Nervous system Flashcards
What is the Spinal reflex. How is it triggered
An autonomic, involuntary response to a certain stimulus.
It is triggered by cells in he spinal cord rather than the brain
This enables an organism to respond faster
Define conscious response
A voluntary, intentional response to sensory stimuli
What is the receptor site
A protein molecule found in the dendrites of neurons which receive chemical signals from neurotransmitters
Define unconscious response
An involuntary, automatic, unintentional response to sensory stimuli
What is a motor neuron
Neuron that sends information away from the CNS to mussels and glands. Eg sends information to hand to make it move.
What is an interneuron
Neurones that send information between sensory and motor neurons. Most are located in the CNS
What is a sensory neuron
A neuron that sends information form the sensory receptors towards the CNS
Define neuron
A specialised nerve cell that receives, processes and/or transmits information
What is the spinal cord
A bundle of nerve fibers that connects the Brian and PNS
What’s the role of axon terminals
Stores chemicals called neurotransmitters which assists in the transmission of neural information form one neuron to another
What’s the role of the axon
Single tube like structure that carries neural impulses away from the cell body towards the axon terminals
Role of the soma (cell body)
Responsible for keeping the neuron alive and controls whether the neuron will be activated. Contains the nucleus
Role of the dendrites
Detects and recieves neural information from neighbouring neurons
What is another name for efferent neurons and what is their role
Also known as motor neurons. They carry signals away from the CNS in order to initiate an action.
What is the myelin sheath and role
White fatty substance on the axon that acts as an electrical insulator which increases the speed of neural signals down the axon. Not present on all cells
What is the sympathetic nervous system
Prepares the body for action by activating the flight, fright, freeze response. Increases responsiveness of muscles and organs during activity, stress or when threatened
What is the autonomic nervous system
The division of the PNS responsible for involuntary unconscious activity. It transmits motor messages from the Brian to the body’s internal organs and glands. Eg controls heart beat
What is the somatic nervous system
The division of the PNS that is responsible for voluntary movement. Eg moving an arm
Parasympathetic nervous system
Counteracts the actions of the sympathetic nervous system by calming the body once the cause of stress or threat is over. It responsible for homeostasis
Peripheral nervous system
Contains all the nerves outside the CNS. Contains two sub divisions autonomic nervous system and somatic nervous system.
Central nervous system
Contain the brain and spinal cord.
What are afferent neurons and their role
Sensory neurons. Carry signals from sensory receptors towards the CNS
Examples of what the sympathetic nervous system does to the body and why
Dilates pupils- for better sight
Dry mouth- conserving energy
Accelerates heart rate- for more oxygen to muscles
Increases breathing - for more oxygen
Decreases digestion- for conserving energy
Examples of what the parasympathetic nervous system does to the body and why
Contracts pupils
Produces more saliva
Decreases heart rate
Decreases breathing
All to return the body back to homeostasis
