CONTROL & COORDINATION
CLASS 10 SCIENCE • RAPID REVISION NOTES
1. CONTROL & COORDINATION
Control and Coordination: The process by which different activities of the body are controlled and coordinated.
Two main systems: Nervous system and Endocrine system.
Nervous System
• Central Nervous System (CNS): brain + spinal cord.
• Peripheral Nervous System (PNS): the nerves of the body.
• Cranial nerves arise from the brain; spinal nerves arise from the spinal cord; the source also identifies visceral nerves
going to internal organs.
2. STIMULUS → RESPONSE
Stimulus: A change in the environment that can cause a physical or behavioural change.
Receptor: A cell or group of cells in sense organs that detects stimuli.
Receptor Detects
Photoreceptor Light / vision
Phonoreceptor Sound
Thermoreceptor Heat and cold
Olfactory receptor Smell
Gustatory receptor Taste
Effector: The body part that responds to the impulse sent by the nervous system, such as a muscle.
Response: The final reaction produced after a stimulus.
Master flow: Stimulus → Receptor → Sensory neuron → CNS → Motor neuron → Effector → Response
3. NEURON
Neuron: Structural and functional unit of the nervous system.
Structure: Dendrites → Cell body → Axon → Nerve ending
• Dendrites receive signals and carry them towards the cell body.
• Cell body is the central part of the neuron.
• Axon carries the electrical signal away from the cell body.
• Nerve ending is the terminal part.
Synapse
The small gap between the nerve ending of one neuron and the dendrite of another neuron is called a synapse.
Signal idea: Chemical → Electrical → Chemical → Electrical
4. TYPES OF NEURONS
, Neuron Direction / Role
Sensory neuron Receptor → CNS
Relay neuron / Interneuron Connects sensory and motor neurons
Motor neuron CNS → Effector
Memory: Sensory → Relay → Motor
5. TYPES OF ACTIONS
Voluntary Involuntary Reflex
Can be controlled Not consciously controlled Very fast action
Walking, running, speaking Heartbeat and other involuntary Removing hand from a hot object
functions
Key distinction: Voluntary and involuntary actions involve the brain. In a reflex action, the brain is not directly involved
in the immediate response.
6. REFLEX ACTION & REFLEX ARC
Reflex action: A very fast response to a stimulus.
Reflex arc: The complete pathway through which the reflex action occurs.
Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector → Response
Example: Hot object → receptor detects heat → sensory neuron → spinal cord → motor neuron → muscle → hand
withdrawn.
Exam point: The information can later reach the brain, although the immediate reflex response is coordinated through
the spinal cord.
7. HUMAN BRAIN
Major part Important functions / structures
Forebrain Cerebrum: thinking, memory and voluntary activities; hypothalamus: hunger; thalamus is also
part of the forebrain.
Midbrain Connects forebrain and hindbrain; involved in some involuntary functions such as pupil-size
changes.
Hindbrain Pons, cerebellum and medulla.
Hindbrain — must remember
Part Main point
Pons Involuntary actions; involved in respiration
Cerebellum Posture and balance
Medulla Several involuntary functions such as vomiting and blood pressure; connected to the spinal
cord
Do not confuse: Cerebrum = thinking/voluntary activities. Cerebellum = balance/posture. Medulla = involuntary
functions.
8. PROTECTION OF BRAIN & SPINAL CORD
• Brain: cranium/skull + meninges + cerebrospinal fluid (CSF).
CLASS 10 SCIENCE • RAPID REVISION NOTES
1. CONTROL & COORDINATION
Control and Coordination: The process by which different activities of the body are controlled and coordinated.
Two main systems: Nervous system and Endocrine system.
Nervous System
• Central Nervous System (CNS): brain + spinal cord.
• Peripheral Nervous System (PNS): the nerves of the body.
• Cranial nerves arise from the brain; spinal nerves arise from the spinal cord; the source also identifies visceral nerves
going to internal organs.
2. STIMULUS → RESPONSE
Stimulus: A change in the environment that can cause a physical or behavioural change.
Receptor: A cell or group of cells in sense organs that detects stimuli.
Receptor Detects
Photoreceptor Light / vision
Phonoreceptor Sound
Thermoreceptor Heat and cold
Olfactory receptor Smell
Gustatory receptor Taste
Effector: The body part that responds to the impulse sent by the nervous system, such as a muscle.
Response: The final reaction produced after a stimulus.
Master flow: Stimulus → Receptor → Sensory neuron → CNS → Motor neuron → Effector → Response
3. NEURON
Neuron: Structural and functional unit of the nervous system.
Structure: Dendrites → Cell body → Axon → Nerve ending
• Dendrites receive signals and carry them towards the cell body.
• Cell body is the central part of the neuron.
• Axon carries the electrical signal away from the cell body.
• Nerve ending is the terminal part.
Synapse
The small gap between the nerve ending of one neuron and the dendrite of another neuron is called a synapse.
Signal idea: Chemical → Electrical → Chemical → Electrical
4. TYPES OF NEURONS
, Neuron Direction / Role
Sensory neuron Receptor → CNS
Relay neuron / Interneuron Connects sensory and motor neurons
Motor neuron CNS → Effector
Memory: Sensory → Relay → Motor
5. TYPES OF ACTIONS
Voluntary Involuntary Reflex
Can be controlled Not consciously controlled Very fast action
Walking, running, speaking Heartbeat and other involuntary Removing hand from a hot object
functions
Key distinction: Voluntary and involuntary actions involve the brain. In a reflex action, the brain is not directly involved
in the immediate response.
6. REFLEX ACTION & REFLEX ARC
Reflex action: A very fast response to a stimulus.
Reflex arc: The complete pathway through which the reflex action occurs.
Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector → Response
Example: Hot object → receptor detects heat → sensory neuron → spinal cord → motor neuron → muscle → hand
withdrawn.
Exam point: The information can later reach the brain, although the immediate reflex response is coordinated through
the spinal cord.
7. HUMAN BRAIN
Major part Important functions / structures
Forebrain Cerebrum: thinking, memory and voluntary activities; hypothalamus: hunger; thalamus is also
part of the forebrain.
Midbrain Connects forebrain and hindbrain; involved in some involuntary functions such as pupil-size
changes.
Hindbrain Pons, cerebellum and medulla.
Hindbrain — must remember
Part Main point
Pons Involuntary actions; involved in respiration
Cerebellum Posture and balance
Medulla Several involuntary functions such as vomiting and blood pressure; connected to the spinal
cord
Do not confuse: Cerebrum = thinking/voluntary activities. Cerebellum = balance/posture. Medulla = involuntary
functions.
8. PROTECTION OF BRAIN & SPINAL CORD
• Brain: cranium/skull + meninges + cerebrospinal fluid (CSF).
