Upload
hary-anggoro
View
220
Download
1
Embed Size (px)
Citation preview
Process of Digestion Hormonal Regulation of Fuel
MetabolismDWI NOVITASARI, S.Kep.,Ns., M.Sc
DIGESTIVE SYSTEM
• The three fundamental processes that take place are: – Secretion: Delivery of enzymes, mucus, ions and the
like into the lumen, and hormones into blood. – Absorption: Transport of water, ions and nutrients
from the lumen, across the epithelium and into blood. – Motility: Contractions of smooth muscle in the wall of
the tube that crush, mix and propel its contents.
FROM MACROMOLECULES INTO MONOMERS
Human Nutritional Needs Food is used for two purposes: as fuel
(to provide energy for cellular metabolism) and as a source of
building blocks (monomers for cellular biosynthesis)
› Basic nutrients: carbohydrates, lipids, proteins, minerals, vitamins
FOOD
BRAINHORMONHORMONHORMONHORMONHORMONHORMONHORMONHORMON
VOLUNTARY
INVOLUNTARY
THE GI SYSTEM
TRACHEA
STOMACH
PANCREAS
SMALL INTESTINE
LARGE INTESTINE
ANUSRECTUM
GALLBLADDER
SUBMANDIBULARSALIVARY GLANDS
SUBLINGUALAND
MOUTH PAROTIDSALIVARY GLAN
Adapted by:Dr. Andreanyta Meliala, PhD.
LIVER
HeartLiver
ABSORPTION
SECRETION
Large intestine
RectumAnusMouth
Food andwater
StomachHepatic
Portal vein
Small intestineSalivary glands
MOTILITY
THE GI DIAGRAM
FECES
enzim asam, dllVitamin
C, D, B2, B12, dllProteinMineral
KarbonhidratLipid
Adapted by:Dr. Andreanyta Meliala, PhD.
Vitamin KAir, Elektrolit
AktifitasBAKTERI
Pembentukan Gas CO2, Metana, dll
FLATUS
Parotid ductParotid gland
Submandibular gland
Sublingual gland
NAMES AND LOCATION OF THE MAJOR SALIVARY GLAND IN THE HUMAN
Adapted by:Dr. Andreanyta Meliala, PhD.
Hard Palate
Tongue
Epiglottis
Upper esophagealsphincter
Soft Palate
Pharynx
Esophagus
Adapted by:Dr. Andreanyta Meliala, PhD.
MOVEMENTS OF FOOD THROUGH THE PHARYNX AND UPPER ESOPHAGUS DURING SWALLOWING
Fundus
Body(secretes mucus
Pepsinogen and HCI)
Esophagus
Duodenum
Pyloricsphincter
Antrium(secretes mucus
Pepsinogen and gastrin)
THE THREE REGIONS OF THE STOMACH :FUNDUS, BODY, AND ATRIUM
Adapted by:Dr. Andreanyta Meliala, PhD.
Adapted by:Dr. Andreanyta Meliala, PhD.
PERISTALTIC WAVESCONTRIBUTE TO THE ANTRAL CONTENTS
Esophagus
LowerEsophagealsphincter
Duodenum
Pyloricsphincter
Stomach Peristalticwave
Intestinal Movements
Segmentation › Mixing mucous and enzyme
Slow peristaltic contractions to encourage absorption
Local contractions (no CNS involvement)
It takes appr. 5 hrs to digest & move chymus from duodenum to ileum
Colon Motility
pattern of motility - Haustration (slow segmentation) - Mass movement (slow peristaltic; 3-4 times/day)DefecationDistension of rectum stimulates sigmoid colon and smooth muscle of rectal wall relaxation of internal sphincter muscle (outonomic nerve) Defecation conducts when external sphincter muscle is relaxed
REGULATION OF GI FUNCTION
Complex regulation with overlappingpathways that involve:
› Neural› Endocrines› Local control mechanism (little brain;
enteric nervous system)
Regulasi sistem GI
Nerve RegulatorsExtrinsic (outside) nervesrelease acetylcholine and another called
adrenaline. Acetylcholine causes the muscle of the digestive
organs to squeeze with more force and increase the "push" of food
Acetylcholine also causes the stomach and pancreas to produce more digestive juice. Adrenaline relaxes the muscle of the stomach and intestine and decreases the flow of blood to these organs.
The intrinsic (inside) nerves are triggered to act when the walls of the organs are stretched by food.
They release many different substances that speed up or delay the movement of food and the production of juices by the digestive organs.
FOOD PROCESSING
Includes: Ingestion Digestion Absorption Elimination
Mechanical Breakdown Biting Chewing Grinding Emulsification
Increases surface area for enzymatic attack
Sekresi lambung: - HCL - pepsinogen - Gastrin
Sekresi di usus halus Kurang lebih 1.8 L Fungsi pelumas Buffer melarutkan enzym dari pankreas
Sekresi Pankreas
Absorbsi
Absorbsi monosakarida
Absorbsi monogliserida dan asam lemak
Absorbsi asam amino
Vitamin Larut lemak (A, D, E, K): lewat bersama lipid Larut air (B, C): masuk bersama airB12 : faktor intrinsik di lambung mengikat B12 dan diabsorbsi di ileum
Air dan mineralMirip reabsobsi di tubulus ginjal dengan aktif transport Na, reabsorbsi air secara pasif mengikuti gradien osmotikNormalnya 95% air masuk usus kecil sebelum masuk kolonCl mengikuti Na dari lumen GI ke dalam darah Kalsium, potassium, magnesium, iodine, bicarbonate, iron
Absorbsi di kolon Reabsorbsi air
› 1500 mL/hr di kolon; 1300 mL reabsorbsi
› Feses terdiri: - 75% air - 5% bakteri - 20% undigested
material, inorganic material,
epitel Reabsobsi garam empedu, vitamin,
bilirubin, toxins
Bile salts› Reabsorbsi, dibawa ke hepar
Vitamin› Bakteri di kolon membentuk 3 vitamin
Vitamin K: fat soluble; diperlukan untuk sintesis faktor pembekuan di hati
Biotin: water soluble; diperlukan untuk metabolisme glukosa
Vitamin B5: water soluble; diperlukan untuk biosintesis hormon steroid dan beberapa neurotransmiter
The blood glucose level involve the combined actions of insulin, glucagon, epinephrine, and cortisol on metabolic processes in many body tissues, but especially in liver, muscle, and adipose tissue.
The pancreas secretes insulin or glucagon in response to changes in blood glucose
GASTRIN
Origin: StomachStimulus: Food in stomachFunction: Stimulates HCl & pepsinogen secretion, increases stomach motility
GASTRIN actions in general: stimulates gastric secretion
& motility1. Stimulates gastric acid secretion2. Stimulates pepsin&intrinsic factor
secretion by the stomach3. Stimulates growth of gastric &
intestinal mucosa (‘thropic action’)4. Increase the tone of musculature of
the LOS,stomach & small intestine5. Stimulates insulin and glucagon
secretion (after a protein meal)6. Stimulates calcitonin secretion
SECRETINOrigin: DuodenumStimulus: AcidFunction: Stimulates pancreatic secretions. Slows stomach motility and acid production
SECRETIN actions1. Stimulates bicarbonate rich-watery alkaline
pancreatic juice by increasing bicarbonate secretion of biliary tract
2. Increases bicarbonate secretion of biliary tract
3. Augments the action of CCK-PZ in producing pancreatic secretion of digestive enzymes
4. Decreases gastric acid secretion5. May cause contraction of the pyloric
sphincter6. Increases insulin secretion; but inhibits
glucagon secretion
Cholecystokininu/ pemecahan lemak
Stressors (anxiety, fear, pain, hemorrhage, infections, low blood glucose, starvation) stimulate hormone cortisol, acts on muscle, liver, and adipose tissue to supply the organism with fuel
In adipose tissue, cortisol leads to an increase in the release of fatty acids from stored TAGs gluconeogenesis in the liver.
Cortisol stimulates the breakdown of muscle proteins and the export of amino acids to the liver for gluconeogenesis.
In the liver, cortisol promotes gluconeogenesis by stimulating synthesis of the key enzyme PEP carboxykinase
Adipose tissue produces leptin that regulates feeding behavior and energy expenditure so as to maintain adequate reserves of fat.
Leptin acts on receptors in the arcuate nucleus of the hypothalamus, causing the release of anorexigenic peptides, including α-MSH, that act in the brain to inhibit eating
Leptin also stimulates sympathetic nervous system action on adipocytes, leading to uncoupling of mitochondrial oxidative phosphorylation, with consequent thermogenesis.
The orexigenic (appetite-stimulating) neurons stimulate eating by producing and releasing:1. neuropeptide Y (NPY)2. α-melanocyte-stimulating hormone (α
MSH)
Ghrelin hormone
Produced in the stomach
Acts on orexigenic neurons in the arcuate nucleus to produce hunger before a
meal
The hormone adiponectin stimulates:
1. fatty acid uptake and oxidation2. inhibits fatty acid synthesis