NERVOUS SYSTEM AND BRAIN Flashcards
Brain
Command centre of the CNS, responsible for the coordination of all the body’s conscious and unconscious activities.
Spinal cord
- Acts like a bridge, relays messages back and forth to and from the brain
- Receive sensory information from the PNS and transmit it to the brain for processing.
- Receive motor messages from the brain and transmit them to the PNS (rest of the body)
Peripheral Nervous System (PNS)
- Network of nerves that branch out from the CNS and carry information to or from the rest of the body.
- Carry sensory information form the rest of the body to the CNS
- Carry motor information from the CNS to the rest of the body
Peripheral Nervous System (PNS) is made up of
- Somatic nervous system
- Autonomic Nervous system
Somatic nervous system
Conveys messages from the sense organs to the CNS and controls the skeletal muscles responsible for voluntary movement.
Autonomic Nervous System
Regulates automatic/involuntary operations of non-skeletal muscles concerned with internal bodily functioning.
Autonomic Nervous System made up of
- Sympathetic nervous system
- Parasympathetic nervous system
Sympathetic nervous system
- The emergency or arousal system
- Provides the extra energy we need for vigorous action, especially in times of stress or threat.
- Activates the fight / flight response
- Increase responsiveness of muscle and organs during activity, stress or when threatened
Parasympathetic nervous system
- Returns the body to a state of calm once the cause of stress or threat is no longer present
- Responsible for maintaining homeostasis, autonomic day to day bodily functions (digestion, heart rate. breathing rate etc)
Example of sympathetic vs parasympathetic changes
Sympathetic:
- Pupils dilate, hr increase, sweat glands increase the production
Parasympathetic:
- Pupils contract, hr decreases, sweat glands decrease the production
Central nervous system
Receive, process and respond to information
- Brain
- Spinal cord
Neuron
Is an individual nerve cell that receives, transmits and processes information so quickly that we are not aware of its activity
Sensory neuron
Sends sensory information from our receptor sites (eg: skin, eyes, nose, tongue) towards the central nervous system to the brian
Motor neuron
Sends information away from the central nervous system (brain) to the peripheral nervous system or to our muscles, organs and glands
Interneuron
Sends information between sensory and motor neurons
Dendrites
The dendrite is a short, thin, widely branching nerve fibre that is specialized to detect and receive neural information in a chemical form.
Soma
The soma is the cell nucleus and determine whether the neuron will be activated and thus transmit (send) messages to other neurons
Axon
An axon is a tube-like fluid-filled extension that transmits messages in the form of an electrical impulse, from the soma to other cells in the body including other neurons, muscles, organs and glands
Myelin sheath
A white fatty substance that encases the axon that helps speed up transmission
→ acts as an electrical insulator
→ increase the rate at which this information travels
Axon terminals
At the end of each axon are branches called axon terminals. They form a synapse with the next neuron. This is where neurotransmitters are released.
Synapse
A synapse is a microscopic gap between neurons over which messages pass, message converts from electrical message to the chemical message
Message travelled through a neuron…
information is received in the dendrite, that neural impulse travels to the soma, along the axon, to the axon terminals. The axon terminals or the buttons have sacs that release chemicals called neurotransmitters across the synapse and those neural transmitters will bind to receptor sites on the dendrites of the postsynaptic neuron.
