The brain LO1-2 Flashcards
The brain
Composed of
Interneurons & neuroglia
organised into areas of gray matter & white matter
gray matter contains:
- cell bodies of interneurons
organised into nuclei
white matter primarily contains:
- myelinated axons of interneurons organised into tracts
Cerebrum
- Largest part of the brain
- Divided into two cerebral hemispheres by the longitudinal fissure (fissure = deep groove)
- Separated from the cerebellum by the transverse fissure
Surface area of brain
- gyrus/gyri (ridge)
- sulcus/sulci (shallow groove)
cover entire surface –> increases the surface area
of the cerebrum = more neurons
Externally, each cerebral hemisphere is divided into
frontal, parietal, temporal, occipital, insula lobes
(central sulcus between frontal lobe and parietal lobe)
Internally, each cerebral hemisphere is divided into
three regions:
-Cerebral cortex: outer region of gray matter - contains nuclei
- Cerebral white matter: inner region of white matter, contains tracts
- Basal nuclee: islands of gray matter deep within the white matte
Cerebral Cortex (outer gray matter)
Contains nuclei that:
- receive, localise and interpret sensory input
- control voluntary skeletal muscle movements
- perform intellectual and language functions
- store memories
- control our emotions, behaviours and
determine personality
Cerebral cortex areas
motor areas
- control voluntary skeletal muscle movements
sensory areas
- receive and localise sensory input
- allow us to consciously perceive sensations
association areas
- interpret sensory input to make sense of the information
- plan and coordinate motor responses
- perform intellectual functions, store memories & determine behaviours and personality
Left and right cerebral cortex
receives sensory
information from, and
controls skeletal muscles
on, the RHS/LHS of body
Left controls right
Right controls left
Primary Motor Cortex (PMC)
- Located in the precentral gyrus of each frontal lobe
- Generates the somatic motor output that stimulates
voluntary skeletal muscle movements - the amount of primary motor cortex devoted to controlling a body part is proportional to the complex nature of its movements
Damage = = paralysis
(loss of voluntary movements_
Motor Association Areas
Plan & coordinate voluntary
motor activities
Act via the primary motor cortex
frontal eye field:
Broca’s area
premotor cortex
frontal eye field
controls voluntary eye movements
Broca’s area
controls the muscles involved in speech
production
- usually located in the left hemisphere (left frontal lobe) only
- damage = Broca’s aphasia
premotor cortex
Controls learned, skilled motor activities of
a complex nature, e.g., typing, tying a bow
- damage = loss of complex motor skills
Sensory Areas of the Cerebral Cortex
Allow us to become consciously aware of (perceive) sensations originating from:
- general sensory receptors for pain, temperature, touch,
vibration, pressure, proprioception
- special sensory receptors for vision, smell, taste, hearing, balance
Primary Somatosensory Cortex (PSC)
- Located in the postcentral gyrus of each parietal lobe
- Receives general sensory information
- Perceives sensations of touch, pain, vibration, pressure, temperature & proprioception
Somatosensory Association Area
- Receives general sensory input from the primary
somatosensory cortex - Interprets general sensory input and compares it to stored memories of past sensory experiences so that you can recognise an object by touch alone
- Damage = failure to
identify objects by
touch alone
Special Sensory Areas
Visual cortex
- receives visual input detected by photoreceptors
- damage = blindness
Visual association area
- interprets visual input à allows us to recognise what we see
- stores memories of past
visual images
- damage = failure to
recognise objects
Olfactory cortex
Temporal lobe
Perceives different
odours
Auditory areas
Auditory cortex
- receives sound input detected by the hair cells in the ear to produce & locate sounds
- damage = deafness
Auditory association area
- interprets auditory input –> allows us to recognise sounds
- stores memories of past sounds
- damage = failure to recognise what is heard
Visceral cortex
Insula
Perceives visceral
sensations
Gustatory cortex
Insula
Perceives taste
sensations
Vestibular (equilibrium)
cortex
Insula
Awareness of balance
Wernicke’s Area
- Usually located in left temporal lobe (left hemisphere) only
- Comprehends written and spoken language
- Damage = Wernicke’s aphasia
Prefrontal Cortex (a.k.a. anterior association area)
- Located in each frontal lobe
- Is responsible for our intellect, complex learning abilities (cognition), personality and behaviour
- Damage = personality changes (moody, impulsive, reckless etc)
