Bio 210 Exam 4 Review Notes

Chapter 12: The Central Nervous System

• Adult Brain Regions: Understand the different areas of the adult brain, which include:

  • Cerebrum: Divided into lobes - frontal, parietal, temporal, occipital.

  • Cerebellum: Coordinates movement and balance.

  • Diencephalon: Thalamus, hypothalamus, and epithalamus functions.

  • Brain Stem: Midbrain, pons, and medulla with vital functions.

• White and Gray Matter:

  • Gray Matter: Comprised of neuron cell bodies, unmyelinated axons; involved in processing information, found on the outer layer of the brain.

  • White Matter: Composed primarily of myelinated axons; responsible for communication between different brain regions.

• Ventricles of the Brain:

  • Four ventricles: Left and right lateral, third, and fourth ventricles.

  • Function: Produce and circulate cerebrospinal fluid (CSF).

  • Know the path of CSF circulation:

    • From lateral ventricles → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space.

• Cerebral Cortex:

  • Major functional areas include sensory, motor, and association areas.

  • Functions of regions:

    • Frontal Lobe: Decision making, problem-solving, motor function.

    • Parietal Lobe: Processing sensory information, spatial orientation.

    • Temporal Lobe: Auditory processing, memory, and language.

    • Occipital Lobe: Visual processing.

• Diencephalon Structures and Functions: Know major features like:

  • Thalamus: Relay station for sensory information.

  • Hypothalamus: Regulates homeostasis, temperature, thirst, and sleep.

  • Epithalamus: Involved in the sleep-wake cycle.

• Brain Stem Regions: Understand individual components:

  • Midbrain: Vision, hearing, motor control.

  • Pons: Relays messages between cerebellum and cerebrum; regulates breathing.

  • Medulla Oblongata: Controls autonomic functions such as heart rate and respiration.

• Cerebellum: Coordinates voluntary movements, balance, and motor learning.

• Limbic System and Reticular Formation:

  • Limbic System: Key role in emotions and memory.

  • Reticular Formation: Regulates arousal and consciousness.

• Meninges: Three layers with distinct characteristics:

  • Dura Mater: Outermost, tough layer.

  • Arachnoid Mater: Middle layer, web-like structure.

  • Pia Mater: Delicate, innermost layer adhering to the brain's surface.

• Cerebrospinal Fluid (CSF):

  • Functions: Cushions the brain, provides nutrients, removes waste.

  • Composition includes water, glucose, electrolytes, and proteins.

• Homeostatic Imbalances: Familiarize with conditions like:

  • Hydrocephalus: Accumulation of CSF leading to increased intracranial pressure.

  • Multiple Sclerosis: Autoimmune disease affecting myelin sheath in CNS.

• Spinal Cord Structure and Function:

  • Comprised of segments: cervical, thoracic, lumbar, sacral regions.

  • Dorsal Horns: Sensory neuron synapses; receive sensory input.

  • Ventral Horns: Motor neurons; send output to skeletal muscles.

• Flaccid vs. Spastic Paralysis:

  • Flaccid Paralysis: Result of lower motor neuron injury; leads to muscle atrophy and weakness.

  • Spastic Paralysis: Result of upper motor neuron damage; characterized by stiff, tight muscles.

• Spinal Cord Trauma: Understand terms like paraplegia (loss of function in legs) and quadriplegia (loss of function in all four limbs).

• Poliomyelitis and ALS:

  • Poliomyelitis: Viral infection affecting spinal cord and motor neurons, leading to paralysis.

  • Amyotrophic Lateral Sclerosis (ALS): Progressive neurodegenerative disease affecting motor neurons, causing muscle weakness and atrophy.

Chapter 13: The Peripheral Nervous System

• Sensory Receptors Classifications:

  • By stimulus type (mechanoreceptors, thermoreceptors, photoreceptors, etc.).

  • By location (exteroceptors for outside stimuli, interoceptors for internal stimuli).

• Unencapsulated vs. Encapsulated Receptors:

  • Unencapsulated: Free nerve endings; example includes nociceptors (pain).

  • Encapsulated: Specialized structures; example includes Meissner's corpuscles (light touch).

• Adaptation:

  • Sensory receptors can decrease sensitivity to constant stimuli, facilitating attention to changes.

• Regeneration of Nerve Fibers:

  • PNS has regenerative capacity due to Schwann cells; CNS has limited regeneration capacities.

• Plexuses: Locations include:

  • Cervical Plexus: Innervates neck and diaphragm.

  • Brachial Plexus: Innervates upper limbs.

  • Lumbar Plexus: Innervates lower limbs.

  • Sacral Plexus: Innervates pelvic region and lower limbs.

• Motor Control Levels:

  • Cortex: Higher control, planning of movements.

  • Basal Ganglia: Coordination and regulation of movement.

  • Cerebellum: Fine-tuning and balance.

• Reflex Arc Components:

  • Sensory receptor, sensory neuron, integration center (CNS), motor neuron, effector.

• Muscle Spindles and Golgi Tendon Organs:

  • Muscle Spindles: Detect muscle stretch and send signals to spinal cord.

  • Golgi Tendon Organs: Monitor tension in muscles.

• Stretch and Crossed Extensor Reflexes:

  • Stretch Reflex: Maintains muscle tone and posture (e.g. patellar reflex).

  • Crossed Extensor Reflex: Allows adjustment of opposite limb during withdrawal from stimulus (e.g. stepping on a nail).

  • Abnormal results in superficial reflex tests can indicate neurological issues.