Physiology II for pharmacy students
Spring 2020 Dr. Saleem L01: introduction to endocrine system
Quick revision:
The endocrine system has a regulatory function for the body just like
the nervous system but with some differences between the two. While
the nervous system gives immediate actions, the endocrine gives delate
actions.
characteristic Nervous system Endocrine system
Mechanism of action Neurotransmitters Hormones delivered
released in. to tissues throughout
response the body by blood.
to nerve impulses.
Cells affected Muscles cells, glands, Virtually all body
and other neurons. cells.
Type of action results Muscular contraction Change in the
or glandular metabolic activities.
secretion.
e-
Time to onset of Typically within Seconds ( like in the
action milliseconds ( case of epinephrine
immediate) secretion) to hours or
days.
Duration of action Generally briefer. Generally longer.
Glands in the body are either
endocrine or exocrine glands.
The difference is that endocrine
glands secret their hormones
into blood capillaries, and so
called classic endocrine glands and
their hormones called classic
hormones.
.
, In the other hand the exocrine glands release their secretions into ducts
either inside the body (like in stomach or intestine) or to outside of the
body (like sweating glands).
Now talking about the endocrine glands, the classic secretion (from the
gland directly to the capillary) is not the only mode of delivery.
Other modes of hormones delivery:
1- Autocrine delivery: the autocrine gland here secrets autocrine
hormones just around the target cell, and the hormone affect
the same tissue of the gland.
2- Paracrine delivery: secretion into the interstitial space affecting the
neighboring cells.
3- Neuroendocrine delivery: sometimes hormones are produced by
neurons (Neuroendocrine glands) and they are released either to
the blood or to the target cells.
4- Pheromonal delivery: in some mammals or insects there are some
glands (pheromonal glands) on the body secret volatile hormones
(pheromones) which affect the olfactory cells in another
individual.
The physiological effects of hormones on the body
The hormones may affect the body function in many ways, and here
they are in general:
Body function Effect of hormones
metabolism Regulate metabolic processes i.e. rate of synthesis
and degradation of carbohydrates, proteins & lipid
reproduction Control reproductive processes, including the
development of sex organs, secondary sexual
characteristics gametogenesis & menstrual cyclo.
Spring 2020 Dr. Saleem L01: introduction to endocrine system
Quick revision:
The endocrine system has a regulatory function for the body just like
the nervous system but with some differences between the two. While
the nervous system gives immediate actions, the endocrine gives delate
actions.
characteristic Nervous system Endocrine system
Mechanism of action Neurotransmitters Hormones delivered
released in. to tissues throughout
response the body by blood.
to nerve impulses.
Cells affected Muscles cells, glands, Virtually all body
and other neurons. cells.
Type of action results Muscular contraction Change in the
or glandular metabolic activities.
secretion.
e-
Time to onset of Typically within Seconds ( like in the
action milliseconds ( case of epinephrine
immediate) secretion) to hours or
days.
Duration of action Generally briefer. Generally longer.
Glands in the body are either
endocrine or exocrine glands.
The difference is that endocrine
glands secret their hormones
into blood capillaries, and so
called classic endocrine glands and
their hormones called classic
hormones.
.
, In the other hand the exocrine glands release their secretions into ducts
either inside the body (like in stomach or intestine) or to outside of the
body (like sweating glands).
Now talking about the endocrine glands, the classic secretion (from the
gland directly to the capillary) is not the only mode of delivery.
Other modes of hormones delivery:
1- Autocrine delivery: the autocrine gland here secrets autocrine
hormones just around the target cell, and the hormone affect
the same tissue of the gland.
2- Paracrine delivery: secretion into the interstitial space affecting the
neighboring cells.
3- Neuroendocrine delivery: sometimes hormones are produced by
neurons (Neuroendocrine glands) and they are released either to
the blood or to the target cells.
4- Pheromonal delivery: in some mammals or insects there are some
glands (pheromonal glands) on the body secret volatile hormones
(pheromones) which affect the olfactory cells in another
individual.
The physiological effects of hormones on the body
The hormones may affect the body function in many ways, and here
they are in general:
Body function Effect of hormones
metabolism Regulate metabolic processes i.e. rate of synthesis
and degradation of carbohydrates, proteins & lipid
reproduction Control reproductive processes, including the
development of sex organs, secondary sexual
characteristics gametogenesis & menstrual cyclo.
