The Nervous System Flashcards
What is the central nervous system?
Brain and spinal cord
What is the spinal cord?
A long, thin structure composed of
neurones that extends from the medulla
oblongata down the spine.
What is the function of the spinal cord?
Connects the peripheral nervous system
(nerves outside of the CNS) to the brain.
Describe the structure of the brain
Consists of three main regions:
● Cerebrum
● Cerebellum
● Medulla oblongata
Describe the structure of the cerebrum
● Largest region of the brain
● Divided into two hemispheres
What is the function of the cerebrum?
Involved in: ● Intelligence ● Language ● Memory ● Emotion ● Visual and sensory processes
What is the function of each cerebral hemisphere?
● Left hemisphere receives sensory information from the right side
of the body and controls muscle coordination on the right
● Right hemisphere receives sensory information from the left side
of the body and controls muscle coordination on the left
Where is the cerebellum located?
Lower region of the brain
What is the function of the cerebellum?
Involved in:
● Coordination of muscles
● Voluntary movement e.g. walking
● Non-voluntary movement e.g. balance
What is the function of the medulla oblongata?
Controls automatic processes in the
body e.g. breathing rate, heart rate,
peristalsis
What methods, other than surgery, are
used by doctors to observe the brain?
● CT scan
● PET scan
What is a CT scan?
A procedure that uses X-rays to produce
3D cross-sectional images of the brain
Describe how CT scans are useful to investigate
brain function
CT scans show damaged regions of the brain e.g. areas
of swelling, bleeding
● Observations of the patient’s symptoms can enable
scientists to determine the function of the damaged region
What does a PET scan involve?
● Radioactive substance injected into a patient’s
bloodstream and taken up by tissues in the brain
● Radiation emitted by tissues detected, enabling the
identification of active and inactive regions of the brain
Describe how PET scans are useful to investigate
brain function
● Show which areas of the brain are active and which areas
are not
● Comparisons of brain activity in healthy patients and
patients with brain damage allow scientists to determine
the functions of inactive regions
Why is it difficult to treat damage to the CNS?
● Damage to neurones is permanent and cannot be
repaired (as nerve cells don’t divide by mitosis)
● Hard to reach some areas of the brain
● Risk of further permanent damage to other areas of the
CNS during surgery
What is the function of the nervous system?
Allows an organism to rapidly react to
environmental and internal changes
What are neurones?
Nerve cells adapted to quickly transmit
nerve impulses. They are the functional
units of the nervous system.
What is the function of the axon?
● Carries impulses away from the cell body
● Enables the transmission of nerve impulses
over long distances
What is the function of the dendrites and dendrons?
● Carry impulses towards the cell body
● Dendrites provide a large surface area to
receive impulses
What is the role of the myelin sheath?
● Electrically insulating layer
● Surrounds the axon and increases the speed
of impulses
Outline the function of a sensory neurone
Carries impulses from receptors to the
central nervous system
Describe the structure of a sensory neurone
● Long dendron carries impulses from receptors to the
cell body
● Cell body found part way along the neurone
● Short axon carries impulses from the cell body to the
CNS
Outline the function of a motor neurone
Carries impulses from the central
nervous system to effectors
