Module 3 Flashcards
How are nutrients delivered to the liver?
nutrients that enter the blood capillaries at the villi will then enter veins that lead to liver.
at liver, material is stored, used, detoxified, or sent off to the rest of the system
material that enters the cardiovascular system can then be transported to where it is needed
How do glucose and amino acids enter the blood/lymph?
through active transport
How do lipids, fats, and soluble vitamins enter the blood/lymph ?
passive diffusion
How does food pass through the esophagus ?
no active digestion or absorption
peristalsis occurs
How does food pass through the pharynx?
pharynx aka the throat, the common passageway for food and inspired air
no active digestion or absorption
epiglottis directs food from pharynx into esophagus instead of down the wrong tube into trachea
How does food pass through the stomach ?
- temporary reservoir for food
- food remains for 4-5 hours
- 3 layers of muscles allow stomach to churn
- lower esophageal sphincter and pyloric sphincter close as stomach churns food nd mixes it with gastric juice.
- when food leaves stomach it is in a semi-liquic form called chyme
How does fructose enter the blood/lymph ?
through facilitated diffusion
How does glucose metabolism work ?
- glycolysis : breakdown of glucose (glucose to pyruvate + ATP)
- breakdown of pyruvate : depends on whether oxygen is present (aerobic, acetyl coA formed) or not (anaerobic, lactate and ATP)
- citric acid cycle : acetyl CoA combines with oxaloacetate to produce CO2, H2O, ATP, and electron transporters
- electron transport chain : electrons are exchanged between the electron transporters and membrane bound proteins. leads to a build up of protons on one side of the membrane. protons get moved through a protein pump. produces more than 30 molecules of ATP.
How does the condensation reaction occur ?
binding of molecules into longer chains of molecules. water is liberated in the process. binding of amino acids into a specific chain begins process of protein synthesis
How does the mouth pass food?
- teeth rip food apart
- tongue pushes food towards teeth and mixes it with saliva
- salivary glands secrete saliva into mouth which contains: salivary amylase, lingual lipase digests lipids, mucus lubricates food, lysozyme = antibacterial substance that disinfects food
- when food leaves the mouth it is a bolus
How does water enter the blood/lymph?
osmosis
How long does it take for material to pass through entire digestive tract ?
2+ days
food spends most time in large intestine
How should you dislodge an object that enters the airways and causes choking ?
- support choking persons upper body so they can lean forward with support.
- apply 5 sharp blows between shoulder blades using the heel of the hand.
- if blockage not cleared, place fist above belly button and use other hand to grasp the fist.
- press into abdomen and in an upward motion.
- forcefully make a J shape 5 times.
- if blockage remains, repeat.
What are gallstones?
hardened bile deposits that form stones in the gallbladder.
can be extremely painful when fat is consumed and gallbladder contracts to release bile
What are hormones ?
hormones are chemical messengers that are required for many physiological processes including digestion.
they are released from one area of the body and travel through the blood to different parts of the body
What are prebiotics?
carbohydrates that act as food for microbiota
supports the health of the microbiome
What are probiotics?
cultures of living organisms
What are the 2 types of digestion?
mechanical/physical: uses physical process such as chewing to break food apart
chemical digestion: uses enzymes to alter the chemical structure of nutrients
What are the 3 sections of the small intestine ?
duodenum, jejunum, ileum
What are the accessory structures of the digestive tract ?
liver, gallbladder, pancreas.
they secrets material into the duodenum of the small intestine
What are the layers of the digestive tract wall from the inside out ?
lumen, mucosa, nerve plexus, submucosa,nerve plexus, muscularis, serosa
What are the parts of the digestive system ?
mouth, pharynx, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine
What are ulcers?
weakened, damaged parts of the lin in of the digestive tract
(canker sores, peptic ulcers)
What do the liver and gallbladder do ?
liver makes bile and the gallbladder stores it.
What does the pancreas secrete?
pancreatic juice:
digestive enzymes: amylase, lipase, proteases
bicarbonate: neutralizes chyme
What happens in the large intestine ?
unabsorbed material is packaged for removal or acted upon by bacteria.
What is amino acid metabolism ?
amino acid—> deamination (nitrogen group removed from amino acid)—> produces pyruvate, acetyl CoA, citric acid cycle intermediates.
there are 21 amino acids, each w unique side chain. (21 possibilities for what remains)
What is anabolism ?
smaller molecules come together to form larger ones
require input of energy
What is beta oxidation (lipid metabolism) ?
splits the fatty acid, 2 carbon atoms at a time. each 2 carbon molecule of a fatty acid can be used to form acetyl CoA.
What is bile?
liquid emulsifier that breaks larger lipid globules into smaller ones and allows them to be suspended in a watery environment
What is catabolism?
larger molecules are broken down into smaller ones
leads to a net release of energy
What is cellular respiration ?
catabolism of energy of the energy-yielding nutrients leading to the production of ATP
primarily occurs in the mitochondria
metabolic pathway
What is constipation?
bowel movements that are difficult to pass or less frequent.
stool tends to be dry, hard, and can be painful to pass
increases risk for hemorrhoids
risk factors: age, female sex, genetics, physical inactivity, diet low in fruits, vegetables, and water
What is diarrhea?
occurs when matter passes too quickly through the large intestine
stools are loose and have liquid like consistency
typically due to bacteria and viral infections
What is digestion?
separation of nutrients in food and breaks larger molecules into smaller ones so they can be absorbed
polysaccharides—> sugar
triglycerides—> fatty acids
proteins—> amino acids
What is diverticula and diverticulitis?
diverticula : weakened walls of large intestine that forms outpouchings
can become diverticulitis when inflamed
age, smoking, obesity, physical inactivity can increase risk
What is found in the large intestine ?
larges population of non-human cells: microbiota (mostly bacteria. 300-500 different species).
roles:
- vitamin synthesis
- energy harvesting
- health/disease
- appetite
What is gastric juice made of ?
mucus, gastric lipase (breaks down lipids), hydrochloride acid (unravels proteins, activates pepsinogen), pepsinogen (becomes pepsin, which digests protein)
What is gastroesophageal reflux ?
when lower esophageal sphincter weakens and acidic stomach contents spill into esophagus (heart burn)
can lead to gastroesophageal reflux disease which can lead to ulcers
What is IBS?
irritable bowel syndrome.
unknown cause
symptoms include abdominal pain, bloating, cramping, diarrhea, constipation, flatulence
treatments focus on alleviating symptoms: avoiding trigger foods, managing stress, drinking plenty of fluids
What is ketogenesis?
on a very low carb diet, fatty acids cannot enter citric acid cycle, and instead form ketones.
(citric acid cycle requires carbohydrates)
What is metabolism ?
sum of chemical reactions that occur in our bodies
What is peristalsis ?
type of movement that occurs in esophagus among other areas.
circular smooth muscle contract behind food in a wave like fashion, pushing it forward through the digestive tract relaxation of the muscle in from of the bolus opens a path for the food to be pushed down.
What is the hydrolysis reaction ?
input of water helps to break down the molecules.
What is the main functional unit of the small intestine ?
villus or villi plural.
villi are invaginations of the small intestine wall.
cells on their surface have extensions called microvilli (known as brush border) which secrete enzymes.
nutrients subunits are absorbed into the centre of the villus where they then enter the blood or the lymph
What is the main part of the large intestine ?
the colon
What is the microbiome ?
genetic material of non-human organisms found in body
What is the primary site of digestion and absorption ?
small intestine
What is the purpose of enzymes?
speeds up the rate of reaction and provides a location for chemical reactions to occur
enzymes can participate in hydrolysis and condensation reactions.
When we consume more energy than we need, where is the excess energy stored?
as lipid i our fat tissue
Describe the process of emulsification of lipids
- Large lipid globules cannot suspend within the watery environment of small intestine. They are also too large for the enzyme lipase to act on
- The liver and gallbladder secrete bile into the small intestine when lipids are present
- Bile’s hydrophobic tails arrange themselves to face the lipid, the heads arrange themselves to face the watery lumen
- Larger lipid globules are broken into smaller lipid droplets surrounded by bile. This structure is called a micelle.
- Micelles allow lipids to be suspended within and freely move around the small intestine lumen. They also allow lipase to act on lipids
