Hormones:the first step

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Pituitary gland locates near optical nerve at the bottom of the brain, and plays the center role of hormonal system.

Pituitary Gland
Pituitary gland's diameter is about one centimeterCand it locates at Turkish saddle of sphenoid bone. It secretes many kinds of hormones, and because it locates near optic nerve, pituitary tumor sometimes causes visual field defects.

Pituitary gland is made up of 2 parts that are developed differently and has different functions, which are anterior lobe and posterior lobe. Anterior lobe develops from endoderm and posterior lobe developes from ectoderm.

Hormone-secreting cells of posterior lobe , which developes from ectoderm just like nerve cells are also a kind of nerve cells. The nerve cell body exists in the hypothalamus, and posterior lobe hormones are produced there. Axons descendCand nerve endings border on blood capillaries. Posterior lobe hormones are produced at hypothalamus, descends down the axons, and secreted internally into blood capillaries from nerve endings in posterior lobe of pituitary gland. The only hormones that have different producing place and secreting place are posterior lobe hormones.

Anterior lobe hormones are produced at anterior lobe of pituitary gland and are also secreted there.

Achievement Quiz
1. Pituitary tumor sometimes compresses [ a. vestibulocochlear nerve / b. optic nerve ] .

2. Pituitary tumor sometimes causes [ a. decrease in visual acuity / b. visual field defects ] .

3. As well as nerve system, posterior lobe of piutitary gland develops from [ a. endoderm / b. ectoderm ] .

4. Hormones are produced and secreted into blood srream at anterior lobe of pituitary gland. [ a. right / b. wrong ]

5. Hormones are produced and secreted into blood stream at posterior lobe of pituitary gland. [ a. right / b. wrong ]

6. Anterior lobe hormones are produced at [a. anterior lobe / b. hypothalamus ] .

7. Posterior lobe hormones are produced at [a. posteior lobe / b.hypothalamus ] .
Answer
1. The correct answer is b. Pituitary gland and vestibulocochlear nerve are quite far away from each other anatomically.

2. The correct answer is b. Visual acuity MAY decrease in patients with pituitary tumor however it is not characteristic.

3. The correct answer is b.

4. The correct answer is a.

5. The correct answer is b. What are distinctive features of posterior lobe hormones?

6. The correct answer is a.

7. The correct answer is b.
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