
<ul>
  <li>Presynaptic neurotransmitter release</li>
  <ul>
    <li>Occurs via exocytosis</li>
    <li>Controlled by calcium influx</li>
    <li>Quantal&nbsp;</li>
  </ul>
  <li>
    Post-synaptic potentials spread through muscle via the transverse tubular system, an extension
    of the sarcolemma
  </li>
  <ul>
    <li>Acetylcholine binds to postsynaptic receptors on the motor end-plate</li>
    <li>This triggers sodium ion influx producing a depolarisation.</li>
    <ul>
      <li>
        An excitatory action potential is produced when a threshold is reached and sodium channels
        are activated bringing about a massive influx of sodium ions
      </li>
      <li>
        The density of sodium channels is highest at the initial segment of the axon (the
        &ldquo;axon hillock&rdquo; of motor neurones or the first node of Ranvier for myelinated
        sensory neurones).
      </li>
      <li>
        The membrane potential reaches positive values, reaching a threshold triggering an action
        potential
      </li>
      <li>
        Repolarisation later occurs due to a decrease in sodium conductance and slow increase in
        potassium conductance allowing potassium to leave the cell
      </li>
    </ul>
    <li>
      The tubular system is a continuation of the sarcoplasmic reticulum and is a calcium ion
      reservoir
    </li>
    <li>
      Action potential stimulates calcium release from this tubular system by opening DHP receptors
    </li>
    <li>Calcium binds to troponin C associated with tropomyosin on the actin filament.&nbsp;</li>
    <ul>
      <li>A conformational change occurs to displace tropomyosin</li>
    </ul>
    <li>The displacement of tropomyosin frees the myosin binding sites in the actin grooves</li>
    <li>The myosin can combine with actin to form &ldquo;cross-bridges&rdquo;</li>
    <li>
      Myosin magnesium-dependent ATPase generates energy which effects the movement of the myosin
      heads and muscle contraction
    </li>
    <li>Calcium accumulates back in the SR via the action of ATPase</li>
  </ul>
</ul>
<ul>
  <li>Striated muscle (and cardiac muscle): organised into units called sarcomeres</li>
  <ul>
    <li>The region where two Z lines overlap</li>
  </ul>
  <li>A band: overlapping myosin and actin</li>
  <li>H band: myosin only</li>
  <li>Skeletal muscle does not require an intrinsic pacemaker like cardiac muscle</li>
  <li>Resting membrane potential is about -90mV: potassium contributes most to this</li>
  <li>Muscle spindles</li>
  <ul>
    <li>Intrafusal fibres</li>
    <li>Innervated by type Ia, type II and gamma fibres</li>
    <li>Respond to rate of change in muscle length</li>
  </ul>
  <li>Action potential length</li>
  <ul>
    <li>Cardiac: 200ms</li>
    <li>Smooth: 50ms</li>
    <li>Striated/skeletal: 10ms</li>
  </ul>
</ul>


Physiology

Muscle Physiology

Intro

FRCOphth Part 1 Study Notes

Orbit and ocular adnexae

Orbit

Extraocular Muscles

Orbital Blood Vessels

Paranasal Sinuses

Lacrimal Glands

Tear Film

Eyelids

Blinking

Anterior segment - ocular surface

Conjunctiva

Conjunctivitis

Sclera

Cornea

Corneal Structure And Development

Corneal Physiology

AC to Lens

Angle

Ciliary Body

Aqueous Humour Dynamics

Iris

Pupil

Lens

Posterior segment

Choroid

Vitreous

Retinal Macrostructure

Neurosensory Retina

Retinal Pigment Epithelium

Neuroanatomy

Venous Sinuses

Cerebral Ventricles

Cerebral Blood Supply

Supranuclear Gaze Pathways

Head And Neck Autonomic Nervous Supply

Head And Neck Glands

Osteology

Nerves

Muscles And Pharyngeal Arches

Extraocular Nerves

Sensory Nerves

Physics Of Blood Flow

Neuronal Control Of Blood Vessels

Oxygen-Haemoglobin Dissociation Curve

Cytochrome p450

Pituitary Gland

Thyroid Hormone Production

Insulin

Glucagon

Parathyroid Hormone

Corticosteroids

Catecholamines

Cardiac Cycle

Renal Physiology

Fluid Balance

Acid-Base Balance

Sensory Fibres

Cutaneous Receptors

Endocytosis

Glycosaminoglycans

Condensed Ocular Biochemistry

Eye Movements

Accomodation

Vision

Visual Cycle And Phototransuction

Visual Pathway

Visual Acuity

Colour Vision

Binocular Vision

Pathology

Collagen

Tissue Damage

Inflammation

Disease Entities

Wound Healing

Thrombosis / Atherosclerosis

Cell Growth

Neoplasia

Histopathology

Nystagmus

Free Radicals And Antioxidants

Immunology

Ocular Immunology

Microbiology

Viral Infections

Bacterial Infections

Fungal Infections

Protozoa

Nematodes

Antimicrobials

Genetics

Chromosomes

Mitosis

Meiosis

Genes

Polypeptide Synthesis

Histones

MicroRNA

Hardy-Weinberg Equilibrium

Mutations

Chromosome Defects

Autosomal Inheritance

X-Linked Inheritance

Mitochondrial Inheritance

Multifactorial Inheritance