Nervous System And Survival Flashcards
Describe taxis and state an advantage of this type of movement
Taxis-whole motile organism(animals) has a directional response to move towards/away from a named stimulus
Advantage=avoid competition,find a mate, increase dispersal, to avoid predators
Describe kinesis and state an advantage of this type of movement
Kinesis-whole motile organism(animals) has a random movement response where rate of movement decreases/increases in response to a named stimulus
Advantage= does not move towards/away from named stimulus so avoids predators/finds a mate/ avoid competition
Describe tropism
A directional growth response part of an organism (plants) to a named stimulus
Describe a reflex arc and state their advantages
A three neuron (sensory neuron, interneuron and motor neuron) that provide a pathway along which action potentials are transmitted from a receptor to an effector without involving ‘conscious’ regions of the brain
-Rapid and automatic adjustments to environment
-Protect against damage to body tissues
-Do not have to be learnt
-Help escape from predators
-Enable homeostatic control
-Posture and balance
-Finding food/mate/suitable living conditions
Describe and explain how the distribution of IAA changes and then effects the growth of plant cells in the shoots
-Shoot tip produces IAA
-IAA moves by diffusion away from light
-Causes more elongation of cells where there is higher concentration of IAA
-Results in shoot growing towards light (positive phototropism/negative geotropism)
Describe and explain how the distribution of IAA changes and then effects the growth of plant cells in the roots
-Root tip produces IAA
-IAA moves by diffusion to lower side of root (either away from light or due to gravity)
-Causes inhibition of elongation of cells where there is higher concentration of IAA
-Results in more elongation of cells in lower concentration of IAA so roots grow downwards away from light (negative phototropism/ positive geotropism)
Name the different types of stimuli a receptor may respond to
-Light
-Pressure
-Touch
-Temperature
-Chemical
-Noise
-Smell
Describe salt story conduction and compare this myelinated neuron to a non-myelinated neuron
Schwann cells produce myelin that acts as an electrical insulator
This causes saltatory conduction
-This means hydrophilic Na+ and K+ ions can’t diffuse over this part of the membrane
-Depolarisation only occurs at nodes of Ranvier so impulse jumps node to node
Non-myelinated neurons transfer nerve impulses by depolarising next section of the membrane occurring along the whole length of the neuron
Therefore nerve impulses faster on myelinated neuron
