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Unit 12: Digestive & Urinary System Lauren Palla, Period 6 - Coggle…
Unit 12: Digestive & Urinary System Lauren Palla, Period 6
Major Functions of the Digestive System
Break foodstuff down into nutrient molecules
Absorb molecules into blood stream
Take in food
Rid body of any indigestible remains
Digestive Enzymes
Most enzymes are supplied by the pancreas in order to digest chyme
Amylase
- produced @ mouth and pancreas to digest carbohydrates into sugars
Lipases
- produced @ pancreas to digest lipids and fats into glycerol and fatty acids
Protease
- produced @ pancreas to digest proteins into amino acids; prevents self-digestion
Nucleases
- produced @ the small intestine to digest nucleic acids
Major Organs of the Digestive System
Alimentary Canal/ GI Tract
- continuous muscular tube that runs from the mouth to anus; breaks down food into smaller pieces and absorbs fragments through lining into blood
Stomach
- a temporary storage tank that starts chem. breakdown of protein digestion; converts bolus into chyme
Glands @ fundus that produce gastric juice:
Mucous Neck Cells
- secrete thin, acidic mucus of unknown function
Parietal Cells
- secretions include hydrochloric acid (HCl) and intrinsic factor
HCl
- denatures protein, activates pepsin, kills bacteria, etc.
Intrinsic Factor
- glycoprotein required to absorb Vitamin B12
Chief Cells
- secretions include pepsinogen and lipases
Pepsinogen
- activated by pepsin (positive feedback mechanism)
Lipases
- digests ~15% of lipids
Enteroendocrine Cells
- secrete chem. messengers into lamina propia (ex. serotonin and histamine)
Rugae
- folds formed by stomach mucosa when stomach is empty
Major Regions:
Cardial Part
- surrounds cardial orifice
Fundus
- dome-shaped region beneath diaphragm
Body
- midportion of stomach
Pyloric Part
- wider and more superior portion of pyloric region
(antrum)
that narrows into pyloric canal that terminates @ pylorus
Digestive Process:
1) Carries out breakdown of food
2) Serves as holding area for food
3) Delivers chyme to small intestine
4) Denatures proteins by HCl
5) Pepsin carries out enzymatic digestion of proteins
6) Lipid-soluble alcohol and aspirin are absorbed into blood
7) Secretes intrinsic factor for Vitamin B12 absorption (needed for RBC mauration)
Small Intestine
- major organ of digestion and absorption
Subdivisions:
Jejunum
- attached post. by mesentary
Ileum
- attached post. by mesentary; joins large intestine @
ileocecal valve
Duodenum
- mostly retroperitoneal; curves around head of pancreas
Microscopic Anatomy:
Small intestine's length and other structural mod. provide huge surface area for nutrient absorption
Villi
- finger-like projections of mucosa that functions in absorption
Microvilli
- cytoplasmic ext. of mucosal cell that give fuzzy appearance
(brush border)
; used to final carbohydrate and protein digestion
Digestive Process:
After Meal:
Segmentation
- most common motion of small intestine; mixes and moves content toward ileocecal valve
Parasympathetic
- increases motility
Sympathetic
- decreases it
Between Meals:
Peristalsis
- increases, initiated by rise in hormone
motilin
in late intestinal phase
Meal remnants, bacteria, and debris are moved toward large intestine
Ileocecal Valve Control:
Ileocecal valve flaps close when chyme exerts backward pressure (prevents regurgitation into ileum)
Ileocecal Sphincter
- relaxes and admits chyme into large intestine
Gastroileal Reflex
- enhances force of segmentation in ileum
Gastrin inc. motility of ileum
Esophagus
- flat muscular tube that runs from the laryngopharynx to the stomach
Is collapsed when not involved in food propulsion
Gastroesophageal Sphincter
- surrounds cardial orifice and keeps it closed (when food isn't being swallowed)
Works w/ pharynx to act as conduits to pass food from the mouth to the stomach
Large Intestine
- organ that functions in the propulsion of feces to anus and defecation, as well as the reabsorption of vitamins, water, and electrolytes
Subdivisions:
Cecum
- first part of large intestine
Appendix
- masses of lymphoid tissue that functions as a bacterial storehouse that's capable of recolonizing gut when necessary
Rectum
- 3 rectal valves stop feces from being passed w/ gas
Colon
- has several regions, most of which are retroperitoneal
Ascending Colon
- travels up right side of abdominal cavity to level of right kidney
Descending Colon
- travels down left side of abdominal cavity
Transverse Colon
- travels across abdominal cavity
Sigmoid Colon
- S-shaped portion of large intestine that opens body ext. to anus
Anal Canal
- last segment of the large intestine that opens to body ext. to anus
Bacteria Flora
- consists of 1000+ diff.types of bacteria
Metabolic functions include: fermentation and vitamin synthesis
Diff. kinds and proportions of gut bacteria can influence: body weight, susceptibility to various diseases, and mood
Pharynx
- allows for the passage of food, fluids, and air
Food passes from mouth into oropharynx and then into laryngopharynx
Major function is propulsion that starts w/ swallowing
Rectum
- stores feces until individual is ready for bowel movement
Mouth
- where food is chewed and mixed w/ enzyme-containing saliva; begins digestion where swallowing process is initiated
Lips
- composed of fleshy orbicularis oris muscle
Cheeks
- composed of buccinator muscles
Palate
- forms roof of mouth; has 2 distinct parts
Hard Palate
- formed by palatine bones and palatine processes of maxillae
Soft Palate
- fold formed by skeletal muscle; closes naropharynx during swallowing
Anus
- carries feces to ext. of body
Accessory Digestive Organs
- contain
digestive glands
that produce secretions that help break down foodstuff
Tongue
- functions in gripping, repositioning, and mixing of food during chewing that eventually forms bolus; initiates swallowing, speech, and taste
Pancreas
- supplies most of enzymes needed to digest chyme and bicarbonate
Protease
- for protein
Amylase
- for carbohydrates
Lipases
- for lipids
Nucleases
- for nucleic acids
Liver
- digestive function is the production of bile
Bile
- yellow-green alkaline solution that functions as a fat emulsifier
Salivary Glands
- cleanses mouth, dissolves food chem, for taste, moistens food to compact into bolus, and begins the breakdown of starch w/
enzyme amylase
Serous Cells
- produce watery secretion
Mucous Cells
- produce mucus
Gallbladder
- chief function is the storage of bile by absorbing water and ions
Urinary and Digestive Disorders
Gastroesophageal Reflux Disease
(GERD)- a chronic disease that occurs when the esophageal sphincter relaxes and the contents of the stomach move back into the esophagus.
Symptoms include chest pain, heartburn, dysphagia (difficulty swallowing), etc.
Can be treated w/ over the counter or prescription medication, as well as surgery.
Risk factors include frequent acid reflux, weakened esophageal sphincter, and obesity.
Inflammatory Bowel Disease
(IBD)- a chronic complex intestinal condition that causes inflammation in digestive tract.
Causes are unknown, but could possibly be from genetics, environmental or immune factors.
Symptoms include abdominal pain, cramping, diarrhea, etc.
Can be treated w/ antibiotics, medication, or fluid replacement.
Cholecystitis
- an inflammation of the gallbladder
Risk factors include the blockage of the gall duct by gallstones, digestive tumors, and blockage of the bile duct.
Symptoms include tender abdomen, bloating, RUQ abdominal pain radiating to the right shoulder/back, etc.
Can be treated w/ medication, fasting, and antibiotics.
Colon Disease
Colorectal Cancer
- uncontrolled cell growth in colon.
Symptoms include changes in bowel movement, bloody stool, bloating, etc.
Risk factors include heredity, chem. exposure, and certain diets.
Can be treated w/ surgery, radiation therapy, and chemotherapy.
Hemorrhoids
- inflamed veins in the rectum or anus.
Risk factors include straining during bowel movement, obesity, and chronic diarrhea.
Symptoms include abdominal pain, cramping, constipation, etc.
Can be treated w/ medication, surgical removal, or injections.
Bladder Cancer
- when the cells of the bladder grow abnormally.
Risk factors include smoking/ inhaling tobacco smoke, exposure to chemicals, and heredity.
Symptoms include
Hematuria
(blood in urine), frequent and urgent urination, pain while urinating, back pain, etc.
Can be treated w/ surgery, chemotherapy, or radiation therapy.
Peptic Ulcers
- sores that develop in the lining of the stomach/ duodenum.
Risk factors include imbalances in gastric juices, bacterial infection, and NSAID overuse.
Symptoms include heartburn, severe chest pain, bloody vomit, etc.
Can be treated w/ lifestyle changes, medication, or endoscopic surgery.
Urinary Tract Infection
(UTI)- the abnormal growth of bacteria anywhere along the urinary tract.
Risk factors include being sexually active, menopause, and diabetes.
Symptoms include burning sensation with urination, pain on the lower pelvic area, cloudy urine, etc.
Can be treated w/ oral antibiotic pills, Phenoazopyridine, or Penicillin.
Kidney Stones
- hard stones that form due to high levels of minerals and salts in urine.
Risk factors include high levels of minerals and salts, lack of water, as well as high levels of protein.
Symptoms include a sharp, cramping pain in the back and side, intense need to urinate, burning sensation during urination, etc.
Can be treated w/
ureteroscopy
(URS),
percutaneous nephrolithotomy
(PCNL), or laparoscopic surgery*.
Nephron Anatomy & Physiology
Nephron
- a structural and functional unit that forms urine @ the kidneys (1 million per kidney)
Renal Corpuscle:
Glomerular Capsule
- cup-shaped, hallow structure surrounding glomerus
Parietal Layer
- simple squamous epithelial
Visceral Layer
- clings to glomerular cappilaries; branching epithilial
Glomerulus
- tuft capillaries composed of fenestrated endothelium
Highly porous capillaries; allows for efficient filtrate formation
Filtrate
- plasma-derived fluid that renal tubules process to form urine
Renal Tubule & Collecting Ducts:
Proximal Convoluted Tubule
- cuboidal cells w/ dense microvilli that forms brush border (closest to renal corpuscle)
Inc. surface area
Has large mitochondria
Confined to cortex
Functions in absorption and secretion
Nephron Loop
- U-shaped structure consisting of 2 limbs
Descending Limb
- proximal part is continuous w/ proximal tubule
Ascending Limb
- thick; cuboidal/ columnar cells
Collecting Ducts
- receive filtrate from many neurons; run through medullary pyramids
Fuse together to deliver urine through papillae into minor calyces
Two Cell Types:
Principle Cells
- sparse w/ short microvilli; maintain water and Na+ balance
Intercalated Cells
- cuboidal cells w/ abundant microvilli; maintains acid-base balance of blood
Distal Convoluted Tubule
- cuboidal cells w/ very few microvilli (farthest from renal corpuscle)
Functions more in secretion rather than reabsorption
Confined to cortex
Urine
- bodily fluid w/ a chemical composition of 95% water and 5% solutes
pH:
Urine is slightly acidic (~6 pH w/ range of 4.5-8.0); keeps down bacterial infections
Acidic Diet
(protein, whole wheat)- can cause drop in pH
Alkaline Diet
(vegetarian)- can cause an inc. in pH; can also be caused by prolonged vomitting or UTI
Odor:
Slightly aromatic when fresh
Develops ammonia odor upon standing as bacteria metabolize urea
Disease may alter small (ex. diabetes have acetone smell to urine)
May be altered by drugs/ vegetables
Color & Transparency:
Clear
- cloudy may indicate UTI
Pale to Deep Yellow
- from urochrome and hemoglobin breakdown; yellow deepens w/ inc. concentration
Abnormal Color
(brown, pink, smoky)- caused by certain foods, drugs, etc.
Nitrogenous Waste:
Creatinine
- metabolite of creatine phosphate
Urea
- assists in amino acid breakdown; is the largest solute component
Uric Acid
- assists in nucleic acid metabolism
Abnormally high concentrations/ components (ex. blood proteins, WBCs, bile pigments) may indicate pathology
Steps to Making Urine:
1)
Glomerular Filtration
- a passive process where hydrostatic pressure forces fluids and solutes through filtration membrane into
glomerular capsule
2)
Tubular Reabsorption
- quickly reclaims most of the tubular contents and returns them to blood
3)
Tubular Secretion
- selected substances (ex. K+, H+, NH4+, etc.) are moved from the pertibular capillaries through tubular cells out into filtrate
Disposes of substances bound to plasma patterns (ex. drugs)
Eliminates undesirable substances that were passively reabsorbed (ex. urea, uric acid)
Controls blood pH by altering amounts of H+/ HCO3- in urine
Rids body of excess K+
Locations of Digestion & Absorption of Each Macromolecule
Carbohydrates
- digested @ the mouth and small intestine
Glucose and galactose are absorbed via contransport w/ Na+
Fructose passes via diffusion
All monossaccharides leave the epithelial cells via facilitated diffusion
Are transported to the liver via the
hepatic portal vein
Monossaccharides enter the capillary blood @ villi
Proteins
- digested @ stomach and small intestine
Amino Acids are absorbed via cotransport w/ Na+
Some dipeptides and tripeptides are absorbed via cotransport w/ H+ and hydolyzed to amino acids w/ in cells
Infrequently, transcytosis of small peptide occurs
Amino acids leave the epithelial cells by facilitated diffusion
They then enter the capillary blood in the villi
Are transported to the liver via the hepatic portal vein
Lipids
- digested @ mouth, stomach, and small intestine
Fatty acids and monoglycerides enter the intestinal cells via diffusion
Fatty acids and monoglycerides are recombined to form triglycerides and then combines w/ other lipids and proteins; results in the extrusion of chylomicrons
The chylomicrons enter the lacteals of the villi and are transported to the systemic circulation via lymph
Some shirt-chain fatty acids are absirbed, moved into the capillary blood in the villi by diffusion, and are transported to the liver via hepatic portal vein
Nucleic Acids
- digested @ the small intestine
Units enter intestinal cells by active transport via membrane carriers
Units are absorbed into capillary blood in the villi and transported to the liver via the hepatic portal vein
Major Organs of the Urinary System
Ureters
- slender tubes that convey urine from kidneys to bladder
Enters base of bladder through post. wall
As bladder pressure inc., distal ends of ureters close to prevent the backflow of urine
Urinary bladder
- muscular sac of temporary storage of urine
Retroperitoneal @ pelvic floor post. to pubic symphysis
Males
: prostate inf. to bladder neck
Females
: ant. to vagina and uterus
Urine Storage Compacity:
Rugae
appear
Expands and rises sup. during filling w/o significant rise @ int. pressure
Collapses when empty
Moderately full bladder is ~12 cm long and can hold ~500 ml
Can hold 2x amount if necessary (can burst if overdistended)
Kidneys
- maintain the body's internal environment and cleanses blood
Excretes metabolic wastes, toxins, and drugs
Produces
erythropoietin
(regulates blood pressure and RBC production)
Ensures long-term acid-based balance
Activates Vitamin D
Regulates ion concentrations in ECF
Carries out
gluconeogenisis
(to make glucose from the breakdown of lipids/ fat)
Regulates total water vol. and solute concentration in water
Adjusts blood's composition so the body can obtain a rich blood supply
Arterial Flow
(carries blood to kidneys):
2) Renal
3) Segmental
4) Interlobar
5) Arcuate
6) Cortical Radiate
1) Aorta
Venous Flow
(carries blood away from kidneys):
1) Cortical Radiate
2) Arcuate
3) Interlobar
4) Renal
5) Inferior Vena Cava
Urethra
- muscular tube that drains urinary bladder and transports the urine out of the body
Layers of GI Tract
4)
Serosa
- outermost layer
2)
Submucosa
- consists of areolar C.T.
Contains blood/lymphatic vessels, lymphoid follicles, and submucosal nerve plexus (supply surrounding GI tract tissues)
Has abundant amt. of elastic tissues (helps organs regain shape after large meal)
1)
Mucosa
- tunic layer that lines lumen (closest to food)
Absorbs end products of digestion
Protects against infectious disease
Secrete mucus, digestive enzymes, and hormones
3)
Muscularis Externa
- muscle layer responsible for segmentation and peristalsis
Contains inner circular muscle layer and outer longitudinal layers
Circular layer thickens, which forms sphincters
Major Functions of the Urinary System
Filter blood
Produce urine
Maintain the body's int. environment