ANS 123 Discussion 1-2 Body Planes and Tissue Case Studies

Dorsal surface

Relating to the upper side or back of a body

Ventral surface

Relating to the underside of a body

Sagittal plane

[does not need to be even]

Divides a body into right & left sides

Transverse plane/ Cross section (on quadrupeds)

Divides body into anterior (head) & posterior (tail)

Transverse plane/ Cross section (on bipeds)

Divides body into superior (upper) & inferior (lower)

Dorsal plane (on quadrupeds)

Divides body into dorsal & ventral

Dorsal plane (on bipeds)

Divides body into dorsal & ventral

Ventral surface

Dorsal plane

Ventral surface

Transverse/Cross-section plane

Ventral surface

Transverse/Cross-section plane

Sagittal plane

Transverse/Cross-section plane

Dorsal surface

Ventral surface

Sagittal plane

Dorsal plane

Transverse/Cross-section plane

Transverse/Cross-section plane

Sagittal plane

Transverse/Cross-section plane

Dorsal plane

Transverse/Cross-section plane

Dorsal: Chicken blastoderm

View from above, looking down onto the dorsal surface of the body

Dorsal Plane: Limb bud

View of the inside of the body/ structure created when it is split into dorsal & ventral with the dorsal half removed

Ventral: Chicken blastoderm

View from below, looking up at the ventral surface of the body

Sagittal: Cow blastula

View of the inside when the body is split into right & left

Transverse (Cross-section): Cow gastrula

View of the inside when the body is split into anterior & posterior

Epithelial tissue answers

Symptoms: Absence of skin and/or fur over legs and muzzle; in the calf with extensive bare patches

Degree of impairment: Varies with severity/extent of area affected

What is defective? Epithelial and dermal cells

o How do you know? Because of the complete absence of the integument in the affected areas

Bovine Epitheliogenesis Imperfecta

Muscle tissue answers

Symptoms: Heart failure, dilated hearts, dilated livers, subcutaneous edema, abdominal cavity fluid; the heart failure typically involved an elevated heart rate\

What is defective? Cardiac fibers (myocytes)

o How do you know? Researchers found evidence of extensive cardiac muscle fiber degeneration and scarring. The scarring indicates areas of past cardiac muscle fiber degeneration that successfully healed. The necropsies revealed that calves experienced heart failure when approximately 50% of their total cardiac fibers had degenerated.

Connective tissue answers

Symptoms: Abnormal standing position, longer, thinner limbs, eye defects, heart murmurs, and enlarged portions of their aortae

What is defective? Connective tissue cells that produce elastin protein create defective elastic fibers

o How do you know? Elastic fibers were abnormal in the samples taken from the ruptured aortae. It appears that the defective elastic fibers failed to allow the aortae to remain elastic enough to withstand the high pressure of blood as it leaves the heart.

Nervous tissue

What are the symptoms?

o Difficulty standing, difficulty coordinating hindquarters, frequent falling, difficulty standing back up again, abnormal limb stride when walking

What is defective?

o Most likely: Oligodendrocytes

o How do you know?

• All calves had the same type of lesions in the white matter of their spinal cords. Since oligodendrocytes produce myelin sheaths that give white matter its “whiteness” in the CNS, it is likely that the oligodendrocytes in the areas of the lesions either did not produce sufficient amounts of myelin or produced myelin that did not wrap the axon properly.