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