Excretion 14 Coordination and response Flashcards
excretion
the removal of the waste
products of metabolism and substances in
excess of requirements from the body
deamination
the removal of the
nitrogen-containing part of amino acids to form
urea
Describe the role of the nervous system
coordination and regulation of body functions
synapse
a junction between two
neurones
Stimuli
changes in the environment that can be detected by organisms
Receptors
cells or groups of cells that detect stimuli
Effectors
part of the body that respond to a stimulus. Muscles and glands are effectors.
Reflex arc
series of neurons ( sensory, relay and motor) that transmit electrical impulses from a receptor to an effector
Sense organs
groups of receptor cells
responding to specific stimuli: light, sound, touch,
temperature and chemicals
Accommodation
changing the shape of the lens to focus on objects at different distances from the eye.
Pupil reflex
an automatic response to a change in light intensity
Describe the function of each part of the eye
(a) cornea – refracts light
(b) iris – controls how much light enters the
pupil
(c) lens – focuses light on to the retina
(d) retina – contains light receptors, some
sensitive to light of different colours
(e) optic nerve – carries impulses to the brain
hormone
a chemical substance,
produced by a gland and carried by the blood,
which alters the activity of one or more specific
target organs
identify in diagrams and images specific
endocrine glands and state the hormones they
secrete
(a) adrenal glands and adrenaline
(b) pancreas and insulin and glucagon
(c) testes and testosterone
(d) ovaries and oestrogen
adrenaline
the hormone secreted in
‘fight or flight’ situations
homeostasis
the maintenance of a
constant internal environment
gravitropism
a response in which
parts of a plant grow towards or away from
gravity
phototropism
a response in which
parts of a plant grow towards or away from the
direction of the light source
