Neuroscience Quiz: Brain Structure & Function

Introduction

• The chapter aims to understand brain organization, protection, and blood supply.
• It also aims to compare and contrast different brain areas and their functions.
• It discusses the functional organization of the brain.
• It covers cranial nerve structure and function.

Brain Organization, Protection, and Blood Supply

• The brain is organized, protected, and supplied with blood.
• Various brain areas and their functions are contrasted and compared.
• The functional organization of the brain is discussed.
• Cranial nerve structure and function are presented.

Development of the Nervous System

• Nervous system development starts with a neural tube.
• The neural tube thickens from the ectoderm.
• A table details the development of the brain into three primary and five secondary brain vesicles, mapping the adult structures.

Brain Organization

• The cerebral cortex receives sensory information, controls skeletal muscles, and integrates incoming/outgoing nerve impulses.
• Thinking, learning, and remembering are performed functions of the cerebral cortex.
• Basal ganglia coordinate slow, sustained movements and suppress useless movement patterns.
• The thalamus relays most sensory information to the cerebral cortex.
• Interpreting pain, temperature, and pressure are sensory functions of the thalamus.
• The hypothalamus has homeostatic functions (body temperature, respiration, heartbeat).
• It controls hormone secretions of the pituitary gland.
• The cerebellum coordinates subconscious movements, contributing to muscle tone, posture, and balance.
• The brain stem contains many cranial nerves, regulates heartbeat, breathing, and consciousness.
• It transmits impulses between the brain and spinal cord.

Protection

• The brain's protection involves cranial bones and meninges.
• The meninges have three layers: pia, arachnoid, and dura mater.
• The cranial dura mater has two layers (periosteal/meningeal).
• Cerebrospinal fluid (CSF) provides another layer of protection.

Cranial Bones and Meninges

• Detailed view of the cranial meninges and bones.
• The layers of the dura mater are labeled.

Extensions of the Dura Mater

• The falx cerebri attaches to the crista galli bone.
• Extensions of the dura mater are illustrated in a sagittal section.

Blood Flow to the Brain

• Blood flows to the brain via vertebral and carotid arteries.
• Blood flows back to the heart via the superior sagittal sinus.
• The Circle of Willis is a network of arteries supplying blood to the brain.

Importance of Blood Flow to the Brain

• The brain uses about 20% of the body's oxygen supply.
• Interruption of oxygen supply can damage or kill brain cells.
• Glucose deficiency causes mental confusion, dizziness, convulsions, and unconsciousness.

Brain Blood Flow

• Tight junctions form the blood-brain barrier.
• This isolates brain parenchyma from blood substances.
• Astrocytes are involved in the blood-brain barrier.

Blood -Brain Barrier (BBB)

• The BBB protects brain cells.
• The BBB prevents harmful substances from entering the brain.
• Injury can break down the BBB, allowing substances to enter brain tissue, preventing the entry of therapeutic drugs.
• The BBB is used in some medications.

Cerebrospinal Fluid (CSF)

• CSF protects the brain and spinal cord from injury.
• It carries oxygen, glucose, and other vital substances from the blood.
• The ventricles of the brain contain CSF.
• Choroid plexuses manufacture CSF.

Ventricles and the Choroid Plexus

• The ventricles are CSF-filled spaces in the brain.
• Choroid plexuses secrete CSF.
• The choroid plexuses filter blood to create CSF.

CSF Flow

• CSF flows through ventricles.
• CSF circulates through the subarachnoid space.
• CSF is absorbed by arachnoid granulations.

Frontal Section of the Brain and Spinal Cord

• Volumes of cranial & spinal subarachnoid spaces.
• CSF volumes in various ventricles

Production and Flow of CSF

• Failure of normal CSF formation & drainage results in built-up pressure known as hydrocephalus.

Hydrocephaly

• Hydrocephalus can occur due to congenital abnormalities, head injury, or bleeding into the brain.

Regions of the Brain

• Overview of locations of different brain regions.

The Brainstem and Reticular Formation

• The brainstem comprises the medulla oblongata, pons, and midbrain.
• The reticular formation is responsible for consciousness and wakefulness.
• Some areas of the brainstem are linked by tracts of information.

The Brainstem (1 of 2)

• Details about the location and structure of the medulla oblongata, the pons, and the midbrain, are presented.

The Brainstem (2 of 2)

• Cranial nerves originating from the brainstem.
• The brainstem has structural regions of the pyramids and inferior olivary nuclei.

Medulla Oblongata (1 of 2)

• The medulla oblongata, which connects to the spinal cord.
• Its tracts of both motor and sensory functions are viewed.

Medulla Oblongata (2 of 2)

• Cranial nerves stemming from and originating in this area.
• The structural regions and functions of the medulla oblongata are described

Pons (1 of 2)

• The pons' location relative to the medulla oblongata.
• How it connects different parts of the brain via tracts.
• Pathways of sensory (impulses from eyes and ears) as well as tracts of information coming from other parts of the body are shown.

Pons (2 of 2)

• Cranial nerves originating within the pons.
• Functional regions of the pons involved in voluntary movements and respiration control.

Midbrain (1 of 3)

• Midbrain's location superior to the medulla oblongata and pons, extending to the diencephalon.
• Views of the midbrain in relation to the rest of the brainstem are provided.

Midbrain (2 of 3)

• Cranial nerves associated with the midbrain.
• Structural regions like cerebral peduncles, corpora quadrigemina, substantia nigra, and medial lemniscus are detailed.

Midbrain (3 of 3)

• Functional regions of the midbrain in terms of motor/sensory communication, and visual/auditory reflexes.

The Cerebellum (1 of 3)

• The cerebellum's location in the inferior and posterior parts of the cranial cavity.
• Its two hemispheres and central vermis are discussed.

The Cerebellum (2 of 3)

• Anatomy Overview - Details regarding the cerebellum's lobes and other aspects

The Cerebellum (3 of 3)

• Functions of the cerebellum in coordinating skeletal muscle contractions and maintaining muscle tone, posture, and balance.

The Diencephalon

• The diencephalon's structures, including the hypothalamus and epithalamus.

The Diencephalon (1 of 2)

• The diencephalon contains the thalamus, hypothalamus, and epithalamus.
• The location of the diencephalon in relation to other parts of the brain.

The Diencephalon (2 of 2)

• Brief overview of the diencephalon.

Thalamus (1 of 2)

• Location of the thalamus is superior to the midbrain.
• Different sections of the thalamus are presented.

Thalamus (2 of 2)

• Function of the thalamus as relay stations for sensory impulses.

Hypothalamus

• Hypothalamus, located inferior to the thalamus.
• Four major regions involved in homeostasis are described.
• Its control of many body activities is discussed.
• The hypothalamus regulates the pituitary gland and is part of both the endocrine and nervous systems.

Epithalamus

• Lies superior and posterior to the thalamus.
• Contains the pineal gland and habenular nuclei.
• Pineal gland secretes melatonin.

Circumventricular Organs (CVOs) of the Diencephalon

• Certain diencephalon parts (CVOs) monitor blood chemistry.
• These structures lack the blood-brain barrier.
• Includes hypothalamus, pineal gland, and the pituitary gland.
• Involved in bodily homeostasis.

Summary of Functions of the Diencephalon

• Thalamus: Relays sensory information to the cerebral cortex and plays a role in maintaining consciousness.
• Hypothalamus: Controls autonomic nervous system activities, produces hormones, regulates emotional and behavioral patterns, and has centers for activities like eating and drinking.
• Epithalamus: Primarily involves the pineal gland (secreting melatonin) and habenula (involved in olfaction).

The Cerebrum

• The cerebral cortex - gray matter composed of billions of neurons.
• Gyri (folds), fissures, and sulci are described.

Anatomical Details of the Cerebral Cortex

• A higher-level view of the anatomical details of the cerebral cortex.
• Shows specific locations of the lobes and important details of the cortex.

Lobes of the Cerebrum

• Divisions of the cerebrum: Frontal, Parietal, Temporal, Occipital lobes & Insula.

Cerebral White Matter Tracts

• Association tracts - connect gyri within the same hemisphere.
• Commissural tracts - connect corresponding gyri between hemispheres.
• Projection tracts - convey impulses to or from lower parts of the CNS.
• There are three types of tracts in the white matter.

The Cerebrum (with corpus callosum)

• The corpus callosum connects the left & right hemispheres.
• This bundle of white matter connects corresponding areas of the two hemispheres, particularly the motor cortex.

The Cerebrum (with Basal Nuclei)

• The basal nuclei (corpus striatum) are masses of gray matter in each cerebral hemisphere.
• The role of basal nuclei includes initiation & termination of movements, suppression of unwanted movements, and regulation of muscle tone.

The Limbic System

• The limbic system plays a role in emotions (e.g., pain, pleasure, anger/affection, etc.).
• The location includes the cerebral hemispheres and diencephalon.
• Structures like Fornix and Mamillothalamic tracts, Cingulate gyrus, Anterior Commissure and Septal nuclei are in this system.
• Structures like Amygdala and Parahippocampal gyrus are part of this system.

Functional Organization of the Cerebral Cortex (1 of 2)

• Specific types of sensory, motor, and integrative signals are processed in various regions of the cerebral cortex.
• Sensory areas, motor areas, and association areas are distinguished.

Functional Organization of the Cerebral Cortex (2 of 2)

• Overview of anatomy of the cerebral cortex.

Functional Areas of the Cerebrum

• Specific functional areas of the cerebral cortex, including location and functions.

The Cerebrum (with the sensory homunculus)

• A larger region of the somatosensory area receives impulses from lips/fingertips in comparison to other body parts.

The Primary Motor Area (area 4)

• The primary motor area (area 4) located in the precentral gyrus of the frontal lobe.
• Controls voluntary contractions of specific muscles or groups of muscles, having a "motor cortex homunculus".

The Cerebrum (Cerebral White Matter)

• The cerebral white matter consists of myelinated axons in three major tract types: association tracts, commissural tracts, and projection tracts.

The Cerebrum (Corpus Callosum)

• The corpus callosum is a major group of commissural tracts that connect corresponding areas between brain hemispheres, connecting the left motor cortex (controlling right body) to the right motor cortex (controlling left body).

The Cerebrum (Basal Nuclei)

• The basal nuclei (corpus striatum), which are paired masses of gray matter situated deep within the cerebral hemispheres, play an indispensable role in regulating movement-related activities, including initiation/termination of movements, suppression of unwanted movements, and control of muscle tone.

Summary of Functions of the Cerebrum

• Sensory areas involved in processing sensory information, motor areas responsible for voluntary movements, and association areas handling complex information processing (memory, personality).
• The corpus striatum helps in initiating & terminating movements.

Hemispheric Lateralization

• The brain's two hemispheres have distinct functions (lateralization).
• The right hemisphere excels in musical/artistic awareness and spatial tasks.
• The left hemisphere has greater importance in reasoning, language, and logic.

Brain Waves

• Various brain wave types and their associations
• Their relationship to brain activity states is explained (e.g., awake, asleep, stressed).
• Electroencephalograms (EEGs) measure brain waves.

Cranial Nerves

• 12 pairs of cranial nerves associated with specific functions.

The Twelve Cranial Nerves

• Detailed view with labels of all 12 pairs of cranial nerves.

Cranial Nerves (as a table)

• Cranial nerves are listed in a table with designations, numbers, origins, number of roots, contents, and targets.

Cranial Nerves (overview details)

• The description of the major cranial nerves and their principal functions.

Olfactory, I (1 of 2)

• The olfactory nerve's structure with olfactory tissue.

Olfactory, I (2 of 2)

• Anatomy Overview - Overview of the olfactory nerve

Optic, II (1 of 2)

• Structure of optic nerves with layers of rods and cones, and bipolar cells.

Optic, II (2 of 2)

• Anatomy overview - detailed overview of the optic nerve

Oculomotor, III (1 of 2)

• The structure and branches of the oculomotor nerve are shown.

Oculomotor, III (2 of 2)

• Anatomy overview - detailed overview of oculomotor nerve.

Trochlear, IV (1 of 2)

• The structure and branches of the trochlear nerve are shown.

Trochlear, IV (2 of 2)

• Anatomy overview - detailed overview of the trochlear nerve.

Trigeminal, V (1 of 2)

• Branches and functions of the trigeminal nerves.

Trigeminal, V (2 of 2)

• Anatomy overview - detailed overview of the trigeminal nerve.

Abducens, VI (1 of 2)

• The branch and functions of the abducens nerve.

Abducens, VI (2 of 2)

• Anatomy overview - overview of the abducens nerve.

Facial, VII (1 of 2)

• CN VII structure and function; 5 branches, muscle of facial expression, carrying taste sensation (tongue anterior 2/3), Bell's Palsy

Facial, VII (2 of 2)

• Detailed overview of the facial nerve.

Vestibulocochlear, VIII (1 of 2)

• CN VIII structure and function, vestibular system for balance and cochlear system for hearing.

Vestibulocochlear, VIII (2 of 2)

• Detailed overview of the vestibular-cochlear nerve.

Glossopharyngeal, IX (1 of 2)

• CN IX structure and function; taste (posterior 1/3 tongue), proprioception for swallowing, monitoring blood pressure and oxygen levels.

Glossopharyngeal, IX (2 of 2)

• Detailed overview of the glossopharyngeal nerve.

Vagus, X (1 of 2)

• CN X structure and function; "wanderer" - vast functions involving the thorax and abdomen.

Vagus, X (2 of 2)

• Detailed overview of the vagus nerve.

Accessory, XI (1 of 2)

• CN XI structure and function; primarily somatic motor, innervating trapezius and sternocleidomastoid muscles.

Accessory, XI (2 of 2)

• Detailed overview of the accessory nerve.

Hypoglossal, XII (1 of 2)

• CN XII structure and function; motor for tongue muscles.

Hypoglossal, XII (2 of 2)

• Detailed overview of the hypoglossal nerve.

Aging and the Nervous System

• Aging affects neurons, nerve impulse transmission, and processing abilities.
• Slowed voluntary movements and increased reflex times.
• Vision and hearing/taste/smell/balance can be impacted..

Cerebrovascular Accident (CVA) or Stroke

• Stroke is cerebrovascular accident with oxygen deprivation of brain cells
• Ischemic strokes (blood clots) and hemorrhagic strokes (leaky or ruptured vessels)
• Symptoms depend on location and severity

Transient Ischemic Attack (TIA)

• Impaired blood flow, causing temporary brain dysfunction.
• Symptoms include dizziness, weakness, and numbness.

Alzheimer's Disease

• Progressive dementia, causing loss of reasoning and self-care abilities.
• Characterized by neuronal degeneration, amyloid plaques (misfolded proteins), and neurofibrillary tangles (hyperphosphorylated tau protein).

Disorders (3 of 3)

• Includes brain tumors (malignant or benign), ADHD (learning disorder with inattentiveness, and impulsivity),

Test your knowledge on the brain's anatomy and the functions of various structures such as the choroid plexus and cerebellum. This quiz covers topics including cerebrospinal fluid dynamics, brain waves, and cranial nerves. Perfect for students of neuroscience or medical professionals looking to refresh their understanding!