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16 Cards in this Set

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Negative feedback

1) Parameter too high/Parameter too low


2) Receptor senses changes


3) Effector receives information from receptor


4) Effector moves to increase/decrease parameter

Steps taken within the nephron

Ultrafiltration - Selective reabsorption - Ionic concentration - Regulation of ions - Urine conc

Ultrafiltration

The significantly larger pressure in the glomerular capillaries than the efferent arteriole forces substances with an Mr smaller than 69000 through the basement membrane and into the filtrate

Selective reabsorption

1) Na-K pumps are actively pumping Na+ out of the cell, causing the [Na+] inside the cell to drop, causing a conc. gradient. Na+, glucose and A.As travel through channel proteins


2) [Glucose] and [A.As] increases, so the conc. gradient forces them to diffuse out into blood vessels


3) Movement of molecules causes osmotic gradients and H20 follows by osmosis

Loop of henle

1) Water lost from descending limb by osmosis


2) NaCl diffuses into descending limb


3) At base of ascending limb, high [NaCl] causes NaCl to diffuse out


4) NaCl actively transported out of ascending limb

Osmoregulation

1) ADH binds to receptors in the cell surface membrane of cells lining the collecting duct


2) Active phosphorylase enzyme produced


3) Enzyme makes vesicles surrounded by aquaporins to move to the plasma membrane


4) Vesicles fuse with membrane


5) Water moves freely through aquaporins down a kPa gradient

Structure of a neurone

Nucleus, dendron, dendrite, axon, schwann cells + uncles, terminal branches, synaptic knob

Synaptic Junction

1) A.P arrives at synaptic knob


2) Voltage gated Ca channels open and Ca2+ flows in


3) Ca2+ bind with vesicles containing neurotransmitter


4) Neurotransmitters released by exocytosis


5) NT bind with receptors in Post-synaptic neurones and open Na channels


6) Enzyme breaks down NT to close channels

Spatial summation

Firing of numerous signals from different neurones to one post-synaptic neurone

Temporal summation

Firing of a string of APs over a nerve junction consecutively to induce a sufficient pD at the post-synaptic neurone.

Exocrine gland

- Secrete chemicals through ducts into cavities or the surface of the body

Endocrine gland

- Secrete hormones directly into the blood

Mode of glucagon

1) Pancreas detects low blood sugar


2) A cells release glucagon, B cells stop releasing insulin


3) Glucagon binds to receptors on liver cells


4) Glycogenolysis and gluconeogenesis is activated


5) Cells release glucose into blood

Mode of insulin

1) Pancreas detects high blood sugar


2) A cells stop releasing glucagon, B cells release insulin


3) Insulin binds to receptors on liver and muscle cells


4) Cells take up more glucose, glycogenesis is activated


5) Less glucose in blood

Phototrophisms

When a coleoptile is exposed to light from only one direction, it causes auxin inside to redistribute along the shaded side of the shoot.


This causes the plant to bend towards the light

Auxin

- Promotes cell elongation


- Can prevent abscission


- Encourages root growth


- Promotes flowering