Digestion and absorption Flashcards
Digestion through the body
- Food enters the mouth , mixed with salivary glands (parotid, submandibular, sublingual), SALIVARY AMYLASE break down CARBS.
- Broken down food is swallowed and travels through the esophagus , propelled by peristalsis.
- Food enters the stomach, collects the fundus and then moves down into the PYLORIC REGION (most digestion occurs) (PEPSIN AND HCL) help break down food (proteolysis)
- CHYME goes into the small intestine through the PYLORIC SPHINCTER of the stomach.
- SMALL INTESTINE: (duodenum, jejunum, ileum) complete digestion absorption of nutrients take place.
- SECRETIN/CCK released by small intestine. BILE aides in digestion and absorption from the GB and PANCREAS.
- Undigested food and water pass through the ILEOCECAL VALVE, allowing them to enter the LI/COLON.
- LI /colon absorbs water, bacteria,-synthesized vitamins and short chain fatty acids, stool forms and exits body.
Mechanical VS Chemical digestion
Mechanical:
1. physcial process that alters composition of the food.
2. reduces the size of food particles, enhancing both their surface area and mobility within the digestive system.
3. Involves mastication, peristalsis, and segmentation
Chemical:
Breakdown of food through enzymes.
Includes the following processes:
a. mouth (salivary amylase - starch into glucose)
b. stomach: pepsin activated by HCL, breaks down proteins into small peptide fragments.
c. small intestine
1. pancreatic amylase (starch-glucose)
2. lactase- lactose into glucose and galactose.
3. sucrase- sucrose into glucose and fructose.
4. Maltase BD maltose into 2 glucose
5. pancreatic lipase - Triglycerides into glycerol & free fatty acids.
6. carboxy - peptidase, trypsin, chymotrypsin break down protein into smaller peptides or amino acids.
Glycolysis
- eat carb- broken down into glucose in blood. Insulin helps transfer glucose from the blood into the body cells.
- IN CELL: GLUCOSE: enzyme and magnesium to transfer a phosphate from ATP to glucose.
- A. Glucose 6 phosphate - enough oxygen present- pyruvate (O2) to mitochondria.
B. Glucose-6-phosphate lacking O2 - lactate
If you LACk CORe muscles, exercise more.
CORI cycle
CORI cycle (lactic acid cycle)
a metabolic pathway in which lactic acid produced in the muscles by anaerobic glycolysis is first converted to glucose in the liver and then moved back to the muscles for further metabolism.
KREB Cycle and electron transport chain
Pyruvate converts to acetyl-coA (irreversible reaction)
-Thiamine, Riboflavin, Niacin, Pantothenic acid, Magnesium, Lipoic acid
(The Rich Ninja PaintedMy Library)
-Acetyl-coA (fatty acid metabolism, amino acid metabolism) leads to oxaloacetate– citric acid
-Byproducts: NADH, FADH2, moves into the ELECTRON TRANSPORT CHAIN makes ATP
Gluconeogenesis
Prolonged fasting
-Creation of GLUCOSE from non-carb sources : Lactate, glycerol, amino acids,
-Fasting lactate, Amino acids (Alanine), Glycerol (FLAG)
GLYCOGENESIS
- Extra blood glucose-
- triggers insulin-
- Each glucose molecule converts to glucose-6-phosphate
- Glucose-6-phosphate eventually converts to glycogen that can get stored in liver or muscle
Glycogenolysis
Low blood glucose
1. pancreas-glucagon-Liver-glucose 6 phosphate- free glucose-free glucose enters blood.
2. Liver-epinephrine-muscle - free glucose 6 phosphate- free glucose 6 phosphate can now enter glycolysis.
deamination
Deamination is the removal of an amino group from a molecule. Enzymes that catalyse this reaction are called deaminases.
proteins are broken down into amino acids. (splitting the amino group from the amino acid )
The removed amino acid group converts to AMMONIA. which is toxic to the body.
AMMONIA sent to LIVER, converts to urea, excreted.
Transamination
Transamination is a chemical reaction that transfers an amino group to a ketoacid to form new amino acids.This pathway is responsible for the deamination of most amino acids. This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids (amino acids that can be synthesized de novo by the organism).
Vitamin B6 helps.
The carbon skeleton remains after deamination.
can be converted to another amino acid
can transform to pyruvate and then acetyl-coA to form ATP or various substrates for the TCA/KReb Cycle or ketone bodies.
Lipogenesis
Extra blood glucose after insulin triggers flucose to be taken in by cells and even after glycogen has been stored.
Glucose goes through glycolysis in cells cytoplasm to become pyruvate, which travels to mitochondria
In mitochondria pyruvate becomes acetyl coA which enters the kreb cycle to join oxaloacetate to form citric acid
The citric acid spolits up and frees acetyl coA which with the help of NADPH turns into fatty acid
Fatty acid + Glycerol = Triglyceride
Lipolysis/ Beta-oxidation (break down of fats during fasting)
Glucagon and Epinephrine can help trigger lipolysis.
Triggers hormone sensitive LIPASE
Triglycerides gets broken down into glycerol and fatty acids.
Fatty acids get sent to the blood and attach to ALBUMIN which escorts them into a cells mitochondria
(Beta Oxidation occurs: breakdown of fatty acids to produce energy).
Fatty acids in the cells mitochondria go through a series of reactions to yield acetyl coA which can enter the kreb/TCA cycle to yield energy.
ketogenesis/ketolysis
When fasting or type I diabetes the body gets triggered into gluconeogenesis in the Liver, uses up alot of the TCA cycle intermediates. (oxaloacetate)
- cGLucose levels are low, body attempts to gain energy from FATTY ACIDS VIA BETA OXIDATION. creates acetyl-coa
Acetyl- CoA builds up and creates ketone bodies in the liver (acetoacetic acid, acetone, beta-hydroxylbutryic acid).
KEtones moves out of LIVER go through KETOLYSIS. which breaks down ketone bodies for energy.
Non liver cells (brain, heart, skeletal muscles)
acid/base balance
A. PH
1. the more acidic the blood the lower the ph
2. The more basic the blood is, the higher the pH
B. CARBONIC ACID
1. The amount of carbonic acid is directly proportional to the amount of hydrogen ions being produced which are acidic.
2. An increase in carbonic acid in the body will lead to an increase in blood acidity, the PH will be lower.
C. BICARBONATE
1.A base made by the kidneys that acts as an antacid,
2. An increase in bicarbonate in the body will lead to a decrease in blood acidity which means that pH will be higher.
- The teams respiratory, carbonic acid and lungs are linked are linked together whereas the terms metabolic, bicarbonate and kidneys are linked together.
Acidosis
Acidosis: the body has too much acid
The pH of the blood is lower
- Respiratory acidosis
a. surplus of carbonic acid, which is causing the blood to become more acidic and causing the ph to drop.
b. Hypoventilation
c. Kidney retains bicarbonate to compensate - Metabolic acidosis
a. storage of bicarb, which is causing the blood to become more acidic and causing the pH level to drop
b. Lungs hyperventilate to compensate.
