Coordination and response Flashcards
electrical impulses travel along..?
electrical impulses travel along
neurones
what does the nervous system consist of
CNS and PNS
What does CNS stand for
Central nervous system
What does PNS stand for
Peripheral nervous system
What does CNS consist of?
the brain and the spinal cord
What does the PNS stand for?
the nerves outside of the brain
and spinal cord
Describe the role of the nervous system
coordination and regulation of body functions
Describe a simple reflex arc in terms of: receptor,
sensory neurone, relay neurone, motor neurone
and effector
Describe a reflex action
a means of automatically and rapidly integrating and
coordinating stimuli with the responses of
effectors (muscles and glands)
Describe a synapse
a junction between two neurones
Describe the structure of a synapse, including the
presence of vesicles containing neurotransmitter
molecules, the synaptic gap and receptor
proteins
Describe the events at a synapse
(a) an impulse stimulates the release of
neurotransmitter molecules from vesicles
into the synaptic gap
(b) the neurotransmitter molecules diffuse
across the gap
(c) neurotransmitter molecules bind with
receptor proteins on the next neurone
(d) an impulse is then stimulated in the next
neurone
What does the synapse ensure?
ensures that impulses travel in one direction only
Describe sense organs
groups of receptor cells responding to specific stimuli:
light
sound
touch
temperature
chemicals
describe the function of the cornea
– refracts light
describe the function of the iris
controls how much light enters the
pupil
describe the function of the lens
– focuses light on to the retina
describe the function of the optic nerve
carries impulses to the brain
describe the function of the retina
– contains light receptors, some
sensitive to light of different colours
define a hormone
a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific
target organs
where is glucagon secreted in?
the pancreas
Describe the role of adrenaline in the control of
metabolic activity
- increasing the blood glucose concentration
- increasing heart rate
Describe adrenaline
hormone secreted in ‘fight or flight’ situations
effects of adrenaline
- increased breathing rate
- increased heart rate
- increased pupil diameter
Differences between nervous and hormonal control, limited to speed of action and duration of effect
which endocrine gland secretes adrenaline?
adrenal glands
which endocrine gland secretes insulin
the pancreas
which endocrine gland secretes testosterone
the testes
which endocrine gland secretes oestrogen?
the ovaries
define homeostasis
the maintenance of a constant internal environment
what does insulin decrease?
insulin decreases blood glucose
concentration
What is gravitropism
a response in which parts of a plant grow towards or away from gravity
What is phototropism
a response in which parts of a plant grow towards or away from the direction of the light source
What are examples of the chemical control of plant
growth
phototropism and gravitropism of a shoot
What is the role of auxin
in controlling shoot growth
describe the pathway of auxin in stimulating cell elongation
(a) auxin is made in the shoot tip
(b) auxin diffuses through the plant from the
shoot tip
(c) auxin is unequally distributed in response to
light and gravity
(d) auxin stimulates cell elongation
