Anatomy Flashcards
What structures make up the Upper GI tract?
oral cavity oropharynx laryngopharynx oesophagus stomach small intestine (duodenum, jejunum, ileum)
What structures make up the lower GI tract?
caecum appendix colon rectum (these are all large intestine) anal canal anus
How do we ensure that we get food and drink safely into and out of our stomach?
- poisons - many have a bitter taste which is detected by our taste buds
- sharp or extremely hot/cold substances - sensory receptors for pain and temperature
- bacteria/pathogens - saliva, tonsils, stomach acid
- obstructions in oesophagus - chewing, lubrication, peristalsis
- aspiration into respiratory tract - cough reflex
what function does the palate serve?
It separates the nasal cavity from the oral cavity
How many pairs of muscles of mastication are there and what are they?
4 masseter temporalis medial pterygoid lateral pterygoid
What are the three main components of the temporomandibular joints?
head of the condylar process of the mandible mandibular fossa (of the temporal bone) articular tubercle (of the temporal bone)
What type of joint are the TMJ’s?
synovial
What joint do the muscles of mastication span and what movements do they bring about?
temporomandibular joints
jaw opening and jaw closing
Describe the muscles of facial expression.
A group of skeletal muscles which attach to the bones of the face and the superficial fascia, just deep to the skin of the face.
When they contract they pull the face into expressions
What does the orbicularis oris do?
muscle of facial expression arranged circularly around the lips. Contract to pull the lips together and create an anterior oral seal to prevent drooling.
What is the name of the tonsils in the oral cavity that are commonly involved in tonsilitis?
palatine tonsils
What type of mucosa lines the mouth?
Stratified squamous epithelium which is non-keratinised apart from on the gingivae and hard palate - these are the only structures covered in keratinised stratified squamous epithelium to protect the mechanical damage by chewing.
Which part of the tongue is visible in the oral cavity?
the anterior two thirds (the posterior third is the vertical part that forms the anterior part of the pharynx)
What are the four types of papilla and what are the functions of each?
folliate, vallate and fungiform papillae are all for taste
filliform papillae are for general sensations
What are the muscles of the tongue and what do they do?
extrinsic muscles: 4 pairs - attach the tongue to the oral cavity, attach external to the tongue and insert into the tongue, move the tongue around the oral cavity during speech and mastication
intrinsic muscles: lie just deep to the mucosa of the tongue, modify shape of the tongue during function.
What is the name of the muscle of the cheek and what does it do?
Buccinator - runs from anterior to posterior
Helps the tongue to position the food bolus between the occlusal surfaces of the teeth during mastication
What should you ask the patient if you suspect a fractured mandible or maxilla and why?
“How does your bite feel?”
a fractured mandible or maxilla will change the occlusion and patients are very sensitive to changes in occlusion
What are the three major pairs of salivary glands?
parotid, submandibular and sublingual
What stimulates saliva production?
Sight, smell, thought of food or presence of food in the mouth
painful oral conditions eg fractured mandible or teething
What is the function of the minor salivary glands and where are they?
thousands in the oral mucosa - background and continuous saliva secretion to keep oral mucosa moist.
Describe the mucosa of the pharynx.
non-keratinised stratified squamous epithelium, containing tonsils
Describe the muscles in the pharynx.
Skeletal muscle that goes round the tube, but not all the way round (incomplete tube)
What is Waldeyer’s ring?
Tonsils (part of the lymphatic system) in the mucosa of the naso- and oro-pharynx which contain white blood cells and help to defend against pathogens.
What is the opening into the larynx called?
laryngeal inlet
What is the function of the uvula of the soft palate and the epiglottis?
to guide the food bolus away from the laryngeal inlet.
What are the two layers of muscles in the pharynx?
inner layer: longitudinal muscles of the pharynx - arranged vertically
outer layer: constrictor muscles of the pharynx - arranged circularly.
What is are the functions of the two layers of pharyngeal muscles?
inner longitudinal muscles: contract to shorten the length of the pharynx to reduce bolus transit time and raise the larynx to the epiglottis to cover the laryngeal inlet
outer constrictor muscles: contract sequentially to push food bolus inferiorly into the oesophagus - peristalsis
Describe the location and function of the oesophagus.
inferior continuation of the pharynx, lies posteriorly to the trachea
conduit for food and drink to the stomach
muscular tube which consists of skeletal muscle proximally which gradually changes to smooth muscle distally - muscles contract in peristalsis
lined by non-keratinised stratified squamous epithelium to protect it from mechanical damage (as opposed to chemical damage)
What are the two muscle layers of the small intestine and what do they do?
inner circular - constricts lumen
outer longitudinal - shortens the tube
these muscles are for peristalsis.
Which structure marks the end of the upper GI tract?
ileocaecal junction
What forms the roof of the pelvic cavity?
parietal peritoneum
What associations with the visceral peritoneum do the intraperitoneal, retroperitoneal and meseteric organs have.
Intraperitoneal: not in the peritoneal cavity but organ is covered with a layer of visceral peritoneum - minimally mobile
Retroperitoneal: organs are stuck to the posterior abdominal wall - only anterior surface is covered by visceral peritoneum
Mesenteric: organ is covered by visceral peritoneum and suspended from the posterior abdominal wall by a mesentery (a double layer of visceral peritoneum) - highly mobile organs
What structures are within the mesentery that pass between intestines and retroperitoneum?
arteries, veins, nerves and lymphatics
What is peritonitis?
severe, painful inflammation of the peritoneum which can be life threatening. Can be caused by blood, pus or faeces in the peritoneal cavity.
What are the organs of the foregut?
oesophagus to mid-duodenum, liver, gall bladder, spleen, half of the pancreas
What are the organs of the midgut?
mid duodenum to proximal 2 thirds of the transverse colon, half of the pancreas
What are the organs of the hindgut?
distal third of the transverse colon to the proximal half of the anal canal