Kinesiology Exam 3 Review

Functions of the Nervous System

• Parts of the CNS:
  • Central Nervous System (CNS): Composed of the brain and spinal cord.
  • Peripheral Nervous System (PNS): All nervous tissue outside the CNS.

Efferent and Afferent Anatomy of Neuron

• Afferent Neurons (Sensory Neurons):

  • Transmit sensory information from receptors to the CNS.
  • Example: Pain, touch, temperature sensors.

• Efferent Neurons (Motor Neurons):

  • Transmit commands from the CNS to muscles and glands.
  • Example: Movement coordination.

Functional Class of Neuron

• Sensory Neurons:

  • Carry signals from sensory receptors to the CNS.

• Motor Neurons:

  • Convey signals from the CNS to muscles for movement.

• Interneurons:

  • Connect afferent and efferent neurons within the CNS.
  • Responsible for reflexes and communication between neurons.

Structure of Neurons

• Meningeal Layers:

  • Protective layers surrounding the brain and spinal cord: dura mater, arachnoid mater, and pia mater.

• Nissl Bodies:

  • Dark-staining structures in neuron cell bodies composed of rough endoplasmic reticulum, indicative of protein synthesis.

• Structural Types of Neurons:

  • Multipolar: Most common type, having multiple extensions (dendrites and a single axon).
  • Bipolar: One axon and one dendrite, found in sensory organs.
  • Unipolar: Single process that splits into two branches, typically found in sensory neurons.

Structure of the Spinal Cord

• Gray Matter: Contains neuron cell bodies, dendrites, and unmyelinated axons forming the shape of a butterfly or the letter 'H'.
• White Matter: Composed of myelinated axons forming columns that ascend and descend within the spinal cord.

Neuronal Functions

• Depolarization: The process where a neuron’s membrane potential becomes more positive, typically due to sodium ions (Na^+) entering the cell.
• Hyperpolarization: The membrane potential becomes more negative, often due to potassium ions (K^+) exiting the cell.
• Action Potentials:
  • Saltatory Conduction: The rapid transmission of action potentials along myelinated axons, jumping from node to node (Nodes of Ranvier).
  • Continuous Conduction: The slow, wave-like propagation of action potentials along unmyelinated axons.

Regions of the Cerebrum and Their Functions

• Frontal Lobe: Responsible for reasoning, planning, parts of speech, movement, emotion, and problem-solving.
• Parietal Lobe: Processes sensory information such as touch, temperature, and pain.
• Temporal Lobe: Involved in processing auditory information and is critical for memory formation.
• Occipital Lobe: Primarily responsible for visual processing.
• Association Areas: Integrate sensory and motor information for complex, higher-order functions.

Diencephalon and Brain Stem Regions

• Diencephalon:
  • Contains the thalamus (sensory relay station), hypothalamus (regulates homeostasis), and epithalamus (involved in sleep/wake cycles).
• Brain Stem:
  • Controls vital functions like heart rate and breathing; includes the midbrain, pons, and medulla oblongata.

Cranial Nerves and Their Functions

• 12 Pairs of Cranial Nerves: Each has specific functions such as sensory function (e.g., vision, smell), motor function (e.g., facial movement), or both.

Nerve Plexuses

• Cervical Plexus: Supplies nerves to the head, neck, and shoulders.
• Brachial Plexus: Supplies nerves to the upper limbs.
• Lumbar and Sacral Plexuses: Supply nerves to the lower limbs and pelvic region.

Autonomic Nervous System

• Sympathetic Nervous System: Activates the fight-or-flight response during stress.
• Parasympathetic Nervous System: Promotes rest and digestion after stress responses.

Senses and Receptors

• General Senses: Include pain, temperature, touch, pressure, and proprioception (body position).
• Special Senses: Include vision, hearing, taste, smell, and equilibrium.
• Receptors: Specialized structures that detect specific types of stimuli, e.g., photoreceptors for light or mechanoreceptors for pressure.