Subdivisions of the Brain Flashcards
What are the three major subdivisions of the brain?
Hindbrain
Midbrain
Forebrain
What is the hindbrain?
The lowest and most primitive level of the brain
What structures are contained within the hindbrain?
The brain stem
The cerebellum
What is the role of the brain stem?
Controls basic but vital life support functions
What structures are contained within the brain stem?
The medulla
The pons
What is the role of the medulla?
Plays a key role in heart rate and respiration, enabling them to occur automatically
What is the role of the pons?
Helps to control vital functions, especially respiration
Helps to regulate sleep
Acts as a relay between the cerebellum and the cerebral cortex
What is the role of the cerebellum?
Control and coordination of muscular movement, learning and memory
What does damage to the cerebellum lead to?
Severe motor disturbances - this can even include temporary damage due to intoxication
What is the midbrain?
It contains clusters of sensory and motor neurons
What is the role of the motor neurons in the midbrain?
Controlling eye movements
What structure is contained within the midbrain?
The reticular formation
What is the general role of the reticular formation?
Plays a role in consciousness, sleep and attention
What are the two parts of the reticular formation?
The ascending general sensory tract
The descending motor projection
What does each part of the reticular formation do?
Ascending - alerts the higher centres of the brain that messages are coming
Descending - admits or blocks these messages
What can damage to the reticular formation lead to?
A permanent coma
There may also be links to chronic fatigue
What is the forebrain?
The most recently evolved part of the brain
What structures are contained within the forebrain?
Cerebrum
Thalamus
Hypothalamus
The limbic system
Cerebral cortex
What is the cerebrum?
The major structure of the forebrain, consisting of two hemispheres that wrap around the brain stem
What is the role of the thalamus?
Organises inputs from the sensory organs and routes them to the appropriate areas of the brain
Which senses is the thalamus concerned with?
Sight
Sound
Touch
Balance
What happens if the thalamus is damaged?
Hearing and vision are confused, producing symptoms similar to schizophrenia, such as hallucinations and not being able to distinguish between what is real and imaginary
What is the role of the hypothalamus?
Plays a major role in motivation and emotion
Controls hormonal secretions that regulate sexual behaviour, metabolism and reactions to stress
Involved in experiences of pleasure/displeasure
What is the role of the limbic system?
Helps coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus
What structures are contained within the limbic system?
Hippocampus
Amygdala
What is the role of the hippocampus?
Forming, consolidating and retrieving memories
Providing the context of a memory
Involved in navigation
What happens if the hippocampus is damaged?
Amnesia can be caused - the individual may struggle to form new memories but their old memories will remain intact
What is the role of the amygdala?
Involved in emotional behaviours (particularly anger and fear) and memories
What happens if the amygdala is damaged?
Individuals may struggle to remember the emotional content of memories
What is the cerebral cortex?
A sheet of unmyelinated cells that forms the outermost layer of the brain
What are the “bulges” in the cerebral cortex called?
Gyri
What are the “grooves” in the cerebral cortex called?
Fissures
What are the two roles of fissures in the cerebral cortex?
Increase the surface area of the brain
Separate the brain into lobes
What are the four lobes of the brain?
Frontal
Parietal
Occipital
Temporal
Where is the motor cortex located?
The frontal lobe
What is the role of the motor cortex?
Controls the approximately 600 muscles involved in voluntary body movements
How do the different hemispheres of the motor cortex operate?
Each hemisphere governs movement on the opposite side of the body
What is the relationship between body parts and the area of the motor cortex allotted to them?
The more sophisticated and complex the movement they produce, the more area is allotted to them, e.g. hands and mouth have the largest allotted area
Where is the somatosensory cortex located?
The parietal lobe
What is the role of the somatosensory cortex?
Receives sensory input and translates this into sensations of heat, touch, cold, balance and body movement
What is the relationship between body parts and the area of the somatosensory cortex allotted to them?
The more sensitive the body part, the more area is allotted to them
Where is the association cortex located?
The cerebral cortex
What is the role of the association cortex?
Involved in important mental functions, such as perception, language and thought
What problems can be caused by damage to the association cortex?
Disruption or loss of speech
Issues with understanding, thinking and problem solving
Agnosia
What is agnosia?
The inability to identify familiar objects
What is the role of the frontal lobes?
Involved in self-awareness, planning and responsibility
Involved in emotional experience
What happens if the frontal lobes are damaged?
An inability to plan and carry out a sequence of actions - individuals struggle to look into the future and consider the consequences of their actions
Individuals tend to be apathetic and emotionless
Where is the prefrontal cortex located?
The front of the frontal lobes
What is the role of the prefrontal cortex?
It is the seat of the executive functions
What are executive functions?
Mental abilities that allow people to direct their behaviour in an adaptive fashion
What happens if the prefrontal cortex is damaged?
Individuals have problems planning strategically, controlling their impulses and setting goals
Poor judgement
Impulsivity
Who is a famous case of damage to the prefrontal cortex?
Phineas Gage
