Brain and Cranial Nerves Structures

Pia Mater

Thin innermost layer adhering to brain

Arachnoid Mater

Subarachnoid Space

Space between pia mater and arachnoid mater with cerebrospinal fluid flowing

Dura Mater

Tough outer layer with two sublayers

• Meningeal Layer: Deeper layer

• Periosteal layer: Superficial to meningeal layer

Both fuse except where they separate to form dural venous sinuses

Cerebrum

Made of left and right hemispheres and divided into 4 lobes

• Surface is the cerebral cortex

Frontal Lobe

Deep to frontal bone and forms anterior part of cerebral hemisphere

• Ends at central sulcus

• Lateral sulcus is the inferior border

Function: voluntary movement, concentration, verbal communication, decision making, planning, personality, and primary motor control.

Parietal Lobe

Superior-posterior part of each hemisphere, just under parietal bones

• Terminates anteriorly at central sulcus, laterally at lateral sulcus, and posteriorly at the parieto-occipital sulcus

Function: general sensory reception and controls somatosensory information

Temporal Lobe

Inferior to lateral sulcus under temporal bone

Function: involved with auditory and olfactory information

Occipital Lobe

Posterior region of each hemisphere, underneath occipital bone

Function: Process incoming visual information and stores visual memories

Insula

Internal lobe

• Deep to lateral sulcus and temporal lobe

Function: Involved in emotional processing and gustatory information

Diencephalon

Internal region of the brain

Epithalamus

Region above thalamus

• Pineal gland: secretes melatonin to regulate circadian rhythm

• Habenular nucleus: aids in relaying information from limbic system (emotional center) to midbrain

Thalamus

Oval in the center

• Large relay station for sensory information that will be projected to sematosensory cortex

Hypothalamus

Region below thalamus

• Regulates body temperature (homeostasis)

• Master control of both autonomic nervous system and endocrine system

• Stalk-like infundibulum that extends inferiorly from hypothalamus to attach to pituitary gland of endocrine system

Brainstem

Passageway for all tracts between cerebrum and spinal cord

• Controls autonomic functions we are not aware of (key in survival)

Midbrain

Superior portion of brain stem and has white and gray matters that help produce dopamine to relay happy sensation throughout

• Substantia nigra: houses neurons that produce dopamine

Pons

Bulging region of anterior brainstem (shaped like a P)

• Key in controlling autonomic function of breathing rate

• Relay information from facial nerve to take in sensory information around face and tongue

• Aid in localizing sound

Medulla Oblangata

The most inferior part of brainstem and is key in SURVIVAL

• Several Autonomic Nuclei:

  • Cardiac Center: regulates heart rate, blood pressure, and other cardiac muscle related

  • Vasomotor Center: controls blood pressure by contributing to size and dilation of blood vessels

  • Medullary respiratory center: regulates respiratory rate

Cerebellum

Second largest part of the brain; also has left and right CEREBELLAR hemispheres

• Have anterior and posterior lobes and narrow vermis sits on midline between

• Folds of cerebellar cortex are called folia

Function: balance coordination center and helps us understand proprioception, where our body is in relation to space overall (general proprioception coordination center)

Corpus Callosum

Large commisural tract that connects left and right cerebral hemispheres

Precentral Gyrus

Elevated ridge in frontal lobe just anterior to central sulcus

Postcentral Gyrus

Elevated ridge in parietal lobe immediately posterior to central sulcus

Longitudinal Fissure

Divides the cerebral hemispheres into left and right halves that extends along the midsagittal brain

Transverse cerebral fissure

Central Sulcus

Shallow groove that separate precentral and postcentral gyrus

Gyrus

Folds/elevated ridges of brain tissue

Sulcus

Depressions of the folds/shallow grooves and separates gyrus

Fissure

Deeper grooves/depressions that separate large regions of the brain