Neuroscience Chapter Quiz

Nervous System and Brain - Anatomical Directions

• In humans, the dorsal parts of the brain form a 90-degree angle with the dorsal parts of the spinal cord.
• Rostral/Anterior - towards the front
• Caudal/Posterior - towards the back
• Ventral/Inferior - towards the underside
• Dorsal/Superior - towards the top
• Midline - an imaginary line dividing the body into two equal halves.
• Ipsilateral - structures on the same side of the midline.
• Contralateral - structures on opposite sides of the midline.
• Medial - towards the midline.
• Lateral - away from the midline.
• Proximal - closer to the center (usually for limbs).
• Distal - further from the center (opposite of proximal).

Planes and Sections

• Coronal/Frontal Plane: Horizontal, axial, or transverse plane
• Sagittal/Longitudinal Plane: Parallel to the midline.
• Midsagittal Section: A sagittal section that divides the brain into two approximately equal halves.
• Parasagittal Plane: Parallel to the midline.
• Horizontal/Axial Section: Divides the brain from top to bottom, parallel to the face.
• Coronal/Frontal Section: Dividing the brain front to back.

Protection of the Nervous Systems

• Layers of membranes (meninges) surround and support the nervous system.

Cerebrospinal Fluid

• A special plasma-like fluid that circulates within the ventricles of the brain, central canal, and the subarachnoid space.
• CSF circulates through the central canal of the spinal cord and 4 ventricles in the brain. The flow of CSF is described in detail.
• CSF is produced continuously, renewed or replaced 3 times a day, and is reabsorbed into the dural venous sinus at the top of the head.

Meninges

• Dura Mater: Outermost layer
• Arachnoid Mater: Middle layer
• Subarachnoid Space: Filled with cerebrospinal fluid, in between arachnoid and pia mater.
• Pia Mater: Innermost layer

Spinal Cord

• A long cylinder of nervous tissue extending from the medulla to the first lumbar vertebra
• The spinal cord is divided into Cervical, Thoracic, Lumbar, Sacral and Coccygeal segments.
• Spinal nerves exit the spinal cord between the surrounding bony vertebrae
• Contains Gray and White Matter, these are the regions responsible for motor and sensory function of the limbs and other parts of the body.
• Spinal Cord sections are defined by the nerves that are connected to them.

Spinal Reflexes

• Spinal cord neurons can generate reflexes without brain input.
• Reflexes include reflexes like the knee-jerk reflex and the withdrawal reflex.
• Damage to the spinal cord can result in loss of sensation and voluntary movement below the damage.

Divisions of the Brain - Hindbrain

• Myelencephalon (Medulla Oblongata): The lower portion of the brainstem, responsible for autonomic functions like breathing, heart rate, and blood pressure.
• Metencephalon: Contains the pons and the cerebellum.
  • Pons: Connects the medulla and higher brain centers, assists in breathing.
  • Cerebellum: Coordinates voluntary movements, maintains muscle tone, and regulates balance.

Divisions of the Brain - Midbrain

• Mesencephalon (Midbrain): Contains the tectum (roof) and tegmentum (covering). The periaqueductal gray matter plays a role in pain perception in this region.

Divisions of the Brain - Forebrain

• Diencephalon: Contains the thalamus and hypothalamus.
  • Thalamus: Relays sensory and motor signals to the cerebral cortex, regulates consciousness, sleep, and alertness.
  • Hypothalamus: Controls autonomic functions, hormone production, body temperature, hunger, thirst, and circadian rhythms.
• Telencephalon: Includes the cerebral hemispheres.
• Cerebral Cortex: The outermost layer of gray matter, involved in complex thought.
  • Gray matter: Consists of cell bodies.
  • White matter: composed of axons, responsible for carrying information to and from the brain.

Cranial Nerves

• 12 pairs of nerves emerging from the brain as part of the peripheral nervous system.
• Some carry motor information (control muscles), others sensory information(transmit information about senses). Some carry both (mixed function).

Sensory Cortex

• Located in the postcentral gyrus of the parietal lobe, responsible for processing touch, pain, position, and temperature information.

Motor Cortex

• Located in the precentral gyrus of the frontal lobe; coordinates voluntary movement.

Prefrontal Association Cortex

• Part of the frontal lobe, plays a role in high-level cognitive functions, including planning, problem-solving, and decision-making.

Corpus Callosum

• Large bundle of axons connecting the right and left cerebral hemispheres, enabling communication between them.

Anterior Cingulate Cortex

• Plays a role in autonomic functions, decision-making, error detection, emotion, anticipation of reward, and empathy.
• Important in processing physical and social pain.

Posterior Cingulate Cortex

• Plays a crucial role in physical survival, navigating complex human interactions, spatial orientation, memory, and is one of the first structures affected by Alzheimer's disease.

Limbic System

• Group of brain structures associated with emotions, memory, and behavior.
• Key areas included: Hippocampus and Amygdala.
• Hippocampus: Crucial for forming long-term memories, especially declarative memories. (Explicit/conscious memories involving facts and events.)
• Amygdala: Plays critical roles in fear, rage, and aggression. It is also part of the emotional processing network in the brain.

Basal Ganglia

• Collection of nuclei in the cerebral hemispheres involved in controlling movement. Degeneration of these areas is associated with Parkinson's and Huntington's disease.

Red Nucleus

• Located within the reticular formation; communicates motor information between the spinal cord and cerebellum.

Autonomic Nervous System

• The sympathetic nervous system prepares the body for action (fight-or-flight).
• The parasympathetic nervous system helps the body to relax and conserve energy after emergencies.
• The Hypothalamus manages vital functions, and plays a key role in the functioning of the autonomic system.

Auditory Nerve (VIII)

• Carries information from the inner ear to the brain.

Facial Nerve(VII)

• Produces facial expressions, and carries taste information back to the brain.

Glossopharyngeal Nerve (IX)

• Manages both sensory and motor functions in the throat

Vagus Nerve (X)

• Serves heart, liver, and digestive tract.

Spindal Nerves

• Spinal nerves carry sensory and motor information.

Medulla Oblongata

• Enlarges extension of the spinal cord and is connected through 12 pairs of cranial nerves. Crucial for reflexes such as breathing, heart rate, vomiting, etc.