Salivary Glands Overview

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Questions and Answers

What effect does high acidity (H+) in the duodenum have on the pyloric sphincter?

It causes the pyloric sphincter to relax.

It has no effect on the pyloric sphincter.

It opens the pyloric sphincter.

It closes the pyloric sphincter. (correct)

Which of the following factors slows gastric emptying?

Increased liquid volume

Particle size less than 1mm

High caloric content (correct)

Low pH levels (correct)

How do solid foods compare to liquids in terms of gastric emptying?

Solid foods empty faster than liquids.

Solid foods have a lag phase that slows down emptying. (correct)

Both solid and liquid foods empty at the same rate.

Liquids always have a lag phase.

What is the consequence of stimulating the duodenum electrically?

Contraction of the pyloric sphincter. Signup and view all the answers

Which combination of factors would result in the slowest gastric emptying?

High caloric content, liquid food, acidic pH Signup and view all the answers

What initiates voluntary control during the swallowing process?

Tongue pressing the bolus against the roof of the mouth Signup and view all the answers

Which phase of swallowing primarily involves the contraction of the pharyngeal constrictors?

Pharyngeal phase Signup and view all the answers

What mechanism helps prevent reflux after a swallow occurs?

Upper esophageal sphincter closure Signup and view all the answers

Which of the following muscles is predominantly involved in the esophageal phase of swallowing?

Smooth muscles of the lower esophagus Signup and view all the answers

What is the primary role of the lower esophageal sphincter (LES)?

Regulating gastric reflux Signup and view all the answers

During which action does the tone of the LES increase due to diaphragm contraction?

Inspiration Signup and view all the answers

What is a common consequence of transient LES relaxation (TLESR)?

Increased risk of gastroesophageal reflux Signup and view all the answers

What triggers the brainstem's swallowing center to activate during the oral phase?

Pressure from the bolus against the roof of the mouth Signup and view all the answers

What is the role of saliva in neutralizing reflux in the esophagus?

Neutralizes acidity with bicarbonate Signup and view all the answers

What condition may lead to extensive ulceration and inflammation in the esophagus?

Gastroesophageal reflux disease (GERD) Signup and view all the answers

What is the primary function of mucins in saliva?

To provide lubrication Signup and view all the answers

Which of the following glands is responsible for producing the majority of stimulated saliva?

Parotid gland Signup and view all the answers

How does the sympathetic nervous system initially affect salivary secretion?

Causes a temporary decrease in blood flow Signup and view all the answers

Which ions are at higher levels in saliva during low food stimuli compared to blood?

K+ Signup and view all the answers

What is the purpose of bicarbonate (HCO3) in saliva during a swallow?

To neutralize stomach acid Signup and view all the answers

What triggers the cephalic phase of salivary secretion?

Thinking or smelling food Signup and view all the answers

What is primarily affected by vagotomy in relation to saliva production?

Significantly decreases saliva production Signup and view all the answers

Which type of cells are responsible for modifying saliva after it is produced by acinar cells?

Duct cells Signup and view all the answers

What role do histatins serve in saliva?

Antibacterial and antifungal Signup and view all the answers

What happens to salivary flow rate when thinking about food?

It significantly increases Signup and view all the answers

Which transport mechanism moves Na+ ions from blood to acinar cells?

Paracellular transport Signup and view all the answers

Which factor negatively influences salivary production?

Acute fear Signup and view all the answers

What is the function of salivary amylase?

Digests starch Signup and view all the answers

Which of the following is NOT a common cause of transient lower esophageal sphincter relaxation (TLESR)?

Frequent burping Signup and view all the answers

What condition is characterized by a lack of peristalsis in the esophagus and a tightly closed lower esophageal sphincter?

Achalasia Signup and view all the answers

In the stomach, which area is primarily responsible for storing food?

Fundus Signup and view all the answers

What is the primary role of the pyloric sphincter?

Control the entry of chyme into the duodenum Signup and view all the answers

Which phase of the migrating motor complex (MMC) is characterized by strong rhythmic contractions?

Phase 3 Signup and view all the answers

Which factor does NOT influence the duration of gastric emptying?

Temperature of food Signup and view all the answers

What type of muscle contraction does the gastric accommodation involve?

Smooth muscle contraction Signup and view all the answers

Which of the following best describes the muscularis externa of the stomach?

Includes three layers of muscles Signup and view all the answers

During fasted motor activity, what primarily triggers the contractions in phase 3?

Motilin secretion Signup and view all the answers

What role does the vagus nerve play in the gastric accommodation process?

Mediates relaxation of the stomach Signup and view all the answers

Which of the following is a treatment for conditions affecting the lower esophageal sphincter (LES)?

Antacids like Maalox or Pepto-Bismol Signup and view all the answers

What is the primary function of the enteric nervous system in the context of the stomach?

Coordinates muscle contractions in the digestive tract Signup and view all the answers

Which condition leads to autoimmune attacks on smooth muscle, particularly affecting the latter third of the esophagus?

Scleroderma Signup and view all the answers

Study Notes

SALIVARY GLANDS

Oral cavity's job includes mechanical digestion (chewing), enzymatic/chemical digestion (salivary enzymes), and chemosensation (taste). Swallowing is also a function.
Saliva is an exocrine secretion, producing 500-600 mL per day. It contains lots of proteins, but 99% is water and 1% protein.
Saliva's functions include lubrication, solubilizing taste molecules, aiding speech, and protection.
Proteins in saliva, such as mucins, create mucus for lubrication.
Histatins and cystatins are antibacterial and antifungal proteins.
Salivary amylase digests starch, while salivary lipase/lingual lipase digests triglycerides.
Salivary immune bodies and lysozyme target bacterial walls.

GLANDS

Submandibular glands produce basal saliva, which is sticky.
Sublingual glands produce saliva in response to stimulation.
Parotid glands, with serous cells, produce 50% of stimulated saliva, which is watery and rich in ions.

AUTONOMIC N.S INPUT

PNS input produces watery saliva in large volumes.
SNS input initially results in low volume due to vasoconstriction, but increases volume later from vasodilation.

SALIVA FORMATION

Acinar cells produce unmodified saliva.
Duct cells modify saliva by adding or removing ions from the blood.
Ions in blood are regulated in the order of Na+ > Cl- > HCO3- > K+.

ACINAR CELLS PRODUCE INITIAL SALIVA

Na+ moves from blood to acinar cells via paracellular transport.
Cl- moves into the cells via a cotransporter and exits via a channel.
K+ moves into the cells via ATPase and out via a channel.
Water also crosses via a paracellular pathway.

DUCT CELLS

Remove Na+ and Cl- from saliva
Add K+
Na+ is removed into the capillary.
K+ is secreted into the lumen.
Cl- is reabsorbed via an anion exchanger.

FLOW RATE

High flow rate occurs during stimulated states (thinking, smelling, seeing food) and chewing.
Low flow rate allows saliva to be modified by duct cells.

HCO3

Saliva is isotonic (290-300 mosmol).
Bicarbonate neutralizes stomach acid reflux.

REGULATION OF SALIVARY SECRETIONS

PNS input stimulates a large volume, watery secretion with HCO3.
SNS input is biphasic, initially reducing blood flow and increasing protein production, then increasing blood flow and secretion.

PHARYNX ANATOMY

The pharynx is the throat, which food and air pass through.
It's made up of skeletal muscle structures, including constrictors.
Three parts of the pharynx are nasopharynx, oropharynx, and hypopharynx.
The pharynx moves food from the mouth to the esophagus and air to the trachea.

DURING A SWALLOW

Food is prevented from going into the trachea.
The upper esophageal sphincter (UES) is opened, allowing food to pass to the esophagus.
The UES is made of skeletal muscle and has high pressure.

ESOPHAGUS ANATOMY

The esophagus is a transit tube for food.
Its upper third is skeletal muscle, followed by mixed and then smooth muscle.

SWALLOWING PROBLEMS

Dysmotility is a lack of coordination with peristalsis.
Scleroderma and other conditions might impact smooth muscle function.
Achalasia is a condition where there is no peristalsis in the esophagus.

STOMACH

The stomach stores ingested food and uses contractions to mix food with acids.
Layers of muscle in the stomach wall contribute to digestion.

ANATOMY AND MOTOR ACTIVITY

The stomach initially accommodates food for up to an hour.
Muscle contractions occur in layers, and prior to a meal, the muscles are contractured.
When a meal is taken, swallowing prompts receptive relaxation.

FED MOTOR ACTIVITY

Peristalsis starts at the stomach top and goes toward the pyloric sphincter.
Food is propelled through the stomach due to contraction, while undigested food is pushed back.

FASTED MOTOR ACTIVITY MMC

There are three phases of contractions in the stomach when there is no food present (fasting).
Phases include quiescence, peristalsis, and rhythmic contractions.

PYLORIC SPHINCTER

The pyloric sphincter regulates food/chyme entry into the small intestine.
It has all circular muscle and significant nerve supply. It's tightly closed during most of the fed state.
Increased peristalsis pushes stuff through to the small intestine during feeding.

GASTRIC EMPTYING

Stomach empties contents during fed activity.
Liquid food empties faster in the absence of a lag phase.
Food density, volume, and other factors influence the speed of emptying.

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Description

This quiz explores the function and structure of salivary glands, including the types of saliva produced and its components. Learn about the roles of different salivary proteins and the autonomic nervous system's influence on saliva secretion. Perfect for students studying human anatomy and physiology.