The Nervous System Flashcards
The nervous system is divided into two parts name these two parts
1) Central nervous system (CNS) = Brain + Spinal Cord
2) Peripheral Nervous System (PNS) = Nerves running to/ from the CNS
What is the nerve cells area also known as?
Neurons
What are the three types of neurons
1) sensory
2) Motor
3) Interneurons
What do sensory neurons do
They take messages to the CNS
What do motor neuron do
They take messages from the CNS
What do interneurons do
They connect motor and sensory neurons in the CNS
What is the pathway of a nerve impulse
Receptor Sensory neuron Interneuron Motor neuron Effector
Definition of a stimulus
A change in the environment
What is a receptor
It detects the stimulus (eg a hot object)
What is an effector
It carries out the response (eg pulling hand away from hot object)
What is the pathway of nerve impulses along a neuron
Dendrite
Cell Body
Axon
Neurotransmitter vesicle
What is the function of a dendrite
Carries impulses (messages) to the cell body
What is the function of an Axon
Carries nerve impulses away from the cell body
What is the function of Schwann Cells
Makes myelin
What is the function of myelin
Insulated the axon and speeds up the transmission of the electrical impulse
What produces neurotransmitters
The cell body
What is the function of neurotransmitters (swellings) (or synaptic knobs)
Release the neurotransmitter (chemical)
What are impulses
They are waves of electrical charge (ions) sling the neuron
What is the threshold
It is the minimum stimulus needed for an impulse to travel
What is the ‘All or Nothing’ Law
- If the threshold is reached, an impulse travels
- If the threshold is not reached, no impulse travels
What is the function of the Myelin Sheath
It insulates and therefore speeds up an impulse
What do impulses cause
They cause the release of neurotransmitters that carry the signal to the next neuron
Symptoms of Parkinson’s Disease
Shaking limbs and a rigid body
Cause of Parkinson’s
A lack of dopamine in the brain
Prevention of Parkinson’s
Cannot be prevented
Treatment of Parkinson’s
Drugs and physio therapy
What is a synapse
It is where two neurons meet
What is the role of a synapse
It controls the direction of impulses
Function of cerebrum
“Forebrain”: memory/ learning/ intelligence/ language/ vision/ smell/ hearing/ taste
Function of the cerebellum
“Hind brain”: movement/ balance
Function of the medulla oblongata
Controls breathing/ heart rate
Function of the hypothalamus
Controls temperature and salt-water balance (osmoregulation)
Function of the pituitary gland
Produces hormones- “the master” endocrine gland
Function of the mengines
3 layers for protection
Function of the spinal cord
1) carries impulses to and from the brain
2) controls many reflex actions
What is a reflex action
A reflex action is an automatic response to a stimulus
Examples of reflex actions
Blinking Sneezing Letting go of a hot plate Change in size of pupil Closure of the epiglottis after swallowing
How do drugs affect the nervous system
1) cause more/ less neurotransmitter to be released by vesicles
2) speed up/ slow down the breakdown of neurotransmitter by enzymes
How do pain killers work?
Impulses are blocked completely
What does the grey matter contain in the spinal cord
Many cell bodies
What does the white matter contain in the spinal cord
Many axons and dendrites (and dew cell bodies)
