Elimination and Nervous System - Bio Exam 3

Elimination

Removing CO2 through the blood transportation system

Main form of nitrogenous waste produced by fish

Ammonia

Toxicity - high

Energy - low

Water loss - high

Main form of nitrogenous waste produced by mammals

Urea

Toxicity - medium

Energy - medium

Water loss - medium

Main form of nitrogenous waste produced by birds

Uric acid

Toxicity - low

Energy - high

Water loss - low

4 Processes of kidney excretory system

1. Filtration

2. Reabsorption

3. Secretion

4. Excretion

Filtration

Bllod squeezed though filter to capillary, plasma enters filtrate

Reabsorption

Returns useful solutes (glucose, salts, vitamins, hormones, amino acids) and water to the blood

Secretion

Adds solutes like wastes to the filtrate. If kidneys reabsorbed something bad, or the filtrate didnt get all of the waste

Excretion

Final filtrate, urine leaves the body

Nephron

Functional units of the kidney
Salt concentration increases the deeper you go

Cortical nephron

Short loops, water is plentiful

Juxtamedullary nephron

Long loops going deep to the medulla

Proximal tubule

First part of the nephron, recovers valuable molecules through secretion and reabsorption

Descending loop of henle

Second part of the nephron, recovering water through osmosis

Thin and Thick ascending limbs

Third A. and B. part of the nephron, recovering salt, helping maintain salt gradient

Fine tuning

Fourth part of the nephron, final adjustments of secretion and reabsorption

Urine collection

Fifth and final part of the nephron, filtrate processed into urine, urine collects in collecting duct

Three types of neurons

Sensory neuron - takes info from PNS to CNS

Interneuron - neurons that talk to each other in the brain

Motor neuron - info from CNS → action for PNS

Resting potential

Puts ions in a concentration gradient pressure, more negative on the inside

Sodium Potassium pump

Maintains concentration gradient and resting potential. 3 Sodiums leave, 2 Potassium goes in

Graded potential

Depolarization and Hyperpolarization. Under the threshold for an action potential, the stronger the stimulus, the larger the change in membrane potential

Action potential

A stimulus strong enough to produce a depolarization that reaches the threshold

Depolarization

The inside of the cell becomes more positive (less negative) as Na+ channels open, and Na+ enters the cell

Hyperpolarization

The inside of the cell becomes more negative, as K+ channels open and K+ leaves the cell

Positive feedback in action potential

Depolarization causes more channels to open, more Na+ rushes into the cell, and the cell becomes more positive

Myelin sheath

Insulated axon gaps cause action potentials to jump from section to section

IPSP

Inhibitory postsynaptic potentials. Makes it less likely for action potentials to occur, negative ions enter the neuron, or positive ions leave the neuron, making membrane potential more negative

EPSP

Excitatory postsynaptic potentials. Makes it more likely for action potentials to occur, positive ions enter the neuron, making membrane potential more positive

Summation

Synaptic integration. EPSPs and IPSPs are added together to determine whether an action potential should occur. Happens in the axon hillock. One input alone is usually too weak to elicit an action potential.