Brain Anatomy

Central Sulcus

Location:

• Lateral aspect of cerebral hemisphere

Description:

• Groove on lateral surface of each cerebral hemisphere

• Forms boundary between frontal and parietal lobes

• Located between precentral and postcentral gyri

Frontal lobe

Location:

• Anterior portion of cerebral hemisphere

Description:

• Extends from anterior pole of brain to central sulcus

• Contains precentral gyrus

Function:

• Controls voluntary motor activity

• Higher mental processing

• Emotional behavior

• Speech output (i.e., Broca's area - usually in left hemisphere)

Comment:

• Named for overlying bone

Longitudinal Fissure

Location:

• Midline, between cerebral hemispheres

Description:

• Deep groove that separates right and left cerebral hemispheres

Comment:

• Contains falx cerebri

Occipital Lobe

Location:

• Posterior portion of each cerebral hemisphere

Description:

• Extends from parieto-occipital sulcus to posterior pole of brain

• Contains lingual gyrus

Function:

• Primary visual area

Comment:

• Named for overlying bone

Parietal Lobe

Location:

• Lateral surface of each cerebral hemisphere of brain

Description:

• Extends from central sulcus (rostral) to parieto-occipital sulcus (caudal)

• Includes postcentral gyrus

Function:

• Reception of general sensory information from body

• Tactile object recognition

• Language, verbatim repetition of terms (i.e., Wernicke's area - usually in left hemisphere)

Postcentral Gyrus

Location:

• Lateral aspect of each cerebral hemisphere

Description:

• Distinct "fold" at anterior border of parietal lobe

• Located along posterior edge of central sulcus

Function:

• Receives somatosensory information from body

Comment:

• Also called primary somatosensory cortex

Precentral gyrus

Location:

• Lateral aspect of each cerebral hemisphere

Description:

• Distinct "fold" at posterior border of frontal lobe

• Located along anterior edge of central sulcus

Function:

• Controls voluntary movement

Comment:

• Also called primary motor cortex

Cerebellum

Location:

• Dorsal to brainstem

Description:

• Composed of many lobes with highly folded cortex

• Attached to pons via cerebellar peduncles

Function:

• Coordinates complex movements

• Monitors muscles to ensure fluid movements

Comment:

• Receives extensive sensory input from body and CNS

• Cerebellar cortex has folds known as folia

• White matter of cerebellar lobes resembles branching tree and is called arbor vitae

• Influences motor function through connections with thalamus and motor cortex

Cerebrum

Location:

• Rostral portion of brain

Description:

• Includes two large cerebral hemispheres separated by longitudinal fissure

• Hemispheres connected by corpus callosum

• Surface gray matter of each hemisphere is known as cerebral cortex

• Within each hemisphere there is a core of white matter

• Additional masses of gray matter located within cerebrum include basal nuclei

Comment:

• Rostral = toward the nose (Latin: rostrum = beak)

Lateral sulcus

Location:

• Lateral aspect of each cerebral hemisphere

Description:

• Deep groove separating temporal from frontal and parietal lobes

Temporal Lobe

Location:

• Lateral and inferior portion of each cerebral hemisphere

• Inferior to lateral sulcus

Description:

• Lateral surface has three parallel gyri

Function:

• Primary hearing and smell areas

• Memory

• Speech perception and recognition (i.e., Wernicke's area - usually in left hemisphere)

Arbor Vitae

Location:

• Cerebellum

Description:

• Composed of the white matter of cerebellar lobes

• It's pattern resembles a branching tree

Corpus Callosum

Location:

• Brain, between cerebral hemispheres

Description:

• Large myelinated fiber tract connecting right and left cerebral hemispheres

• Forms floor of longitudinal fissure

Diencephalon

Location:

• Cerebrum

Description:

• Composed of thalamus, hypothalamus, and epithalamus

Function:

• Thalamic nuclei relay sensory information to cerebral cortex

• Hypothalamic nuclei maintain homeostasis

• Epithalamus includes pineal gland (produces melatonin)

Hypothalamus

Location:

• Ventral diencephalon

Description:

• Collection of nuclei located inferior to thalamus

• Includes infundibulum and mammillary bodies

Function:

• Considered master control center for endocrine system

• Secretes releasing and inhibiting hormones that control anterior pituitary gland

• Produces hormones that are transported to and stored in posterior pituitary gland

• Controls autonomic nervous system

• Regulates body temperature, food, and water intake

• Regulates emotional behavior

• Maintains sleep/wake cycle

Medulla Oblongata

Location:

• Most caudal portion of brain

Description:

• Extends from pons to spinal cord

• Associated with cranial nerves IX, X, XI, and XII

Function:

• Contains respiratory, cardiac, and vasomotor centers

Midbrain

Location:

• Brainstem

• Between diencephalon and pons

Description:

• Composed of white matter tracts and gray matter nuclei

• Associated with cranial nerves III and IV

• Prominent features include superior and inferior colliculi, cerebral peduncles, substantia nigra, and cerebral aqueduct

Function:

• Coordinates movements in response to visual and auditory stimuli

• Conveys motor information from cerebral cortex to pons

• Conveys sensory information from spinal cord to thalamus

Pituitary gland

Location:

• Midline of middle cranial fossa

• Rests in hypophysial fossa of sphenoid bone

Description:

• Small, oval bilobed endocrine gland

• Two functional lobes: anterior (adenohypophysis) and posterior (neurohypophysis)

• Connected by infundibulum to hypothalamus

Function:

• Anterior pituitary produces the following hormones: thyroid-stimulating (TSH), prolactin (PRL), adrenocorticotropic (ACTH), growth (GH), luteinizing (LH), melanocyte-stimulating (MSH), and follicle-stimulating (FSH)

• Posterior pituitary stores and releases: antidiuretic hormone (ADH) and oxytocin (OT)

Also known as:

• Hypophysial gland or hypophysis

Comment:

• Posterior pituitary does not produce any hormones; ADH and OT produced in hypothalamus

Pons

Location:

• Ventral aspect of brainstem

• Between midbrain (rostral) and medulla oblongata (caudal)

Description:

• Characterized by distinct ventral "bulge"

• Attached to cerebellum by middle cerebral peduncle

• Associated with cranial nerves V, VI, VII, and VIII

Function:

• Involved in control of sleep and respiration

• Transfer of information to and between cerebellar hemispheres

Comment:

• Latin: pons = bridge

Thalamus

Location:

• Diencephalon

Description:

• Paired groups of nuclei separated by third ventricle

• Largest portion of the diencephalon

• Composed primarily of gray matter

Function:

• Primarily for relay of sensory information to cortex

• Relay of motor information for movement planning

Brainstem

Location:

• Caudal portion of brain

Description:

• Vertical, stalk-like portion of brain

• Includes midbrain, pons, and medulla oblongata

Left cerebral hemisphere

Location:

• Cerebrum

Description:

• Two hemispheres separated by longitudinal fissure

• Composed of gray and white matter

• Highly folded surface (sulci and gyri)

• Four lobes visible on surface of each hemisphere: frontal, parietal, temporal, and occipital

• Insular cortex (sometimes considered a fifth lobe) located in floor of lateral sulcus

Comment:

• Surface gray matter is called cerebral cortex

• Hemispheres connected by corpus callosum

Right crerbral hemisphere

Location:

• Cerebrum

Description:

• Two hemispheres separated by longitudinal fissure

• Composed of gray and white matter

• Highly folded surface (sulci and gyri)

• Four lobes visible on surface of each hemisphere: frontal, parietal, temporal, and occipital

• Insular cortex (sometimes considered a fifth lobe) located in floor of lateral sulcus

Comment:

• Surface gray matter is called cerebral cortex

• Hemispheres connected by corpus callosum

Parieto-occipital sulcus

Location:

• Medial aspect of each cerebral hemisphere of brain

Description:

• Groove that separates parietal and occipital lobes

• Most obvious on medial aspect of cerebral hemisphere