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Physiology Pt. 2, Staining for myosin-ATPase - Coggle Diagram

- - - - Water, mucins, glycoproteins craete a barrier that prevents drying, irritants
      - Lubricates for speech and swallowing, and aids in the clearance of bacteria
    - - Bicarbonate, phosphate and proteins
      - pH varies 6 and 7.5
      - H2O + CO2 <-- carbonic anhydrase --> H2CO3 <--> HCO3- + H+
      - Salivary flow washes around substrate for bacteria (in Xerostomia, poor salivary flow increases substrate for bacteria and increases caries rate)
    - - Critical point for supersat is ~ pH 5.5
      - Source of Ca++ and phosphate
      - Saliva helps to buffer, push the pH above 5.5 and aid in remin, fluoride helps this as well and forms flurohydroxyapeitie
    - - IgA = ab agents, nuetralizes viruses, reduces adherence/incraeses aggregation
    - - Tastants need to be dissolved in saliva to interact with taste buds
      - Salivary amylase and lipase- breakdown of starch and Triglycerides
    - - Produces > 1L pd
      - When ECF low = RAAS stimulates a thirst response in the hypothalamus --> to drink water
    - - Saliva contains tissue factor (thromboplastin)
      - Growth factors to enhance healing
  - - - Stensons Duct
      - Serous acinii = watery, amylase
      - P/SNS Efferent CN IX
    - - Warton's Duct
      - Mixed, mainly muscous
      - P/SNS Efferent CN VII
    - - Mixed, mainly mucous
      - P/SNS efferent CN VII
    - - Afferent signals CN VII&IX (taste) and CN V (somatic) in the oral cavity are integrated in the nucleus tractus solitaris and the trigeminal nucleus and then inputs in the superior and inferior salivatory nucleus as efferents (SNS via T2/L5 SCG stimulation)
  - - - Receptor activated Na+/K+/Cl- ion channels and pumps as well as G-couple protein recerptors produce proteins/mucin
    - - reabsorbtion of Na+, Cl-, without H2O, and secretion of K+
      - Becomes Hypotonic (higher K+) as the final saliva
  - - - ADH = incraeses water reabsorbption (reduces saliva volume)
      - Aldosterone = incraeses Na+ reabsorption, H2O reabsorb (saliva volume reduced)
  - - - Increased salivation
      - Musurinic drugs (pilocarpine), Denture insertions, Oral irritations
    - - Subjective "dry mouth"
      - Hyposalivation = reduced sailvary output
      - Risks = high caries risk, candisasis, angular chelitis, dysphagia, halitosis
      - Associated with = systemic conditions (Srojerns, RA, SLE) or medications (Anticholinergics, TCAs, AntiHTNs)
- - - - A fiber contains individual myofibrils
        
        comprosing of sacromeres
        
        Thick Filamanents
        
        Myosin - have heads which bind to actin
        
        Myosin head has an actin binding had and ATPase site
        
        Thin Filaments
        
        Actin - fibers contain troponin and tropomyosin
        
        Calcium bound to troponin moves to the tropomyosin to reveal binding sites and allow for the myosin to bind, ATP is then splinted on the myosin head and the power stroke occurs, shortening the overlap and contracting the sarcomere
        
        Rate limiting step is the ATP-ase on the myosin head (determines slow vs fast twitch)
        
        Scroplasimic reticlum and T-tubles store and distibute calcium to the sacromeres
  - - - Phosphocreatinine --> ATP + creatine (2 ATP)
      - Glycogen/glucose --> Lactate + ATP (2 ATP)
    - - Glycogen/glucose --> ATP + H2O (32 ATP)
      - FFA --> ATP + H2O (138 ATP)
  - - - Staining at: pH 10 (light), ph 4.3 (dark)
      - S = Long twitch contraction, low force, low fatiguability
      - No. myosin ATPase = low, crossectional area = small
    - - Staining at: pH 10 (dark), ph 4.3 (light)
      - FF = short twitch contraction, high force, high fatiguability
      - No. myosin ATPase = high, crossectional area = large
    - - Staining at: pH 10 (dark), ph 4.3 (light), ph 4.6 (even lighter)
      - FR = short twitch contraction, intermediate force, low fatiguability
      - No. myosin ATPase = high + crossectional area = intermediate
    - - Closing Muscles
        
        high proportion of Type I (fatigue resistant)
        
        Masseter, Temporalis and Med. Pterygoid
      - Opening Mucles
        
        Lat. Pterygoid = high portion of Type 1 (fatigue resistance)
        
        Diagastrics = mixed composition of type I, IIa, IIx (this may be better for unloaded fast contractions seen in speech)
  - - - Rate coding leads to twitch summation and tetanus
  - - - Hypertrophy = seen in bruxism or cleching
      - Resistance training results in = Increased no. of fast and slow types, myofilaments, fibril no.s strength
      - Atrophy = detraining/immobilization, reduce of muslce size/types
        
        Intermaxillary fixation
    - - Myosin Heavy Chain (MyHC) = I, IIa, IIx (similar to the muscle fiber types)
      - Strength training promotes chnages from Fast types to slow (fatigue resiatnce types)
      - Disuse/atrophy promotes chnages from slow to fast twitch fibers
    - - Loss of motor nuerons = reduce in fiber numbers and activity promotes the transition from slow to fast (fatiguable) fibers
      - Edentulisim
        
        Similar to disuse atrophy = seen jaw closer muscles, from S and FR to more FF (fatiguable) fibers
- - - - External events - Fight/flight response
      - Internal events = homeostasis regulating MABP
  - - - Visceral sensory afferents
        
        Carotid and Aortic bodies (Chemo/mechano receptors) = associated with CN IX, X and XI
    - - Somatic
        
        Skeletal (somite derived) muscle
      - Autonomic
        
        SNS
        
        Short-pre & long-post synapses
        
        cell bodies T1/L2 exit on the intermediate horn becoming the White then grey communicates, ascend and synapse on the SCG for the H&N
        
        post-ganglionic N.T is noradrenaline
        
        P/SNS
        
        Long-pre, short-post
        
        From nuclei (eg. Edinger-Westphal) travels w/ occulomotor to synapse at ciliary ganglion, joins the short ciliary (CN V1) to act on the dilator puipllae muscles
        
        Post-ganglionic N.T is acetycholine
        
        Nicotinic receptors for N.T Acetylcholine (all SNS + P/SNS presynpastic N.T)
        
        Nicotinic receptors inhibited by atropine
  - - - NA > Adr > I
      - Contraction
        
        G-coupled protein receptor - IP3 --> Ca++ = activates myosin kinase
    - - I > Adr > NA
      - mb: I = isoproterenol
      - Relaxtion
        
        G-coupled p receptor - cAMP = inactive myosin kinase
    - - Heart
        
        SNS = increases HR and force of contraction
        
        P/SNS = reduced HR and force of contraction
      - Salivary Glands
        
        SNS = small vol, thick saliva
        
        P/SNS = large vol, watery saliva
    - - Only SNS ouput = Catecholamines (NA, Adr)
    - - Multi-unit
        
        smaller than MSK fibers
        
        Independant contraction (phasic)
        
        Ie. large bv, airways, ciliary muscles, piloerector m.
      - Single Unit
        
        electrically linked smooth muscle
        
        Can be self-excitable (PACE MAKER CELLS) - SA and AV nodes
      - S. Muscles - no sarcomeres, t tubles, or troponin/tropomyosin = actin, and myosin interaction occurs with Ca++ influx, and the filaments slide and contract (via myosin kinase)
      - "latch-state" actin-myosin interaction held for x8 longer per cycle (less ATP per unit of time)
  - - - Digests foodstuffs
      - Absorbs digested materials
      - Expels undigestion materials
    - - Myenteric Plexus
        
        Between the circular and longitudinal muscle layers
        
        regulates GI ,mmotility
        
        responsible for peristalsis
      - Meissner's Plexus
        
        found in submucosa
        
        secretions and local blood flow
      - Afferent nerves in both layers (muscl. and musc. mucosae)
- - - - Large portion of the motor homunculus that makes up the face, mouth, tongue
    - - Begins in the somatosensory cortex abd ends in the brainstem to control motor nuerons in the brain stem (MPM)
      - This then stimulates the ie trigeminal nucleus to create a motor programme and and efferebt signal out to the face
      - For CN V - corticobulbular is bilateral, therefore well preserved after unilateral stroke
  - - - Basic pattern is driven by the brainstem CENTRAL PATTERN GENERATOR
      - Fast close, slow close (power stroke), slow open, fast open
      - Slow closw (power) = Dual activation acts a seat belt to make sure if food breaks it does not damage the jaw while closing into opening
    - - Stretch reflex (Tendon Jerk) = maintains rest position (monosynaptic)
      - Load compensation reflex = increases bite force when load resistance is high (Hard BITE!!)
      - Protective/unloading reflex = rapid unloading results in jaw closing muscles to stop (ie biting it through a hard nut, and prevents teeth crashing together)
      - Periodontal Reflexes
        
        Di-synaptic (withdrawl reflex) = inhibits jaw closing muscles, prevnts damage to teeth
  - - - (Voluntray)
      - Bolus is formed by toubgue, and raised up to hard palate
      - Soft palate is raised by tendor veli palatini (CNV3) and levator palati (CN IX) and seals off the nasopharynx
      - teeth are brought together (seal) and support the suprahyoid muscles
      - Mylohyoid contracts and tongue propels the food backward
    - - (involuntary)
      - Iniated by receptors in the pahrynx and layrnx - and is intergrated by the medullarly swallowing centre
      - Larynx is elevated and epiglottis is tilted backward to close the glottis (seals trachea)
      - Pharyngeal-eosphagual sphinctor opens and bolus is passed down by peristalsis
      - Glottis opens, and breathing resumes
    - - (involuntary)
      - Peristaltic contractions and timed opening of sphincters (aided by pressure chnages in the diaphragm)
      - Food enters in the stomach
    - - Elicted by the mechanical stimulation of the faucal pillars, base of tongue and soft palate - mediated by CN IX, X and S.N.S
      - Can be conditioned by odours and sights associated with gaging or illness
      - Can be supressed by distraction, hypnosis, sedation and LA
      - Vomitting
        
        Forceful expulsion of gastric contents
        
        Preceded by prodromal signs (pallor, sweating, salivation)
        
        Caused by gastric distention, drugs, and gag reflexes
        
        Clinical considerations = Dehydration, alkalosis, hypokalemia, and EROSION of TEETH (seen in bulimia nervosa, binge eating, and GORD)