B14 Response and Stimuli Flashcards
What is the difference between kinesis and taxis?
Taxis is a behavioural mechanism that animals to respond to the direction/position of a stimulus. Kinesis is a behavioural mechanism that animals to respond to the presence and intensity of a stimulus such as changing their speed or rate it changes direction
WHat are the main types of tropism
Phototropism, hydrotropism and gravitropism
What is a plant’s main natural auxin?
Indoleactic acid
How do auxins promote plant growth?
They make the cell walls loose and stretchy , allowing the cell to elongate
How does IAA differ in roots than in shoots?
In roots, high conc of IAA inhibit cell elongation but in shoots, high conc of IAA promote cell elongation
What is an action potential?
An electrical impulse sent by a receptor to the effector
What is a generator potential?
The change in voltage of a receptor due to a stimulus
What is the structure of the Pascinian Corpuscle receptor?
It has a sensory nerev ending surrounded by lamellae which contain Na+ channels
How does Pascinian Corpuscle respond to pressure?
The lamellae will press on the sensory nerve ending. This causes the sensory neurone’s cell membrane to stretcg, deforming the Na+ channels. This causes the channels to open and the ions to diffuse into the cell, creating a generator potential
What are the photoreceptors in your eye?
Rod cells and Cone cells
What is visual acuity?
The ability to tell apart two points that are close together
What are the differences between rod and cone cells
Multiple rods are attached to one bipolar neurone unlike cone cells.Cone cells produce images in colour but rod cells give it in black and white.
What are the two divisions of the autonomic nervous system?
the parasympathetic nervous system and the sympathetic nervous system
How is the heart rate controlled by electrical impulses
A wave of electrical activity spreads out from the SAN. The wave spreads across botjh atria, causing them to contract and reaches the AVN. The AVN releases a wave of electrical activity between the ventricles, along the bundle of His and releases it at the apex , causing the ventricles to contract
