Ch. 15 The Special Senses
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
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Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
Chapter 15, Problem 31
Assume that a tumor in the pituitary gland or hypothalamus is protruding inferiorly and compressing the optic chiasma. What could be the visual outcome?
Verified step by step guidance1
Step 1: Understand the anatomical relationship between the pituitary gland, hypothalamus, and the optic chiasma. The optic chiasma is located just above the pituitary gland, where the optic nerves partially cross.
Step 2: Recognize that compression of the optic chiasma typically affects the crossing fibers from the nasal (medial) halves of both retinas. These fibers carry visual information from the temporal (lateral) visual fields of each eye.
Step 3: Recall that damage to the crossing fibers in the optic chiasma results in loss of peripheral vision on both sides, a condition known as bitemporal hemianopsia.
Step 4: Connect the tumor's inferior protrusion compressing the optic chiasma to the expected visual deficit, which is loss of the outer (temporal) visual fields in both eyes.
Step 5: Summarize that the visual outcome of such compression would be bitemporal hemianopsia, characterized by loss of peripheral vision bilaterally, while central vision remains intact.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Anatomy of the Optic Chiasma
The optic chiasma is the X-shaped structure where the optic nerves partially cross. It lies just above the pituitary gland and hypothalamus. Understanding its location is crucial because compression here can affect visual pathways, leading to specific visual field defects.
Recommended video:
Guided course
5:04
Optic Components
Visual Pathway and Field Defects
The optic chiasma contains crossing fibers from the nasal halves of both retinas, which correspond to the temporal visual fields. Compression of these fibers typically causes bitemporal hemianopia, a loss of peripheral vision on both sides.
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4:40Alternative Pathway
Effects of Pituitary or Hypothalamic Tumors
Tumors in the pituitary gland or hypothalamus can grow upward and compress the optic chiasma from below. This mechanical pressure disrupts nerve signal transmission, often resulting in characteristic visual disturbances such as bitemporal hemianopia.
Recommended video:
Guided course
3:02The Hypothalamus and Pituitary Gland Example 2
Related Practice