Chapter 12 Flashcards
Neural tube
Beginning of the nervous system as we think about it.
Gives rise to ventricles and spinal cord
What does the brain look like at 13 weeks and why?
Smooth because cranium hasn’t developed
What does the brain look like at 26 weeks and why?
Ridges and grooves in the brain now
What does the folding of the brain allow?
Have lots of neurons and cell bodies while minimizing total volume within the cranium
Describe gray matter and its properties.
Composed of neuron cell bodies.
Not myelinated.
Interneuron: unmyelinated axon.
Describe white matter and its properties.
Bundles of axons.
Forms tracts that connect parts of brain.
Ascending and descending tracts in the spinal cord.
What are clusters of neuron cell bodies called in the PNS and CNS?
PNS: ganglia
CNS: nuclei
What are bundles of myelinated axons called in the PNS and CNS?
PNS: nerves
CNS: tracts (white matter)
What are the ventricles of the brain connected to?
Each other and the central canal of the spinal cord
What are ventricles lined by? What do they contain?
Lined by: ependymal cells
Contain: cerebrospinal fluid
List the ventricles and how they are connected.
Lateral ventricles are connected by interventricular foramen, which connects lateral ventricles to third ventricle (located in diencephalon).
3rd ventricle is connected to 4th via cerebral aqueduct.
From the 4th ventricle, CSF can go down into the spinal cord.
Define aperture
one way valve
Define ventricles
hollow fluid filled holes
Why are ependymal cells important when lining the ventricles
to produce and absorb CSF in certain areas
Define gyrus, sulcus, and fissure
Gyrus: ridge
Sulcus: separates two gyri. Cortex descends into the sulcus, allows us to package more cell bodies
Fissure: deep sulcus. Not very many
Where is the transverse cerebral fissure?
Separates cerebrum from cerebellum
Where is the frontal lobe?
Anterior to the central sulcus
Where is the parietal lobe?
Posterior to central sulcus
Where is the occipital lobe?
Posterior to the parieto-occipital sulcus
Where is the temporal lobe?
Inferior to the parieto-occipital sulcus
Where is the gyri of insula?
Hidden by the frontal and temporal lobe
What are the three types of functional areas?
Motor areas: control voluntary movement
Sensory areas: conscious awareness of sensation
Association areas: integrate diverse information
Properties of the frontal lobe.
No sensory goes directly to the frontal lobe.
Complex executive function and voluntary motor.
Most dorsal portion of the frontal lobe?
Precentral gyrus (primary motor cortex)
What is anterior to the primary motor cortex?
Premotor cortex
Location of frontal lobe in relation to sulci?
Ventral to the central sulcus and superior to the lateral sulcus.
Properties of the primary motor cortex
Large pyramidal cells of the precentral gyri.
Long axons –> pyramidal (corticospinal) tracts.
Allows conscious control of precise, skilled, voluntary movements.
Motor homunculi
“little man.”
Precentral gyrus.
Fine motor control is in proportion to the size of the body part.
Fine motor control –> lot of small motor units –> larger surface area
Ex. Speech has a lot of motor control
Locations:
- Medial inferior: toes
- Medial superior: legs
- Superior: trunk muscles
- Lateral inferior: tongue and parts of face
- Lateral: thumb and forehead
- Lateral superior: hands
Properties of the premotor cortex.
Controls learned, repetitious, or patterened motor skills.
Coordinates simultaneous or sequential actions.
Involved in the planning of movements that depend on sensory feedback.
Does receive information from the cerebellum.
Properties of Broca’s area.
Present in one hemisphere (dominant; usually left).
A motor speech area that directs muscles of the tongue.
Is active as one prepares to speak.
If you think about saying a word, you activate Broca’s area.
Injury: can still read and understand spoken speech, you just can’t say words. You can still make sounds.
Name the sensory areas
Olfactory cortex
Gustatory cortex
Visceral sensory area
Vestibular cortex
What cortex does the parietal lobe contain?
Primary somatosensory cortex and somatosensory association cortex
What region specifically is the primary somatosensory cortex in?
Postcentral gyrus
Properties of the primary somatosensory cortex
Receives sensory information from the skin, skeletal muscles, and joints.
Capable of spatial discrimination: identification of body region being stimulated.
Where we become aware of the strength or magnitude of the sensory input or even textures.
There is a sensory map in the postcentral gyrus
Properties of the somatosensory association cortex.
Integrates sensory input from primary somatosensory cortex.
Determines size, texture, and relationship of parts of objects being felt.
Processes information.
Store memories and can compare stimuli to certain things, like the difference between a quarter and a nickel based on the ridges.
Location of the somatosensory association cortex.
Posterior to the primary somatosensory cortex
List the visual areas
Primary visual cortex
Visual association area
Properties of the primary visual cortex
Receives visual information from the retinas
Properties of the visual association area
Uses past experiences to interpret visual stimuli (ex. color, form, and movement).
Complex processing involves entire posterior half of the hemispheres.
Makes sense of the information delivered from primary visual cortex.
List the auditory areas
Primary auditory cortex
Auditory association area
Properties of the primary auditory cortex
Interprets information from inner ear as pitch, loudness, and location
Properties of the auditory association area
Stores memories of sounds and permits perception of sounds