Sheep Brain Anatomy Quiz

Sheep Brain Overview

• Sheep brain closely resembles the human brain, though it has a smaller cerebrum and different spinal cord orientation (anterior-posterior in sheep vs. superior-inferior in humans).
• The location of the brain stem differs, residing more posteriorly in sheep; this is reflected in the foramen magnum's placement—the rear in sheep and centrally in humans.

Meninges and Brain Protection

• Dura Mater: Tough outer covering that protects the brain and spinal cord; thickest layer of the meninges.
• Arachnoid Membrane: Middle layer of the meninges, providing additional protection and cushioning.

Major Brain Structures

• Pituitary Gland: Located at the brain's base, regulates growth and other endocrine functions; influenced by the hypothalamus and produces hormones for reproductive functions.
• Optic Chiasma: X-shaped structure where optic nerves cross, crucial for visual processing.
• Olfactory Bulb: Primary brain structure for processing smell, situated below the frontal lobes and above the nasal cavity.

Brain Fissures

• Longitudinal Fissure: Deep groove separating the two cerebral hemispheres.
• Transverse Fissure: Fissure that divides the cerebrum from the cerebellum.

Connective Structures

• Infundibulum (Pituitary Stalk): Connects the hypothalamus to the pituitary gland; consists of axons projecting from the hypothalamus.
• Corpus Callosum: A thick band of axons that links the two cerebral hemispheres, facilitating interhemispheric communication.

Brain Regions and Functions

• Cerebellum: Responsible for balance and coordination; processes sensory input and fine motor skills.
• Cerebrum: Largest brain region, responsible for higher-order functions like thinking, planning, vision, and voluntary muscle control.
• Thalamus: Acts as the brain's sensory relay station, directing messages to sensory areas and coordinating responses.
• Hypothalamus: Regulates autonomic functions such as hunger, thirst, temperature, and governs the endocrine system through the pituitary gland.

Brain Stem Components

• Medulla Oblongata: Controls autonomic functions like heartbeat, breathing, and blood pressure; continuous with the spinal cord.
• Pons: Connects the medulla with the thalamus and regulates sleep and arousal.

Ventricular System

• Lateral Ventricle: C-shaped structure within each brain hemisphere; part of the ventricular system housing cerebrospinal fluid.
• Third Ventricle: Midline cavity facilitating communication between lateral and fourth ventricles.

Additional Brain Structures

• Arbor Vitae: Tree-like arrangement of white matter within the cerebellum, contributing to its distinctive structure.
• Pineal Body: Secretes melatonin, regulating sleep-wake cycles; located between the cerebral hemispheres.

Nervous Tissue Composition

• White Matter: Composed of myelinated axons, facilitating fast communication within the CNS.
• Grey Matter: Rich in unmyelinated neuron cell bodies and short axons, involved in processing and integrating information.

Reflex and Sensory Processing

• Superior Colliculus: Involved in visual reflexes.
• Inferior Colliculus: Associated with auditory reflexes; collectively known as the tectum, it directs sensory information processing.

Gyri and Sulci

• Gyri: Surface bumps on the brain.
• Sulci: Grooves or indentations on the brain's surface.