Digestive system and metabolism Flashcards
Organs in the digestive tract
Mouth Pharynx Oesophagus Stomach Small intestine Large intestine
Accessory organs
Teeth Tongue Salivary glands Gallbladder Liver Pancreas
Ingestion
Taking food and water into the digestive tract
Propulsion
Moving food through the digestive tract
Peristalsis
Involuntary alternate waves of muscle contraction and relaxation
Mechanical breakdown
Physically breaking the food up into smaller fragments so that it can be chemically digested
Segmentation
Moving bolus back and forth to break it into smaller fragments
Mixing food with digestive juices
Chemical digestion
Enzymes break down complex food molecules into their building blocks (monomers)
Absorption
Passage of end products from the lumen of the digestive tract into the blood or lymph
Defaction
Elimination of indigestible substances in the form of faeces, via the anus
Mucosa
Innermost layer
Secretes mucus
Secretes digestive enzymes and hormones
Absorbs nutrients that have been digested
Submucosa
Covers mucosa
Elastic tissue - recoil
Muscularis externa
Surrounds submucosa
Smooth muscle cells
Peristalsis and segmentation
Sphincter to ensure food travels in one direction
Serosa
Outermost layer
Anchors digestive organs to surrounding tissue
Digestive processes of mouth
Ingestion
Chem BD
Mech BD
Propulsion
Digestive processes of stomach
Propulsion
Mech BD
Chem BD - pepsin (proteins)
Absorption
Digestive processes of small intestine
Propulsion
Mech BD
Chem BD - brush boarder enzymes
Absorption
Digestive processes of large intestine
Chem BD
Absorption
Propulsion
Defaection
Liver function
Produces bile
Gallbladder function
Stored bile
Pancreas function
Produces alkaline pancreatic juice to neutralise chyme
Produces enzymes
Parietal cells
Stomach
Produce hydrochloric acid
Chief cells
Stomach
Produce pepsinogen = inactive form of pepsin ==> pepsin
Goblet cells
Stomach
Produce mucus
Metabolism
Sum total of chemical reactions occurring in an organism
Anabolism
Reactions that BUILD larger molecules from small ones
Catabolsim
Reactions that BREAKDOWn large molecules into smaller ones
Anabolic/absorptive state
When nutrients are in abundance
Controlled by insulin
Excess nutrients stored
Catabolic/post-absorptive state
When no food is being digested and the body reserves must be broken down to provide nutrients
Controlled by glucagon
Glycogenolysis
Breakdown of glycogen to glucose
Gluconeogenesis
Production of glucose from non CHO products
