Page 75 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
Endocrine physiology

There are four ways to influence the activity of another.

Along which nerve impulses are directed between particular cells
1- Nerve along defined nerve fibers.

 All cells affect their immediate neighbors non-specifically by

consuming O2 or metabolites from the interstitial fluid &
2- Consuming 02
releasing CO2 or other products into it.
 Such changes are incidental to general metabolism

3. release of specific ♠ Into the surrounding interstitial fluid  have local effects
chemicals restricted to cells within a very small radius.
♠ called paracrine actions.

4. Endocrine ► In which cells affect other cells by releasing particular
chemicals called hormones into the circulating blood.

Endocrine system Endocrine glands = Ductless glands

consists of glands  Groups of secretory cells ➔ surrounded by capillaries ➔
[distinct gland] ➔ no diffusion of hormones (chemical messengers) from the

direct anatomical secretory cells into bloodstream.
connections  Called Ductless: because hormones ➔ secreted and diffuse
directly into the bloodstream

Hormone

Definition Amount

Substance secreted directly into the blood present in only minute concentrations in
by specialized cells (grouped into an blood & when carried to their target cells 

endocrine gland) in response to a specific exert specific effects which always involve
stimulus (neural or blood borne) & in the regulation of pre-existing cellular
amount which vary with the strength of the reactions
stimulus

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