Wk 4- Gastrointestinal Tract

The gastrointestinal tract runs from the ? to the ? The function of gastrointestinal organs~ Mechanical and ? digestion A? of food and n?

Key structures of the GI tract: M? Oral cavity P? O? S? * key organ Small ? * key organ Large ?

Histology of the GI tract: What are the 4 layers? • M? • S? M? • M? Externa • S?

Mucosa: ? most layer Moist due to ? secretions Made up of ~ Surface Ep? Lamina ? ? Muscle : muscularis mucosa

Sub mucosa: Dense irregular connective tissue Vascularisation N? supply L? (Sub mucosal gland)!

Muscularis Externa: C? muscle L? muscle : opposing axis= pinch and contract) Food movement = p? (mixing wave in stomach part of a? Nervous system)

Serosa: ? Layer Thin connective tissue surrounds tract Anchors tract to a? wall

Oesophagus: Carries food and liquid from mouth to stomach. Hollow tube M? and s? m? tightly scrunched = allows for expand and ? Oesophageal glands of sub mucosa secrete m?

Stomach: What are the 4 regions? 1. C? Close to the heart 2. F? sits rear diaphragm 3. B? Main part and largest size , secrets digestive e? and a? 4. P? 3 parts P Antrum : continues from body P canal : region next to duodenum P sphincter : regulates c? into duodenum

Stomach functions: What are the 4 functions? • S? ingested food • M? breakdown • B? breakdown • Production of in? factor = vitamin b12 a?

Stomach muscles : Specific muscle types for different regions Outer= l? Middle = c? Inner= o? Muscle on a different axis allowed for contraction and digestion

Stomach: alkaline mucous protects stomach lining 2 secretory cells • Parietal = ? Ph secretes hydrochloric acid and in? F? • Chief= secretes pep? the precursor to pep? (Pep? is activated by an increase in ph acid)

Small intestine: Main organ of nutrient a? = -0% 3 segments of intestine are~ 1. D? 2. J? 3. I? Small intestine receives ? first , ^ acidic environment

Small intestine: Area of most nutrient absorption = need for large s? a? Modes of increasing SA~ Plicae= internal lining Intestinal vili= cover mucosa in m? v? Increases the sa by -00 times. = absorption process more efficient ? Acids and proteins absorb into blood transport to liver and lymph. Lacteals = allows for larger l? molecules in and absorption

Small intestine: Duodenum= receives ? first , digestive enzymes and secretions Jejunum= most ? digestion and n? ? here Ileum= last part of small intestine. Illocecal valve (sphincter muscle) flows into l? in?

Large intestine: Runs from the ileum to anus. 3 main parts ~ 1. C? Starts process of compaction 2. C? Allows expansion, travels up across down motion. 3. R? Undirected material left , connects to anus