Exam 2 Ch. 11-12

Question 1

Compare the anatomy and functions of the somatic and autonomic motor divisions.

Answer 1

Somatic motor division: carry signals to skeletal muscles (ONE message, ONE neuron)
Autonomic motor division: sympathetic and parasympathetic neurons carry signals to organs (smooth and cardiac muscle cells & glands)(MULTIPLE messages, TWO neurons)

Question 2

Explain at least three important anatomical differences between the sympathetic and parasympathetic divisions

Answer 2

Parasympathetic:
• origin:craniosacral
Contains CN X which control hindgut & genitourinary organs
Preganglionic neuron=long postganglionic=short
Parasympathetic ganglia close to effector organ
Sympathetic:
Origin: thoracolumbar
Preganglionic neuron=short Postganglionic neuron=long
Sympathetic ganglia in sympathetic trunk

Question 3

What segmental nerve levels and preaortic ganglia are associated with the sympathetic innervation of the foregut, midgut, and hindgut?

Answer 3

Foregut: T5-T9, celiac ganglion
Midgut: T10-T11, superior mesenteric ganglion
Hindgut: T10-L2, interior mesenteric ganglion

Question 4

What splanchnic nerves are associated with the foregut, midgut, and hindgut?

Answer 4

Foregut: greater splanchnic
Midgut: lesser splanchnic
Hindgut: lesser, least & lumbar splanchnic

Question 5

What is the parasympathetic innervation of the foregut, midgut, and hindgut?

Answer 5

Foregut: vagus n. (X)
Midgut: vagus n. (X)
Hindgut: sacral outflow (S2-S4)

Question 6

What type of muscle tissue is associated with the gut tube?
• Where is it derived from?
• Describe how it is innervated.

Answer 6

Branchial
Splanchnopleure
-Derived from endoderm but muscle derived from mesoderm
-Motor supply is from visceral motor neurons associated with the autonomic nervous system.

Question 7

What type of muscle tissue is associated with muscles of the torso and limbs?
• Where is it derived from?
• Describe how it is innervated.

Answer 7

Somatic
musculature of the somite & somatic mesoderm.
• Innervated by somatic motor neurons.
• Recall that these operate under a single neuron that extends from the CNS thru the ventral roots of segmental spinal nerves to the target organ…meaning that the innervation will be segmental e.g., L3-4

Question 8

What are the two types of attachment points for skeletal muscles?

Answer 8

• Origin – less movable attachment
• Insertion – more movable attachment
When the muscle contracts, the insertion moves toward the origin.