excretion Flashcards
process of the urinary system?
produces urine
what are the components of urine?
excess water, salts or waste products
what is excretion?
the process in which the metabolic waste and toxic material is removed from the body
define metabolism
the total amount of chemical reactions occurring inside living cells
what do the lungs excrete?
co2
what do the kidneys excrete?
mineral salts
what does the skin excrete?
sweat (urea, n2 waste, creatinine and uric acid)
what does the liver excrete?
bile pigments
diff between cat and anabolism?
catabolism- breakdown of complex substances
anabolism- building of smaller substances
what is meant by ventral and dorsal side?
ventral- front
dorsal- back
what is the function of the kidney?
remove excess water, heat and urea (osmoregulation)
controlled by nephrons
define osmoregulation
the process in which organs keep the fluid level of the body constant as well as the osmotic pressure (salts)
what is the ureter and its function?
a narrow tube which runs from the kidney to the urinary bladder, it moves the urine by peristalsis
what is the urinary bladder and what does it do?
a hollow, muscular bag which stores the urine
what is the renal pelvis?
enlarged portion of the ureter inside the kidney
what do the sphincter muscles do?
contracts and relaxes to control the flow of urine into the urethra
what is the urethra?
the duct from which urine flows out
what are kidneys enclosed in?
fibrous capsule
what are the names of the regions in a kidney?
cortex (outer)
medulla (inner)
how many pyramids are in the kidney?
12-16
what is the functional unit of the kidney?
nephron
how many nephrons are present in akidney?
about a million
what is a hilus?
the point from where a tube emerges from any organ
describe the structure of a nephron
- bowman’s capsule
- first convoluted tubule
- loop of henle
- distal convoluted tubule
- enters the collecting duct
describe the blood distribution in a nephron
- artery that enters the capsule is known as the afferent arteriole
- glomerulus is the capillary network at the capsule
- glomerulus connects again to form the efferent arteriole
what are the processes of urine formation?
ultrafiltration and selective reabsorption
what is ultrafiltartion?
the leakage of tissue fluid which contains all nutrients into the bowman’s capsule
what is selective reabsorption?
where the blood reabsorbs the nutrients and water it needs from the tissue fluid moving in the nephron
describe the process of osmoregulation
brain detects a high or low water level when blood passes thru it, the hypothalamus either increases or inhibits the amount of adh produced and the pituitary gland releases it
