The nervous system functioning Chapter 2 Flashcards
The central NS consists of:
Brain and spinal cord
The Peripheral NS consists of:
Autonomic and somatic NS
The autonomic NS consists of:
Sympathetic and parasympathetic
Function of the CNS
-CNS receives and interprets sensory information sent from the PNS
-Transmits motor messages to the PNS
Function of the PNS
-The PNS transmits sensory information to the CNS
-Transmits motor messages from the spinal cord to appropriate body parts.
Brain
Coordinates all the nervous system activities
Spinal cord
-Receives sensory information from the PNS and transmits motor messages from the brain to the PNS.
-Responsible for the spinal Reflex.
Somatic NS
- Transmits sensory information inwards towards the spinal cord.
- Transmits motor messages outwards from the spinal cord to the appropriate body parts
- Controls voluntary movements via its control of the skeletal muscles.
Autonomic NS
- Regulates internal bodily functions.
- Controls involuntary activity of internal muscles and glands.
-BRANCHES: sympathetic and para sympathetic
Sympathetic NS
- Automatically energises and arouses the body during times of stress or need for increased physical activity.
- Activation triggers the fight-or-flight response.
Parasympathetic NS
Calms the body and returns internal system to normal levels of activity when the stressor or need for increased physical activity disappears.
neuron
A neuron is an individual nerve cell. The entire nervous system is comprised of neurons, organised into complex chains and networks that form neural pathways.
structure and function of a neuron
-dendrites
-soma
-axon
-myelin sheath
-Nodes of Ranvier
-axon terminals
-Neurotransmitters
Dendrites
Branch-like extensions of the neuron that receives (chemical) information from the other neurons and transmits it to the soma
Soma
The cell body that transfers information from the Dendrites to the Axon. The Soma also contains the nucleus, which keeps the neuron functioning.
axon
A long tube-like structure that transmits (electrical) information away from the Soma and to the next neuron in the neural pathway.
myelin sheath
A white, fatty substance that coats the Axon. insulating it and preventing the information from leaving the neuron too early. It also speeds up the neural transmission.
Nodes of Ranvier
the gaps formed between the myelin sheath where the axons are left uncovered. Because the myelin sheath is largely composed of an insulating fatty substance, the nodes of Ranvier allow the generation of a fast electrical impulse along the axon
Axon terminals
Branches extend out from the axon and end in knob-like structures called terminal buttons. Each terminal button contains chemicals called neurotransmitters that transmit the information from the Axon to the next neuron in the neural pathway
Neurotransmitters
The chemical form of a neural message is known as a neurotransmitter.
-a signalling molecule secreted by a neuron to affect another cell across a synapse.
Efferent
motor neurons: the nerve fibres responsible for carrying signals from the brain to the peripheral nervous system in order to initiate an action.
afferent
sensory neurons: the nerve fibres responsible for bringing sensory information from the outside world into the brain
Motor neurons
- Sends information AWAY from the CNS to muscles, organs and glands.
- Enable movements in the body via muscles, organs and glands.
sensory neurons
Sends information from sensory receptors (e.g. in skin, eyes, nose, tongue, ears) TOWARDS the CNS