fibre type is mixed cementum and what is it’s role
Extrinsic and intrinsic
Functional adaptation
What is the role of acellular afibrillar cementum
Unknown
What are the canals of cellular cementum cementocytes called
Canuliculi
What is the role of canuliculi and what direction do they face
Canals for nutrients to cementum, point towards periodontal ligament
What are the three forms of cemento enamel junction and what are their prevalancies
Gap - 5-10%
Edge to edge- 30%
Overlap- 60-65%
What is a gap CEJ linked to
Hypersensitivity
Where do the inner and outer cortical plates of alveolar bone face
Inner cortical plates face tongue
Outer cortical plates face cheek
What is the central spongiosa of alveolar bone filled with
Yellow marrow
What structure line’s alveolus
Bundle bone
Where is periodontal ligament thinnest
Middle 1/3 of root
What fibres run through periodontal ligament from cementum to alveolar bone, what direction do they run
Collagen fibres run transversely
What fibres run perpendicularly to collagen fibres along periodontal ligament
Oxytalan elastin fibres
What components make up the organic matrix of periodontal ligament
4
Collagen- primarily type 1
Proteoglycans
Glycoproteins
Oxytalan elastic fibres
What are the names of the types of sharpeys fibres
5
Alveolar crest fibres Horizontal fibres Oblique fibres Peri apical fibres Inter radicular fibres
What is the path of blood supply to periodontal ligament
Origionates from
Periodontium, alveolus, adjacent periosteum
Blood passes in coronal direction
Vessels terminate in
Dento gingival plexus, sub capillary loops
Which lymph nodes does lymph from periodontal ligament drain into
2
Where do these drain
Sub mental lymph nodes
Submandibular lymph nodes
Deep cervical chain of lymph nodes
What dental cement is composed of zinc oxide and polyacrylic acid
Zinc polycarboxylate cement
Which dental cement is composed of polyacrylic acid and allumino silicate glass
Glass ionomer cement
What dental cement is composed of phosphoric acid and alumino silicate glass
Silicate cement
What dental cement is composed of zinc oxide and phosphoric acid
Zinc phosphate
What is in the liquid component of glass ionomer cement
3
Polyacrylic acid
Tartic acid
Water
What is in the powder component of glass ionomer cement
Aluminium fluorosilicate glass particles
What is the role of polyacrylic acid in glass ionomer cement
2
Decrease viscosity
Reduce gelato on
What is the role of tartic acid in glass ionomer cement
5
Increases working time Increases translucency Improves handling Decreases viscosity Lengthens shelf life
What are the uses of glass ionomer cement
Temporary restorations Paediatric restoration Lining Base Luting
What are the three phases of the acid base setting reaction of GIC
Dissolution- silica gel ring on aluminium fluorosilicate particles breaks down and ions released from glass
Gelation- cross linking of polyacrylic acid molecules due to presence of calcium ions
Hardening- cross linking of polyacrylic acid molecules due to presence of aluminium ions
What are the advantages of GIC
8
Versitile
Aesthetically pleasing
Anticariogenic A’s has fluoride release
Can bond chemically and directly to enamel and dentine
Radiopaque
Compatible with other materials
Biocompatible as polyacrylic acid can’t penetrate into dentine tubules
Adhesive strength greater than cohesive strength
What are the disadvantages of GIC
6
Limited working time Long setting time Prone to wear Early water soulubility Mild pulpal toxicity Can crack
What is the liquid component of RMGIC
3
Polyacrylic acid
Hydroxyethymethacrylate resin HEMA
Water
What is the solid component of RMGIC
Fluoroaluminosilicate glass particles
What are the advantages of RMGIC over GIC
4
Stronger
Stronger bonding strength
Longer working time
Shorter setting time
What are compomers composed of
5
Fluoroaluminosilicate glass Dimethacrylate monomer Photoinitiator Special resin containing carboxyl groups Hydrophilic monomer
What is the setting reaction of compomers
2 phases
Phase 1
Polymerisation forms 3D network of acid copolymer
Phase 2
Water uptake initiates acid base reaction between carboxyl group on copolymer and acid souluble glass, leading to fluoride release
What are the uses for compomers
3
Linings
Bases
Permanent and temporary restoration
Properties of compomer
4
Anticariogenic due to fluoride release
Can’t bond chemically to enamel or dentine
Polymerisation shrinkage
Worse mechanical properties than composite but better than GICs and RMGIC
