COORDINATION AND RESPONSE
Definitions:
Conjunctive: A thin, transparent membrane that covers and protects the front of the
eye.
Coordination: The way in which receptors pick up stimuli and pass the information
into the effectors.
Effectors: The physical areas in an organism’s which reacts to what have been
sensed.
Endocrine system: The use of chemicals (hormones) to transmit information from
one part of the body to another.
Geotropism: a response in which the plant grows towards or away from gravity.
Myelin: The layer of fat and protein that is wrapped around some nerve fibres.
Nerve fibres: Long, thin fibres of cytoplasm that carry electrical impulses.
Nervous system: The network of nerve cells and fibres which transmits nerve
impulses between parts of the body.
Neurone: A cell adapted to be able to carry messages very quickly via nerve fibres.
Phototropism: a response in which a plant grows towards or away from light.
Receptors: Specialised cells responsible for sensing changes in the environment
(e.g., changes in temperature, light, sound, etc..).
Reflex action: A reaction that takes place without your thinking about it, these are
reliant on quick coordination between the receptor and effector.
Reflex arc: The pathway along which nerve impulses travel – includes the sensory
neurone, relay neurones and motor neurone.
Relay neurons: Neurones in the central nervous system that pass an impulse on
to several other neurons. These neurons relay the impulse on tho other neurons.
Rods and Cones: Light receptors found in the retina of the eye.
Sensory neurone: A cell which carries impulses from a sensory receptor.
, Sense organs: groups of receptor cells responding to specific stimuli: light, sound,
touch, temperature, and chemicals.
Stimuli / Stimulus: Changes in an organism’s environment that are sensed by
specialised cells.
The orbit: The bony socket in the skull in which the eye is set.
The retina: The part of the eye that contains receptor cells. This is the part that is
sensitive to light. It is located at the back of the eye.
Tropism: a growth response by a plant.
RESPONSE AND COMMUNICATION IN ANIMALS:
Nerves and hormones allow communication.
Stimuli are changes in the environment. These are picked up by specialised cells
called receptors. And the organism responds using effectors (e.g., muscles and
glands).
The way in which receptors pick up stimuli and pass the information into the effectors
is called coordination.
In order for effectors to react/ respond effectively to stimuli, there needs to be a good
communication system between receptors and effectors.
E.G., touch a hot plate → pain receptors → muscle contracts → pull hand away.
(stimulus) (receptor) (effector = muscle) (response)
Two methods of sending information:
(1) Nerves and receptors: nervous system.
(2) Hormones (chemicals): endocrine system.
THE HUMAN NERVOUS SYSYTEM
Neurons carry nerve impulses
Human nervous system is made up of special cells called neurons.
Neurons differ from other cells in that their structure adapted to be able to carry
messages very quickly.
, Structure of a neuron:
Neurons contain the same basic structures of any other cell (a nucleus, cytoplasm,
and cell membrane) plus other structures that allow them to carry electrical impulses
from one cell to the next. These structures are long, thin fibres of cytoplasm that stretch
out from the cell body (nerve fibres).
- the longest fibre is the axon, and the shorter ones are dendrites.
Dendrites are important because they pick up signals from nearby neurons and carry
them along the axon to the cell body to be passed to the next neurotransmitter.
Myelinated neurons carry impulses quickly
Myelin layer of fat and protein that is wrapped around some nerve fibres.
This myelin sheath insulates the nerve fibres so that they can carry nerve impulses
faster
Every now and then there are gaps in the myelin sheath these are the nodes.
Central nervous system (CNS)
All mammals have a central nervous system and a peripheral nervous system.
Peripheral nervous system = nerves and receptors
The central nervous system = brain and spinal cord
- Coordinates messages in the nervous system
- Receives electrical impulses from the receptor and send them to the
appropriate effector.
Receptor → CNS (brain + spinal cord) → effector
Definitions:
Conjunctive: A thin, transparent membrane that covers and protects the front of the
eye.
Coordination: The way in which receptors pick up stimuli and pass the information
into the effectors.
Effectors: The physical areas in an organism’s which reacts to what have been
sensed.
Endocrine system: The use of chemicals (hormones) to transmit information from
one part of the body to another.
Geotropism: a response in which the plant grows towards or away from gravity.
Myelin: The layer of fat and protein that is wrapped around some nerve fibres.
Nerve fibres: Long, thin fibres of cytoplasm that carry electrical impulses.
Nervous system: The network of nerve cells and fibres which transmits nerve
impulses between parts of the body.
Neurone: A cell adapted to be able to carry messages very quickly via nerve fibres.
Phototropism: a response in which a plant grows towards or away from light.
Receptors: Specialised cells responsible for sensing changes in the environment
(e.g., changes in temperature, light, sound, etc..).
Reflex action: A reaction that takes place without your thinking about it, these are
reliant on quick coordination between the receptor and effector.
Reflex arc: The pathway along which nerve impulses travel – includes the sensory
neurone, relay neurones and motor neurone.
Relay neurons: Neurones in the central nervous system that pass an impulse on
to several other neurons. These neurons relay the impulse on tho other neurons.
Rods and Cones: Light receptors found in the retina of the eye.
Sensory neurone: A cell which carries impulses from a sensory receptor.
, Sense organs: groups of receptor cells responding to specific stimuli: light, sound,
touch, temperature, and chemicals.
Stimuli / Stimulus: Changes in an organism’s environment that are sensed by
specialised cells.
The orbit: The bony socket in the skull in which the eye is set.
The retina: The part of the eye that contains receptor cells. This is the part that is
sensitive to light. It is located at the back of the eye.
Tropism: a growth response by a plant.
RESPONSE AND COMMUNICATION IN ANIMALS:
Nerves and hormones allow communication.
Stimuli are changes in the environment. These are picked up by specialised cells
called receptors. And the organism responds using effectors (e.g., muscles and
glands).
The way in which receptors pick up stimuli and pass the information into the effectors
is called coordination.
In order for effectors to react/ respond effectively to stimuli, there needs to be a good
communication system between receptors and effectors.
E.G., touch a hot plate → pain receptors → muscle contracts → pull hand away.
(stimulus) (receptor) (effector = muscle) (response)
Two methods of sending information:
(1) Nerves and receptors: nervous system.
(2) Hormones (chemicals): endocrine system.
THE HUMAN NERVOUS SYSYTEM
Neurons carry nerve impulses
Human nervous system is made up of special cells called neurons.
Neurons differ from other cells in that their structure adapted to be able to carry
messages very quickly.
, Structure of a neuron:
Neurons contain the same basic structures of any other cell (a nucleus, cytoplasm,
and cell membrane) plus other structures that allow them to carry electrical impulses
from one cell to the next. These structures are long, thin fibres of cytoplasm that stretch
out from the cell body (nerve fibres).
- the longest fibre is the axon, and the shorter ones are dendrites.
Dendrites are important because they pick up signals from nearby neurons and carry
them along the axon to the cell body to be passed to the next neurotransmitter.
Myelinated neurons carry impulses quickly
Myelin layer of fat and protein that is wrapped around some nerve fibres.
This myelin sheath insulates the nerve fibres so that they can carry nerve impulses
faster
Every now and then there are gaps in the myelin sheath these are the nodes.
Central nervous system (CNS)
All mammals have a central nervous system and a peripheral nervous system.
Peripheral nervous system = nerves and receptors
The central nervous system = brain and spinal cord
- Coordinates messages in the nervous system
- Receives electrical impulses from the receptor and send them to the
appropriate effector.
Receptor → CNS (brain + spinal cord) → effector
