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Alayna Dixon Period 3 Anatomy and Physiology Digestive and Urinary…
Alayna Dixon Period 3 Anatomy and Physiology
Digestive and Urinary Systems
Major functions of the digestive system
Digestion: mechanical and chemical breakdown of foods and
absorption of nutrients
The digestive system carries out the process of digestion
Mechanical digestion breaks down large pieces of food into
smaller ones; chemical composition is not changed by this process
Chemical digestion breaks down large nutrient molecules into
smaller chemicals, by breaking chemical bonds
The digestive system consists of the alimentary canal (digestive
tract), leading from mouth to anus, and several accessory organs
whose secretions help the processes of digestion
Major functions of the urinary system
Filters salts and wastes from the blood
• Helps maintain normal concentrations of electrolytes and water
• Regulates pH and body fluid volume
• Helps control red blood cell production and blood pressure
Major organs of the digestive system
Stomach
Cardia(c), a small region near opening to the esophagus
• Fundus, a small, rounded region superior to the cardia
• Body region, main portion of the stomach, between fundus and
pylorus
• Pylorus, distal portion, near small intestine
• Pyloric canal is a narrowed area close to small intestine
• Pyloric sphincter, at end of pyloric canal, is a muscular ring
that controls release of food from stomach into small
intestine
Small intestine
Small intestine is a long tubular organ, which runs from the
stomach to the beginning of the large intestine
Fills a large part of the abdominal cavity
Functions of the small intestine:
• Receives chyme from stomach
• Receives pancreatic juice from pancreas and bile from liver and
gallbladder
• Finishes digestion of nutrients that arrive in the chyme
• Absorbs digestive end products
• Transports the remaining residue to the large intestine
Large intestine
Large intestine is named “large” because its diameter is larger
than that of the small intestine
About 1.5 meters long
Begins in lower right portion of abdominal cavity at the cecum,
ascends on right, crosses to left side, and descends on left side
Opens to outside of body as the anus
Absorbs water and electrolytes, and forms and stores feces
Rectum
a straight section of the large intestine, which lies next
to the sacrum
Mouth
• First portion of the alimentary canal
• Functions: receives food, and begins mechanical digestion by
mastication (chewing)
• Surrounded by lips, cheeks, tongue, and palate
• Oral cavity is the chamber between the palate and tongue
• The narrow space between the teeth, cheeks, and lips is called
the vestibule
Major organs of the urinary systems
Kidneys
• A reddish brown, bean-shaped organ, 12 cm long
• Enclosed in a tough, fibrous capsule
• Kidneys are retroperitoneal, behind the parietal peritoneum
Ureters
• Muscular tube that conveys urine from the kidney to the
urinary bladder
• Begins as the funnel-shaped renal pelvis
• Due to the angle at which ureters enter the urinary bladder,
wall of the bladder acts as a one-way valve, propelling the urine
into the bladder, but preventing it from flowing backward
Urinary Bladder
• Hollow, distensible, muscular organ lying in the pelvic cavity
• Stores urine, and excretes it through the urethra
• Portion of the lower bladder forms the internal urethral
sphincter
Urethra
• Tubular organ that transports urine from the urinary bladder to
the outside of the body
• In females, it is 4 cm long, with its opening between the vaginal
opening and the clitoris
• In males, the urethra is much longer, and serves both the
urinary and reproductive systems; it runs through the prostate
gland and penis
• Contains internal urethral sphincter (smooth muscle) and
external urethral sphincter (skeletal muscle)
Digestive enzymes (including names and functions)
Enzymes: secreted by epithelial cells of the mucosa, and
embedded in their microvilli:
• Peptidases: break down dipeptides to amino acids
• Sucrase, maltase, and lactase: break down disaccharides to
monosaccharides
• Intestinal lipase: breaks down triglycerides to fatty acids and
glycerol
Location of digestion and absorption of each macromolecule
The stomach absorbs only small quantities of the following
substances:
• Water
• Certain salts
• Alcohol
• Some lipid-soluble drugs
Layers of the GI tract (including stomach)
Mucosa
The inner layer of the wall
• A mucous membrane that surrounds the lumen of the tube
• Consists of epithelium, underlying connective tissue, a little smooth
muscle
• Protects tissues of the canal
• Carries on secretion and absorption of dietary nutrients
• In some regions, the mucosa is modified into folds or projections,
which increase surface area
Sybmucosa
Lies under the mucosa
• Consists of loose connective tissue, housing blood and lymphatic vessels,
nerves, and glands
• Nourishes the surrounding layers of the canal
• Vessels transport absorbed nutrients away from digestive
Muscularis
Consists of 2 layers of smooth muscle: inner circular layer and outer
longitudinal layer
• Propels food through the canal
Serosa
Outer serous layer, or visceral peritoneum
• Protects underlying tissues, and secretes serous fluid to reduce friction
between organs
Nephron anatomy and physiology: in the kidneys
Glomerular
• First step of urine formation
• Glomerulus filters water and small substances from blood
plasma, and transports it into the glomerular capsule as
glomerular filtrate
• Filtrate then moves into the renal tubules
• Produces about 180 liters of fluid per day
Nephron
• Functional unit of kidney; can produce urine independently
• About one million nephrons per kidney
• Consists of a renal corpuscle and a renal tubule
renal capsule
Filtration structure in renal cortex, which performs the first
step of urine formation
• Consists of cluster of capillaries, the glomerulus, and a
glomerular capsule, a cup-shaped sac that receives filtrate
• Glomerular capsule is actually the expanded proximal end of
a renal tubule
• Renal tubule consists of the following parts, in this order:
• Glomerular capsule
• Proximal convoluted tubule
• Nephron loop (descending and ascending limbs)
• Distal convoluted tubule
• Collecting duct
• Several distal convoluted tubules join to become a collecting
duct, which passes from the renal cortex into the renal medulla,
emptying into a minor calyx at the papilla
Disorders of the digestive and urinary systems
Cholecystitis: An inflammation of the gallbladder; primarily cause by blockage of gall duct; digestive tumors; blockage of bio ducts. Tender abdomin, sweating and nausea; Medication, fasting and antibiotics
Gastroesophageal Reflux Disease (GERD): Chronic disease occurs when esophageal sphincter contracts allowing stomach acid in the esophagus; pregnancy, smoking and diabetes; chest pain, dry cough, and sour taste; medications, prescription meds, and surgery
Inflammatory Bowel Disease (IBD): Chronic complex intestinal condition that causes inflammation in digestive tract; genetics, environment, or immune; abdominal pain, cramping , and diareah; medication, antibiotics and fluid replacement
Peptic Ulcers
Sores that develop in the lining of the stomach of duedenum; bacterial infection, smoking, alcohol abuse' Nausea, severe chest pain, bloody stool; lifestyle change, medication, endoscopic surgery
Hemorrhoids
Hemorrhoid inflammed veins in rectum or anus;straining during bowel movement, obesity, chronic diarrhea;rectal bleeding, anal pain, lumps near anus; Medication, surgical removal, injections