Digestion in the Mouth: Saliva and Salivary Glands

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What is the primary function of the parotid glands in the oral cavity?

To aid in swallowing

To secrete mucus to protect the oral mucosa

To facilitate mechanical decomposition of food

To produce saliva for chemical digestion (correct)

What is the main component of saliva?

Lysozyme

Mucus

Solutes

Water (correct)

Which of the following is NOT a function of saliva in oral digestion?

Producing lysozyme to protect the oral cavity

Facilitating swallowing

Helping to buffer acidic foods

Aiding in mechanical decomposition of food (correct)

What is the primary mechanism of control for salivary secretion?

The autonomic nervous system Signup and view all the answers

What is the correct sequence of events in the oral cavity during digestion?

Chewing, saliva secretion, swallowing Signup and view all the answers

What type of decomposition occurs during chewing?

Mechanical decomposition Signup and view all the answers

What type of receptors do postganglionic fibers interact with on the acinar and ductal cells?

Beta-adrenergic receptors Signup and view all the answers

What is the effect of beta-AR stimulation on saliva secretion?

Increases saliva secretion Signup and view all the answers

What is the purpose of lingual lipase in saliva?

Breaks down fats Signup and view all the answers

What is the end product of starch breakdown by salivary amylase?

Maltose, maltotriose, and oligosaccharides Signup and view all the answers

Why is the time available for amylase to break down starch in the mouth so short?

The food is usually swallowed quickly Signup and view all the answers

What is the effect of concurrent stimulation of alpha-AR on saliva secretion?

Decreases saliva secretion Signup and view all the answers

What is the primary function of water in saliva?

To dissolve foods for tasting and digestion Signup and view all the answers

What is the role of lysozyme in saliva?

To kill bacteria Signup and view all the answers

What is the average pH of saliva?

6.7 Signup and view all the answers

What is unique about the ionic composition of saliva compared to blood plasma?

Higher K+ and HCO3- concentrations Signup and view all the answers

What is the daily amount of saliva secreted, and how does it vary?

1 liter, varying with the type of food consumed Signup and view all the answers

What is the tonicity of saliva compared to blood plasma?

Hypotonic Signup and view all the answers

What is the primary source of signals that stimulate the secretion of saliva?

Taste buds in the tongue Signup and view all the answers

Which nerves are responsible for transmitting parasympathetic signals to the salivary glands?

Facial (VII) and glossopharyngeal (IX) nerves Signup and view all the answers

What is the effect of parasympathetic stimulation on blood flow to the salivary glands?

Increased blood flow Signup and view all the answers

Which segments of the spinal cord are associated with the origin of sympathetic nerves that innervate the salivary glands?

Th1-Th3 segments Signup and view all the answers

What is the effect of sympathetic stimulation on salivary secretion?

Decreased secretion Signup and view all the answers

What is the function of the salivary nuclei in the brain stem?

To integrate signals from taste buds Signup and view all the answers

What is the primary function of the chewing muscles?

To move the jaw Signup and view all the answers

Which cranial nerve is responsible for innervating the chewing muscles?

Vth cranial nerve Signup and view all the answers

What is the initial response of the chewing muscles when food is present in the mouth?

Reflex inhibition Signup and view all the answers

What type of reflex is initiated when the jaw drops?

Stretch reflex Signup and view all the answers

What is the role of the cerebral cortex in chewing?

It controls the voluntary component of chewing Signup and view all the answers

How many stages are involved in the swallowing process?

Three stages Signup and view all the answers