Chapter 2 - The Nervous system Flashcards
What is the the human nervous system?
a network of neurons that enable the brain to receive and respond to information and stimuli appropriately and maintain bodily functions.
What are the function s of the human nervous system?
- receive information
- process information
- coordinate a response to information
What is the Central nervous system (CNS) ?
The brain and spinal cord, responsible for transmitting and receiving neural messages to and from the peripheral nervous system.
What does the brain do in CNS?
• Brain: controls the activity of entire nervous system and is responsible for initiating and processing actions, thoughts and behaviours.
What does the spinal cord do in CNS?
a long cable of nerve tissue (neurons) part of the CNS connecting the brain to the PNS responsible for sending motor information to the body and sensory information to the brain.
What is the peripheral nervous system?
The peripheral nervous system are all the nerves outside the CNS responsible for transmitting information to and from the CNS.
What is the somatic nervous system?
A subdivision of the PNS responsible for sending motor information from the CNS to the body’s skeletal muscle, bringing sensory information from the body to the CNS in order to coordinate voluntary responses.
What neurons are involved in SNS and what are their functions?
- Sensory Neurons (afferent neurons): Neurons that transmit sensory neural messages via afferent pathway from the sensory receptors of the PNS to the CNS.
- Motor Neurons (efferent neurons) : Neurons that transmit motor neural messages from the CNS to the PNS.
what is the Autonomic nervous system
A subdivision of the PNS that connects the CNS and the body’s visceral (non-skeletal organs), muscles and glands to regulate the internal bodily functions.
How can the ANS be consciously controlled?
• The ANS can be partially controlled by the brain
o Using biofeedback, we can control some ANS functions
o Such as heart rate
What is the Sympathetic nervous system and what does it do?
A branch of the ANS responsible for activating the body’s visceral organs, muscles and glands for increased activity or under threat/stress during the fight-flight-freeze response.
define the fight-flight-freeze response?
Fight-flight freeze response: initiated by the sympathetic division of the ANS and prepares the body to confront a stressful situation, to optimise chance of survival.
What is the Parasympathetic nervous system?
A branch of the ANS responsible for restoring homeostasis and maintaining the body’s organs, muscles and glands at optimal and balanced functioning after increased activity or state of arousal.
What is conscious and unconscious response?
Conscious response: is a reaction that involves awareness and is likely to be.
- voluntary, goal directed and involve a level of control by the individual
- somatic nervous system controls voluntary conscious responses.
Unconscious response is a reaction that does not involve awareness it is.
- involuntary, unintentional, automatic (often reflexive)
- autonomic nervous system controls these bodily responses.
what is a reflex?
Reflexes are a unconscious and involuntary response, they are unlearned and innate and tend to be simple behaviours that contribute to safety and survival.
describe the spinal reflex/reflex arc (3 points)
- automatic response that is initiated by interneurons in the spinal cord instead of the brain.
- The spinal cord responds directly before sensory message is carried to the brain where the pain is then registered after the motor response is carried out.
- Spinal reflex has both an unconscious and conscious component.
Why is the spinal reflex advantageous to survival?
The spinal reflex optimises survival as it has a faster response time than conscious response therefore less pain/damage is caused in a harmful situation therefore increasing their chances of survival.
What is the role of the interneuron?
Interneurons are found in the CNS and communicate between sensory and motor neurons.
Describe a monosynaptic reflex arc
Where a sensory neuron (affector) communicates directly with the motor neuron (effector), therefore involving only one synapse. Example. Rare, simplest reflexes such as the knee jerk.
Describe the polysynaptic reflex arc
When an affector communicates via an interneuron which relays the information to effector neuron. Therefore including at least two synapses. Example. The withdrawal reflex, moving a hand away from fire.
What are the functions of the parasympathetic NS?
MAINTAINING the body at an optimal level of functioning (state of homeostasis)
RETURNING the body to optimal level after heightened arousal
In terms of nervous system functioning, describe how the human body would consciously coordinate a voluntary response after touching a hot pan.
- The heat from the hot pan is detected by sensory receptors
- The sensory information is sent from the PNS to the brain via the spinal cord
- The brain coordinates a response and initiates a motor response of the withdrawal of the band by sending motor messages to the PNS
- Motor messages travel to the skeletal muslces in hand via the spinal cord to cause the hand to move away.
Outline the processes involved in the spinal reflex arc (3 marks)
Sensory neurons carry sensory information via the PNS to the spinal cord.
Interneurons in the spinal cord immediately relay motor messages to motor neurons in PNS to tell the body to move
As the motor response occurs, the sensory information is recieved by the brain
In terms of nervous system functioning, name and explain Pierce’s response when he yanked his hand away.
Pierce’s response was unconscious spinal reflex involving the spinal sensory-motor circuit
Pierce’s receptors feels the heat from the flame, a sensory neural message is sent to the spinal cord.
The interneurons initiates a motor response by immediately relaying motor messages to initate a motor response causing Pierce’s hand to quickly withdraw his hand from the flame.
The sensory information travels further brain, so pain is registered after the unconscios motor response has occured.
