Excretion Flashcards
Ammonotelic
Requirement of water
Mechanism of excretion
Toxicity
Examples
Very large
By diffusion across body surface or through gill surface ( in fish ) as ammonium ion
Highest
Teleosts ( many bony fishes ),aquatic insects,aquatic amphibians
Ureotelic
Requirement of water
Mechanism of excretion
Toxicity
Examples
Less then ammonia
Ammonia produced by metabolism is converted into urea in the liver and released into the blood which is filtered and excreted by kidneys
Less than ammonia
Mammals , marine fishes , many terrestrial amphibian
Uricotelic
Requirement of water
Mechanism of excretion
Toxicity
Examples
Least
In form of paste or pellet
Least
Birds, insects ,land snails ,reptiles
Protonephridia example
Primarily concerned
Kidneys
Platyhelminthes
Rotifers
Cephalochordate ( amphioxus )
Some annelids
With osmoregulation
All vertebrates
Nephridia
Malpighian tubules
Green glands /
Urea is produced in , by
Annelida ( earthworm)
Most of insects ( cockroaches)
Antennal glands eg Crustaceans / prawn
Iiver , urea cycle or ornithine cycle , kerb - Henseleit cycle
Homeostatic Father
Homeostatic mechanism
In humans excretory system consists of
Maintenance of steady state ( Walter Cannon
Important for normal life as they maintain condition within a range in which the metabolic processes can occur
A pair of kidneys, one pair of ureters , a urinary bladder , a urethra
Kidneys are ( shape , structure, situated b/w , close to
Adult measure length
Width
Thickness , weight
Reddish brown , bean shaped structure, b/w the levels of last thoracic and third lumbar vertebrae close to dorsal inner wall of abdominal cavity
10-12 cm. 5-7 cm ,
2-3 average weight 120-170 kg
Hilum , fn
Renal pelvis, with
Retro - peritoneal kidney /
Outer layer of kidney is
Towards the centre of inner concave surface of kidney, through which ureter , blood vessels m nerves enter
Inner to the Hilum is a broad funnel shaped space , with projections called calyces
Extra peritoneal kidney, dorsal attached to dorsal abdominal wall , so only it’s ventral surface is covered by peritoneum
Is a tough capsule
Inside the kidney two zones
Medullary pyramids , projecting into
Columns of Bertini
An outer cortex , inner medulla
The medulla is divided into a few conical masses, into calyces
The cortex extends in between the medullary pyramids as renal columns
Each nephron of pyramids performs
Major calyx
Minor calyx
Urine passes from pelvis into , both ureters open
Fn
Urine formation which comes in collecting the form here it enters into calyx via a papilla ( tip of pyramid)
Pelvis divides into 3 or 4 branches when enters kidney
Each major calyx further divides into (3 or 4 ) sub branches
Ureter , through separate oblique opening into urinary bladder
The oblique opening prevents the back flow of urine
Urinary bladder externally ( nature) , internally lined by
Opening controlled by inner , outer
Urinary bladder opens into a
In females both sphincter are
Detrusor muscle, (involuntary), transitional epithelium or urothelium
By sphincters made up of circular muscles, inner = internal sphincter ( involuntary muscles) outer = external sphincter ( voluntary muscle) during micturition these relax to release urine
A membranous duct called ureters
Are present in membranous urethra
Urethra leads to ( males , females )
In males urethra has
Passage of urine
To end of penis , into vulva in females
3 parts , prostatic, membranous, penile urethra .
Nephron ➡️collecting duct ➡️ duct of Bellini ➡️papilla ➡️renal calyx ➡️renal pelvis ➡️ureters ➡️urinary bladder ➡️urethra
Nephron is , no . Each nephron has
Glomerulus is
Blood carried from ⬆️
Bowman’s capsule
Each kidney has nearly 1 million complex tubular structures . Glomerulus & renal tubule
Tuft of capillaries formed by afferent arteriole - a fine branch of renal artery
Is carried away by efferent arteriole
The renal tubule begins with a double walled cup like structure, which encloses glomerulus
Malpighian body/
PCT
A _______ shaped Henle loop
DCT
Cortical region
Medulla
Renal corpuscle = glomerulus along with bowman’s capsule
Proximal convoluted tubule = the tubule continues to form a highly coiled network
Hairpin , which has a descending and an ascending limb
Distal convoluted tubule = The ascending limb continues as another highly coiled tubular region
Malpighian corpuscle , PCT , DCT
Loop of henle
Collecting duct, many which “””””””” and open
Cortical nephron
Juxta medullary nephron
DCTs of many nephron open into a straight tube many of converge and open into renal pelvis through medullary pyramids in calyces
( majority) the loop of henle is too short and extends only very little into medulla (80-85%)
The loop of henle is very long and runs deep into medulla
Peritubular capillaries
Vasa recta ,,,,,,,,,, shape
Absent or
Efferent arteriole emerging from glomerulus forms a fine capillary network around the renal tubule
A minute vessel of this network runs parallel to henles loop forming a ‘ U’ shaped
Or highly reduced in cortical nephrons
Juxtaglomerular apparatus consists
Is a special
Built in location for
Juxtaglomerular cells ( cells of walls of afferent modified) + macula dense ( modified DCT wall ) + lacis / polkissen / mesangial cell
Sensitive region formed by cellular modifications in DCT and afferent arteriole at location of contact
Regulation of GFR
Fall in gfr can activate the
Oxygenated blood
Deoxygenated
JG cells to release renin which can stimulate glomerular blood flow and thereby gfr back to Normal
Heart ➡️ dorsal aorta.➡️ Renal arteries➡️. Afferent arteriole ➡️ glomerulus➡️ Efferent➡️. Vasa recta
Vasa recta ➡️ venules ➡️ renal vein ➡️ inferior vena cava
Urine formation process
On average blood filtered (constitute)
—- pressure causes filtration
Glomerular / ultra filtration Selective reabsorption , tubular secretion
1100-1200, which constitute roughly 1/5th of blood pumped out by each ventricle of heart
The glomerular capillary blood pressure
Glomerular capillary blood pressure 3 layers
Podocytes , slit pores / filtration
Endothelium of glomerular blood vessels
The epithelium of bowman’s capsule
A basement membrane between them
Epithelial cells of bowman’s capsule are arranged In an intricate manner so as to leave some minute spaces called
Filtration plasma exception
Glomerular filtration rate , value
Efficient mechanism for regulation of GFR
The proteins pass onto lumen of bowmen’s capsule
The amount of filtrate formed by kidneys per minute , 125ml/minute i.e 180 litres per day
Juxta glomerular apparatus is a special sensitive region formed by cellular modifications in DCT and afferent arteriole at location of their contact
Volume of filtrate,urine released ____ suggest
Who perform this (reabsorption ) and by how
Eg active
Passively reabsorption
1.5 litres , that nearly 99 % of filtrate has to be reabsorbed by renal tubules
Tubular epithelial cells in different segments of nephron perform, active / passive mechanisms
Glucose,amino acids, na +
Nitrogenous waste , also occurs in initial segments of nephron
During urine formation tubular cell secrete
Also imp cause
Filtration fraction
The effective filtration pressure that causes ultrafiltration is determined by - pressure
Substance like H+,K+ and ammonia into filtrate
It’ helps in maintenance of ionic and acid base balance of body fluids
GFR/RPF=125 (ml/min)/650 (ml/min) = 1/5
Glomerular hydrostatic pressure
Blood colloid osmotic pressure of blood
Capsular hydrostatic pressure
Glomerular hydrostatic pressure , due to , is the ( value )
Blood colloid osmotic pressure is ,due to ,resists ( value )
Bp in glomerular capillaries , difference in diameter of afferent and efferent arteriole ,main driving force to cause filtration ( 60 to 75 mm hg)
Is osmotic pressure created in blood of glomerular capillaries due to plasma proteins , the filtration of fluid from capillaries ( 30 to 32 mg )
Capsular hydrostatic pressure ,resists
Net filtration pressure
Pressure caused by fluid (filtrate) that reaches into bowmen’s capsule , filtration
NGP = GHP -[ BCOP + CHP]
=(75 or 60) - (32-18) mm of hg
= 10 to 25 mm of hg
Proximal convoluted tubule lined by (fn
Reabsorbed ,
fn
By
Simple cuboidal brush border epithelium , increases the surface are for reabsorption
Nearly all the essential nutrients, 70-80% of electrolytes , water ,
Maintain. The ph and ionic balance of body fluids by
selective selection of h ions ,ammonia , potassium ions into filtrate and by absorption of HCO3 from it
Henles loop ascending limb reabsorption,fn
Descending limb permeable/ impermeable fn ,
Ascending limb ——-
So
Minimum, in maintenance of high osmolarity of medullary interstitial fluid
Permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down
Is impermeable to water but allows transport of electrolytes actively or passively
Concentrated fluid pass upward , it get diluted due to passage of electrolytes to medullary fluid
Distal convolutions tube ———- reabsorption
Selective reabsorption , fn
Collecting tube extends , reabsorbed to what
Conditional reabsorption of Na + , water , HCO3
Of hydrogen and potassium ions , NH3 to maintain the pH and sodium potassium balance in blood
This long duct extends frm cortex of kidney to inner part of medulla , large amounts of water could be reabsorbed to produce a concentrated urine
Collecting duct allows
Also plays a role
Chemical composition of urine, water
Salts
Urea.
Other materials
Passage of small amounts of urea into medullary interstitium to keep the osmolarity
In maintenance of pH and ionic balance of blood by selective reabsorption of H+ , K+
95%
2
2.7
0.3 % ( Durgs , hippuric acid , uric acid , vitamin-C ,dyes
Urine pigment , formed due to
Ph of urine , specific gravity
Ions excreted out through urine
Ions removed out through
High threshold substances
Pale yellow colour of urine due to urochrome pigment , reduction of Hb
6 , = 1.01to 1.05
Monovolent ions = Na+,K+,Cl-,HCO3,H3O
Faecal matter are mainly divalent and trivalent ions eg Ca2+,mg2+,CO-2 3, Po-3 4
Substance which are completely reabsorbed eg glucose , amino acid
Athreshold substance
Water electrolyte are examples of what
Low threshold substances
Human excrete value urea
Diuretic substance
Substance which are not reabsorbed at all eg Inulin,sulphates,para amino hippuric acids (PAHA )
Substance which are reabsorbed the body are demand of variable threshold substances
Less reabsorbed eg urea
25 gm urea / day
Substance which increases the urine formation eg tea , coffee , alcohol
Glycosuria , diseases
Disease due to deficiency of ADH , characterised
Urine formation , elimination
Blood vessel with maximum urea is , minimum
Average urine excrete
Amount of urea in urine
If glucose remains unreabsorbed from PCT than comes out through urine , diabetes mellitus
ADH or vasopressin = diabetes insipidus , by more dilute urine
In liver , kidney
Hepatic vein , renal vein
1-1.5 liters per day
Alpha protein diet
—- plays a significant role in counter current mechanisms
Forms a counter current
What helps in maintaining an increasing osmolarity towards the
Gradient is mainly caused by
Henles loop and vasa recta
The flow of filtrate in two limbs of henles loop is in opposite direction
The flow of blood through two limbs of vasa recta
The proximity between henles loop and vasa recta as well as the counter current mechanism in them
The inner medullary inetrstitium i,e from 300 mOsmolL-1 in cortex to about 1200 mOsmolL-1 in inner medulla
NaCl and urea
______ maintains the interstitial gradient of NaCL, Nacl returned to interstituim by
NaCl is transported by , exchanged by
Urea is added to interstitial medullary fluid
Urea re enter
Loop of henles , ascending part of vasa recta
Ascending limb of henles loop , descending limb of vasa recta
In small amount by diffusing out of collecting duct
In ascending thin segment of loop of henle by diffusion
Counter current mechanism helps
How filtrate makes blood hypertonic
Final — initial filtrate
Osmoreceptors in body are activated by
To maintain a concentration gradient in medullary interstitium
As filtrate flow down in CD more and more water moves out of tubule by osmosis
»> 4 more times
Changes in blood volume, body fluid volume and ionic concentration
What activates the osmoreceptors ,
stimulates the
How ADH prevents diuresis
Switch off ADH
An excessive loss of fluid from the body ,
the hypothalamus to release anti diuretic hormone ( ADH) or vasopressin from neurohypophysis
It facial water reabsorption from latter part of tubule
Increase in body fluid volume
ADH also affects
This causes an increase in
A fall in glomerular blood flow / , to release, which converts
Angiotensin fn
Kidney function by its constrictory effects on blood vessels
In blood pressure-> increase the glomerular blood flow , thereby the GfR
Glomerular blood pressure/ GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin 1 and further angiotensin 2
A powerful vasoconstrictor increases the glomerular blood pressure and then GFR
Angiotensin 2 also activates
It causes
Also leads to
What can cause release of atrial natriuretic factor
The adrenal cortex to release Aldosterone
Reabsorption of Na+ and water from distal parts of tubule
An increase in Bp and GFR
An increase in blood flow to atria of heart
ANF can cause
Acts as
Urine is stored in , till a
In response
Vasodilation (dilation of blood vessels) and thereby decrease blood pressure
A check on renin angiotensin mechanism
Urinary bladder , a voluntary signal is sent to CNS
The stretch receptors on walls of bladder send signal to CNS
CNS passes message to
Average urine , urea
Indicatives of diabetes mellitus
Initiate the contraction of smooth muscles of bladder and simultaneous relaxation of urethral sphincter causing the release of urine
1 to 1. 5 liters , 25-30 gm
Glycosuria. , ketonuria
Lungs eliminate Co2
Water
Skin glands
1 contains
Primary fn
200 ml/min
400 ml/min
Sweat , sebaceous gland
99.5% water, NaCl , lactic acid, small amount of urea , amino acid , glucose
Is to facilitate a cooling effect on body surface
Sebum contains , secretion provides
Liver is main site for elimination of
Bole carries these materials to
Waxes , sterols , other hydrocarbons , fatty acids ,,,,, a protective oily covering for skin
Cholesterol, bile pigments ( bilirubin, biliverdin) , degraded steroids hormones , some vitamins, drugs
Intestine from where they are excreted with faeces
Uraemia
Blood drained from convenient _____ , is pumped into
The units contain , fluid same composition as
The ______ _______ mem of tube allows
Malfunctioning of kidneys can lead to accumulation of urea in blood
Artery , into a dialysing unit after adding an anticoagulant like heparin
A coiled cellophane tube surrounded by a fluid , plasma except nitrogenous waste
Porous cellophane , allows the passage of molecules based on concentrations gradient
The cleared blood is pumped through
Renal failure syndrome characteristed by
Glomerulonephritis
Vein
Renal dysfunction,oliguria, anuria , sudden rise in metabolic waste products like urea & creatine ( n2 waste ) in blood (uremia)
Disease where due to infection/ injury in the basement membrane, the inflammation of glomerulus leads to renal failure & death
Renal calculi /
Calculi made up of
Urolithiasis = formation of stone within kidney ,
Calcium phosphate, uric acid , cystine / calcium oxalate
