Brain Structures and Functions

Brain Structures and Functions

• Frontal lobe: Located rostral to the central sulcus, separated from the temporal lobe and parietal lobe by the lateral sulcus. Responsible for personality, emotion, motivation, voluntary movement, and higher-level executive functions.

• Precentral gyrus: Located rostral to the central sulcus. Crucial for initiating voluntary movements, houses the primary motor cortex.

• Precentral sulcus: Separates the precentral gyrus from the postcentral gyrus.

• Parietal lobe: Located caudal to the frontal lobe, and separated from it by the central sulcus. Essential for sensory integration, spatial awareness, and coordinating motor actions, in addition to cognitive functions like memory and attention, and language processing. This region includes the primary somatosensory cortex, important for processing touch, pressure, temperature, and pain.

• Postcentral gyrus: Located caudal to the central sulcus, and plays a key role in processing sensory information from the body.

• Temporal lobe: Located inferior to the lateral sulcus, which is also responsible for hearing, language, and memory, along with emotion. Includes Wernicke's area for language comprehension.

• Occipital lobe: Located superior to the cerebellum, and caudal to the parieto-occipital sulcus. Responsible for processing visual information.

• Cerebellum: Located inferior to the occipital and temporal lobes, superior to the brainstem. Essential for balance, postural maintenance, coordination, and movement. Cerebellar hemispheres, separated by the vermis, are involved in motor planning and aspects of coordinating movement.

• Diencephalon: A deep structure in the brain, responsible for many crucial bodily functions. Includes the thalamus, hypothalamus, and epithalamus.

• Thalamus: Located near the center of the brain, superior to the midbrain, and involved in regulating sleep, alertness, and wakefulness. It relays information between subcortical and cortical areas.

• Hypothalamus: Located deep in the brain, between the cerebral hemispheres. Plays a crucial role in regulating several physiological functions, including thirst, hunger, body temperature, blood pressure, breastfeeding, learning, memory, sexual drive, and emotional expression.

• Epithalamus: The most dorsal part of the diencephalon. Responsible for secreting melatonin and regulating various bodily functions.

• Midbrain: The most rostral part of the brainstem, connecting the pons and cerebellum with the forebrain. It is involved in motor control, vision, and hearing.

• Pons: Part of the brainstem located between the midbrain and medulla. Involved in movement coordination, facial sensations, hearing, and eye movements.

• Medulla: The inferior part of the brainstem, connecting the brainstem to the spinal cord. It helps regulate vital processes like breathing, heart rate, and blood pressure. It also sends motor commands to the body and receives sensory information.

• Spinal cord: Begins at the brainstem and runs along the spine. Crucial for transmitting motor commands from the brain to the body, and sensory information from the body to the brain.

• Longitudinal fissure: A deep groove separating the two cerebral hemispheres.

• Central sulcus: Separates the frontal and parietal lobes.

• Lateral sulcus: Separates the frontal lobe from the temporal lobe.

• Corpus callosum: A major bundle of white matter fibers connecting the left and right cerebral hemispheres.

• Parieto-occipital sulcus: Separates the parietal and occipital lobes.

• Cingulate gyrus: Part of the limbic system, involved in emotion processing, learning, and memory.

• Calcarine sulcus: Located in the occipital lobe and part of the visual processing pathway.

• Fornix: Bundle of white matter fibers that arches around the corpus callosum.

• Ventricles: Spaces filled with cerebrospinal fluid (CSF) that cushion and protect the brain.

  Medulla 

  Most inferior part of the brain that connects the brain to the spinal cord.

  Regulates vital processes within the cardiovascular, respiratory, digestive, motor, sensory, and autonomic nervous systems. 

  Medullary pyramids 

  Triangular structures in the ventral portion of the medulla. 

  Carry corticospinal tracts to their decussation at the medullary spinal junction; provides a pathway for motor signals from the brain to the spinal cord.

  Ventral median sulcus 

  On the front surface of spinal cord, separates the left and right halves of the spinal cord. Deep groove found directly in the center of spinal cords anterior surface. 

  Primarily to divide the spinal cord into two distinct halves, organization of neural pathways within the cord.

  Posterior median sulcus 

  Shallow groove in the spinal cord that separates the left and right halves of the posterior side.

  Primarily to divide the spinal cord into two distinct halves, organization of neural pathways within the cord.

  Posterior intermediate sulcus 

  OLIVES 

  lateral to the gracile fasciculus 

  Lateral to medullary pyramids 

  divides the dorsal sensory ascending column into two halves, allowing the gracile fasciculus and cuneate fasciculus. 

  Relays sensory information to the cerebellum and is important for movement and balance. 

  Cuneatus fasciculus 

  lateral to the gracile fasciculus 

  transmits fine touch, proprioception, vibration

  Cuneate tubercle

  laterally to the gracile fasciculus in the upper thoracic and cervical (C1 to T6) spinal cord segments

  transmitting sensory information—including vibration, conscious proprioception, and two-point discrimination—from the upper extremities

  Gracile fasciculus 

  present throughout the length of the spinal cord and contains afferents from the lower trunk and extremities, below the T6 spinal cord segment

  carries sensory input from vertebral level T6 and below and ascends into the gracile nucleus to form the gracile tubercle

  Gracile tubercle 

  Found on the dorsal surface of the medulla at the junction of the brainstem and spinal cord. Visible bump that corresponds to the location of the gracile nucleus.

  Responsible for processing sensory information from the lower body, such as touch, vibration, and proprioception.

Cranial Nerves

• CN II (Optic): Transmits visual information.
• CN III (Oculomotor): Motor innervation to extraocular muscles.
• CN IV (Trochlear): Motor innervation to superior oblique muscle.
• CN V (Trigeminal): Sensory and motor functions related to the face.
• CN VI (Abducens): Controls lateral rectus muscle.
• CN VII (Facial): Controls facial muscles and taste, plus parasympathetic innervation to salivary glands.
• CN VIII (Vestibulocochlear): Related to hearing and balance.
• CN IX (Glossopharyngeal): Sensations from pharynx, tonsils, middle ear and carotid sinus, plus taste and motor to stylopharyngeus.
• CN X (Vagus): Controls many involuntary bodily functions like digestion and heart rate.
• CN XI (Spinal Accessory): Innervates the sternocleidomastoid and trapezius muscles.
• CN XII (Hypoglossal): Innervates tongue muscles.

Additional Notes

• Detailed information on a specific structure or function can be requested.