chapter 13 excretion

def excretion

remov toxic material waste product substance in xcess from body

importance of excretion

avoid accumulation of waste products
products toxic, remove
homeostasis constant environment
osmoregulation
formation of urea in liver

urea waste product explanation

produced in liver during deamination of excess amino acid can denature enzymes. excess amino acid ammonia urea

lungs excrete

carbon dioxide water

kidneys excrete

urine

urine consists

urea uric acid salt water

skin excretes

sweat

sweat consists

water salts low conc urea

liver excretes

deamination of amino acids

assimilation definition

digested food molecule convert to other molecule body will use

assimilation in liver

assimilate amino acids convert them into protein

what happens when the liver has excess amino acids

break down through deamination

what is deamination

removal of nitrogen containing part of amino acids to form urea

where is urea formed

in liver from excess amino acids

what happens after urea is formed

dissolves in blood taken to kidney to excrete

function of ureter

carries urine from kidney to urinary bladder

function of bladder

temporary storage urine

function of urethra

transport urine from bladder to out of the body

function of kidney

regulation of water and salt balance regulation of osmotic pressure & ionic pressure in blood excretion of waste products regulation of blood pH

what is a nephron

functional unit of kidney

arterioles of the nephron

afferent efferent

convoluted tubule in nephron

proximal distal

function of afferent arteriole

carries blood into glomerulus

function of efferent arteriole

carries blood away from glomerulus

function of glomerulus

ultrafiltration of blood

function of bowmans capsule

collects filtrate

function of proximal convoluted tubule

reabsorb glucose, amino acid, most salts and most water

function of loop of henle

reabsorb water and salts

function of distal convoluted tubule

selective reabsorption of salts and water

function of collecting duct

formation of urine

explain the process of ultrafiltration

• blood enters glomerulus through afferent arteriole

• afferent arteriole wider than efferent arteriole and capillaries

• creates high hydrostatic pressure in glomerulus

• hydrostatic pressure force small substances to enter bowmans capsule

• fluid that enters bowmans capsule: (glomerular) filtrate

explain the (glomerular) filtrate

• X blood cells or plasma proteins (too large)

• consists of mainly water dissolved salts glucose amino acids urea uric acid

explain selective reabsorption

• filtrate passes from renal tubule to capillary

• pass through proximal convoluted tubule, useful substance absorbed into surrounding blood capillaries

• active transport

types of transport for selective reabsorption

• all glucose absorbed by active transport into surrounding blood capillaries

• most salts / mineral ions are reabsorbed by active transport into surrounding blood capillaries

• water reabsorbed by osmosis

types of transport for selective reabsorption

• all glucose absorbed by active transport into surrounding blood capillaries

• most salts / mineral ions are reabsorbed by active transport into surrounding blood capillaries

• water reabsorbed by osmosis

adapatio of the wall of the proximal convoluted tubule 4 its function

convoluted, microvilli, inc surface area for reabsorption

more mitrochondria release energy by aerobic respiration

factors affecting amount of urine

water intake, salt sugar intake, environmental temperature, excercise

explain how the amount of water intake affects the amount of urine produced

the more water a person drinks, the more excess water is removed by kidneys.

larger volume of dilute urine produced

if less water is drank, kidneys reabsorb more water, produce smaller volume of concentrated urine

explain how the amount of salt or sugar consumed (diet) affects the amount of urine produced

consuming too much salt or sugar lowers the water potential of the blood

more water is retained in blood to restore the water potential, less water available to produce urine

smaller volume of more concentrated urine

explain how environmental temperature affects the amount of urine produced

at high temperatures, more sweat is produced to cool the body

sweat contains mainly water, so more water is lost through the skin

the kidneys absorbs more water, producing a smaller volume of concentrated urine

at low temperatures, less sweating occurs, so a larger volume of dilute urine is produced

explain how exercise affects the amount of urine produced

during excercise body temperature increases, more sweating

more water lost through sweat, kidney reabsorbs more water

smaller volume of concentrated urine is produced