Brain and Special Senses: Lab Study Guide

Brain and Special Senses Lab

Introduction

This study guide covers the major anatomical structures and functions of the brain and special senses, as outlined in the lab objectives for Anatomy & Physiology. It is designed to help students identify, describe, and understand the key features of the central nervous system and sensory organs using models, diagrams, and dissections.

Brain Anatomy

Major Brain Regions and Lobes

• Cerebrum: The largest part of the brain, responsible for higher brain functions such as thought, action, and sensory processing.

• Lobes of the Cerebrum:

  • Frontal lobe: Involved in voluntary movement, reasoning, planning, and problem-solving.

  • Parietal lobe: Processes sensory information such as touch, temperature, and pain.

  • Temporal lobe: Responsible for auditory perception and memory.

  • Occipital lobe: Main center for visual processing.

• Cerebellum: Coordinates voluntary movements and balance.

• Brainstem: Includes the midbrain, pons, and medulla oblongata; controls basic life functions such as breathing and heart rate.

Key Surface Features

• Gyrus (plural: gyri): Elevated ridges of the cerebral cortex that increase surface area.

• Sulcus (plural: sulci): Shallow grooves between gyri.

• Fissure: A deep groove, such as the longitudinal fissure that separates the two cerebral hemispheres.

• Central sulcus: Separates the frontal and parietal lobes.

• Precentral gyrus: Primary motor cortex, located anterior to the central sulcus.

• Postcentral gyrus: Primary somatosensory cortex, located posterior to the central sulcus.

Gray and White Matter

• Gray matter: Contains neuron cell bodies, dendrites, and unmyelinated axons; forms the cortex and some deeper brain structures.

• White matter: Composed of myelinated axons that connect different brain regions.

Major Brain Structures (Sagittal and Superior Views)

• Cerebral hemispheres: The right and left halves of the cerebrum.

• Longitudinal fissure: Deep groove dividing the two hemispheres.

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

• Pons: Relays signals between the cerebrum and cerebellum; involved in sleep and respiration.

• Thalamus: Relay station for sensory and motor signals to the cerebral cortex.

• Optic chiasma: The crossing point of the optic nerves.

Example: Identifying Brain Lobes

• On a superior view of the brain, the frontal lobe is located at the anterior (front), the parietal lobe is posterior to the frontal lobe, the occipital lobe is at the back, and the temporal lobe is on the lateral sides.

Additional info:

• The precentral gyrus is the primary motor cortex, while the postcentral gyrus is the primary somatosensory cortex.