Responses Keywords

Responses Keywords

• taxis = a directionally determined response to a stimulus

• kinesis = a non-directionally determined response to a stimulus 

• tropism = a positive or negative growth towards or away from a  stimulus, the rate at which is controlled by hormonal growth factors

• synergism = 2 work together to reinforce the same effect

• apical = continuous extension of an apex at the roots or shoots

• lateral bud = extension of the length of side shoots (away from the bud)

• lateral = extension of the width of columns of roots and shoots 

• intercalary = extension of the length between nodes of a stem

• indoleacetic acid (IAA) = type of auxin that increases cell plasticity in plants, and travel by the acid growth hypothesis

• acid growth hypothesis = protons are actively transported into the cell wall from the cytoplasm, activating enzymes which digest cellulose to make walls more flexible

• phototropism = shoot growth towards light and root growth inhibition, using IAA

• gravitropism = inhibition of root growth using IAA, causing roots to grow towards the centre of the Earth

• pacinian corpuscle = a receptor that responds to mechanical pressure, in many places around the body including skin, tendons and joints; contain a blood vessel, sensory neurone, viscous gel and layers of connective tissue

• transducer = converts one form of energy to another (e.g mechanical pressure to a generator potential, or light to electrical energy)

• retina = inner-most layer of the eye, containing eye receptor cells

• retinal convergence = number of rod cells connected to a bipolar cell

• rhodopsin = pigment in rod cells which is broken down to create a generator potential

• visual acuity = sharpness of vision

• fovea = area of the eye (retina) that light strikes the most, and where cones cells are found

• iodopsin = pigment that requires high light intensities to break down to produce colour image

• myogenic = a muscle that initiates its own contractions

• atrioventricular septum = non-conductive tissue that separates the atria and the ventricles

• Purkyne tissue = collection of cells making up the Bundle of His that conduct electrical waves

• medulla oblongata = part of the brain that controls heart rate; divided into an ‘increase’ (sympathetic) and ‘decrease’ (parasympathetic) centre

• carotid arteries = round in the neck; where chemoreceptors are situated

• cell body = contains organelles (e.g large amounts of endoplasmic reticulum); associated with the production of proteins and neurotransmitters

• Schwann cells = provide electrical insulation, nerve regeneration, phagocytosis and the membranes for myelin sheaths 

• nodes of Ranvier = contractions between adjacent Schwann cells

• nerve impulse = temporary reversal of the electrical potential difference across the axon membrane

• polarised =…