Chapter 11 Flashcards
Urinary systems roles
- the urinary system plays a vital role in maintaining homeostasis
- balancing pH levels in the blood
- regulation of blood pressure
- 85% of erythropoietin (EPO) produced to stimulate RBC produced is produced in the kidneys
- Vitamin D production
ETC! (Electron Transport Chain)
Excretion
Processes that remove wastes and excess materials from the body
Different systems excretions
Digestive system: excretes food residue and wastes produced by the liver
Respiratory system: excretes carbon dioxide
Integumentary system: (skin) excretes water and salt
Urinary system: (kidneys) excretes nitrogenous wastes, excess solutes, and water
Urea: waste product of amino acid metabolism
Creatinine: waster product that results from the breakdown of Creatine phosphate
Uric acid: formed from the metabolic processing of nucleotides (Gout)
The kidney regulate nitrogenous wastes and other solutes
- protein metabolism produces nitrogenous wastes
- initially, NH3 (ammonia) is produced during breakdown of amino acids
- liver detoxifies NH3, producing urea
- urea is transported from the liver to kidneys for disposal
Other added solutes regulated by the kidneys
Sodium
Chloride
Potassium
Calcium
Hydrogen ions
Creatinine
Maintenance of water levels
To maintain homeostasis, water input = water output
Kidneys adjust to water output as necessary
Water input: food, drink, metabolism
Water output: lungs, skin, feces, kidneys
Kidneys modify output based on intake and loss
Output varies from 1/2 liter/day to 1 liter/hour
Water from food
- water from food usually occurs for 20-25% of recommended total fluid intake
- fruits and vegetables contain a high amount of water
- butter, oils, dried meats, chocolate, cookies, and other sweets that have a low water content
- lettuce, raw strawberries, cucumbers, watercress, Swiss chard, boiled squash, green peppers, bean sprouts, watermelon, cantaloupe, celery, and raw peaches
Water from liquids
- on average an individual consumes 41 ounces of water daily
- physical activity and thermals tress can increase fluid needs by 5-6 times.
- In the U.S., majority of water intake is not from plain water ,but from a variety of foods and beverages.
- other beverages: 43.6% of total water intake
- water: 31.4% of total water intake - during activities, increased sweating and temperature can contribute to greater water loss (drink more water)
- young children, pregnant and lactating women, the elderly, and people with certain illnesses require increased fluid intake
Alcohol is what
A diuretic
Metabolic water
- breakdown of macronutrient molecules in energy metabolism form carbon dioxide and water
- metabolic water provides about 14% of daily water requirements for a sedentary person
The principal organ of the urinary system
Kidney: Lima bean like structures
- located on either side of the vertebral column and extend from the level of the las thoracic vertebra to just above the third lumbar vertebra
- between the T12 and L3
Primary functions of the kidney
Process blood and form urine as a waste product
Micturition
Urination or voiding of the bladder and waste products
The three primary structures of the kidney
Cortex: outer portion of the kidney
Medulla: inner region of the kidney
Renal pelvis: hollow space in center of kidney where urine collects
Ureters
Muscular tubes that transport urine from kidneys to the bladder
Urinary bladder
Three layers of smooth muscle, lined with epithelial cells
Stores urine (600-1,000ml)
Urethra
Carries urine from bladder to outside of the body
Two sphincters control urination
Detrusor muscle
Made mostly of smooth muscle
Network of crisscrossing bundles of muscle fibers
- circular
- oblique
- lengthwise
Nephrons
Functional units of the kidney
- 1 million nephrons per kidney
Two main part of nephrons:
Renal corpuscle: glomerulus (capillaries); bowman capsule (glomerular capsule)
Renal tubule: proximal consulates tubule; henle loop (nephron loop); distal convoluted tubule
Special blood vessels supply the tubules
- renal arteries supply the kidneys
- blood vessels associated with tubules
Arterioles
Efferent: leave the glomerular capsule
Afferent: enters the glomerular capsule
Capillaries
Glomerular: network within the glomerular capsule
Peritubular: surround proximal and distal tubule
Vasa recta: parallels the loop of henle
Renal vein
Collects filtered blood from the kidneys
Filtration defined
Movement of water and protein-free volutes from plasma in the glomerulus, across the capsular membrane, and into the capsular space
Tubular reabsorption
Movement of molecules out of the various segments of the tubule and into the peritubular blood
Tubes -> Blood