Nervous system Flashcards
What percentage of total body weight does the brain make up?
2%
How many neurons is the brain roughly comprised of?
86 billion
What is the cerebrum?
The largest and most superior structure of the CNS
What 2 structures does the cerebrum contain?
Cerebral cortex
Basal ganglia
What are the two hemispheres of the cerebrum connected by?
Corpus collosum
What are the crests of folded tissue in the brain called?
Gyri
What are the grooves/fissures in the brain called?
Sulci
What are the four lobes of the cerebral cortex?
Frontal
Temporal
Parietal
Occipital
Where is the motor cortex?
In the frontal lobe, anterior to the central sulcus
What is the motor cortex responsible for?
Voluntary motor control and deciding/planning actions
What is the role of the primary motor cortex (M1)?
Motor commands to motor neurons, initiation and coordination of voluntary movements
What is the role of the premotor cortex?
Organisation of movements before they are initiated
What is the role of the supplementary motor area (SMA)?
Preparation and control of sequential movements
Where is Broca’s area?
The frontal left area
What is the role of Broca’s area?
Contains neurons involved in speech and language
How is the motor cortex organised?
Somatotopically
What is somatotopic organisation?
Relating to the movement capacity of the body
What are the basal ganglia?
A set of subcortical neural nuclei strictly interconnected with the cortex and the brainstem
What five areas does the basal ganglia include?
Striatum (caudate and putamen)
Globus pallidus
Substantia nigra
subthalamic nucleus
Nucleus accumbens
What is the role of the basal ganglia?
Important in the control of voluntary movements, motor learning, cognition and emotion. Proper functioning of the basal ganglia are required to relay motor commands to the lower levels
What are the two pathways involved in basal ganglia connectivity?
Direct pathway
Indirect pathway
What is the direct pathway of the basal ganglia involved in?
The excitation of a desired motor programme
What is the indirect pathway of the basal ganglia involved in?
Inhibition of a competing motor programme
What is the cause of Parkinson’s disease?
Degeneration of neurons in the substantia nigra. It causes an increase in activity in the indirect pathway, and a decrease in activity in the excitation motor cortex
What are the symptoms of Parkinson’s disease?
Likelihood of falling, shuffling gait, tremor at rest (less voluntary movements), slowness of voluntary movements (bradykinesia), difficulty in initiating movements (akinesia), inadequate amplitude of movements (mypometria)
What is the cause of Huntington’s disease?
Selective loss of striatal neurons. This causes an increase in activity in the direct pathway, and a decrease in activity in the inhibition motor cortex
