Chapter 14 Review Flashcards
Organs of Alimentary Canal (6)
Mouth Pharynx Esophagus Stomach Small intestine Large intestine
Digestion
The bodily process of breaking foods down chemically and mechanically
Absorption
Passage of a substance into or across a blood vessel or membrane. In this case, it is often the nutrients from food that will be used to fuel the body
Basic function: Mouth
Major player in mechanical digestion
Though, salivary glands breakdown foods chemically
Basic function: Pharynx
A tract on the way to the esophagus.
Basic function: Esophagus
A tract leading to stomach
Basic function: Stomach
Major player in chemical breakdown
Basic function: Small intestine
First duodenum - first 4% - is where most absorption takes place
Basic function: Large Intestine
Prepares food for exit
Composition of saliva
Mucus
Salivary Amylase
Lysozyme
IgA antibodies
Function of saliva
Mucus: moistens and binds food together
Salivary Amylase: begins starch digestion in mouth
Lysozyme and IgA: inhibit bacterial growth
Saliva dissolves food chemicals so we can taste
Deciduous Teeth
Baby teeth
Starts around 6 months; full set (20) by 2 years
Lower central incisors appear first
Permanent teeth
Second set of teeth
Except wisdom teeth, all in by end of adolescence
Wisdom teeth between 17-25
Basic tooth anatomy
Crown
Neck
Root
Lacteal
Villi containing a rich capillary bed and a modified lymphatic capillary
Digested foodstuffs are absorbed through mucosa AND lacteal
Once foodstuffs absorbed in villi/lacteal…
Foodstuffs is transported in blood to the liver via hepatic portal vein
Process: Swallowing
- Complex process involving the coordinated activity of several structures
- Tongue, soft palate, pharynx, and esophagus
- Two phases: Buccal and Pharyngeal-esophageal
Process: Vomiting
Reverse peristalsis occurring in the stomach, and contraction of the abdominal muscles and diaphragm
Process: Defecation
- Defecation reflex triggered when rectum is full
- Sigmoid colon and rectum contract, while sphincter relaxes.
Bolus
Food mass formed in mouth by mastication and saliva
How food is mixed in stomach
- Peristalsis begins in upper half of stomach, and contractions increase in force as food approaches
- Small amounts of liquids and small particles are squeezed through pyloric valve
- The rest is propelled backwards and broken down more and more
How foodstuffs moves through small intestine
- Mainly peristalsis
- Waves of contraction, moving along the length of intestine, followed by wave of relaxation
Haustral contractions
- Slow, segmenting movements lasting about one minute, occurring every 30 minutes or so
- As Haustrum fills, it triggers contraction, moving it to next Haustrum
Mass Movements
Long, slow-moving, powerful contractile waves that move over large areas of the colon 3 or 4 times daily, pushing it towards rectum
Defecation reflex
Sigmoid colon and rectum contract, while sphincter relaxes
Gastrin
- Stimulates release of gastric juice
- Stimulates stomach emptying
Secretin
- Increases output of pancreatic juice rich in bicarbonate ions
- Increases bile output by liver
- Inhibits gastric mobility and gastric gland secretion
Cholecystokinin (CCK)
- Increases output of enzyme-rich pancreatic juice
- Stimulates gall bladder to expel stored bile
- Relaxes sphincter of duodenal papilla to allow bile and pancreatic juice to enter duodenum
Brush Boarder Enzymes
- Breakdown double sugars into simple sugars
- Complete protein digestion
Pancreatic Juice
- Pancreatic amylase (starch digestion)
- Typsin, chymotrypsin, and carboxypeptidase (protein digestion)
- Lipase (fat digestion)
- Nuclease (nucleic acid digestion)
Pepsinogen/Pepsin
Protein digestion
Renin
Milk protein (mother’s milk) converted to a substance that looks like sour milk
End product(s) of proteins digestion
Amino acids (some dipeptides and tripeptides)
End product(s) of fat digestion
- Monoglycerides and fatty acids
- Glycerol and fatty acids
End product(s) of carb digestion
- Galactose (from lactose only)
- Glucose (from both lactose and sucrose)
- Fructose (from sucrose only)
Function: bile
Emulsify fats by physically breaking down into smaller pieces, providing more surface area for fat-digesting enzymes to work on
Nutrient
A substance in food that is used by the body to promote normal growth, maintenance, and repair
Kilocalorie
Measurement of energy value of foods
Six nutrient categories (4 major, two minor)
Water
Carbs
Lipids
Proteins
Vitamins
Minerals
Enzyme
A protein that helps speed up a chemical reaction
Metabolism
Broad term referring to all chemical reactions that are necessary to maintain life
Anabolism
An aspect of metabolism in which larger molecules or structures are build from smaller ones
Catabolism
An aspect of metabolism in which substances are broken down to simpler substances
Glycogenesis
- “glycogen formation”
- Glucose molecules are converted to glycogen
- Glycogen molecules are stored in liver
Glycogenolysis
- “glucose splitting”
- Glucose is released from liver after conversion from glycogen
Gluconeogenesis
- “Formation of new sugar”
- Glucose is produced from fats and proteins
Carbs use in cell matabolism
- ATP production
- Excess carbs stored as glycogen or fat
(Glycogen and fat broken down for ATP; broken down to glucose and released to blood)
Fats use in cell metabolism
- Insulation to cushion and protect body organs
- ATP production
- Build myelin sheaths and cell membranes
Proteins use in cell metabolism
- ATP formation (if not enough of other stuff)
- Functional proteins (enzymes, antibodies, hemoglobin, etc)
- Structural proteins (connective tissue fibers, muscle proteins, etc)
Basal Metabolic Rate (BMR)
- The amount of heat produced by the body per unit of time when it is under basal - resting - conditions
- Average adult BMR is 60-72 kcal/hour
Total Metabolic Rate (TMR)
The total amount of kilocalories the body must consume to fuel ALL ongoing activities
What increases BMR (5)?
- Being thin/small
- Being male
- High thyroxine production
- Being young/maturing quickly
- Strong emotions (anger/fear)
What decreases BMR (4)?
- Being large/heavy
- Being female
- Low thyroxine production
- Aging/being elderly
Heat-gain mechanisms
- Vasoconstriction of blood
- Shivering
Heat-loss mechanisms
- Radiation/evaporation
- Sweat
- Fever (controlled hyperthermia)
Congenital disorders
- Cleft palate/cleft lip defect
- Tracheoesophageal fistula
Inborn errors
- Cystic fibrosis (CF)
- Phenylketonuria (PKU)
When does the alimentary canal fully develop?
By fifth week of development
Digestive glands bud from…
Mucosa of the alimentary tube
What feeds fetus?
Placenta
If peristalsis is inefficient in newborns, then _________ is common
Vomiting
Rooting reflex
Helps newborn find nipple
Sucking reflex
Helps infant hold onto the nipple and swallow
Teething begins…
Around 6 months
Gastroenteritis
Inflammation of the gastrointestinal tract
Appendicitis
Inflammation of the appendix
Middle-age digestive problems
- Ulcers
- Gallbladder problems
Activity of the digestive tract in old age
- Fewer digestive juices
- Peristalsis slows
- Diverticulosis and cancer are more common
