The Mouth and Oesophagus Flashcards
What are the three phases of swallowing?
- Oral Phase
- Pharyngeal Phase
- Oesophageal phase
What is the role of the Oral Phase in swallowing and is it voluntary or reflexive?
- Preparation of the bolus and transportation of the bolus into the pharynx
- Tongue pressed against hard pallet to push bolus towards pharynx
- Voluntary
What is the role of the Pharyngeal Phase in swallowing and is it voluntary or reflexive?
- transport of bolus through the upper oesophageal sphincter into the oesophagus
- reflexive
What is the role of the Oesophageal Phase in swallowing and is it voluntary or reflexive?
- transport through the lower oesophageal sphincter
- reflexive
Fuction of the mouth
-mastication
- chemical digestion
-lubrication of food bolus
What is the role of longitudinal muscle in the oesophagus?
Oesophageal shortening increases density of muscle fibres above the food bolus, causing stronger contraction above that area.
This mechanism aids in propelling the food bolus down the oesophagus.
What type of muscle is found in the top 1/3 of the oesophagus?
Striated muscle
This part of the oesophagus is responsible for voluntary control during swallowing.
What type of muscle is found in the middle 1/3 of the oesophagus?
Mixed muscle (transition zone)
This zone contains both striated and smooth muscle, transitioning between voluntary and involuntary control.
What type of muscle is found in the bottom 1/3 of the oesophagus?
Smooth muscle
This section is primarily responsible for involuntary movements and peristalsis.
What is the function of circular muscle in the oesophagus?
Propulsive peristaltic contractions
These contractions help move the food bolus down the oesophagus.
What type of epithelium is found in the oesophagus?
Squamous Epithelium
This type of epithelium provides protection against mechanical and chemical injury.
What are the two types of mouth secretions?
Serous secretions and mucus secretion
Serous secretions are enzyme-rich, while mucus secretion lubricates food and protects the GI tract lining.
What is the function of salivary amylase?
Responsible for starch digestion
Salivary amylase is an enzyme found in serous secretions.
What is the role of lysozyme in mouth secretions?
Bactericidal
Lysozyme helps to kill bacteria in the mouth.
What do mucins mix with to create mucus?
Water
Mucins are glycoproteins that when mixed with water form mucus.
What is the primary function of mucus in the gastrointestinal tract?
Lubricates food and protects GI tract lining
Mucus plays a crucial role in facilitating the passage of food and protecting the lining from damage.
Which glands are responsible for secreting enzymes and mucins?
Submandibular and submaxillary glands
These glands play a significant role in the digestive process.
What do sublingual glands primarily secrete?
Mucins (mucus)
Sublingual glands contribute to lubrication in the mouth.
What type of glands are the parotid glands, and what do they produce?
Serous glands that produce enzymes
Parotid glands are the largest salivary glands, primarily secreting enzyme-rich fluid.
What nervous system mediates swallowing?
Parasympathetic
How is the central nervous system involved in swalling
Involved during fight or flight to divert blood away from GIT
What triggers the Pharyngeal Phase?
Contact with tonsillar pillars and pharyngeal wall
How long does the Pharyngeal Phase last?
1 second to complete
Which areas of the nervous system are involved in the Pharyngeal Phase?
High cortical centres, brain stem and cranial nerves
