Chapter 51-Osmotic Regulation and the Urinary System

Question 1

Osmoregulation

Answer 1

regulation of water and solute balance of tissues and organs

Question 2

excretion

Answer 2

removal of metabolic rates

• include CO2
• nitrogenous wastes produced as a result of deamiations of amino acids and nucleotide breakdown

Question 3

water distributed between?

Answer 3

intracellular compartment

-extracellular compartment-tissue fluids

Question 4

Important ions in osmolarity

Answer 4

sodium is the major cation in extracellular fluids

-chloride is major anion

Question 5

Osmotic pressure

Answer 5

force of water moving into cell by osmosis

-measure of a solutions tendency to take in water by osmosis

Question 6

tonicity

Answer 6

solute concentration of a solution

-solutions may be hypertonic, hypotonic, or isotonic

Question 7

osmoconformers

Answer 7

• organisms that are in osmotic equilibrium with their environment (adjust tonicity to match their environment)
• only hagfish, sharks and relatives are isotonic

Question 8

Osmoregulators

Answer 8

majority of organisms

-maintain a relatively constant blood osmolarity despite different concentrations in their environment

Question 9

Freshwater vertebrates with osmolarity

Answer 9

hypertonic to environment

-adapted to prevent water from entering their bodies and to actively transport ions back into their bodies

Question 10

Marine vertebrates and osmolarity

Answer 10

hypotonic to their environment

-adapted to retain water by drinking seawater and eliminating the exess ions through kidneys and gills

Question 11

terrestrial vertebrates and osmolarity

Answer 11

• higher concentration of water than surrounding air

- tend to lose water by evaporation from skin and lungs

Question 12

osmoregulatory organs in flatworms

Answer 12

use protonephridia which branch into bulblike flame cells

Question 13

Earthworms

Answer 13

• use nephridia

- open both to the inside and outside of the body

Question 14

Insects

Answer 14

-use mapighian tubules

Question 15

Vertebrate kidneys

Answer 15

create a tubular fluid by filtering the blood under pressure through the glomerulus

• most of the water and molecules are reabsorbed into the blood
• waste products are eliminated from the body in the form of urine

Question 16

nitrogenous wastes

Answer 16

made up of amino acids and nucleic acids

• first step is deamination
• combined with H+ to form ammonia

Question 17

Urea

Answer 17

ammonia and other solutes that are released through urine

Question 18

uric acid

Answer 18

only in mammals, from degradation of purines, not amino acids

Question 19

Which organisms directly eliminate ammonia

Answer 19

fish through their gills

Question 20

mammalian excretory system consists of

Answer 20

• 2 kidneys-filters blood; forms urine
• 2 ureters-connects kidneys to bladder
• 1 bladder-urine storage system
• 1 urethra-exit from body

Question 21

where does the kidney get blood from

Answer 21

• each kidney receives blood from a renal artery
• blood flows to kidneys over and over again and is filtered many times per day
• kidney produces during from this blood

Question 22

where does urine go from kidneys

Answer 22

drains from each kidney through a ureter into a urinary bladder for temporary storage
-urine is passed out of body through urethra by urination

Question 23

where are the nephrons located

Answer 23

inner renal memdulla

Question 24

nephrons consist of what?

Answer 24

glomerulus and tubular system

Question 25

kidney is made up of what?

Answer 25

1 million function nephrons

Question 26

steps of blood filtration

Answer 26

carried by an afferent artiole to the glomerulus

• filtered as it is forced through porous capillary walls of the glomerulus into the bowmans capsule to for the renal filtrate
• goes into proximal convoluted tubule
• moves down medulla and back up into cortex of loop of henle
• leaves henle, fluid is delivered to distal convoluted tubule in cortex
• drains into collecting duct
• merges w/other collecting ducts, emptys urine into pelvis

Question 27

3 basic kidney functions

Answer 27

1. filtration-between glomerulus and bowmans capsul (non selective)
2. reabsorption-mostly proximal tubule
   - selective movement of certain solutes out of the filtrate back into the blood via peritubular capillaries
3. secretion-mostly distal tubule
   - selective movement of substances from the blood into the extracellular fluid, then into the filtrate in the tubular system

Question 28

where is water reabsorbed in the kidneys

Answer 28

proximal convoluted tubule, descending loop of Henle, and collecting duct

Question 29

what else do the kidneys reabsorb besides water

Answer 29

glucose and amino acids through active transport

Question 30

proximal convoluted tubule

Answer 30

actively, selectively, reabsorbs virtually all nutrient molecules in the filtrate, and two thrids of the NaCl and water

Question 31

loop of henle

Answer 31

• creates a gradient of increasing osmolarity from the ocortex of the medulla
• allows reabsorption of water from descending loop and collecting duct

Question 32

ADH

Answer 32

antidiuretic hormone

• produced by the hypothalamus and secreted by the posterior pituitary gland
• stiumulated by an increase in the osmolarity of blood (dehydration)
• more ADH increases reabsorption of water

Question 33

aldosterone

Answer 33

secreted by adrenal cortex

• stimulated by low levels of Na+ in blood
• causes reabsorption of of na+
• low levels of Na+ in blood are accompanied by a decrease in blood volume

Question 34

ANH

Answer 34

atrial natriuretic hormone

• opposes the action of aldosterone in promoting salt and water retention
• promotes the excretion of salt and water in the urine and lowering blood volume