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Justin Cabrera P.6 Digestive & Urinary system - Coggle Diagram
Justin Cabrera P.6
Digestive & Urinary system
Major functions of the urinary system
Kidneys
major excretory organ, maintain the body’s internal environment
Ensuring long-term acid-base balance
Excreting metabolic wastes, toxins, drugs
Regulating ion concentrations in extracellular fluid (ECF)
Producing erythropoietin (regulates blood pressure and renin (regulates RBC production)
Regulating total water volume and total solute concentration in water
Activating vitamin D
Carrying out gluconeogenesis, if needed
Urinary bladder
temporary storage reservoir for urine
Urethra
transports urine out of body
Ureters
transport urine from kidneys to urinary bladder
Glomerular Filtration
passive process
No metabolic energy required
Hydrostatic pressure forces fluids and solutes through filtration membrane into glomerular capsule
No reabsorption into capillaries of glomerulus occurs
Tubular Reabsorption
Includes active and passive tubular reabsorption
Substances can follow two routes
Paracellular
Transcellular
Selective transepithelial process
Water and ion reabsorption is hormonally regulated and adjusted
Almost all organic nutrients are reabsorbed
quickly reclaims most of tubular contents and returns them to blood
Tubular Secretion
reabsorption in reverse
Occurs almost completely in PCT
Selected substances are moved from peritubular capillaries through tubule cells out into filtrate
𝐾+,𝐻+,𝑁𝐻4
+,creatinine, organic acids and bases
Substances synthesized in tubule cells also are secreted
Tubular secretion is important for
Ridding body of excess 𝐾+
Eliminating undesirable substances that were passively reabsorbed
Controlling blood 𝑝𝐻 by altering amounts of H+ or 𝐻𝐶𝑂3– in urine
Disposing of substances, such as drugs or metabolites, that are bound to plasma proteins
Major organs of the digestive system
Accessory digestive organs
Gallbladder
chief function is storage of bile
thin-walled muscular sac on ventral surface of liver
Functions
store and concentrate bile by absorbing water and ions
Tongue
occupies floor of mouth
Functions
Formation of bolus, mixture of food and saliva
Initiation of swallowing, speech, and taste
Gripping, repositioning, and mixing of food during chewing
Lingual frenulum
attachment to floor of mouth
Digestive glands
Salivary glands
types of secretory cells
Mucous cells
produce mucus
Serous cells
produce watery secretion, enzymes, ions, bit of mucin
Functions
Dissolves food chemicals for taste
Begins breakdown of starch with enzyme amylase
Cleanses mouth
Moistens food; compacts into bolus
Liver
digestive function is production of bile
Bile
fat emulsifier
Composition and enterohepatic circulation
Yellow-green, alkaline solution
Bile salts
cholesterol derivatives that function in fat emulsification and absorption
Bilirubin
pigment formed from heme
Bacteria break down in intestine to stercobilin that gives brown color of feces
Cholesterol, triglycerides, phospholipids, and electrolytes
Gross anatomy of the liver
Largest gland in body; weighs ~3 lbs
Consists of four primary lobes
caudate
quadrate
left
right
Bile ducts
Cystic duct connects to gallbladder
Bile duct formed by union of common hepatic and cystic ducts
Common hepatic duct leaves liver
produce secretions that help break down foodstuffs
Pancreas
supplies most of enzymes needed to digest chyme, as well as bicarbonate to neutralize stomach acid
Exocrine function
produce pancreatic juice
Endocrine function
secretion of insulin and glucagon by pancreatic islet cells
Composition of pancreatic juice
Watery, alkaline solution (pH 8) to neutralize acidic chyme coming from stomach
Teeth
Dentition and the dental formula
32 deep-lying permanent teeth enlarge and develop while roots of milk teeth are resorbed from below, causing them to loosen and fall out
Primary dentition consists of 20 deciduous teeth, or milk or baby teeth, that erupt between 6 and 24 months of age
Teeth Shape
Canines
fanglike teeth that tear or pierce
Premolars (bicuspids)
broad crowns with rounded cusps used to grind or crush
Incisors
chisel shaped for cutting
Molars
broad crowns, rounded cusps: best grinders
During chewing, upper and lower molars lock together, creating tremendous crushing force
Mastication
process of chewing that tears and grinds food into smaller fragments
lie in sockets in gum-covered margins of mandible and maxilla
Tooth structure
Each tooth has two major regions
Root
portion embedded in jawbone
Connected to crown by neck
Crown
exposed part above gingiva (gum)
Covered by enamel, the hardest substance in body
Alimentary canal (gastrointestinal/GI tract/gut)
Absorbs fragments through lining into blood
Digests food
breaks down into smaller fragments
Organs
esophagus
Flat muscular tube that runs from laryngopharynx to stomach
Is collapsed when not involved in food propulsion
Gastroesophageal (cardiac) sphincter surrounds cardial orifice
Mucus cells on both sides of sphincter help protect esophagus from acid reflux
Keeps orifice closed when food is not being swallowed
Function
propulsion that starts with deglutition (swallowing)
stomach
temporary storage tank that starts chemical breakdown of protein digestion
When empty, stomach mucosa forms many folds called rugae
Empty stomach has ~50 ml volume but can expand to 4 L
Converts bolus of food to paste-like chyme
Major regions of the stomach
Body
midportion
Pyloric part
wider and more superior portion of pyloric region, antrum, narrows into pyloric canal that terminates in pylorus
Pylorus is continuous with duodenum through pyloric valve (sphincter controlling stomach emptying)
Fundus
dome-shaped region beneath diaphragm
Cardial part (cardia)
surrounds cardial orifice
Gross Anatomy of the Stomach
Mesenteries extend from curvatures and tether stomach to other digestive organs
Greater omentum
drapes inferiorly from greater curvature over intestine, spleen, and transverse colon
Contains fat deposits and lymph nodes
Blends with mesocolon, mesentery that anchors large intestine to abdominal wall
Lesser omentum
Runs from lesser curvature to liver
Lesser curvature
concave medial surface of stomach
Greater curvature
convex lateral surface of stomach
Types of Gland Cells
Glands include secretory cells
Parietal cells
Secretions include
Intrinsic factor
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Hydrochloric acid (HCl)
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Mucous neck cells
Secrete thin, acidic mucus of unknown function
Chief cells
Secretions
Pepsinogen
inactive enzyme that is activated to pepsin by HCl and by pepsin itself (a positive feedback mechanism)
Lipases
Digests ~15% of lipids
Glands in fundus and body produce most gastric juice
Enteroendocrine cells
Secrete chemical messengers into lamina propria
Act as paracrines
Serotonin
histamine
Hormones
Somatostatin
gastrin
Mucosal barrier
Harsh digestive conditions require stomach to be protected
protects stomach and is created by three factors
Damaged epithelial cells are quickly replaced by division of stem cells
Surface cells replaced every 3–6 days
Thick layer of bicarbonate-rich mucus
pharynx
Food passes from mouth into oropharynx and then into laryngopharynx
External muscle layers consists of two skeletal muscle layers
Allows passage of food, fluids, and air
Function
propulsion that starts with deglutition (swallowing)
Mouth(oral (buccal) cavity)
Oral orifice is the anterior opening
Walls of mouth lined with stratified squamous epithelium
Lips and cheeks
Lips (labia)
composed of fleshy orbicularis oris muscle
Cheeks
composed of buccinator muscles
Labial frenulum
median attachment of each lip to gum
Palate
forms the roof of the mouth and has two distinct parts
Hard palate
formed by palatine bones and palatine processes of maxillae with a midline ridge called raphe
Soft palate
Closes off nasopharynx during swallowing
Uvula
fingerlike projection that faces downward from free edge of soft palate
fold formed mostly of skeletal muscle
small intestine
major organ of digestion and absorption
from pyloric sphincter to ileocecal valve, point at which it joins large intestine
Subdivisions
Jejunum
attached posteriorly by mesentery
Duodenum
mostly retroperitoneal
curves around head of
pancreas
Has most features
Ileum
attached posteriorly by mesentery; joins large intestine at ileocecal valve
Modifications of small intestine for absorption
Small intestine’s length and other structural modifications provide huge surface area for nutrient absorption
Villi
Fingerlike projections of mucosa
a core that contains dense capillary bed and lymphatic capillary called a lacteal for absorption
Microvilli
Cytoplasmic extensions of mucosal cell that give fuzzy appearance called the brush border
contains membrane-bound enzymes brush border enzymes, used for final carbohydrate and protein digestion
large intestine
three unique features not seen
Haustra
pocketlike sacs caused by tone of teniae coli
Epiploic appendages
fat-filled pouches of visceral peritoneum
Teniae coli
three bands of longitudinal smooth muscle in muscularis
Subdivisions
Colon
has several regions, most which are retroperitoneal (except for transverse and sigmoid regions)
Descending colon
travels down left side of abdominal cavity
Sigmoid colon
S-shaped portion that travels through pelvis
Transverse colon
travels across abdominal cavity
Ends in another right-angle turn, left colic (splenic) flexure
Ascending colon
travels up right side of abdominal cavity to level of right kidney
Ends in right-angle turn called right colic (hepatic) flexure
Rectum
three rectal valves stop feces from being passed with gas (flatus)
Appendix
masses of lymphoid tissue
Twisted shape of appendix makes it susceptible to blockages
Bacterial storehouse capable of recolonizing gut when necessary
Anal canal
last segment of large intestine that opens to body exterior at anus
Has two sphincters
External anal sphincter: skeletal muscle
Internal anal sphincter: smooth muscle
Cecum
first part of large intestine
anus
Continuous muscular tube that runs from the mouth to anus
Major organs of the urinary systems
Kidneys
Renal medulla
deep to cortex, composed of cone-shaped medullary (renal) pyramids
Renal pyramids are separated by renal columns, inward extensions of cortical tissue
Lobe
medullary pyramid and its surrounding cortical tissue; about eight lobes per kidney
Papilla, tip of pyramid, points internally
Broad base of pyramid faces cortex
Renal pelvis
Funnel-shaped tube continuous with ureter
Major calyces
Areas that collect urine from minor calyces
Empty urine into renal pelvis
Minor calyces
Cup-shaped areas that collect urine draining from pyramidal papillae
Urine flow
1.Renal pyramid
2.minor calyx
3.major calyx
4.renal pelvis
5.ureter
Renal cortex
granular-appearing superficial region
Blood and Nerve Supply
Blood
kidneys cleanse blood and adjust its composition, so it has a rich blood supply
Renal arteries deliver about one-fourth (1200 ml) of cardiac output to kidneys each minute
Venous flow
arcuate
interlobar
cortical radiate
renal veins
Arterial flow
2.segmental
3.interlobar
1.renal
4.arcuate
cortical radiate
Physiology of Kidney
180 L of fluid processed daily, but only 1.5 L of urine is formed
Consume 20–25% of oxygen used by body at rest
Filtrate (produced by glomerular filtration) is basically blood plasma minus proteins
Kidneys filter body’s entire plasma volume 60 times each day
Urine is produced from filtrate
Urine
Contains metabolic wastes and unneeded substances
<1% of original filtrate
Chemical composition
95% water and 5% solutes
Nitrogenous wastes
Uric acid (from nucleic acid metabolism)
Creatinine (metabolite of creatine phosphate)
Urea (from amino acid breakdown): largest solute component
Abnormally high concentrations of any constituent, or abnormal components such as blood proteins, WBCs, and bile pigments, may indicate pathology
Physical characteristics
Odor
May be altered by some drugs or vegetables
Disease may alter smell
Patients with diabetes may have acetone smell to urine
Develops ammonia odor upon standing as bacteria metabolize urea
Slightly aromatic when fresh
pH
Urine is slightly acidic
Acidic diet (protein, whole wheat) can cause drop in 𝑝𝐻
Alkaline diet (vegetarian), prolonged vomiting, or urinary tract infections can cause an increase in 𝑝𝐻
Color and transparency
Pale to deep yellow from urochrome
Pigment from hemoglobin breakdown
Yellow color deepens with increased concentration
Abnormal color (pink, brown, smoky)
Can be caused by certain foods, bile pigments, blood, drugs
Clear
Cloudy may indicate urinary tract infection
urethra
Muscular tube that drains urinary bladder
Ureters
slender tubes that convey urine from kidneys to bladder
Enter base of bladder through posterior wall
As bladder pressure increases, distal ends of ureters close, preventing backflow of urine
Urinary Bladder
Urine storage capacity
Expands and rises superiorly during filling without significant rise in internal pressure
Moderately full bladder is ~12 cm long (5 in.) and can hold ~ 500 ml (1 pint)
Can hold twice that amount if necessary but can burst if overdistended
Rugae appear
Collapses when empty
Urinary bladder anatomy
Muscular sac for temporary storage of urine
Retroperitoneal, on pelvic floor posterior to pubic symphysis
Females: anterior to vagina and uterus
Males: prostate inferior to bladder neck
Major functions of the digestive system
Absorb molecules into the bloodstream
Break it down into nutrient molecules
Rid body of any indigestible remains
Take in food
Digestive process
Mechanical breakdown
includes chewing, mixing food with saliva, churning food in stomach, and segmentation
Segmentation: local constriction of intestine that mixes food with digestive juices
Digestion
series of catabolic steps that involves enzymes that break down complex food molecules into chemical building blocks
Propulsion
movement of food through the alimentary canal
Swallowing
Peristalsis
major means of propulsion of food that involves alternating waves of contraction and relaxation
Absorption
passage of digested fragments from lumen of GI tract into blood or lymph
Ingestion
eating
Defecation
elimination of indigestible substances via anus in form of feces
Digestive process of stomach
Denatures proteins by HCl
Delivers chyme to small intestine
Pepsin carries out enzymatic digestion of proteins
Milk protein (casein) is broken down by rennin in infants
Serves as holding area for food
Lipid-soluble alcohol and aspirin are absorbed into blood
Carries out breakdown of food
Only stomach function essential to life is secretion of intrinsic factor for vitamin B12 absorption
Treated with B12 injections
Lack of intrinsic factor causes pernicious anemia
B12 needed for red blood cells to mature
Digestive process of Small Intestine
Chyme from stomach contains partially digested carbohydrates and proteins and undigested fats
Takes 3–6 hours in small intestine to absorb all nutrients and most water
Motility of the small intestine
After a meal
Segmentation
most common motion of small intestine
Intensity is altered by long and short reflexes and hormones
Mixes/moves contents toward ileocecal valve
Initiated by intrinsic pacemaker cells
Parasympathetic increases motility; sympathetic decreases it
Between meals
Meal remnants, bacteria, and debris are moved toward large intestine
Complete trip from duodenum to ileum takes ~2 hours
Peristalsis increases, initiated by rise in hormone motilin in late intestinal phase
Ileocecal valve control
Ileocecal sphincter relaxes and admits chyme into large intestine
Gastrin increases motility of ileum
Gastroileal reflex enhances force of segmentation in ileum
Ileocecal valve flaps close when chyme exerts backward pressure
Prevents regurgitation into ileum
Digestive process of Large Intestine
Residue remains in large intestine 12–24 hours
No food breakdown occurs except what enteric bacteria digest
Major functions
Reabsorption of vitamins,water, and electrolytes
Propulsion of feces to anus and defecation
Defecation
Mass movements force feces toward rectum
Muscles of rectum contract to expel feces
Digestive enzymes
Lipases (for lipids)
Amylase (for carbohydrates)
Nucleases (for nucleic acids)
Proteases (for proteins)
secreted in inactive form to prevent self-digestion
Nephron anatomy and physiology
structural and functional units that forms urine in the Kidneys
1 million per kidney
Two main parts
Renal tubule
Consists of single layer of epithelial cells, but each region has its own unique histology and function
Three major parts
Nephron loop
Distal convoluted tubule
Distal, farthest from renal corpuscle
Cuboidal cells with very few microvilli
Function more in secretion than reabsorption
Confined to cortex
Proximal convoluted tubule
Proximal, closest to renal corpuscle
Cuboidal cells with dense microvilli that form brush border
Increase surface area
Also have large mitochondria
Functions in reabsorption and secretion
Confined to cortex
Distal convoluted tubule drains into collecting duct
Proximal convoluted tubule (PCT)
Distal convoluted tubule (DCT)
Nephron loop(loop of Henle)
U-shaped structure consisting of two limbs
Ascending limb
Thick ascending limb
Thin in some nephrons
Cuboidal or columnar cells
Descending limb
Proximal part of descending limb is continuous with proximal tubule
Distal portion also called descending thin limb; simple squamous epithelium
Collecting ducts
Two cell types
Intercalated cells
Cuboidal cells with abundant microvilli
Two types of intercalated cells
A and B: both help maintain acid-base balance of blood
Principal cells
Sparse with short microvilli
Maintain water and 𝑁𝑎+ balance
Collecting ducts receive filtrate from many nephrons
Run through medullary pyramids
Give pyramids their striped appearance
Ducts fuse together to deliver urine through papillae into minor calyces
Renal corpuscle
Glomerular capsule(Bowman’s capsule)
cup-shaped, hollow structure surrounding glomerulus
Consists of two layers
Visceral layer
clings to glomerular capillaries; branching epithelial podocytes
Filtration slits between foot processes allow filtrate to pass into capsular space
Extensions terminate in foot processes that cling to basement membrane
Parietal layer:
simple squamous epithelium
Glomerulus
Tuft of capillaries composed of fenestrated endothelium
Highly porous capillaries
Allows for efficient filtrate formation
Filtrate: plasma-derived fluid that renal tubules process to form urine
Layers of the GI tract
Peritoneum
serous membranes of abdominal cavity
Visceral peritoneum
membrane on external surface of most digestive organs
Parietal peritoneum
membrane that lines body wall
Peritoneal cavity
Fluid lubricates mobile organs
Fluid-filled space between two peritoneum's
Mesentery
double layer of peritoneum; layers are fused back to back
Provides routes for blood vessels, lymphatics, and nerves
Extends from body wall to digestive organs
Holds organs in place and also stores fat
Intraperitoneal (peritoneal) organs
organs that are located within the peritoneum
Retroperitoneal organs
located outside, or posterior to, the peritoneum
Includes most of pancreas, duodenum, and parts of large intestine
Histology of Alimentary Canal
Submucosa
Contains blood and lymphatic vessels, lymphoid follicles, and submucosal nerve plexus that supply surrounding GI tract tissues
Has abundant amount of elastic tissues that help organs to regain shape after storing large meal
Consists of areolar connective tissue
Muscularis externa
Muscle layer responsible for segmentation and peristalsis
Contains inner circular muscle layer and outer longitudinal layers
Circular layer thickens in some areas to form sphincters
Mucosa
Functions: potentially perform one/all three
Protects against infectious disease
Absorbs end products of digestion
Secretes mucus, digestive enzymes, and hormones
Tunic layer that lines lumen
Serosa
Outermost layer, which is made up of the visceral peritoneum
Stomach
contains regular four tunics; however, muscularis and mucosa are modified
Muscularis externa has circular and longitudinal smooth muscle layers, as well as extra third layer, the oblique (diagonal) layer
together, smooth muscles allow stomach not only to churn, mix, and move chyme,but also to pummel it, which increases physical breakdown and ram it into small intestine
Mucosa layer is also modified
Consists of simple columnar epithelium entirely composed of mucous cells
Secrete two-layer coat of alkaline mucus
Surface layer traps bicarbonate-rich fluid layer that is beneath it
Dotted with gastric pits, which lead into gastric glands
Gastric glands produce gastric juice
Location of digestion and absorption of each macro molecule
Absorption of water
9 L water, most from GI tract secretions, enter small intestine
Most of rest is absorbed in large intestine
95% is absorbed in the small intestine by osmosis
Net osmosis occurs if concentration gradient is established by active transport of solutes
Water uptake is coupled with solute uptake
Absorption of electrolytes
𝑁𝑎+ absorption is coupled with active absorption of glucose and amino acids
𝐶𝑙− is transported actively
Iron and calcium are absorbed in duodenum
𝐾+ diffuses in response to osmotic gradients; lost if water absorption is poor
Most ions are transported actively along length of small intestine
Usually amount in intestine is amount absorbed
Iron and calcium absorption is related to need
When needed, transported in blood by transferrin
Ionic iron is stored in mucosal cells with ferritin
𝐶𝑎2+ absorption is regulated by vitamin D and parathyroid hormone (PTH)
Vitamin absorption
In small intestine
Vitamin B12 (large, charged molecule) binds with intrinsic factor and is absorbed by endocytosis
Water-soluble vitamins (C and B) are absorbed by diffusion or by passive or active transporters
Fat-soluble vitamins (A, D, E, and K) are carried by micelles; diffuse into absorptive cells
In large intestine
vitamin K and B vitamins from bacterial metabolism are absorbed
Disorders of the digestive and urinary systems
urinary
Urinary Tract Infection(UTI)
infection in any part of the urinary system, the kidneys, bladder, or urethra
Kidney Stones
stones that are within the ureters, the tubes that allows urine to pass through
Bladder Cancer
Mostly affecting the elderly which has the presence of cancer cells in the bladder
Digestive
Gastroesophageal Reflux Disease(GERD)
stomach acid/bile flows into the food pipe and irritates the lining.
Inflammatory Bowel Disease(IBD)
chronic inflammation of the digestive tract
Cholecytisis
redness and inflammation of the gallbladder
Peptic ulcers
open sores that are open within the lining of the stomach and portion of the smaller intestines