1. Adrenal Gland

2. Adrenal Gland Anatomy was first described in 1563.
Is located above (or attached to) the upper pole of the kidney.
Is pyramidal in structure and weighs ~ 4 g.
Consists of the adrenal cortex and adrenal medulla
Activities are regulation of fluid volume and stress response

3. The Adrenal Gland: Anatomy

4. Adrenal Histology

5. Adrenal Cortex
Is divided into 3 zones in the adult gland: Zona Glomerulosa, Zona Fasciculata, Zona Rericularis.
Is divided onto 4 zones in the fetal gland.
The three zones of the permanent cortex constitutes only 20% of the fetal gland’s size. The remaining zone (fetal cortex) comprises up to 80% of gland’s size during fetal life.

6. Adrenal Cortex: Steroid Hormone Production
Aldosterone, sex hormones, cortisol
Synthesized from cholesterol–steroid ring

7. Adrenal Cortex: Steroid Hormone Production

8. Cortisol and Chronic Stress
Prolonged exposure to high cortisol levels can lead to break down of muscle, excessive epinephrine release, hyperglycemia, weakening of bone, destruction of the immune system, inhibition of reproductive function, and other complications.

9. Cortisol Effects: Body Responses to Stress
Permissive effect on glucagon
Memory, learning and mood
Gluconeogenesis
Skeletal muscle breakdown
Lipolysis, calcium balance
Immune depression
Circadian rhythms

11. The General Adaptation Syndrome

12. The General Adaptation Syndrome

13. The General Adaptation Syndrome

14. Permissive Effects of Cortisol on Development
Cortisol is required for normal development:
- permissive role in final maturation of many organs
- required for synthesis of digestive enzymes, surfactant
- required for skeletal growth in children

15. Mechanisms of Cortisol Action
The actions of cortisol are mediated through the glucocorticoid receptor.
Intracellular receptor in steroid receptor superfamily.
Stimulates transcription of target genes by interaction of bound receptor with GRE in 5’ flanking region.
Inhibits transcription of some genes by interaction of receptor with AP1 (jun/fos dimer), decreasing AP1-mediated gene expression.
AP1
transcription GR
cortisol
AP1
site

16. Hormone Effects on Gene Activity
Cortisol

17. Cortisol Effects: Body Responses to Stress to living

18. Control of Cortisol Secretion: Feedback Loops
External stimuli
Hypothalamic
Anterior Pituitary
Adrenal cortex
Tissues

19. Cortisol: Role in Diseases and Medication
Use as immunosuppressant
Hyperimmune reactions (bee stings)
Serious side effects
Hypercortisolism (Cushing's syndrome)
Tumors (pituitary or adrenal)
Iatrogenic (physician caused)
Hypocortisolism (Addison's disease)

20. Aldosterone Exclusively synthesized in Z. Glomerulosa
Essential for life.
Promotes sodium retention and Potassium elimination by the kidney.
Expands ECF volume

21. Regulation of Aldosterone Secretion

22. Aldosterone: Role in Diseases
Complete failure to secrete aldosterone leads to death (dehydration, low blood volume).
Hyperalsdosterone states: Contribute to hypertension associated with increased blood volume.

23. Adrenal Medulla: A Modified Sympathetic Ganglion
Sympathetic stimulation
Catecholamine release to blood
Epinephrine
Norepinephrine
Travel to:
Multiple targets
Distant targets

24. Adrenal Medulla: A Modified Sympathetic Ganglion

25. Mechanism: Norepinephrine Release and Recycling

26. Review of Efferent Pathways: Motor and Autonomic

27. Catechalomines: Activity
Stimulates the “fight or fight” reaction
Increased plasma glucose levels
Increased cardiovascular function
Increased metabolic function
Decreased gastrointestinal and genitourinary function

28. Activity of Epinephrine