Excretion NCERT Flashcards
Animals accumulate ammonia, urea, uric acid, carbon dioxide, water and ions like Na +, K+, Cl– ,phosphate, sulphate, etc., either by —— or by other means like ——.
metabolic activities, excess ingestion
These accumulated substances have
to be removed —– or —-.
totally or partially
—-,—- and —- are the major forms of nitrogenous wastes excreted by the animals.
Ammonia, urea and uric acid
—– is the most toxic form and requires large amount of water for its elimination, whereas —–, being the least toxic, can be removed with a minimum loss of water.
Ammonia, uric acid
The process of excreting ammonia is —- , seen in:
——, aquatic amphibians and aquatic insects are
Ammonotelism, Many bony fishes
Ammonia, as it is —–, is generally excreted by —- across body surfaces or through gill surfaces (in fish) as ammonium ions. —– do not play any significant role in its removal.
readily soluble, diffusion
Kidneys
———— necessitated the production of lesser toxic nitrogenous wastes like urea and uric acid for —–.
Terrestrial adaptation
conservation of water
Mammals, many terrestrial amphibians and —– mainly excrete urea and are called ureotelic animals.
—-produced by metabolism is converted into urea in the —- of these animals and released into the blood which is filtered and
excreted out by the kidneys.
marine fishes
Ammonia
liver
Some amount of urea may be retained in the
—– of some of the ureotelic animals to maintain a desired osmolarity.
kidney matrix
Reptiles, birds,—— and —excrete nitrogenous wastes as uric acid in the form of —- or —- with a minimum loss of water and are called uricotelic animals.
land snails, insects
pellet or paste
In most of the —– , excretory structures are simple —- forms
whereas —- have complex tubular —-.
invertebrates, tubular
vertebrates, organs called kidneys
—- or —- are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria) —-, some annelids and the cephalochordate(—).
Protonephridia or flame cells
Rotifers, Amphioxus
Protonephridia are primarily concerned with —– volume regulation, i.e., osmoregulation.
ionic and fluid
—– are the tubular excretory structures of earthworms and other annelids.
Nephridia
Annelids- excretory structure:
Some: Protonephridia,
Many: Nephridia
Nephridia help to remove —– wastes and maintain a fluid and ionic balance.
nitrogenous
—– are the excretory structures of most of the insects including cockroaches.
Malpighian tubules
Malpighian tubules help in the removal of nitrogenous wastes and —-.
osmoregulation
—– or green glands perform the excretory function in —- like prawns
Antennal glands, crustaceans
In humans, the excretory system consists
of a pair of —-, one pair of ureters, a —- and a urethra
kidneys, urinary bladder
Kidneys are —-colour, bean shaped structures situated between the levels of —– and —- vertebra close to the —- wall of the abdominal cavity.
reddish brown
last thoracic and third lumbar
dorsal inner
Each kidney of an adult human measures —-in length, —- in width, — in thickness with an average weight of —-.
10-12 cm, 5-7 cm, 2-3 cm
120-170 g
Towards the centre of the —– surface of the kidney is a notch called —-through which ureter, blood vessels and nerves enter.
inner concave, hilum
Inner to the hilum is a —– shaped space called the
renal pelvis with projections called —–.
broad funnel
calyces
The outer layer of kidney is a —–.
tough capsule
Inside the kidney, there are two zones, an —– and an ——-.
outer cortex, inner
medulla
The medulla is divided into a few —- masses (medullary pyramids)
projecting into the —-
conical, calyces
The cortex extends in between the medullary pyramids as renal columns called—-
Columns of Bertini
Each kidney has nearly —- complex tubular structures called —–
which are the functional units.
one million
nephrons
Each nephron has two parts – the
—– and the ——.
glomerulus, renal tubule
Glomerulus is a —– formed by the —- arteriole – a fine branch of renal —. Blood from the glomerulus is carried away by an efferent arteriole.
tuft of capillaries, afferent
artery
The renal tubule begins with a ——like structure called Bowman’s
capsule, which encloses the glomerulus.
double walled cup
Glomerulus along with Bowman’s capsule, is
called the —- or —
malpighian body or renal
corpuscle
The tubule continues further to form a highly coiled network – ——
proximal convoluted tubule
A —- shaped Henle’s loop is the next part of the tubule which has a descending and an ascending limb. The ascending limb continues as another highly coiled tubular region called ——–.
hairpin
distal
convoluted tubule (DCT)
The DCTs of many
nephrons open into a —-tube called
—–, many of which converge and
open into the —- through medullary pyramids in the —
straight , collecting duct
renal pelvis, calyces.
The Malpighian corpuscle, PCT and DCT
of the nephron are situated in the —-
region of the kidney whereas the loop of Henle
dips into the —-.
cortical, medulla
In majority of nephrons, the loop of Henle is —-and extends —- into the medulla. Such nephrons are called —- nephrons.
too short, only very little
cortical
In some of the nephrons, the loop of Henle is
very long and —- into the medulla.
These nephrons are called —– nephrons.
runs deep
juxta medullary
The —– emerging from the glomerulus forms a fine capillary network around the renal tubule called the —-.
efferent arteriole
peritubular
capillaries
A minute vessel of the peritubular runs —- to the Henle’s loop forming a —- shaped vasa recta. Vasa recta is absent or —- in cortical nephrons.
parallel , ‘U’,
highly reduced
Urine formation involves three main processes namely,—-, —-,—-, that takes place in different parts of the nephron.
glomerular
filtration, reabsorption and secretion
The first step in urine formation is the —- of blood, which is carried out by the —– and is called glomerular filtration.
filtration , glomerulus
On an average, —- of blood is filtered by the kidneys per minute which constitute roughly — of the blood pumped out by —- of the heart in a minute.
1100-1200 ml
1/5th, each ventricle
The glomerular capillary blood pressure causes filtration of blood
through 3 layers, i.e., the —– of glomerular blood vessels, the —- of Bowman’s capsule and a —- between these
two layers.
endothelium , epithelium, basement membrane
The epithelial cells of Bowman’s capsule called —- are arranged in an —manner so as to leave some minute spaces called —- or —
podocytes, intricate
filtration slits or slit pore