Module 5 Flashcards
list the 6 structures of the digestive tract
- mouth
- pharynx
- oesophagus
- large intestine
- stomach
- small intestine
list the 6 digestive processes
- ingestion
- propulsion
- mechanical digestion
- chemical digestion
- absorption
- defecation
list the 4 accessory organs of the digestive system
- teeth + tongue
- salivary glands
- gall bladder
- pancreas
ingestion
taking food into digestive tract
propulsion
moving food through digestive tract
peristalsis
muscle contraction
mechanical digestion
physically breaking up food
mouth, stomach, small intestine
chemical digestion
enzymes break down food complexes
mouth to small intestine
absorption
passage of digested and products from tract into blood or lymph
structure of oral cavity
sratified squamous cells to protect
processes the oral cavity performs
- ingestion
- propulsion
- mechanical digestion
- chemical digestion
structure of pharynx + oesophagus
no adaptations
processes the pharynx + oesophagus performs
propulsion
structure of the stomach
- epithelial tissue arranged into gastric pits
- additional oblique layer of muscle for pummelling food + forcing chyme into duodenum
processes the stomach performs
- propulsion
- absorption
- chemical digestion of proteins
structural adaptations of the small intestine
- circular folds
- villi
- microvilli
processes the small intestine performs
- propulsion
- mechanical digestion
- chemical digestion
- nutrient absorption
structural adaptations of the large intestine
- epithelium rich in mucus to ease passage of faeces
- protect from acids + gases
processes the large intestine performs
- absorption (water + electrolytes)
- propulsion
- chemical digestion
list the layers of the tissues of digestive system (4)
- mucosa
- submucosa
- muscularis externa
- serosa
mucosa
- innermost layer
- rich in secretory cells
- capillaries for absorption
- smooth muscle layer
- lymphoid follicles for immunity
- secrete, absorb, protect
submucosa
- external to mucosa
- stretch + recoil
- vessels for absorption, and transport of lipids
- lymphoid tissue for immunity
muscularis externa
- surrounds submucosa
- inner circular, outer longitudinal muscle
- inner circular = sphincters to control passage of food
- responsible for peristalsis, segmentation
serosa
- outermost layer
- protects digestive tract
- anchors tract within peritoneal cavity
3 factors of the mucosal barrier
- bicarbonate rich fluid under insoluble mucus
- mucosal epithelial cells
- damaged mucosal epithelial cells shed + replace
what do gastric pits produce
- HCI
- Pepsin
- Mucus
- Hormones
structural divisions of the small intestine (3)
- duodenum
- jejunum
- ileum
duodenum
curls around pancreas
- receives bile + pancreatic juice for chemical digestion
jejunum
- mechanical and chemical digestion
- absorption
ileum
ends at large intestine
nutrient absorption - circular folds
- deep folds of mucosa + submucosa
- slows movement of chyme to increase absorption
nutrient absorption - villi
- finger like
- absorptive epithelial cells
- capillary bed + lacteal
nutrient absorption - microvilli
- densely packed villi on surface of epithelial cells = brush border
what do brush border enzymes complete the digestion of
- carbs
- proteins
- nucleic acid
defection reflex
- stretch of rectal walls
- spinal reflex initiated
- voluntary motor neurons allowing external anal sphincter to relax
role of enteric flora of the large intestine
- metabolises mucus
- synthesizes vitamin B + K
what does saliva help to digest
- carbs
- bolus forms
function of bile
emulsifies fats
produced by liver + stalled in gall bladder
function of pancreatic juice
alkaline to neutralise chyme, containing enzymes
what does pepsin digest + its location
- proteins
- located in stomach
what does pancreatic amylases digest + its location
- carbs
- duodenum
what does pancreatic proteases digest + its location
- proteins
- duodenum
what does pancreatic lipases digest and its location
- lipids
- small intestine
what does pancreatic nucleases digest + its location
- nucleic acid
- small intestine
define metabolism
the sum total of the chemical reactions occurring in an organism
define anabolism
the reactions that build larger molecules from smaller ones
define catabolism
reactions that break down complex structures into smaller ones
metabolic rate
the energy the body uses to drive metabolsim
basal metabolic rate
the energy the body uses to perform only essential activities
cellular respiration
biochemical processes that lead to the production of ATP
glycolysis
- anaerobic
- 1 molecule broken in half to become 2 (pyruvate)
tricarboxylic acid cycle (TCA cycle)
- occurs in mitochondria
- pyruvate converted into energy
electron transport chain
- occurs in mitochondria
- aerobic
- H+ ions produced by TCA cycle = chemical reactions = ATP
Metabolism - Absorptive state
when nutrients are in abundance (during and for after 4 hours of eating) anabolism exceeds catabolism and nutrients are stored
Absorptive State - Glucose - Immediate and excess use
Immediate: produces ATP
Excess: glycogen - stored in liver and skeletal muscles
Absorptive State - Amino Acids - immediate and excess use
Immediate: protein synthesis + produces ATP if necessary
Excess: converted to trigylicerides
Absorptive state - Glycerol & fatty Acids - Immediate & Excess Use
Immediate : produce ATP if needed
Excess: stored as triglycerides
Metabolism - Post Absorptive State
when no food is being digested + body reserves must be broken down to provide nutrients; catabolism exceeds anabolism
glycogenolysis
breakdown of glycogen into glucose in liver + skeletal muscles
gluconeogensis
production of new glucose
which hormone is used to maintain fasting blood glucose levels
glucagon
