HMI202 - Week 7 GIT

What are the types of teeth and their main function?

• Incisor: slicing through things

• Canine: puncture through things

• Premolars: basic crushing as well as some cutting

• Molars: mainly crushing and grinding

How many of each teeth type does a typical adult have?

8 incisors, 4 canines, 8 premolars and 12 molars

What does non-keratinized mean?

There is no extra layer of keratin

• this usually means that mouth will stay dry unless properly lubricated

What are the two enzymes in the mouth and what do they break down?

• Lipase: lipids

• Amylase: carbohydrates

What’s the difference between the oral cavity and the buccal cavity?

Buccal cavity is between the cheeks and teeth, whereas the oral cavity is between teeth, tongue on floor, palate on roof

There are three salivary glands on each side of the head. What are the three different salivary glands called and where are they located?

Parotid - below and front of each ear

Sublingual - floor of oral cavity under the tongue

Submandibular - below of mandible

The pharynx has 3 parts. What is the starting and finishing point of each part

• Nasopharynx: posterior nares of nasal cavity to posterior of soft palate

• Oropharynx: soft palate to epiglottis

• Laryngopharynx: epiglottis to oesophagus

What epithelium is found covering the oral, buccal cavities, as well as lining of the lumen of the pharynx and oesophagus?

Stratified squamous epithelium

what is the function of Stratified squamous epithelium?

Function is to protection against microorganisms from invading, physical abrasions and chemical damage

What is the epithelium type of the oesophagus?

Stratified squamous

What is the epithelium type of the stomach?

Simple columnar

What is the epithelium type of the duodenum?

simple columnar

What is the epithelium type of the jejunum?

Simple columnar

What is the epithelium type of the ileum?

Simple columnar

What is the epithelium type of the large intestine/ colon?

Simple columnar

What is the epithelium type of the rectum?

Simple columnar

What is the epithelium type of the anus?

Simple columnar → stratified squamous

Function of brunner’s glands?

Secrete alkaline mucosa to protect the intestinal wall of gastric acid, as well as lubricates the intestine

Function of rugae

Increased surface area of flexibility

Function of g-cells/ enteroendocrine cells

• Regulat digestion, metabolism

  • G cells: secrete gastrin

Function of haustra?

Helps to move food to the next haustra, along with mixing chyme to help water absorption

What are the two main flexures in the large intestine?

Right/ hepatic flexure

Left/ splenic flexure

Function of epiploic/ omental/ fatty appendages?

Fat reservoir

Please label

Label the coronary angiogram

Which part of the small intestine has the most plicae circularis and why?

Jejunum, because it does the most absorption

Which part of the small intestine has peyer’s patches?

ileum

What happens to the plicae circulares when it goes closer towards the caecum?

It flattens off, meaning it becomes more of a smoother tube

Where does the ileum finish at?

ileocecal valve

What is the peritoneal relationship of the cecum + appendix, and the 5 parts of the large intestine?

cecum + appendix - intraperitoneal

Ascending - retroperitoneal

Descending - intraperitoneal

Sigmoid - retroperitoneal

What are the two flexures in the large intestine?

right - hepatic flexure

Left - splenic flexure

How long is the large intestine?

1.5m

What are we absorbing in the large intestine?

Water out of the fecal matter, and water soluble vitamins

What is the omentum structures in the stomach made up of?

Peritoneal membranes, blood vessels, adipose tissue

When you have a gastric ulcer, what happens to the rugae?

Instead of travelling longitudinally, it goes towards the direction of the ulcer

What number of the L spine is the duodenum in?

L1 to L3

Label the parts of the duodenum

A & B - superior

C - descending

D - horizontal

E - ascending

What are the two flexures of the duodenum?

Superior and inferior duodenum

What is the peritoneal relationship of the duodenum?

Retroperitoneal (except first 1 - 2cm)

What is the peritoneal relationship of the ileum?

intraperitoneal

What is the peritoneal relationship of the jejunum?

intraperitoneal

What is the function of plicae circularis

Increase surface area for nutrient absorption

How to differentiate the small intestine from the large intestine

• Small intestine has plicae circularis, large intestine doesn’t

• Large intestine has a higher density of goblet cells

• Small intestine has lots of villi, large intestine lacks it

In the duodenum, why do we lose the oblique layer from the stomach and only have longitudinal and circular layers (muscular externa)?

To enable peristaltic movement to help move chyme in the small intestine

Functions of duodenum?

• neutralize acid

• mixing

• bile/ pancreatic secretions

• begins absorption

What happens to the laryngeal cartilage when you are swallowing?

It moves up

What is lamina propria?

Connective tissue that is holding onto the epithelium and connecting it to a muscular layer

What is the name of the thin layer of muscle which changes the shape of the epithelium?

Muscularis mucosa

Name for connective tissue covering the muscle

Adventitia layer

What is the type of muscle in the oesophagus?

• upper 1/3: skeletal muscle (voluntary control)

• lower 2/3: smooth muscle (no voluntary control)

Where does the oesophagus begin?

C5/C6 - upper oesphageal sphincter

Where does the oesophagus end?

• at the lower oesophageal sphincter (physiological sphincter) at t10 to t11

What an additional thing in the stomach?

Oblique muscular layer

Function of goblet cells

Creating mucus which creates a coating substance to create a bit of a barrier

What does the bottom of the gastric pit contain?

Chief cells

What is the function of chief cells?

Creates an enzyme called pepsin, which becomes activated when in contact with the acid

What is the function of G cells?

• To produce gastrin

• Gastrin helps promote the production of hydrochloric acid by parietal cells, promotes the production of pepsin by chief cells, and also promotes movement in the stomach

• Gastrin also helps to promote activity of the pancreas and the activity of the bile

Where are chief and parietal cells mostly found in?

Body and fundus of stomach

Function of rugae?

Allows stomach to expand

What is an ulcer?

Destruction of epithelium or even layers of it

Why do we need an oblique layer?

• Because circular and longitudinal muscular layer only allows for peristaltic movement

• By adding an oblique layer, it adds the extra movement to help with the breakdown

What do we surround the whole stomach with?

Serosa - thin layer of connective tissue