Filtration under pressure that separates small molecules from the blood plasma
7 of 31
What happens to these small molecules after ultrafiltration?
The small molecules are filtered from the knot of capillaries (glomerulus) to form a filtrate in the bowman's capsule
8 of 31
How is hydrostatic pressure generated in the glomerulus?
Through the afferent arteriole is wider than the efferent arteriole
9 of 31
Name the 6 labels that can be found on a glomerulus diagram
Cells of proximal convoluted tubule, squamous epithelial cells of bowman's capsule, afferent arteriole, efferent arteriole and podocyte cells
10 of 31
How does filtration occur through a molecular sieve?
Pores in the endothelium of capillary, pores in basement membrane, the feet of podocytes
11 of 31
During ultrafiltration what passes into the filtrate?
Water, urea, glucose, salt and mineral ions
12 of 31
During ultrafiltration what remains in the blood?
Red blood cells, white blood cells, plasma proetins
13 of 31
Definition of selective reabsorption
Useful products are reabsorbed from the filtrate into the blood
14 of 31
What features do Proximal Convoluted Tubules have and why are they useful?
Intrinsic Proteins - selectively uptake substances from the filtrate, Microvilli - large surface area for absorption, Mitochondria - provide ATP for active transport
15 of 31
What does the loop of henle do?
Concentrates ions in the tissue fluid of the medulla
16 of 31
What principle does the loop of henle use?
hair-pin counter current multiplier
17 of 31
What happens in the descending limb of the loop of henle?
It's permeable to water, so water moves out into the tissue fluid of medulla by osmosis, thereore increasing the water potential of the tissue fluid in medulla
18 of 31
When in the loop of henle is the filtrate most concentrated?
In the apex
19 of 31
What happens in the ascending limb of the loop of henle?
It's impermeable to water, so Na+ Cl- ions move out through active transport and lowers tissue fluid of medulla
20 of 31
How does water leave the tissue fluid in the medulla?
It's carried away by the blood by the vasa recta
21 of 31
What is the function of the loop of henle?
Create a concentration gradient/ lower water potential in the medulla
22 of 31
What happens in the collecting duct?
Water leaves the collecting duct walls through osmosis from a low to high water potential
23 of 31
Osmoregulation
The homeostatic control of body water - controls water potential of the blood
24 of 31
How do humans gain water/lose water?
Gain it through eating/drinking and lose it by sweating/urine/faeces
25 of 31
What is the excretory substance of fish?
Ammonia
26 of 31
What are the features of the excretory substance of fish?
highly toxic, extremely soluble in water, diffuses across gills and is quickly diluted to non-toxic levels
27 of 31
What is the excretory substance of birds?
Uric Acid
28 of 31
What are the features of the excretory substance of birds?
Insoluble in water, small mass for storage to help organisms fly, important in conserving water (allows organisms to live in dry environments) low toxicity so safely build up in eggs, large energy cost for production, little water cost 4 excretion
29 of 31
What is the excretory substance of mammals?
Urea
30 of 31
What are the features of the excretory substance of mammals?
Production requires energy, long loop of henle, less toxic than ammonia, tissues can tolerate large concentrations for short period of time, can live in low water environment, more water reabsorbed into filtrate,seeds need oils to form metabolic H20
31 of 31
Other cards in this set
Card 2
Front
Why is homeostasis important?
Back
To maintain optimum pH and temperature for enzymes, to prevent damage to structures in the body
Comments
No comments have yet been made