Lesson 63 pt 1: Salivary function and Control

The three physiological phases of digestion are known by what names

Pregastric, gastric, and intestinal

The pregastric phase is also known by what name

Cephalic phase

What is the first step of mechanical digestion that occurs during the cephalic phase

Chewing/Mastication

What three major glands produce approximately 90% of saliva

Parotid gland, Sublingual gland, and Mandibular gland

Name two types of minor salivary glands

Buccal, labial, lingual, palatine, molar, or zygomatic

Salivary glands are classified microscopically as what type of glands

Compound (tubulo-) acinar glands

Name the three types of epithelial cells found in the secretory units (acini) of salivary glands

Mucous cells, Serous cells, and Myoepithelial cells

What two cranial nerves are responsible for the parasympathetic innervation of the salivary glands

Facial Nerve (CN VII) and Glossopharyngeal Nerve (CN IX)

What system provides sympathetic innervation to the salivary glands

Vago-sympathetic trunk

What ion do acinar serous cells actively pump into the acinar space to begin saliva secretion

Cl ions

In the formation of primary saliva, what ion follows the electrical gradient created by Cl ions

Na

In the formation of primary saliva, what follows the osmolality gradient

H2O

What is the characteristic description of primary saliva as it leaves the acini

Plasma-like and rich in NaCl

What do acinar mucous cells produce and exocytose into the acinar lumen

A mucin mixture

What process do duct cells use to actively reabsorb Na and Cl ions

Exchange against bicarbonate and K

How do duct cells ensure that water remains in the saliva, leading to hypotonicity

They are impermeable to water

Saliva reaching the mouth is characterized by what three properties regarding tonicity, K concentration, and pH

Slightly hypotonic, K-rich, and slightly alkaline (in most species)

What component makes up 99% of saliva

Water

Besides moistening and softening food, what is water's function in relation to other salivary components

It acts as a solvent for all other components, including taste molecules

What component of saliva lubricates food and aids in binding it into a bolus

Mucous

What two components of saliva act as buffers and maintain oral pH

Bicarbonate and phosphates

The buffering action of saliva helps to protect what in the oral cavity

The oral microbiome

Ruminants produce a massive amount of saliva daily to buffer what specific acidic products in the rumen

Fermentation products (acids)

How much saliva per day do ruminants, such as cattle, produce

150-200 L

What is the digestive function of electrolytes in saliva regarding tonicity

Hypotonic saliva mixes with hypertonic food resulting in normotonicity

What specific electrolyte in saliva is needed in the stomach for HCl production

K+

Which digestive enzyme is present in the saliva of omnivores, such as pigs and humans

Alpha amylase

What type of digestion does alpha amylase initiate

Carbohydrate digestion

What specific digestive enzyme is present in the saliva of neonates to begin milk fat digestion

Lingual lipase

Name two components in saliva that function as antibacterial and antifungal enzymes

Lysozymes, histatins, peroxidases, or defensins

What protective component in saliva binds iron

Lactoferrin

What three types of Immunoglobulins (antibodies) contribute to mucosal immunity in saliva

A, G, M

What component of saliva aids in tissue healing

Growth factors

What proteins in saliva, such as Statherin, keep Calcium (Ca) and Phosphorus (P) in solution

Tooth protecting proteins

What is the benefit of salivary proteins keeping Ca and P in solution

They avoid precipitation and tartar build-up (tooth protection)

What is the process used by dogs and birds for thermoregulation involving saliva

Panting

What is the process used by rodents and ruminants for thermoregulation involving saliva

Licking

Saliva plays a role in social behavior by containing what two chemical components

Pheromones and hormones

Saliva becomes hypotonic because the duct cells actively reabsorb solutes but are impermeable to what substance

Water

What kind of secretion of saliva occurs constantly, even without stimulation, to keep the oral mucosa moist

Basal secretion

What type of reflex involves the stimulation of oral taste and touch receptors transmitting signals to the medulla

Unconditioned Parasympathetic Reflex

Name one thing that stimulates the conditioned reflex leading to increased salivation

Visualizing, anticipating, smelling food, or certain sounds

What is the primary neurotransmitter involved in sympathetic stimulation that inhibits saliva flow

Norepinephrine

Sympathetic stimulation leads to vasoconstriction, resulting in what change to the volume of saliva

Decreased volume of saliva

Sympathetic stimulation causes saliva to become viscous by increasing the secretion of what substance

Mucin

What medical term refers to the condition of dry mouth

Xerostomia

Name a physiological state that causes Xerostomia due to sympathetic dominance

Fear, anxiety, or stress

Name a pathological cause of Xerostomia listed in the sources

Dehydration or Hypothyroidism

The saliva of which animal contains Draculin (an anticoagulant) and an anesthetic

Vampire bats

What unique adaptation of salivary glands do snakes possess

They are modified to produce venom

What unusual material do Asian Swiftlets use for nest building

Gelatinous saliva

Mastication is primarily what type of neurological action

A reflex action

What four structures are involved in mastication

Jaws, teeth, tongue, and muscles

What sensory stimuli are activated by food entering the mouth during mastication

Mechanoreceptors (touch, pressure)

The sensory stimuli from the mechanoreceptors are transmitted via which cranial nerve to the brain stem

Trigeminal Nerve (CN V)

What nerve stimulates the rhythmic contractions of the muscles of mastication

Trigeminal Nerve (CN V)

Name two muscles of mastication whose contractions are stimulated by the Trigeminal Nerve

Masseter, temporalis, or pterygoid

Damage to the Trigeminal Nerve can lead to what physical condition related to the jaw

Paralysis of the muscles of mastication (drop-jaw)

What organ pushes the lubricated bolus toward the pharynx to initiate the swallowing reflex

The tongue

Activation of smell, touch, and taste receptors during the cephalic phase are transmitted to what brain structure

Vagal nuclei / brain stem

What cranial nerve is activated during the cephalic phase to prepare the stomach for incoming food

Vagus Nerve (CN X)

Name two ways activation of the Vagus Nerve (CN X) prepares the stomach during the cephalic phase

Stimulates secretion of gastric fluids and increases stomach motility

The primary saliva produced by serous cells is plasma-like because its secretion is actively driven by the mechanism of what ion

Chloride (Cl)

What is the process called when the stomach starts to prepare for food based on anticipation or sensing food

Warming up

What specific physiological condition can result from a dominant sympathetic outflow to the salivary glands

Xerostomia (dry mouth)

Salivation and chewing together achieve what three preparation steps for incoming food

Preparation for swallowing, first step of mechanical digestion, and initiating some chemical digestion

Besides the oral microbiome, what specific condition does saliva help prevent on the teeth

Tartar build-up

Which branch of the autonomic nervous system is mainly responsible for greatly stimulating salivation

Parasympathetic

What is the digestive phase that occurs before the gastric phase

Pregastric phase

What is the action of grasping food called

Prehension

Besides serous and mucous cells, what other cells are part of the acini in salivary glands

Myoepithelial cells

What is the general tonicity of the saliva that reaches the mouth

Slightly hypotonic

The parotid, sublingual, and mandibular glands are classified as what type of glands

Major glands

What are the two main effects of sympathetic stimulation on the volume and viscosity of saliva

Decreased volume and increased viscosity

What type of drugs can cause Xerostomia as a side effect

Anti-cholinergic drugs

What stage of digestion involves sending signals to the stomach, accessory glands, and small intestines to prepare for incoming food

Pregastric (= Cephalic) Phase

The acinar serous cells join apically by tight and adherent junctions to form what spherical unit (from conversation history)

An acinus

What cranial nerve is NOT involved in salivation or mastication but is involved in preparing the stomach

CN X (Vagus Nerve)