L22 Brain areas and pathways

Flashcards covering the structure and layout of major brain areas, sensory and motor pathways, based on HUBS191 Lecture 22 notes.

Sulcus

Furrow or valley on the brain's surface.

Gyrus

Hills on the brain's surface.

Lateral sulcus

Separates the temporal lobe from the frontal and parietal lobes.

Transverse fissure

Separates the cerebrum from the cerebellum.

Parieto-occipital sulcus

Separates the parietal and occipital lobes.

Central sulcus

Separates the frontal and parietal lobes.

Occipital lobe

Lobe associated with vision.

Parietal lobe

Lobe associated with somatosensory functions.

Frontal lobe

Lobe associated with motor control, personality, and language.

Temporal lobe

Lobe associated with memory and hearing.

Diencephalon

Includes the thalamus and hypothalamus, not part of brain stem.

Brainstem

Consists of the midbrain, pons, and medulla oblongata. Regulate basal functions like breathing. Below diencephalon and above spinal chord.

Cerebellum

Fine motor control

Cerebral cortex

Cerebrum, gray matter, cell bodies.

White matter

Oligodendracites in CNS, schwann cells is PNS.

Commissural tracts

Axons cross from one side of the brain to the other (both directions), e.g., Corpus callosum.

Projection tracts

Axons extend between the cortex and other CNS areas outside the cerebrum; e.g., Corticospinal tract. First nueron in chain.

Association tracts

Axons on the same side within the cerebral cortex, short or long distance.

Primary motor cortex

Located in the precentral gyrus; involved in voluntary movement. Upper motor nuerons. Specific regions control specific body parts.

Primary somatosensory cortex

Located in the postcentral gyrus; involved in somatosensory perception.

Corticospinal pathway

2 neurons, upper and lower. Upper cell body in primary motor cortex, axon crosses over at brain stem and extends to spinal chord. Synapse onto lower neuron cell body in ventral horn, lower oxan leaves via ventral root and synapse onto muscle.

Dorsal column pathway Nueron 1

Cell body in dorsal root ganglion (unipolar). Peripheral fibre (input zone) from sensory receptor in skin. Central fibre (output zone) ascend towards brain in dorsal columns, synapse onto neuron 2 in medulla oblongata.

Dorsal colum pathway Neuron 2

Cell body in medulla oblongata, axon crosses to opposite side and ascends, synapsing onto neuron 3 in thalamus.

Dorsal column pathway Neuron 3

Cell body in thalamus, axon ascends to somatosensory cortex and makes synapse onto somatosensory cortex neuron. Touch is percieved.

Spinothalamic tract (faster, sensory like pain)

3 neurons. Neuron 1 cell body in dorsal root ganglion synapse onto neuron 2 cell body in spinal chord. Axon crosses via anterior white commissure to opposite side and makes synapse to neuron 3 in thalamus. Axon ascends to somatosensory cortex and synapse to neuron.