

## Thyroid gland
<ul>
  <li>Two symmetrical lobes connected by isthmus</li>
  <li>Contained within pretracheal fascia</li>
  <li>Sit in front of the second, third and fourth tracheal rings</li>
  <li>Development</li>
  <ul>
    <li>Begins on the floor of the early pharynx</li>
    <li>Descends to its adult position</li>
    <li>Thyroglossal duct develops from the foramen caecum of the tongue</li>
    <ul>
      <li>Descends between the first and second pharyngeal arches to the opening of the trachea</li>
    </ul>
  </ul>
</ul>
<ClinicalCorrelate>
  <p>Remnants may produce cysts anywhere along the course of the duct</p>
</ClinicalCorrelate>
<ul>
  <li>Arterial supply</li>
  <ul>
    <li>Superior thyroid artery (branch of the external carotid)</li>
    <li>Inferior thyroid artery (branch of the thyrocervical trunk from the subclavian)</li>
    <li>Thyroidea ima artery (present in only 3% people)</li>
  </ul>
  <li>Venous drainage</li>
  <ul>
    <li>Superior thyroid vein (enters internal jugular or facial vein)</li>
    <li>Middle thyroid (enters internal jugular)</li>
    <li>Inferior thyroid (forms a plexus draining into the left brachiocephalic vein)</li>
  </ul>
  <li>
    The recurrent laryngeal nerve is closely associated with the inferior thyroid artery and passes
    behind the middle part of the glands lobes to enter the larynx
  </li>
  <li>The external laryngeal nerve runs alongside the superior thyroid artery</li>
  <li>The thyroid moves upwards with the larynx on swallowing</li>
</ul>

## Submandibular gland
<ul>
  <li>Mixed mucous and serous gland</li>
  <li>Large superficial and small deep parts</li>
  <li>Embryology: develops as a tubular endodermal outgrowth from the floor of the mouth</li>
  <li>
    Submandibular duct emerges from the superficial part and runs between the mylohyoid and the
    hyoglossus (which is overlies)
  </li>
  <ul>
    <li>Opens into the floor of the mouth beside the frenulum</li>
  </ul>
  <li>Related to the facial artery antero-superiorly</li>
  <li>
    Parasympathetic secretomotor fibres derive from the chorda tympani and synapse in the
    submandibular ganglion with postganglionic fibres which directly reach the gland
  </li>
</ul>

## Parotid gland
<ul>
  <li>Serous gland</li>
  <li>Enclosed in tough capsule derived from cervical fascia</li>
  <li>
    Located between the mastoid process, the sternomastoid, ramus of the mandible and the styloid
    process
  </li>
  <ul>
    <li>Positioned behind the temporomandibular joint</li>
  </ul>
  <li>Associated with (superficial to deep)</li>
  <ul>
    <li>Facial nerve (divides into 5 terminal branches within the gland)</li>
    <li>Retromandibular vein</li>
    <li>External carotid and its branches</li>
    <li>
      Auriculotemporal nerve (postganglionic parasympathetic fibres from the otic ganglion and
      inferior salivatory nucleus. The preganglionic fibres are from the lesser petrosal nerve of
      the glossopharyngeal)
    </li>
  </ul>
  <li>Parotid emerges anteriorly and opens opposite the second upper molar</li>
</ul>
<ClinicalCorrelate>
  <p>When enlarged/inflamed, pain is transmitted along the great auricular nerve</p>
</ClinicalCorrelate>


Thyroid gland Two symmetrical lobes connected by isthmus Contained within pretracheal fascia Sit in front of the second, third and fourth tracheal rings…

Neuroanatomy

Head And Neck Glands

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

Venous Sinuses

Cerebral Ventricles

Cerebral Blood Supply

Supranuclear Gaze Pathways

Head And Neck Autonomic Nervous Supply

Osteology

Nerves

Muscles And Pharyngeal Arches

Extraocular Nerves

Sensory Nerves

Physiology

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

Muscle Physiology

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