Topic Test T2 Wk2 (digestion & excretion) Flashcards
Digestive System Functions
Ingestion of food Absorption of digested food Mechanical digestion Chemical digestion Elimination of waste
Mouth
Mechanical Digestion: teeth and tongue undertake chewing
Chemical Digestion: salivary amylase breaks down carbohydrates
Swallowing
Tongue forms food into bolus
Peristalsis carries bolus into stomach through waves of muscle contraction
Stomach
Mechanical Digestion: muscular churning producing chyme
Chemical Digestion: protein into amino acids through gastric juices containing gastric protease
Leaves stomach via pyloric sphincter
Duodenum
Mechanical Digestion: contraction
Mechanical Digestion: lipid emulsification by bile (breaking up)
Chemical Digestion: through pancreatic amylase, pancreatic lipase and protease
Small Intestine
Contain finger like projections called villi
Increases surface area for nutrient absorption
Enzymes in SI
Intestinal Amylase
Intestinal Lipase
Intestinal Protease
Absorption in SI
Glucose, amino acids, water, minerals are absorbed into blood capillaries
Fatty acids and glycerol absorbed into lacteals in the lymphatic system
Large Intestine
No villi, no enzymes
Water and vitamin absorption
Liver
Produces bile
Bile is stored in gall bladder and carried to duodenum
Pancreas
Secretes pancreatic juice into duodenum
Controls blood insulin levels
Rectum and Anus
Faecal storage and defecation
Anal sphincter muscles open allowing waste to be expelled
Mechanical Digestion
Breakdown of food into smaller particles without changing its chemical makeup
Teeth
4x incisors
2x canines
4x premolars
6x molars
Incisors
Chisel shaped for cutting and biting
Canines
Cone shaped for tearing