Studied by 2 people
why does an action potential only move ahead toward axon terminus?
Sodium channels remain inactivated after an AP, there is a refractory period
The strength of an action potential is always the same. How, then, do we distinguish between stronger and weaker signals such as louder vs softer sounds?
rate of AP being produced
Repolarization
Return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell.
Depolarization
The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.
2 ways action potentials are sped up
myelin sheath 2. wide axon
myelin sheath
A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.
saltatorial transmission
Rapid transmission of a nerve impulse due to jumping over myelin sheath
synaptic vesicles
Enclosed comparements that release neurotransmitters
what ion enters axon at the terminal causing the synaptic vesicles to fuse with the terminal membrane to release the neurotransmitter?
calcium
voltage gated channels
open and close in response to changes in membrane potential
action potential arrives and _______________ the membrane
depolarizes
influx of ______________ causes vesicles to fuse to membrane
calcium
What does the neurotransmitter bind to on the post-synaptic cell?
Ligand gates ion channels
What happens to create an EPSP?
Depolarization of membrane of post synaptic cell caused by binding of a excitatory neurotransmitter
What happens to create an IPSP?
Hyperpolarization in membrane of post synaptic neuron caused by biniding of inhibitory NT
What sequence of events results in spatial summation?
When multiple presynaptic inputs each stimulate the postsynaptic neuron at the same time
Where does summation occur?
axon hillock
What type of signals are associated with long distance communication
electrical
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Neurotransmitters
chemical messengers that cross the synaptic gaps between neurons
function of sensory neurons
Transmit impulses from sensory receptors toward the CNS
function of interneurons
connect sensory and motor neurons
function of motor neurons
carry impulses from the CNS to effectors
peripheral nervous system
the sensory and motor neurons that connect the central nervous system to the rest of the body
central nervous system
brain and spinal cord
motor neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
Where is the highest concentration of potassium ions?
inside cell
Where is the highest concentration of sodium ions
outside the cell
Where is the highest concentration of chloride ions?
outside the cell
Where is the highest concentration of large anions
inside the cell
Which direction does the sodium-potassium pump sodium?
outside the cell
. Which direction does the sodium-potassium pump potassium
inside the cell
When voltage-gated potassium channels open, they allow for K+ to move down its concentration gradient across the cell membrane: Which direction will it flow?
outside the cell
what happens to the charge inside the cell when k+ leaved?
becomes negative
Mutualism
A relationship between two species in which both species benefit (+,+)
Exploitation (+/-)
interactions in which one species benefits and the other is harmed
competition (-,-)
the struggle between organisms to survive in a habitat with limited resources
competition interaction
both species harmed
What is an example of a resource for which there is no need for competition?
oxygen
competitive exclusion
When two species compete for limited resources, one will use it better than the other
What is predation?
the preying of one animal on others.
feeding adaptations of predators
claws, teeth, fangs, stingers, and poison
predator avoidance adaptations
camouflage, warning coloration, mimicry
Herbivory
harms plants but does not kill them
herbivore adaptations
-acute chemosensors -specialized teeth/jaws and digestive systems -detoxification systems
Parasitism
A relationship between two organisms of different species where one benefits and the other is harmed
host
An organism on which a parasite lives.
Ectoparasites
Parasites that feed on external surface of host.
endoparasite
parasite living on the inside of its host
Parasitoid
A specialized type of predator that lays eggs inside other organisms - referred to as its host
Commensalism
A relationship between two organisms in which one organism benefits and the other is unaffected
trophic levels
primary producers, primary consumers, secondary consumers, tertiary consumers, quaternary consumers
foundation species
species that plays a major role in shaping a community by creating and enhancing a habitat that benefits other species
keystone species
a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.
What do plants and other photosynthetic organisms convert solar energy into
chemical energy
what is energy during transfer of energy lost as?
Heat energy
does energy FLOW or CYCLE through an ecosystem?
flow
do chemical elements FLOW or CYCLE through an ecosystem?
cycle
How does an element become limited in a given system?
becomes a gas in atmosphere
Autotrophs Trophic Level
primary producer
Herbivore trophic level
primary consumers
Carnivore trophic level
secondary/tertiary consumer
What are detritivores?
decomposers
decomposer role in nutrient movement
Convert organic matter to inorganic matter for plants to eat
List the three ways ingested food is partitioned by the caterpillar:
feces, growth, cellular respiration
In general, how much energy is lost each time it is transferred from one trophic level to the next
90%
What role does decomposition play in biogeochemical cycling?
breaks down organic matter into carbon dioxide
Water biological importance is:
essential to all
Carbon biological importance
o Basis of organic molecules (Nucleic acids, proteins, carbohydrates, lipids)
Phosphorus biological importance
o Nucleic acids, phospholipids, ATP, bones, teeth
nitrogen biological importance
create amino acids and bacteria use
What are two mechanisms that add carbon (in the form of CO2) back into the atmosphere?
burning fuels, respiration
What process moves carbon from the atmosphere into the biosphere (living organisms)?
photosynthesis
nitrogen fixation is the:
Process of converting nitrogen gas into ammonia
nutrient cycling
The circulation of chemicals necessary for life, from the environment (mostly from soil and water) through organisms and back to the environment.
how does carbon move from atmosphere to biosphere?
photosynthesis
how does carbon move from biosphere to atmosphere
respiration
waterproofing
wax coating, thick shells, thick skin
Nitrogenous waste products
ammonia, urea, uric acid
Ammonia
very toxic, little energy to produce
urea
less toxic, comes from the breakdown of proteins
uric acid
nitrogenous waste excreted in the urine
urea is produced by _____
those who live on land where water is abundant and not shelled eggs
ammonia is produced by _____
those who live in water
uric acid is produced by _____
those who need to conserve water and develop in shelled eggs
Nephrons
Functional units of the kidneys
filtrate enteres ________ from blood
tubule
water reclaimed as filtrate moves thru the system creating ________
urine
Bowman's capsule
cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.
glomerulus
A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney.
filtrate
fluid entering the nephron tubule
lumen
inside the space of the tubule
descending loop of henle
water reabsorption, permeable to water
in the descending loop of henle, filtrate becomes more _______
concentrated
is the ascending loop of henle permeable to water? What molecule is pumped out of filtrate?
No, Na+ is pumped out of filtrate, decreasing filtrate concentration
ascending loop of henle is permeable to________
salts
in the ascending loop of henle, filtrate becomes more _______
dulited
collecting duct is permeable to ____________
water and salt
ADH (antidiuretic hormone)
Produced by Posterior lobe of Pituitary Gland. Targets kidneys for water conservation.
when ADH is present, it_____________ water permeability
increases
Note 
Flashcard (38)