Chapter 27-29 Flashcards
Excretion
What are the 4 primary functions?
What are the 4 primary organ systems?
- Control internal organic solute levels
- Control plasma water volume
- Remove non-useful and harmful substances
- Maintain osmotic balance
- Respiratory
- Digestive
- Integumentary (and glands)
- Renal
Excretion of Nitrogenous Wastes
What are the 3 different products of protein & nucleic acid catabolism?
- urea uric acid ammonia
Depend on water availability:
- Ammonia: ammonotelic animals
- In animals with lots of water-1 g : .5 L
- Urea: ureotelic animals
- Ammonium and bicarbonate are combined
- Less water – 1 g : .05L
- Uric acid: uricotelic animals
- Requires more ATP
- Less soluble, does not cause tonicity
- Removes more ammonium
- Requires less water 1g:.001L
Renal Organs
Protonephridia
Found in simple animals with one _____
examples?
- Cilia lower hydrostatic pressure in ducts
- Low pressure sucks small solutes out of flame cells
- Cilia force fluid and solutes out of body
internal fluid cavity
rotifers, flatworms, larva of annelids & mollusks
Renal Organs 2
Metanephridia
Found in simple animals with two or more fluid spaces
Examples?
Circulatory fluid is filtered into ___
Crustaceans, and adult annelids & mollusks
tubules
Renal Excretory Systems
What are the 4 jobs? 3 major ones.
- Filtration
- Secretion
- Reabsorption
- Osmoconcentration
- Mammals & birds
The Mammalian Kidney
Path of filtrate and urine
nephron
minor calyx
major calyx
renal pelvis
ureter
bladder
urethra
The ___ is the functional unit
nephron
The Mammalian Kidney: Urine Production
Urine production involves 3 main steps. What are they?
- Glomerular filtration (renal corpuscle)
- Tubular reabsorption
- Tubular secretion
Glomerular Filtration
The renal glomerulus is a unique ___ composed entirely of ___; therefore, it has a much ___ pressure than a normal capillary
Bowman’s capsule is ?
capillary network
arterioles
higher
the first part of the nephron, and is the site of collection of the initial glomerular ultrafiltrate
Glomerular Filtration 2
The glomerular capillaries are fenestrated to allow plasma and smaller compounds through while retaining blood cells and larger plasma proteins
Podocytes are ?
Filtration slits between the pedicels act like a sieve allowing the filtrate to enter the lumen of the nephron
cells in Bowman’s capsules which have multiple processes called pedicels
Regulation of Glomerular Blood Flow
maintained at a steady level by both intrinsic and extrinsic mechanisms:
Extrinsic: 2?
Intrinsic: 2?
- sympathetic nervous system – vasoconstriction of the afferent arteriole and a reduction in glomerular filtration
- hormones
- myogenic — smooth muscle of afferent arteriole; increase in blood pressure stretches the afferent arteriole causing reflex contraction which reduces the diameter and increases the resistance to flow.
- Juxtaglomerular apparatus – macula densa and granular cells
Juxtaglomerular Apparatus
Juxtaglomerular apparatus consists of:
Macula densa –?
Granular cells – ?
1. specialized tubule cells which monitor osmolarity and flow. If flow is high, vasoactive substances are released that constrict the afferent arteriole (may also do the reverse)
2. release renin which increases Na+ reabsorption in tubules via renin-angiotensin-aldosterone system
Tubular Reabsorption
99% of the glomerular filtrate is reabsorbed back into the bloodstream via the renal tubules
Different parts of the tubule have different properties regarding water and solute transport and permeability
Tubular Reabsorption: Proximal Convoluted Tubule
Apical microvilli on the epithelial cells of the proximal convoluted tubules increase surface area for the reabsorption of water and solutes
Tubular Reabsorption: Proximal Convoluted Tubule 2
In the proximal convoluted tubule, Na+ diffuses __ through the ___ membrane; and is pumped out ___ into the blood in the ___ membrane
Glucose and K+ are ___ cotransported with Na+ by a carrier protein in the apical membrane
A water channel allows reabsorption of water
- passively
- apical
- actively
- basolateral
- passively