Digestive Flashcards
GI tract consists of
1) Mouth
2) Pharynx
3) Oesophagus
4) Stomach
5) Small intestine
6) Large intestine
7) Anus
Accessory structure consists of
1) Tongue
2) Salivary glands
3) Spleen
4) Pancreas
5) Liver
6) Gallbladder
Small intestine subdivisions are
1) Duodenum
2) Jejunum
3) Iluem
Large intestine subdivisions are
1) Cecum
2) Ascending
3) Transverse
4) Descending
5) Sigmoid
6) Rectum
7) Anal canal
Process of ingestion
Selective intake of food and drink
Process of secretion
Secretion of water, HCL, salts, buffers, digestive enzymes
Process of propulsion
Moving food along the digestive tract form one part to the next
Digestion: Mechanical
Physical breakdown of food into smaller pieces
Digestion: Chemical
Breakdown of food by digestive enzymes – Carbohydrates → Sugars – Proteins → Amino acids – Fats → Fatty acids – Nucleic acids → Nucleotides and acids
Process of absorption
Uptake nutrients into digestive cells, blood and lymph
Process of defacation
Elimination of undigested material
Basic structure of alimentary canal (from inside to out)
1) Mucosa
2) Submucosa
3) Muscularis
4) Serosa
Mucosa functions
- Secrete mucus/digestive enzymes/hormones
- Absorb the end products of digestion to blood
- Protect against infectious disease
Submucosa functions
Regulates the movement of stomach/intestine/blood vessels vasoconstriction
Muscularis functions
Contraction moves food along the digestive tract
Serosa functions
Secretes serous fluid (Reduces friction as it moves over other organs in the abdominal cavity)
Peristalsis is
- Propulsion of food along GI tract by circular muscle layers
- Strongest in oesophagus & stomach
- Weakest in small intestine
Segmentation is
Alternating ring-like, evenly spaced / localised contractions in the small intestine
Mass peristalsis is
- Progressive, strong & vigorous peristaltic waves
* Starts in the transverse colon propel colon contents into rectum/anus
Mouth
- Ingestion (food in)
- Chewing (mastication)
- Saliva (mucous, amylase, lysozyme)
Pharynx
Swallowing (deglutition)
Oesophagus
Peristalsis
Stomach
1) Churning (mixing of food with gastric juices)
2) Secretions
• Hydrochloric Acid
• Pepsinogen
• Lipase
• Rennin
• Intrinsic Factor
• Mucus
• Hormones
Liver functions
Produces and secretes bile
Excretion: Bilirubin
Processing: The liver detoxifies certain substances and excretes drugs into bile
Metabolises: Carbohydrates, proteins and fats
Stores: Carbohydrates, fats, vitamins and minerals
Phagocytosis: The Kupffer cells of the liver phagocytise aged red & white blood cells and some bacteria
Activation of vitamin D: Synthesises the active form of vitamin D
Gallbladder
Stores and concentrates bile
Pancreas types of glands
Endocrine glands
Exocrine glands