XI Chap 19 Excretory Products Flashcards
Animals accumulate ammonia, urea, etc. by metabolic activities or means like excess ingestion. T or F?
True
What are the 3 major forms of nitrogenous wastes excreted by animals?
Ammonia, urea and uric acid
________ is the most toxic form of nitrogenous waste and requires large amounts of water for its elimination
Ammonia
________ is the least toxic form of nitrogenous waste and requires minimum amounts of water for its elimination
Uric acid
What is Ammonotelism?
Process of excreting ammonia
Many bony fishes, aquatic amphibians and aquatic insects are __________ in nature.
[uricotelic, ureotelic, ammonotelic]
ammonotelic
Ammonia is insoluble. T or F?
False, soluble
Ammonia is generally excreted by diffusion across body or gill surfaces as ________
ammonium ions
Kidneys play a significant role in the removal of ammonia ions. T or F?
False
Terrestrial adaptation necessitated the production of ________ (more / lesser) toxic nitrogenous wastes like ________ and ________ for the conservation of water
lesser, urea, uric acid
Mammals, terrestrial amphibians and marine fishes ________.
[uricotelic, ureotelic, ammonotelic]
ureotelic
In ureotelic animals, ammonia is converted to _________ in the _________ (organ) and released into the blood which is filtered and excreted out by _________ (organ)
urea, liver, kidney
Some amount of uric acid may be retained int he kideny matrix of some ureotelic animals to maintain a desired osmolarity. T or F?
False, small amount of urea, rest is correct
Reptiles, birds, land snails and insects are ___________ in nature
[uricotelic, ureotelic, ammonotelic]
uricotelic
Uric acid is excreted in the form of _________ with minimum loss of water
pellet / paste
In most invertebrates, excretory structures are _______________ whereas vertebrates have _______________
simple tubular forms, kidneys (complex tubular organs)
Protonephridia aka _______________ are excretory structures in _______________
flame cells;
Platyhelminthes (Flatworms e.g. Planaria), rotifers, some annelids and the cephalochordate Amphioxus
Protonephridia are primarily concerned with _______________
osmoregulation (ionic and fluid volume regulation)
_______________ are the tubular excretory structures of earthworms and other annelids.
Nephridia
Nephridia help to remove _______________ and maintain a _______________ and _______________ balance
nitrogenous wastes,
fluid,
ionic
Malphigian tubules are the excretory structures of most _______________
insects
Malphigian tubules help in removal of _______________ and _______________
nitrogenous wastes, osmoregulation
_________ glands (aka _________ glands) perform excretory function in crustaceans like prawns.
Antennal glands (aka green glands)
Human excretory system consists of:
pair of kidneys, pair of ureters, a urinary bladder and urethra
Kidneys are reddish-brown, bean-shaped structures situated between the levels of _________ and _________ vertebra close to the _________ wall of the abdominal cavity
last thoracic, third lumbar, dorsal inner
Length, width, thickness and weight of human kidney?
L: 10-12cm
W: 5-7cm
T: 2-3cm
Weight: 120-170g on average
Towards the centre of the inner concave surface of the kidney is a notch called _________ through which the _________, _________ and _________ enter
hilum;
ureter, blood vessels and nerves
Inner to the hilum is a broad funnel shaped space called the _________ with projections called _________
renal pelvis, calyces
The outer layer of the kidney is a soft capsule. T or F?
False, tough capsule
Inside the kidney there are two zones:
outer cortex and inner medulla
Medulla is divided into a few _________ projecting into the calyces
medullary pyramids (conical masses)
Cortex extends in between the medullary pyramids as renal columns called _________
Columns of Bertini
Each kidney has nearly a million complex tubular structures called nephrons. T or F?
True
Nephrons are functional units with two parts:
glomerulus and renal tubule
Glomerulus is a tuft of _________
capillaries
Efferent vs Afferent arteriole
Afferent - brings in blood to glomerulus
Efferent - takes away blood from glomerulus
Glomerulus is a tuft of capillaries formed by _________ arteriole
(afferent or efferent)
afferent
Renal tubule begins with a _________-walled (single or double) cup-like structure called _________
double, Bowman’s capsule
Bowman’s capsule encloses the _________
glomerulus
Glomerulus + Bowman’s capsule is together called the _________ or _________
malphigian body OR renal corpuscle
The renal tubules continues beyond Bowman’s capsule to form a highly coiled network called _________
Proximal convoluted tubule
Henle’s Loop is shaped like a _________ and has an _________ and _________ limb
hairpin, descending, ascending
The _________ limb of Henle’s loop continues as another highly coiled tubular region of the renal tubule called _________
ascending, distal convoluted tubule
DCT’s of many nephrons open into a straight tube called the _________, many of which converge and open into the _________ through medullary pyramids in the calyces.
collecting duct, renal pelvis
Malphigian corpuscle, PCT and DCT are situated in the _________ region of the kidney whereas the loop of Henle dips into the _________
cortical, medulla
In most nephrons, loop of Henle is too short and extends very little into medulla. T or F?
True
Cortical vs. juxta medullary nephrons?
Cortical - Henle’s loop is too short - majority of nephrons
Juxta medullary - long Henle’s loop and runs deep into medulla
Efferent arteriole emerging from the glomerulus forms a fine capillary network around the renal tubule called the _________
peritubular capillaries
A minute vessel of peritubular network runs parallel to the Henle’s loop forms a U-shaped _________
vasa recta
Vasa recta is present in cortical nephrons only. T or F?
False, absent or highly reduced in cortical nephrons (since Henle’s loop is also very short)
What are the 3 main processes involved in urine formation?
- Glomerular filtration
- Reabsorption
- Secretion
The three main processes involved in urine formation take place int he same part of the nephron. T or F?
False, different parts
First step in urine formation is _________
glomerular filtration (filtration of blood)
During glomerular filtration, _________ml of blood is filtered by the kidneys per minute which constitutes roughly _________th of the blood pumped out by each ventricle in a minute.
1100-1200.
one-fifth
Glomerular capillary _________ causes filtration of blood
blood pressure
What are the 3 layers through which blood is filtered?
- Endothelium of glomerular blood vessels
- Epithelium of Bowman’s capsule
- Basement membrane between the 2 above layers
Epithelial cells of Bowman’s capsule are called _________ and are arranged in an intricate manner so as to leave some minute spaces called _________ or _________
podocytes, filteration slits or slit pores
Why is glomerular filtration considered as a process of ultra filtration?
Such fine filtration => Almost all constituents of plasma except proteins pass onto lumen of Bowman’s capsule
Amount of filtrate formed by kidneys per minute is called _________
glomerular filtration rate (GFR)
GFR in a healthy individual is approximately _________ml per minute or _________ litres per day
125 ml/min OR 180 litres/day
Kidneys have build-in mechanisms like JGA for regulation of glomerular filtration rate. T or F?
True
What is JGA?
Juxta glomerular apparatus is a special sensitive region,
formed by cellular modification in the distal convoluted tubule (DCT) and the afferent arteriole at the location of their contact
A _________ (rise/fall) in GFR can activate the JGA cells to release _________ which can stimulate the glomerular blood flow and thereby the GFR back to normal.
fall, renin
_________ percent of filtrate has to be reabsorbed by renal tubules aka reabsorption
~99%
The _________ cells in different segments of the nephron perform reabsorption by active or passive mechanisms
tubular epithelial
Glucose, amino acids, Na+ in the filtrate are reabsorbed _________, whereas nitrogenous wastes are absorbed _________ and finally water is absorbed _________ in the initial segments of the nephron
(passively / actively)
actively, passively, passively
During urine formation, the tubular cells secrete substances like ____, ____ and ____ into the filtrate
H+, K+ and ammonia
Tubular secretion is an important step in urine formation as it helps maintain _________ and _________ balance of body fluids
ionic and acid-base
PCT is lined by _________ epithelium which increases the surface area for reabsorption
simple cuboidal brush border
Nearly all of the essential nutrients and 70-80% of the electrolytes and water are reabsorbed by _________
PCT
PCT also helps to maintain the pH and ionic balances of the body fluids by selective secretion of ____, ____, and _____ into the filtrate and absorption of ____ from it
H+, ammonia, potassium ions
HCO3
Reabsorption is minimum in the descending limb of Henle’s loop. T or F?
False, minimum in the ascending limb
Ascending limb of Henle’s loop plays significant role in maintenance of high _________
osmolarity of medullary interstitial fluid
The _________ limb of Henle’s loop is permeable to water but almost impermeable to electrolytes
The _________ limb of Henle’s loop is impermeable to water but permeable to electrolytes
descending, ascending
Why does the filtrate become concentrate as it moves down the descending Henle’s limb?
permeable to water, impermeable to electrolytes => water is reabsorbed
As the concentrated filtrate passes upward in the ascending Henle’s limb, it becomes _________ (diluted / concentrated)
diluted
Why does filtrate become diluted in ascending Henle’s limb?
Passage of electrolytes to the medullary fluid
The descending limb of Henle’s loop has a thick and thin segment. T or F?
False, ascending limb does
Conditional reabsorption of Na+ and water and reabsorption of HCO3- takes place in _________
DCT
DCT selectively secretes ______ and ______ ions and ____ to maintain the pH and sodium-potassium balance in blood
H+, K+, NH3
Collecting duct is a long duct that extends from the _________ to the _________
cortex, inner parts of medulla
Large amounts of water can be absorbed from _________ region to produce a concentrated urine.
Collective duct
Why does collecting duct allow passage of small amounts of urea into medullary interstitium?
To keep up osmolarity
How does collecting duct play a role in maintenance of pH and ionic balance of blood?
Selective secretion of H+ and K+ ions
Mammals have the ability to produce concentrated urine. T or F?
True
_________ and _________ play a significant role in producing concentrated urine
Henle’s loop, vasa recta
Flow of filtrate in 2 limbs of Henle’s loop is in _________ (same or opposite?) directions and thus forms a _________ current
opposite, counter
Flow of blood through the two limbs of vasa recta is in a _________ current pattern
Counter current
Proximity between Henle’s loop and vasa recta as well as counter current help in maintaining an increasing osmolarity towards the _________
inner medullary interstitium
Osmolarity is _________ mOsmol/L in the cortex to about _________ mOsmol/L in the inner medulla
300, 1200
The osmolarity gradient in nephron is mainly caused by _________ and _________
NaCl and urea
NaCl transported by the _________ limb of Henle’s loop is exchanged with the _________ limb of vasa recta
ascending, descending
Small amounts of _________ enter the thin segment of the ascending Henle’s limb which is transported back to the _________ by the collecting tubule
urea, interstitium
_________ mechanism helps to maintain a concentration gradient in the medullary interstitium
Counter current mechanism
Human kidneys can produce urine nearly ______ times concentrated than the initial filtrate formed
4
from 300mOsmol/L to 1200mOsmol/L
The functioning of the kidneys is efficiently monitored and regulated by hormonal feedback mechanisms involving the _________, _________ and to some extent the _________
hypothalamus, JGA and heart
Osmoreceptors in the body are activated by changes in _________, _________ and _________
blood volume, body fluid volume and ionic concentration
An excessive loss of fluid from the body can activate osmoreceptors which stimulate the _________ to release _________ or _________ from the _________
hypothalamus, antidiuretic hormone (ADH), vasopressin, neurohypophysis
ADH facilitates water reabsorption from latter parts of the tubule thereby preventing _________
diuresis
An _________ (decrease/increase) in body fluid volume can switch off the osmoreceptors and suppress the _________ release.
increase, ADH
ADH can affect the kidney function by its constricting effects on blood vessels, which causes a _________ (increase / decrease) in blood pressure thereby _________ (increasing/decreasing) the glomerular blood flow and thereby the GFR.
increase, increasing
The JGA plays a _________ (simple or complex) role in regulation of kidney function.
complex
A fall in glomerular blood flow/glomerular BP/GFR can activate the JG cells to release _________ which converts _________ in blood to _________ and further to _________
renin, angiotensinogen, angiotensin I, angiotensin II
_________ is a powerful vasoconstrictor and increases glomerular blood pressure and GFR
Angiotensin II
_________ activates the adrenal cortex to release Aldosterone
Angiotensin II
_________ causes reabsorption of Na+ and water from the distal parts of hte tubule
Aldosterone
Aldosterone leads to an increase in blood pressure and GFR. T or F?
True
An increase in blood flow to the atria can cause the release of _________ which causes _________ and thereby decreases the blood pressure.
Atrial Natriuretic Factor (ANF),
vasodilation
Atrial Natriuretic Factor (ANF) acts as a check on _________ mechanism
renin-angiotensin
Urine formed by nephrons is ultimately carried to the _________ where it is stored until a _________ (involuntary/voluntary) signal is given by the _________
urinary bladder, voluntary, CNS
The micturition signal is initiated by the stretching of the ____________
urinary bladder as it gets filled with urine
The _________ receptors on the walls of urinary bladder send signals to _________
stretch, CNS
CNS passes on motor messages to initiate the contraction of _________ and the simultaneous relaxation of the _________ causing the release of urine
smooth muscles of bladder,
urethral sphincter
What is micturition and micturition reflex?
Micturition - process of release of urine
Micturition reflex - neural mechanisms that cause micturition
Adult human on average excretes _________ litres of urine per day
1 to 1.5 litres
Urine formed is slightly _________ (alkaline or acidic) with pH _________
acidic, 6.0
On average _________ gm of urea is excreted out per day
25-30 gm
Presence of _________ and _________ in urine are indicative of diabetes mellitus.
glucose (Glycosuria) ketone bodies (Ketonuria)
What organs other than kidneys help in elimination of excretory wastes?
Lungs,
Liver,
Skin
Lungs remove large amounts of CO2 (_________ mL per minute) and significant quantities of _________ every day.
300mL, water
_________ is the largest gland in the body
Liver
Liver secretes bile-containing substances like _________, _________, _________, _________, _________ and _________
bilirubin, biliverdin, cholesterol, degraded steroid hormones, vitamins drugs
Most substances secreted by the liver ultimately pass out alongwith digestive wastes. T or F?
True
_________ and _________ glands in the skin can eliminate certain substances through their secretions
Sweat, sebaceous
Sweat produced by the sweat glands is a watery fluid containing _________, small amounts of _________ and _________ acid
NaCl, urea and lactic
Though the primary function of sweat is to _________, it also helps in removal of some wastes
facilitate a cooling effect on body surface
Sebaceous glands eliminate _________, _________ and _________ through sebum
sterols, hydrocarbons and waxes
_________ provides a protective oily covering for the skin
Sebum
Small amounts of nitrogenous wastes could be eliminated through saliva too. T or F?
True
What is uremia?
malfunctioning of kidneys => accumulation of urea in blood
Uremia is very harmful in that it can lead to _________
kideny failure
What is haemodialysis?
process to remove urea in uremic patients;
blood is drained from an artery is pumped into an artificial kidney, cleared blood is pumped back to the body through a vein
In haemodialysis, an anticoagulant like _________ is added to the blood.
heparin
The artificial kidney contains a ______________ tube surrounded by a fluid having the same composition as plasma except _________
coiled cellophane, the nitrogenous wastes
Cleared blood from an artificial kidney is pumped back to the body through a vein after adding _________ to it
anti-heparin
_________ is the ultimate method in correction of acute renal failures
Kidney transplantation
What is renal calculi?
Stone or insoluble mass of crystallised salts (oxalates, etc.) formed within kidney
Inflammation of glomeruli of kidney is called _________
glomerulonephritis
Nature of nitrogenous wastes formed and their excretion vary among animals mainly depending on the habitat and availability of water. T or F?
True
Filteration is a ____________ (non-selective / selective) process performed by the glomerulus
non-selective
___________ part of nephron is the major site of reabsorption and selective secretion
PCT
