coursepack Flashcards
3 functions of triglycerides
‘‘FAIP’’
1) insulation and protection (keep body temp steady and protect us from shocks)
2) important fuel source for the body
3) absorption of fat-soluble vitamins
what is a macromolecule?
+ 4 types with their examples
- complex, large, organic molecule
ex:
1) carbs (sugars)
2) lipids (fats + oils)
3) proteins
4) nucleic acid (DNA/RNA)
CARBS:
difference between monomer and a polymer
+ examples
m: macromolecule made of only 1 unit = monosaccharides or disaccharides
ex of disaccharides:
- lactose (di) = galactose + glucose
- sucrose (di)= glucose + fructose
- maltose (di)= 2x glucose
p: macromolecule made of MANY monomer subunits=polysaccharides
ex of polysaccharides: ALL polymers of glucose
- starch: plant based, very energetic and digestible (we have the right enzymes to digest it by breaking down into monomers)
- cellulose: plant based, indigestible (no enzymes to digest it) ex: fibers
- glycogen: stored in animal tissues: muscles and liver
Carbohydrates functions (2):
1) glucose:
- favorite fuel for the cell
- ATP produced from glucose breakdown
2) combines with other macromolecules to form cell structures (carb attached to…)
ex: glucoproteins and glycolipids
Lipids:
what are the 3 major groups?
*lipids= hydrophobic
- triglycerides
- phospholipids
- steroids (sterols)
triglycerides:
- where?
- structure?
- how to they vary? (2)
- functions? (4)
where: body tissues as fat (adipose tissue)
structure: glycerol backone + 3 fatty acids
* diglyceride= 2 fatty acid
* monoglyceride = 1 fatty acid
vary by:
lenght (# of carbon, 10-20)
and degree of saturation
-saturated= C-C, animal source, solid at RT, ex: fat and butter
- unsaturated: C=C or triple bond, plant source, liquid at room temp, ex: oil, mono/polyunsaturated
functions : FAIP
- fuel
- absorption of fat soluble vitamins
- insulation
- protection
phospholipids:
- what are phospholipids+ structure?
- where is it found?
modified triglycerides:
glycerol backbone, 2 fatty acids, phosphate group
hydrophilic head, hydrophobic tail
component of cell membrane
steroids:
structure?
function?
synthesized by?
structure: 4 hydrocarbon rings + 1 side chain
function: important for
- bile acids
- hormones
- vitamins (B, K?)
synthesized by: plants & animals
proteins:
what are they made of?
made of amino acids linked by peptide bonds
amino acids:
- carboxyl group
- amino group
- side chain (R group) * variable up to 20 amino acids
peptide bonds:
- carboxyl group & amino group bond
dipeptide: 2 amino acids
tripeptide: 3
poly: <100
protein: >100
proteins:
structural levels
+ 1 example
primary = sequence of amino acids
secondary= alpha helix, pleated or beta sheet
tertiary = folding of alpha helixes and pleated sheets (3D)
quaternary (not all proteins) = assembly of many folded polypeptides to have a functional protein
ex: hemoglobin carries 02in RBCs
proteins:
functions (6) + example
SSSDMC
- structure
(keratin found in nails & hair) - storage
(albumin in egg whites provides nutrients for the embryo) - signaling
(growth hormone is a hormonal messenger) - defense
(antibodies of immune system) - movement
(actin & myosin in muscle cells) - catalyzing rx
(enzyme amylase breas down starch)
what are enzymes?
their functions?
anabolic vs catabolic reactions
- enzymes are proteins with specific functions
- they are biological catalysts; increase rate of rx by decreasing the AE
- substrates form product
- enzyme is left unchanged
anabolix rx=synthesis= energy stores
catabolic rx = breakdown = energy released
list the organs making up the gastrointestinal tract (7)
list the accessory organs (3)
Mouth/tongue
Pharynx
Esophagus
Stomach
Small intestine (duodenum, jejunum, ileum)
Large intestine (transverse, ascending, descending colon)
Anus
Liver
Gallbladder
Pancreas
what are the goals of digestion? (2)
what is an essential nutrient? + ex
- extract nutrients form food to make energy (ATP), kcal or Cal
- obtain building blocks for growth and repair so that our body saves energy and gets essential nutrients
essential nutrient: must be obtained from the diet because body can’t synthesize it
ex: omega 3 and 6
explain the digestive activities
1) INGESTION
2) PROPULSION
3) MECHANICAL DIGESTION
INGESTION:
- entry of food through oral cavity (mouth, teeth, tongue)
- chewing, mixing w/ saliva, 1st enzymes to form bolus
PROPULSION:
- moving bolus towards digestive tract
- deglutition/swallowing (voluntary)
- peristalsis; contraction waves of smooth muscles in 1 direction (involuntary)
MECHANICAL DIGESTION:
- increases surface area and mobility of food
physical process:
- mastication (mouth)
- churning (stomach; bolus → chyme)
- segmentation (small intestine; homogenizes chyme, contracts in different directions)
explain the digestive activities
4) CHEMICAL DIGESTION
5) ABSORPTION
6) DEFECATION
CHEMICAL DIGESTION:
- enzymes break down macromolecules
- starts in mouth, completed in small intestine
ABSORPTION:
(size of molecules matters for absorption)
- simple columnar epithelieum of small intestine (microvilli on apical surface)
- nutrients exit intestinal lumen and go through intestinal wall to enter the body
- nutrients go to bloodstream or lymphatic circulation
DEFECATION:
- not all food is (chemically) digested and absorbed
- accumulation of feces in the rectum
anatomy and physiology of the oral cavity:
teeth
tongue
saliva
functions
2 enzymes
1) teeth (mechanical digestion)
incisors → biting
canines → tearing
premolars → mashing/smooth swallowing
molars → crushing
2) tongue PMHP
- positions food for chewing
- mixes food with saliva (bolus)
- helps in deglutition process
- produces lingual lipase
3) saliva
- 3 salivary glands:
- parotic
- sublingual
- submadibular
- water, mucus, molecules, ions= slighly acidic
4) functions of saliva ‘‘MSCD’’
- moistens food (bolus)
- starts chem breakdown (starch, triglycerides)
- cleans mouth (antimicrobial activities)
- dissolves food chemicals (taste)
5) enzymes
1- salivary amylase
active in mouth + stomach
starch → maltose
2- lingual lipase
active in mouth + stomach
triglycerides digestion
pharynx:
where?
role?
anatomy?
- links mouth and esophagus
- not actively participating in digestion (accessory organ)
DURING DEGLUTITION
- uvula: protects airway, prevents bolus from getting in airway/nose
- epiglottis: closes the entry of the trachea (no food)
- if not blocking= choke on food
esophagus:
anatomy?
functions?
anatomy:
upper esophageal sphincter
esophagus
lower esophageal sphincter
* malfunction = acid reflux (heartburn)
esophagus: long muscular tube linking pharynx to stomach
propulsion: peristalsis occurs: smooth muscles allow descent oof bolus
stomach:
anatomy
starts with lower esophagal sphincter
stomach: reservoir for boluses and thick walls made of 3 layers: CLO
- circular muscle
- longitudinal muscle
+ oblique muscle
gastric glands secrete gastric juices ans secrete HCl which activates protein-digesteding enzyme:
pepsinogen + HCl→ pepsin
(inactive → active)
stomach: role of digestion (2)
1) mechanical digestion
- churning
- absorption of lipid-soluble substance
ex: alcohol, aspirin
2) chemical digestion
for proteins:
- pepsinogen + HCl→ pepsin
(inactive → active)
- proteins → peptides
for lipids: 2 enzymes
- lingual lipase
- gastric lipase is activated
bolus → chyme
exits (and controlled by) pyloric sphincter in small qty, regular pace, peristaltic waves (prolonged unidirectional smooth muscle contraction)
what is the stomach pH with its pros and cons
and its disorders (3)?
pH= acidic (1 to 3)
pros:
kills most pathogenic bateria
protein denaturation
cons:
digest itself: inflammation or gastritis (disorders)
3rd disorder: peptic ulcers/gastric
- very specialized/localized disorder
- persistent damage to protective mucus layer
- cause: helicobacter pylori or drugs
that drill its way down mucus and neutralize acidity to create ideal living conditions
- treatment: anitibiotics or drug change
a healthy liver has what kind or surface?
smooth and uniform surface
anatomy & physiology of small intestines
3 sections + their functions
1) duodenum (shortest)
- acidic environment (chyme)
- susceptible to uclers
- production of alkaline mucus
- connected to liver and pancreas (accessory organs)
- chyme continues to mix (segmentation)
- chyme moves forward (peristalsis)
2) jejunum
- main site for nutrients absorption
1) circular folds (large)
- increase surface area for more nutrients absorption
2) villi
-cover mucosa
- simple columnar epithelium
3) microvilli (smallest)
- on apical side of epithelial cells (brush border)
3) ileum (largest part*?)
- processes whatever is left
- chemical digestion completed and most nutrients absorbed
