Digestive system Flashcards
What is the function of the digestive system?
Breakdown of larger food molecules into ones that can utilised by the body for specific functions
Name the 8 organs of the digestive system?
- Mouth
- Pharynx
- Oesophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
Name the 7 accessory organs
- Pancreas
- Teeth
- Tongue
- Gallbladder
- Digestive glands
- Salivary glands
- Liver and bilary duct
Describe the 6 processes in digestion
- Ingestion - taking food into the mouth
- Secreition - release of water, acids, buffers and enzymes
- Propulsion - the process of moving food through the GI tract
- Digestion - the process of breaking down food either mechanically or chemically
- Absorption - products are absorbed into the blood or lymph
- Elimiation - waste products leave the body
Name the structure of the digestive system (4 layers)
- Muscoa
- Innermost layer
- Produces mucus, hormones and digestive enzymes
- Protects the GI tract from continuous wear and dear and infections through acid in the tomach - Submucosa
- Thick layer of connective tissue
- Contains blood and lymph
- Helps to maintain shape - Muscularis
- Contains an inner layer of circular muscle and an outer layer of longitudinal smooth muscle
- Creates wavelike contraction and relaxtion which is responsible for peristalisis - Serosa
- Protective outer layer
What is peristalsis?
Wavelike contraction and relaxation to move food through the GI tract
What do the lips and cheeks do?
Lined with mucus secreting cells which provide protection agaisnt wear and tear
They help move and hold food in the mouth whilst the teeth grind the food
What is mastication?
Act of chewing
What does the tongue do?
Covered in papillae that contain taste buds
Glands secrete linguual lipase which digests triglycerides once in the acid environment of the stomach
Aids swalloing and holding and moving food
What does the palate do?
Plays a role in swallowing
What do the teeth to?
Mechanical digestion
They a comprised of dentin and covered in enamal
Canines are incisors are cutting and tearing teeth
Promolars and molars are used for grinding and chewing
The function is to masticate food and when mixed with saliva shape a bolus
What are the 3 salivary glands? Where are they located?
- Parotid - anterior to the ears
- Submandibular - below the jaw on either side of the face
- Sublongual - floor of the mouth
What do the salivary glands do? What does salivia do?
Parasympathetic fibres - increase secretion
Sympathetic fibres - decrease secretion
Salivary amalyse is a digestive enzyme reponsible for breaking down carbs
It helps moisten and lubricate food
Cleans and helps moisten the mouth
Has antibacterial properties
Taste is only possible when food is moist
What are the 3 parts of the pharynx?
Oropharynx
Nasopharynx
Laryngopharnx
What is the epiglotis?
Epiglotis is responsible for closing the enterence to the laynx during swallowing and prevents food entering the lungs
Draw and label the digestive system
What are the 3 stages of swallowing?
- Voluntary
Voluntary muscles move food into the oropharynx
Tongue is pressed agaisnt palate to prevent food moving forward - Pharungeal
Reflex action is inhitated
Soft palate elevates closing of the nasopharynx
Larynx moves up and foward allowing epiglottis to cover enterence to the lungs - Oesophogeal
Food moves into the oesophagus and peristilasis happens
What does the oesophagus do?
Transport food from the mouth to the stomach
Secretes a muscus that aids the passage of food and prevents abrasion
What are the 3 areas in the stomach?
- Fundus
- Body
- Antrum
What is the enterence to the stomach called?
Lower oesophageal schincter
What is the schincter called that controls movement from stomach to small intestine?
Pyloric
What acid is produced by the stomach?
Hydrochloric
How is chyme made?
Mechanical digestion in the stomach mixed with gastic juice
Why does the stomach have an extra layer of circular and longitudinal muscle?
Facilates churning and mixing
What is rugae?
Folds in the stomach to increase surface area
What are the 3 phases of digestion?
- Cephalic
Salivary glands secrete saliva and gastric glands secrete gastic juice to prepare the mouth and stomach for food - Gastric
Food promotes gastric juice secreition and gastric movement - Intestinal
Food is digested in the small intestine
Gastric movement and secretion decrease to slow the exit of chyme which prevents small intestine being overloaded
What are the 3 parts of the small intestine?
- Duodenmum
- Jejunum
- Ileum
What is the primary function of the small intestine?
Absorption of nutrients
What adaptions does the small intestine have to faciliate absorption?
- Circular folds within mucosa and submucosa slow the movement of products allowing time for absorption
- Microvilli allow nutrients to be absorbed into blood or lymph
- Microvilli increase surface area
What are the end product of carb digestion?
Monosaccharides
What are the end product of fat digestion?
Fatty acids and glycerol
What are the end product of protein digestion?
Amino acids
What do the two accessory organs help with?
Breakdown of fats, carbs and protein
What is the pancreas?
Pale grey gland
Consists of a broad head and narrow tail
Has exocrine function - produces pancreatic juice containing enzymes that digest carbs, protetin and fat
Endocrine function - produces hormones such as insulin and glucagon which controls carb metabolism and blood glucose
What is the liver?
Largest gland in the body
How many lobes does the liver have?
4
What does the liver produce?
1l of bile
What is the role of bile?
Emulsiy fats
Name 7 functions of the liver
- Detoxication of drugs
- Manufactures and secretes bile
- Carb metabolysm - maintains plasma and glucose levels
- Recycling of erthrocytes
- Deactivation of hormones
- Production of clotting protetins
- Storage of vitamins
What happens to glucose when it is stored in the liver?
Turns into glycogen under the influence of insulin
When levels fall, glycogen is turn backed into glucose again and put into the blood stream
What transports the bile made by the liver?
Common hepatic duct to the gall bladder
Common bile duct to duodenum
Where is bile stored?
Gall bladder
What is the valve called between small and large intestine?
Ileocecal sphincter
What does Cholecystokinin do?
Stimulates the release of bile from the gallbladder
What cells in the liver secrete bile?
Hepocytes
Why would glucagon be released from the pancreas?
High levels of amino acid in the blood
