NURS 150 PHYSIOLOGY QUESTIONS
AND VERIFIED ANSWERS
Role of pharynx in digestion - ANSWER-muscular propulsion of materials into the esophagus
Two roles of stomach in digestion - ANSWER-Chemical digestion via acid and enzymes, mechanical
digestion via muscular contractions
Role of small intestine - ANSWER-enzymatic digestion and absorption of water, organic substrates,
vitamins, and ions
Role of large intestine - ANSWER-Absorption of remaining water and nutrients, compact indigestible
materials in preparation for elimination
The rhythmic contractions of visceral muscles in the digestive tract are controlled by: - ANSWER-
Pacesetter cells
What is peristalsis? - ANSWER-wave-like muscle contractions that propel bolus along tract.
Circular muscles behind bolus contract, circular muscles ahead of bolus relax, longitudinal muscles ahead
of bolus contract to shorten adjacent segments
What is segmentation? - ANSWER-Cycles of contraction that churn the bolus (no set pattern)
3 types of factors that regulate digestive functions - ANSWER-Local, neural, and hormonal
Local factors that regulate digestive functions - ANSWER-pH, volume or chemical composition of
intestinal contents
stretching of intestinal wall
3 neural mechanisms that regulate digestive functions - ANSWER-1. Visceral motor neurons
2. Short (local) reflexes
3. Long reflexes
What kind of neurons control smooth muscle contraction and glandular secretion of the digestive
system? - ANSWER-Parasympathetic, visceral motor neurons located in the myenteric plexus
What kind of reflexes control small segments of the digestive tract? How do they relate to the CNS? -
ANSWER-Short (local) reflexes / Myenteric Reflexes. Completely outside of CNS control
What triggers short / myenteric reflexes? - ANSWER-Stretch receptors or chemoreceptors in the wall of
the digestive tract
What kind of reflexes stimulate large-scale peristalsis? How do they relate to the CNS? - ANSWER-Long
reflexes. Involve interneurons and motor neurons in CNS, may involve motor neurons from cranial nerves
that synapse in myenteric plexus
Enteroendrocine cells in the digestive tract produce: - ANSWER-Peptide hormones that regulate
digestion by enhancing or diminishing the sensitivity of smooth muscle cells to neural commands
4 functions of oral cavity - ANSWER-1. Sensory analysis of food
2. Mechanical digestion
3. Lubrication (mixing with mucus and saliva)
4. Limited chemical digestion of carbs and lipids
, What does the tongue secrete - ANSWER-Mucins and lingual lipase
Three salivary glands - ANSWER-parotid, submandibular, sublingual
What is secreted in large amounts by the parotid glands to help break down starches? - ANSWER-Salivary
amylase
What is secreted by the sublingual glands? - ANSWER-Mucus that acts as a buffer and a lubricant
What is secreted by the submandibular glands? - ANSWER-Mixture of buffers, mucins, and salivary
amylase
function of salivary amylase - ANSWER-initiate digestion of complex carbohydrates
Saliva helps keep the mouth's pH near: - ANSWER-7.0
What substances in saliva help limit bacterial growth? - ANSWER-IgA and lysozyme
True or false: salivary glands have both sympathetic and parasympathetic innervation - ANSWER-True
_________ stimulation accelerates secretion by all salivary glands - ANSWER-Parasympathetic
Parasympathetic efferent neurons that innervate salivary glands originate in the: - ANSWER-superior and
inferior salivatory nuclei of the medulla oblongata
What stimulates the parasympathetic innervation of the salivary glands? - ANSWER-Any object in the
mouth, other brainstem nuclei, and activities of higher centres (eg: thinking about food)
True or false: irritation in any part of the digestive tract and nausea slow down salivary production -
ANSWER-False: speeds it up
The esophagus enters the abdominopelvic cavity via the: - ANSWER-Esophageal hiatus (opening in the
diaphragm)
Resting muscle tone in circular muscle of esophagus - ANSWER-Prevents air from entering esophagus
(upper sphincter)
Prevents backflow of stomach contents (lower sphincter)
The esophagus is innervated by: - ANSWER-Parasympathetic and sympathetic fibres from the esophageal
plexus
How is the swallowing reflex initiated? - ANSWER-Tactile receptors on palatal arches and uvula are
stimulated by bolus, information relayed to swallowing center of medulla oblongata
Three phases of the swallowing reflex - ANSWER-Buccal
Pharyngeal
Esophogeal
Buccal phase of swallowing (3 aspects) - ANSWER-1. compression of bolus against hard palate
2. tongue forces bolus into oropharynx
3. soft palate lifts and seals off nasopharynx
Pharyngeal phase of swallowing (2 aspects) - ANSWER-1. Bolus comes into contact with back of pharynx
2. Larynx lifts and epiglottis folds over glottis
esophogeal phase of swallowing - ANSWER-1. Pharyngeal muscles force bolus through entrance to
esophagus
2. Esophagus pushes bolus towards stomach with peristaltic wave
AND VERIFIED ANSWERS
Role of pharynx in digestion - ANSWER-muscular propulsion of materials into the esophagus
Two roles of stomach in digestion - ANSWER-Chemical digestion via acid and enzymes, mechanical
digestion via muscular contractions
Role of small intestine - ANSWER-enzymatic digestion and absorption of water, organic substrates,
vitamins, and ions
Role of large intestine - ANSWER-Absorption of remaining water and nutrients, compact indigestible
materials in preparation for elimination
The rhythmic contractions of visceral muscles in the digestive tract are controlled by: - ANSWER-
Pacesetter cells
What is peristalsis? - ANSWER-wave-like muscle contractions that propel bolus along tract.
Circular muscles behind bolus contract, circular muscles ahead of bolus relax, longitudinal muscles ahead
of bolus contract to shorten adjacent segments
What is segmentation? - ANSWER-Cycles of contraction that churn the bolus (no set pattern)
3 types of factors that regulate digestive functions - ANSWER-Local, neural, and hormonal
Local factors that regulate digestive functions - ANSWER-pH, volume or chemical composition of
intestinal contents
stretching of intestinal wall
3 neural mechanisms that regulate digestive functions - ANSWER-1. Visceral motor neurons
2. Short (local) reflexes
3. Long reflexes
What kind of neurons control smooth muscle contraction and glandular secretion of the digestive
system? - ANSWER-Parasympathetic, visceral motor neurons located in the myenteric plexus
What kind of reflexes control small segments of the digestive tract? How do they relate to the CNS? -
ANSWER-Short (local) reflexes / Myenteric Reflexes. Completely outside of CNS control
What triggers short / myenteric reflexes? - ANSWER-Stretch receptors or chemoreceptors in the wall of
the digestive tract
What kind of reflexes stimulate large-scale peristalsis? How do they relate to the CNS? - ANSWER-Long
reflexes. Involve interneurons and motor neurons in CNS, may involve motor neurons from cranial nerves
that synapse in myenteric plexus
Enteroendrocine cells in the digestive tract produce: - ANSWER-Peptide hormones that regulate
digestion by enhancing or diminishing the sensitivity of smooth muscle cells to neural commands
4 functions of oral cavity - ANSWER-1. Sensory analysis of food
2. Mechanical digestion
3. Lubrication (mixing with mucus and saliva)
4. Limited chemical digestion of carbs and lipids
, What does the tongue secrete - ANSWER-Mucins and lingual lipase
Three salivary glands - ANSWER-parotid, submandibular, sublingual
What is secreted in large amounts by the parotid glands to help break down starches? - ANSWER-Salivary
amylase
What is secreted by the sublingual glands? - ANSWER-Mucus that acts as a buffer and a lubricant
What is secreted by the submandibular glands? - ANSWER-Mixture of buffers, mucins, and salivary
amylase
function of salivary amylase - ANSWER-initiate digestion of complex carbohydrates
Saliva helps keep the mouth's pH near: - ANSWER-7.0
What substances in saliva help limit bacterial growth? - ANSWER-IgA and lysozyme
True or false: salivary glands have both sympathetic and parasympathetic innervation - ANSWER-True
_________ stimulation accelerates secretion by all salivary glands - ANSWER-Parasympathetic
Parasympathetic efferent neurons that innervate salivary glands originate in the: - ANSWER-superior and
inferior salivatory nuclei of the medulla oblongata
What stimulates the parasympathetic innervation of the salivary glands? - ANSWER-Any object in the
mouth, other brainstem nuclei, and activities of higher centres (eg: thinking about food)
True or false: irritation in any part of the digestive tract and nausea slow down salivary production -
ANSWER-False: speeds it up
The esophagus enters the abdominopelvic cavity via the: - ANSWER-Esophageal hiatus (opening in the
diaphragm)
Resting muscle tone in circular muscle of esophagus - ANSWER-Prevents air from entering esophagus
(upper sphincter)
Prevents backflow of stomach contents (lower sphincter)
The esophagus is innervated by: - ANSWER-Parasympathetic and sympathetic fibres from the esophageal
plexus
How is the swallowing reflex initiated? - ANSWER-Tactile receptors on palatal arches and uvula are
stimulated by bolus, information relayed to swallowing center of medulla oblongata
Three phases of the swallowing reflex - ANSWER-Buccal
Pharyngeal
Esophogeal
Buccal phase of swallowing (3 aspects) - ANSWER-1. compression of bolus against hard palate
2. tongue forces bolus into oropharynx
3. soft palate lifts and seals off nasopharynx
Pharyngeal phase of swallowing (2 aspects) - ANSWER-1. Bolus comes into contact with back of pharynx
2. Larynx lifts and epiglottis folds over glottis
esophogeal phase of swallowing - ANSWER-1. Pharyngeal muscles force bolus through entrance to
esophagus
2. Esophagus pushes bolus towards stomach with peristaltic wave
