Oral and Neurophysiology Review

Comprehensive flashcards covering Oral Physiology, Neurophysiology, Cardiovascular, and Endocrine/GI topics based on the lecture transcript.

Parotid Gland

A salivary gland characterized by serous only secretion, contributing ~25% of total saliva, and rich in amylase.

Submandibular Gland

The largest volume contributor of saliva (~70%), providing mixed but predominantly serous secretion.

Sublingual Gland

The least contributor of saliva (~5%), providing mixed but predominantly mucous secretion.

Parasympathetic Stimulation (Saliva)

Nerve stimulation that results in watery, serous saliva.

Sympathetic Stimulation (Saliva)

Nerve stimulation that results in thick, viscous, mucin-rich saliva.

Secretory IgA

The primary immunoglobulin in saliva serving as a first-line mucosal defence that is protease-resistant.

Bicarbonate

The main buffer in saliva that neutralises plaque acid.

Xerostomia

A condition of reduced salivary flow caused by factors such as Sjögren's syndrome, radiotherapy, or anticholinergic drugs.

Muscles of Mastication Motor Supply

All muscles involved in chewing are supplied by the mandibular division of the trigeminal nerve (CN V3).

Jaw jerk reflex

The only purely trigeminal reflex where both the afferent and efferent limbs travel via CN V.

Pharyngeal Stage (Swallowing)

An involuntary reflex stage where the soft palate rises to close the nasopharynx and the epiglottis covers the larynx.

Swallowing Centre

The physiological control centre located in the medulla oblongata.

Chorda tympani

A branch of the facial nerve (CN VII) responsible for taste from the anterior 2/3 of the tongue.

Filiform Papillae

Papillae found across the entire dorsal tongue surface that are tactile only and do NOT contain taste buds.

$A\delta$ fibres

Myelinated nerve fibres that transmit sharp, well-localised, short duration pain associated with cold or reversible pulpitis.

C fibres

Unmyelinated nerve fibres that transmit dull, aching, poorly localised, prolonged pain associated with heat or irreversible pulpitis.

Hydrodynamic Theory (Br%%nnstr%%m)

The theory that stimuli cause rapid fluid movement within dentinal tubules, activating $A\delta$ nerve endings at the pulp-dentine junction.

Mesencephalic Nucleus

A unique nucleus where primary afferent cell bodies for PDL proprioception are located INSIDE the CNS.

Resting Membrane Potential

The value of $-70\,mV$ maintained by the $Na^+/K^+$ ATPase pump and $K^+$ leak channels.

Threshold Potential

The voltage level of $-55\,mV$ required to fire an all-or-nothing action potential.

Depolarisation

The action potential phase characterized by a rapid rise to $+30\,mV$ as $Na^+$ rushes into the cell.

Local Anaesthetics (e.g., Lidocaine)

Drugs that work by blocking voltage-gated $Na^+$ channels, preventing depolarisation and pain signal transmission.

Trigeminothalamic tract

The pathway responsible for transmitting pain and temperature sensation from the face to the cortex.

Muscle Spindle

A sensory receptor located within the muscle belly that detects muscle length and rate of stretch.

Golgi Tendon Organ (GTO)

A sensory receptor located at the muscle-tendon junction that detects muscle tension.

Gate Control Theory

A theory by Melzack & Wall suggesting that large diameter $A\beta$ fibres can inhibit pain transmission at the dorsal horn.

Phase 2 (Cardiac Action Potential)

The plateau phase caused by $Ca^{2+}$ influx via L-type channels, which prevents tetanic contraction.

SA Node

The primary pacemaker of the heart with an intrinsic rate of $60\u2013100\,bpm$.

S1 Heart Sound

The "lub" sound caused by the closure of the mitral and tricuspid valves at the start of systole.

Cardiac Output (CO) Formula

$CO = HR \times SV$; the normal value is approximately $5\,L/min$ at rest.

Frank-Starling Law

The principle that an increase in end-diastolic volume (preload) leads to an increase in stroke volume by stretching the ventricle.

Baroreceptors

Stretch receptors in the carotid sinus and aortic arch that fire less when blood pressure is low to activate the sympathetic nervous system.

Angiotensin II

A potent vasoconstrictor produced via the RAAS that also stimulates aldosterone release.

P wave

The component of an ECG that represents atrial depolarisation.

Left Anterior Descending (LAD)

The coronary artery supplying the anterior left ventricle; its occlusion is known as the "widow maker" MI.

Ductus arteriosus

A fetal structure that bypasses the lungs by connecting the pulmonary artery to the aorta; it becomes the ligamentum arteriosum after birth.

Beta (\u03b2) cells

Cells in the pancreatic Islets of Langerhans that secrete insulin to lower blood glucose.

T3 (triiodothyronine)

The active and most potent form of thyroid hormone.

Zona Glomerulosa

The outer layer of the adrenal cortex that produces aldosterone (Salt).

Zona Fasciculata

The middle layer of the adrenal cortex that produces cortisol (Sugar).

PTH (Parathyroid Hormone)

An endocrine hormone that raises serum $Ca^{2+}$ by activating osteoclasts and increasing renal reabsorption.

Calcitonin

A thyroid-derived hormone that lowers serum $Ca^{2+}$ by inhibiting osteoclasts.

Acromegaly

A condition of excessive growth hormone in adults resulting in mandibular prognathism, macroglossia, and tooth spacing.

Parietal Cells

Gastric cells that secrete hydrochloric acid ($HCl$) and Intrinsic Factor.

Secretin

A GI hormone triggered by acid in the duodenum that stimulates pancreatic bicarbonate release.

Cholecystokinin (CCK)

A GI hormone triggered by fat and protein that stimulates gallbladder contraction and pancreatic enzyme release.

Terminal Ileum

The specific site in the small intestine where Vitamin B12 and bile salts are absorbed.