Gastrointestinal System Flashcards
(46 cards)
What is the gastrointestinal tract
The gastrointestinal tract is a continuous tube commencing at the oral cavity and ending at the anus.
What are the components of the Gastrointestinal tract?
The Components of the Gastrointestinal Tract:
Head: Oral Cavity, Pharynx
Neck: Pharynx, Oesophagus
Thorax: Oesophagus
Abdomen: Stomach, Small intestine, Large Intestine (most), Most accessory organs of GI tract.
Pelvis: Rectum
Perineum: Anal Canal, Anus
What are the functions of the gastrointestinal system?
The Functions of the Gastrointestinal System:
1. Introduce food into the body
2. Digest and absorb nutrients (and toxins)
3. Excrete residual waste out of the body
What are the functions of the oral cavity?
Oral Cavity:
* Sensing
* Salivation
* Chewing
* Initiating Swallowing
What are the functions of the pharynx?
- Defence against infection (tonsils)
- Swallowing
- Airway Protection
What are the functions of the Oesophagus?
Transit from Pharynx to Stomach
What are the functions of the stomach and small intestine?
Transit (movement of food and partially digested material)
Defence against infection (acid)
Digestion and absorption (accessory organs of GI tract)
The small intestine is attached to the body wall by mesentry and has three parts:
(proximal to distal)
* Duodenum
* Jejunum
* Ileum
The Jejunum and Ileum are both about 6-7m long.
What is the function of the large intestine, rectum and anus?
Transit
Reabsorption of H2O and electrolytes
Stool formation
Rectum and Anus, located at the end of large intestine:
Stool formation and storage
Waste excretion
What are the components of the oral cavity?
Hard Palate
Soft Palate
Nasal Cavity
Oral Cavity
Teeth (Dentition)
Mandible
Tongue
Hyoid Bone
Muscle of the Floor of the mouth
What is the components of the surface anatomy of the oral cavity?
Hard Palate
Soft Palate
Arches of Soft Palate
Palatine Tonsil
Uvul
Tongue
Lower Dental Arch
Gingiva
What is mastication and what is it’s characteristics?
Mastication is the act of chewing
It is conducted by the movement of the jaw and tongue, to break down food.
It is controlled by the ‘muscles of mastication’.
Also facilitates taste and digestion by mixing food with Saliva.
How does mastication occur?
Movement of opening and closing the mouth occur by muscles acting on the temporomandibular joint (TMJ) to elevate and depress the mandible.
There are four muscles at each TMJ (3 close, 1 opens the mouth)
They are:
Temporalis
Masseter
Lateral Pterygoid
Medial Pterygoid
What does TMJ stand for?
The temporomandibular joint
What muscles work to close the mouth?
The Muscles which closes the mouth:
Temporalis, Masseter and Medial Pterygoid
What muscle works to open the mouth?
The Lateral Pterygoid
What are the characteristics of the tongue?
The tongue has a posterior side and anterior side.
The posterior side consists of one third of the tongue and is the vertical part
The Anterior side consists of two thirds and is the horizontal part.
It has four different types of papillae (singular, Papilla)
Foliate Papillae
Circumvallate Papillae
Fungiform Papillae
All have taste buds
What are the features of the Filliform Papillae
Filliform Papillae exist at the tip of your tongue and are responsible for touch, temperature and pain.
What does the tongue do during mastication, speech and wallowing and what muscles does the tongue consist of?
The tongue moves around during mastication, speech and swallowing.
It consists of extrinsic muscles and intrinsic muscles.
Extrinsic refers to muscle away from the part it moves
Intrinsic refers to muscle that are contained within the part it moves
Extrinsic muscles
* Four pairs
* Attach tongue to bony skeleton
Intrinsic muscles
* Changes shape of the tongue
What characteristics does saliva have?
Saliva is 99% water, but is a solute to allow tasting to occur
Contains a lubricant (mucin) to aid swallowing and Speech and for keeping the mucosa moist
It is a buffer for plaque acids
Also contains antimicrobial elements
Amylase to begin Carbohydrate digestion
What salivary glands does the tongue have?
The tongue has major glands and Minor Glands
Major Glands:
3 Bilateral Pairs:
- Parotid (‘near ear’)
- Submandibular ‘under mandible’
- Sublingual ‘under tongue’
Minor Glands:
- 1000s in oral mucosa
- Basal secretion (background and
continuous) to keep mouth moist
What is saliva stimulated by?
- Thought, sight, smell of food or presence of food in the mouth.
- Painful oral conditions eg. teething or fractured mandible.
What is the surface anatomy of the major salivary glands? Where does it secrete into?
Parotid Gland
* Parotid duct crosses face; secretes into buccal cavity by upper 2nd molar.
Submandibular Gland
* Submandibular duct enters floor of mouth; secretes via sublingual caruncle
Sublingual Gland
* Located in floor of mouth; secretes via several ducts superiorly
What is the dashed red line in the image below and what can clogging/blockage of that feature cause?
DASHED RED LINE = DUCT
Duct clogging/blockage can cause swelling, due to back up of secretions
Where can the muscles of facial expression be found and what do they cause?
Muscles of Facial Expression:
They lie between superficial fascia and facial skeleton.
Their contraction causes skin of the face to be pulled into expressions.