Nervous System and Brain Function Quiz

Introduction to the Nervous System

• The nervous system acts as the body's communication and control system.
• It receives input from the outside world.
• It enables communication between cells, tissues, and organs.
• It coordinates bodily movements.
• Neurology is the study of the nervous system.
• A neurologist is a physician specializing in neurology.

Nervous System Function Organization

• The nervous system has three main functions: sensory, integrating, and motor.
• Sensory functions involve receiving information from the body and the outside environment.
• Integrating functions analyze, store, and process incoming sensory information.
• Motor functions involve responding to the processed information.

Nervous System Signaling

• The nervous system senses change then relays the information to the brain and spinal cord (from peripheral nerves).
• The brain integrates the information which then forms a response that is relayed to the body to initiate the appropriate action.

Nervous System Organization

• The nervous system has two main subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS).
• The CNS consists of the brain and spinal cord.
• The PNS contains nerves, including cranial nerves originating from the brain that take information to and from the brain.

Nerve Signals

• Neurons are the functional units of the nervous system.
• The cell body contains the nucleus.
• Dendrites receive impulses from the body.
• Axons (also called nerve fibers) conduct impulses to the body.
• Chemicals are released from axon terminals (synaptic knobs) to activate an effect; this action is typically a cause muscle movement or gland secretions.

The Central Nervous System (CNS)

• The CNS includes the brain and spinal cord.
• The brain and spinal cord make up the CNS.
• Brain matter (gray matter) contains neuron cell bodies, giving it a gray appearance.
• Spinal cord matter (white matter) contains myelinated nerve fibers.

The Brain

• The brain is divided into left and right hemispheres.
• The cerebrum is the area for higher learning and intelligence.
• The cerebellum coordinates movement.
• The brain contains a diencephalon which coordinates motor control and primitive portions of the brain (brainstem & primitive brain).

The Cerebrum

• The cerebrum is the largest part of the brain in domestic animals.
• The cerebrum is composed of the cerebral cortex (outer layer) which is gray matter.
• Beneath the cerebral cortex is the white matter, that connects the two hemispheres via the corpus callosum.

Functions of the Cerebrum

• The cerebrum is responsible for learning, reasoning, intelligence, receiving sensory information, controlling voluntary muscle movements, and integrating neurological activity related to consciousness.
• It's also involved in communications, emotional responses, learning, memory, and recall.

Cerebrum Structure

• Wrinkles (gyrus/gyri and sulcus/sulci) increase the surface area of the cerebrum.
• Fissures are deep grooves that separate areas of the cerebrum.
• The longitudinal fissure separates the brain into right and left hemispheres.
• Each hemisphere is divided into lobes with distinct functions.

Damage to the Cerebrum

• Damage to the cerebrum can occur due to trauma, hypoxia, drugs, toxins, and stroke..
• Possible consequences of damage include seizures, decreased or absent voluntary movement, memory problems and behavioral changes.

Clinical Case: Traumatic Brain Injury

• Traumatic brain injury (TBI) is common in animals.
• Diagnosis involves neurological evaluations, identification of clinical signs (such as seizures and abnormal mentation), and imaging.
• Treatment focuses on providing oxygen, pain relief, elevating the head, reducing external stimuli, supporting bodily functions, and using anticonvulsants.
• Prognosis varies depending on the extent of the injury.

The Cerebellum

• The cerebellum is the second-largest part of the brain located behind and beneath the cerebrum.
• It consists of gray matter cortex and white matter deep to the cortex.
• It's characterized by its wrinkled appearance.

Cerebellum Functions

• The cerebellum coordinates movement, maintains balance, and regulates posture.
• It fine-tunes movements according to commands from the cerebrum.
• It plays a role in complex reflexes.

Damage to the Cerebellum

• Cerebellar damage can lead to hypermetria (exaggerated movements), jerky movements, and a lack of coordination.

Clinical Case: Cerebellar Hypoplasia in Cats

• Cerebellar hypoplasia is a disease marked by the failure of the cerebellum to develop properly.
• This condition is frequently observed in kittens born to mothers affected with feline panleukopenia during gestation.
• Clinical signs include jerky, uncoordinated, spastic movements, lack of fine motor movement, tremors, and a wide-stance.
• The prognosis for this condition is usually good, with affected animals often showing no pain and experiencing full recovery.

Diencephalon

• The diencephalon is located between the brainstem and cerebrum.
• It does not have distinct grey and white matter areas.
• It contains three major components: the thalamus, hypothalamus, and pituitary gland.
• The thalamus is a relay station for sensory input to the cerebrum.
• The hypothalamus interfaces between the nervous system and endocrine system.
• The pituitary regulates hormones throughout the body.

Diencephalon - The Hypothalamus

• The Hypothalamus is a very important structure.
• It controls homeostasis, including temperature regulation, hunger and thirst.
• This structure also regulates responses such as rage and anger.

The Brainstem

• The brainstem connects the brain and spinal cord.
• It is the most primitive part of the brain.
• Brain stem components include the medulla oblongata, pons, and midbrain.
• Many cranial nerves originate from the brainstem.

Brainstem Functions

• The brainstem supports basic life-sustaining functions of the body, such as controlling the heart, breathing, blood vessel diameter, swallowing, and vomiting.

Injury to the Brainstem

• Brainstem injury is uncommon.
• It is well-protected, but injury can rapidly result in death.

Other Important Brain Structures

• Other important brain structures are the meninges.

The Meninges

• The meninges are connective tissue layers surrounding the brain and spinal cord.
• The three meninges include the pia mater (inner layer), arachnoid layer (middle layer), and dura mater (outer layer).
• The meninges protect the brain and spinal cord.
• They have fluid, fat, and connective tissues that provide cushioning for the brain.

Clinical Case: Meningitis

• Meningitis is inflammation of the meninges.
• This condition may be infectious or immune-mediated.
• Clinical signs can include spinal pain, neck rigidity, abnormal gait, lethargy, and fever.
• Diagnosis is based on cerebrospinal fluid (CSF) analysis, imaging, and other tests.
• Treatment typically involves antibiotics (bacterial cases), supportive care, and corticosteroids (immune-mediated cases).
• The prognosis for immune-mediated meningitis is generally better than for infectious meningitis.

Cerebrospinal Fluid (CSF)

• Cerebrospinal fluid (CSF) protects the brain and spinal cord from bony casings.
• CSF is located between the meninges of the brain and spinal cord, within ventricles of the brain, and in the central canal of the spinal cord.
• CSF continuously circulates through the CNS.

Clinical Info: Diagnostic Tests for Neurological Disease

• Neurological exams, radiology (including radiographs of the spine and head, MRI, and CT scans) and cerebrospinal fluid (CSF) testing (including lumbar puncture) play fundamental roles in evaluating neurological diseases.
• These examinations/tests assess aspects such as mental function, cranial nerves, posture, spinal reflexes.
• They also help in assessing gait, reactions to stimuli, pain, and identification of potential infectious agents or cancerous cells in the CNS.

Blood-Brain Barrier (BBB)

• The blood-brain barrier (BBB) isolates the brain from the blood.
• The barrier prevents drugs, proteins, ions, and infectious agents from entering the brain.
• The BBB is made up of specialized capillaries found in the brain.

Cranial Nerves

• Cranial nerves are nerve bundles that carry signals to and from the brain, enabling particular bodily functions.
• Cranial nerves are numbered I through XII.
• Cranial nerves can contain sensory, motor, or mixed sensory and motor neurons.

The Spinal Cord

• The spinal cord extends caudally from the brainstem.
• It contains gray matter (nerve cell bodies) and white matter (nerve fibers).
• The spinal cord conducts nerve impulses to and from the brain and body periphery.
• It processes and modifies nerve impulses.

Spinal Cord Structure

• The spinal cord's gray matter, resembling a butterfly, is located centrally.
• White matter, containing myelinated nerve fibers, surrounds the gray matter.
• Dorsal and ventral spinal nerve roots unite to form spinal nerves.
• Dorsal nerve roots are sensory (afferent).
• Ventral nerve roots are motor (efferent).
• Spinal nerves exit between vertebrae.

Test your knowledge on the functions and structures of the brain and nervous system. Questions cover key components such as the cerebellum, cerebrum, and nervous system treatments. Perfect for students of neuroscience or anyone interested in brain anatomy.