This chapter should help the student to:

• Describe the location and embryonic origins of the pituitary gland.
  
• Name the divisions of the pituitary gland and describe their location.
  
• Name the cell types in each pituitary division and indicate any characteristic staining properties.
  
• List the pituitary hormones, indicating for each the division and cell type of origin, and the target of the hormone.
  
• Describe the role of the hypothalamus in controlling pituitary gland function.
  
• Describe the blood supply to the pituitary gland and its role in pituitary function.
  
• Explain the role of negative feedback in pituitary gland function.
  
• Distinguish between the neurohypophysis and the adenohypophysis and identify their subdivisions, sinusoids, and cell types in a micrograph of the pituitary gland.

1. Describe endocrine gland characteristics in terms of embryonic origin (I.B), secretory cell arrangement (I.C), abundance of blood capillaries (I.C), mode of secretion release and transport (I.D), and typical secretory product (I.D).

2. Describe hormones in terms of:

1. 
   

   Chemical composition (two basic types; I.D.1 and 2)

   
   
2. 
   

   Relative distance and the route between the secretory cell and the target site (I.D)

   
   
3. 
   

   Relative amount needed to elicit a response from the target cell (I.D)

   
   
4. 
   

   General function (I.D)

3. Describe the location of the pituitary gland (hypophysis) and its relations to the hypothalamus, sella turcica, and optic chiasm (II).

4. Name the pituitary gland’s two major divisions (Table 20–1) and compare them in terms of:

1. 
   

   Embryonic origin

   
   
2. 
   

   Microscopic structure

   
   
3. 
   

   Hypothalamic connections (vascular versus neural; III.F; IV.D; Fig. 20–2)

   
   
4. 
   

   Major hormones released (III.A.2.a and b; IV.A.1; Table 20–1)

5. Sketch the adult pituitary gland and hypothalamus and label the following (Fig. 20–2):

1. 
   

   Adenohypophysis

   
   
2. 
   

   Neurohypophysis

   
   
3. 
   

   Hypothalamus

   
   
4. 
   

   Anterior lobe

   
   
5. 
   

   Posterior lobe

   
   
6. 
   

   Optic chiasm

   
   
7. 
   

   Pars distalis

   
   
8. 
   

   Pars tuberalis

   
   
9. 
   

   Pars intermedia

   
   
10. 
    

    Rathke’s cysts

    
    
11. 
    

    Median eminence

    
    
12. 
    

    Infundibulum

    
    
13. 
    

    Pars nervosa

    
    
14. 
    

    Supraoptic nucleus

    
    
15. 
    

    Paraventricular nucleus

    
    
16. 
    

    Primary capillary plexus

    
    
17. 
    

    Secondary capillary plexus

    
    
18. 
    

    Hypophyseal portal veins

6. Name the three major subdivisions of the adenohypophysis (Table 20–1).

7. Name the parenchymal cell types in the adenohypophysis, based on their staining properties (III.A.1, 2.a and b).

8. Compare pituitary acidophils and basophils (III.A.2.a and b; Table 20–2) in terms of:

1. 
   

   Staining properties, including:

   
   
   
   
   
   
   1. 
      

      Affinity for acidic dyes (e.g., eosin)

   
   
   
   
   2. 
      

      Affinity for basic dye (e.g., hematoxylin)

   
   
   
   
   3. 
      

      PAS staining

   
   
   
   
2. 
   

   Hormones secreted by each cell type

9. Name the primary target organs of (and response to) the following hormones (Table 20–2):

1. 
   

   FSH

   
   
2. 
   

   LH

   
   
3. 
   

   ICSH

   
   
4. 
   

   TSH

   
   
5. 
   

   Growth hormone

   
   
6. 
   

   Prolactin

   
   
7. 
   

   ACTH

10. Beginning with neural stimulation of the hypothalamus, trace the events leading to thyroid hormone secretion (T3 and T4) by the thyroid gland. Name, in order, the neural, endocrine, and vascular components involved (III.A.2.b and E; Table 20–2).

11. Name the major subdivisions of the neurohypophysis (Table 20–1).

12. Where are the cell bodies of the pars nervosa’s unmyelinated axons located (IV.A)?

13. Describe Herring bodies in terms of their contents, appearance, and location (IV.A).

14. List the contents of the neurosecretory vesicles in the axons of the pars nervosa (IV.A.1–3).

15. Describe pituicytes in terms of structure and function (IV.C).

16. Name the two major neurohypophyseal hormones, their target organs, and the effects they elicit (IV.A.1; Table 20–2).

I. General Features of the Endocrine System

A. Components of the System

The endocrine system includes several organs (e.g., adenohypophysis, thyroid gland, adrenal gland), islands of endocrine tissue in exocrine glands (e.g., islets of Langerhans), and some isolated endocrine cells (e.g., cells with DNES functions in the digestive tract mucosa).

B. Origin

Endocrine glands are ductless glands that develop as invaginations of epithelial surfaces, such as oral ectoderm or gut endoderm, and subsequently pinch off, losing contact with the parent epithelium.

C. Microscopic Structure

Endocrine glands typically contain secretory cells arranged as cords, clumps, or follicles in direct contact with abundant capillaries or sinusoids.

D. Secretions