NERVOUS SYSTEM
Spinal cord – serves as a pathway for impulses from receptors to brain and from
brain to effectors.
Spinal reflexes – they serve to protect the body
Central nervous system – brain and spinal chord
Peripheral nervous system – made up of the nerves that link the CNS to the
receptors and effectors of the body.
Somatic nervous system (peripheral) – conducts impulses from CNS to skeletal
muscles, thus it controls all voluntary muscular movements
Autonomic nervous system (peripheral) – largely involved in maintain a constant,
balanced internal environment – homeostasis.
Sympathetic – stimulation by these nerves result in more O2, glucose and
blood being sent to the skeletal muscles – works closely with adrenalin.
Parasympathetic – enables body to rest and return to normal
Antagonistic effects
3 types of neurons:
1. Sensory – afferent neurons that carry impulses towards CNS where the
information is interpreted
2. Connector (interneuron) – make up 99% of neurons, receive impulses
from sensory neurons and pass them onto other neurons (motor), found
in CNS.
3. Motor – efferent neurons as they carry impulses away from the CNS to
the effectors so that the appropriate response can be brought about.
Neurons membrane, cytoplasm, organelles and a nucleus – in addition they have
long thin fibres of cytoplasm that extend from the cell body – this makes it possible
for impulses to be carried long distances
FIBRES:
Dendrites conduct impulses towards the cell body, provide a large surface
area to receive signals from other neurons
Axon conducts impulses away from the cell body, each neuron has a single
axon – usually branches at the end to form terminal branches
Cell body contains the DNA material for that neuron
Neurons – cannot undergo mitosis, cannot be replaced if destroyed. Have a high
metabolic rate – need continuous supply of O2 and glucose to survive.
Direction – always from dendrites, to cell body, and then down to axon
Synapses:
The junction across which a nerve impulse passes from an axon terminal to a
neuron/muscle/gland cell.
Neurotransmitter a chemical substance released from axon terminals at a
synapse to carry impulses across the gap
Allow the billions of neurons in the nervous system to communicate with
each other
Spinal cord – serves as a pathway for impulses from receptors to brain and from
brain to effectors.
Spinal reflexes – they serve to protect the body
Central nervous system – brain and spinal chord
Peripheral nervous system – made up of the nerves that link the CNS to the
receptors and effectors of the body.
Somatic nervous system (peripheral) – conducts impulses from CNS to skeletal
muscles, thus it controls all voluntary muscular movements
Autonomic nervous system (peripheral) – largely involved in maintain a constant,
balanced internal environment – homeostasis.
Sympathetic – stimulation by these nerves result in more O2, glucose and
blood being sent to the skeletal muscles – works closely with adrenalin.
Parasympathetic – enables body to rest and return to normal
Antagonistic effects
3 types of neurons:
1. Sensory – afferent neurons that carry impulses towards CNS where the
information is interpreted
2. Connector (interneuron) – make up 99% of neurons, receive impulses
from sensory neurons and pass them onto other neurons (motor), found
in CNS.
3. Motor – efferent neurons as they carry impulses away from the CNS to
the effectors so that the appropriate response can be brought about.
Neurons membrane, cytoplasm, organelles and a nucleus – in addition they have
long thin fibres of cytoplasm that extend from the cell body – this makes it possible
for impulses to be carried long distances
FIBRES:
Dendrites conduct impulses towards the cell body, provide a large surface
area to receive signals from other neurons
Axon conducts impulses away from the cell body, each neuron has a single
axon – usually branches at the end to form terminal branches
Cell body contains the DNA material for that neuron
Neurons – cannot undergo mitosis, cannot be replaced if destroyed. Have a high
metabolic rate – need continuous supply of O2 and glucose to survive.
Direction – always from dendrites, to cell body, and then down to axon
Synapses:
The junction across which a nerve impulse passes from an axon terminal to a
neuron/muscle/gland cell.
Neurotransmitter a chemical substance released from axon terminals at a
synapse to carry impulses across the gap
Allow the billions of neurons in the nervous system to communicate with
each other
