Please enable JavaScript.
Coggle requires JavaScript to display documents.
Gastrointestinal & The Renal System, Medinna Rasha - 2506557816 -…
Gastrointestinal & The Renal System
GASTROINTESTINAL SYSTEM
Organs and Functions
Mouth: mechanical digestion (chewing), saliva starts starch digestion.
Pharynx: passage for bolus, swallowing.
Esophagus: transports food to stomach via peristalsis.
Stomach: stores food, begins protein digestion, produces chyme.
Small Intestine (duodenum, jejunum, ileum): digestion and nutrient absorption.
Large Intestine (cecum, colon, rectum): absorbs water/electrolytes, forms/stores feces.
Rectum: stores feces.
Anus: controls feces elimination.
Digestive Glands and Functions
Salivary glands: saliva production with enzymes, lubricate food.
Gastric glands: HCl, pepsinogen, mucus secretion.
Liver: bile production for fat emulsification, nutrient processing.
Gallbladder: stores/concentrates bile.
Pancreas: digestive enzymes, bicarbonate secretion.
Intestinal glands: mucus and enzyme secretion.
Vasculature
Celiac trunk supplies foregut (stomach, liver, spleen, pancreas).
Superior mesenteric artery supplies midgut (small intestine, proximal colon).
Inferior mesenteric artery supplies hindgut (distal colon, rectum).
Venous drainage via portal vein to liver.
Lymphatics absorb dietary fats.
Innervation
Enteric Nervous System: myenteric (motility), submucosal (secretion, blood flow).
Parasympathetic (vagus nerve, pelvic splanchnics): stimulates digestion, motility.
Sympathetic (T5-L2): inhibits digestion, constricts blood vessels.
Sensory afferents convey stretch, chemical, pain signals
Four Basic Processes of Digestion
Ingestion: intake of food/liquids.
Digestion: mechanical (chewing, churning) + chemical (enzymes).
Absorption: nutrients into blood/lymph, mostly in small intestine.
Elimination: defecation of undigested material.
Phases of Digestion
Cephalic: before eating, triggered by sight/smell/taste.
Gastric: food in stomach, stimulates secretion/mixing.
Intestinal: chyme in small intestine, regulates gastric emptying and secretion.
Digestion and Metabolism of Macromolecules
Carbohydrates → monosaccharides.
Proteins → amino acids and small peptides.
Fats → monoglycerides and free fatty acids.
Defecation Reflex
Feces enter rectum → stretch receptors activated.
Signal to sacral spinal cord → parasympathetic stimulation.
Rectal muscles contract, internal anal sphincter relaxes.
Voluntary control of external sphincter determines defecation.
Energy Balance and Control
Balance between calories consumed and burned.
Regulated by neuroendocrine, autonomic, hormonal, and environmental factors.
Maintains stable body weight.
Energy Balance and Body Temperature Regulation
Heat generated by metabolism (ATP production).
Hypothalamus controls thermoregulation.
Responses: vasodilation, sweating (cooling); vasoconstriction, shivering (warming).
Energy expenditure adjusts to maintain body temperature.
RENAL SYSTEM
Parts and Functions
Kidneys: filter blood, regulate water/electrolytes, produce hormones.
Ureters: transport urine to bladder.
Bladder: stores urine, signals need to urinate.
Urethra: expels urine, sphincter control.
Urine Formation Process
Glomerular filtration: plasma filtered into Bowman's capsule.
Tubular reabsorption: valuable substances reabsorbed into blood.
Tubular secretion: wastes and ions secreted into tubules
Body Fluids Distribution and Composition
Intracellular fluid (ICF): 40% body weight, high K+.
Extracellular fluid (ECF): 20% body weight, includes plasma and interstitial fluid, high Na+.
Transcellular fluid: small specialized compartments (CSF, synovial).
Water Balance and Control
Intake equals output to maintain stable fluid volume.
Regulated by osmoreceptors and baroreceptors.
ADH controls kidney water reabsorption.
Thirst mechanism regulates intake.
Electrolyte Balance and Control
Intake equals loss, maintaining plasma and fluid electrolyte levels.
Kidneys regulate via filtration, reabsorption, secretion.
Hormones: aldosterone (Na+, K+), PTH and vitamin D (Ca2+, phosphate).
Neural and cardiovascular inputs adjust balance.
Blood pH Maintenance
Chemical buffer systems (bicarbonate, proteins, phosphate).
Respiratory control: CO2 regulation via ventilation.
Renal regulation: excretion/reabsorption of H+ and HCO3-.
Medinna Rasha - 2506557816