The document describes several endocrine glands and their roles in regulating various bodily processes. It discusses the adrenal glands which secrete hormones like epinephrine, cortisol, and aldosterone to regulate metabolism, immune function, and electrolyte balance. The pancreas produces insulin and glucagon to maintain blood glucose levels. The gonads and pituitary gland regulate the reproductive system through sex hormones and LH/FSH. The pineal gland secretes melatonin to influence circadian rhythms and reproduction.

1. • Are two small glands located superior to each
kidney.
• Each adrenal gland has an inner part, called
adrenal medulla, and outer part, called
adrenal cortex.

3. Adrenal Medulla
• Epinephrine or adrenaline is the principal
hormone released from the adrenal medulla
and small amounts of norepinephrine.
• These are released in response to stimulation
by the sympathetic nervous system.
• Epinephrine and norepinephrine are referred
to as fight-or-flight hormones.

4. Major effects of hormones from adrenal
medulla:
• Increase the breakdown of glycogen to
glucose in the liver, release of glucose into the
blood and release of fatty acids from fat cells.
These serves as energy sources to maintain
the body’s increased rate of metabolism.
• Increased heart rate, which causes blood
pressure to rise.

5. Major effects of hormones from adrenal medulla:
• Stimulation of smooth muscle in the wall off
arteries supplying the internal organ and the skin.
Blood flow to internal organs and the skin
decreases, blood flow through skeletal muscles
increases.
• Increased blood pressure due to smooth muscle
contraction in the walls of blood vessels in the
internal organs and the skin.
• Increased metabolic rate of several tissues.
Specially in skeletal muscle, cardiac muscle, and
nervous tissue.

6. In general:
• Responses to hormones fro the adrenal
medulla reinforce the effect of the
sympathetic division of the autonomic
nervous system.
• It prepares the body for physical activity and
to produce fight-or-flight response and other
responses to stress.

8. Adrenal Cortex
• Secretes 3 classes of steroid hormones:
– Mineralocorticoids
– Glucocorticoids
– Androgens

9. • Secreted by the outer layer of adrenal cortex
• Helps regulate blood volume and blood levels
of K+ and Na+

10. binds to receptor
molecules of kidney
and also affects
intestine, sweat glands
and salivary gland.
Aldosterone
causes Na+ and H2O to
be retained in the body
and increase
elimination of K+
Blood levels of K+ and
Na+ directly affect the
adrenal cortex to
influence aldosterone
secretion.
More sensitive to
changes in blood K+
levels than to changes
in blood Na+ levels.
increases when blood
K+ levels increase or
when blood Na+ levels
decrease.

11. • Changes in blood pressure indirectly affect the
rate of aldosterone secretion.
• Low blood pressure causes the release of a
protein molecule called renin from the kidney,
which acts as an enzyme.
• Renin causes a blood protein called
angiotensinogen to be converted to
angiotensin I.

12. • Angiotensin –converting enzyme causes
angiotensinogen I to be converted to
angiotensin II.
• Angiotensin II causes the smooth muscle in
blood vessels to constrict and it also increases
aldosterone secretion.
• Increases in blood volume causes by
aldosterone and blood vessel constriction help
raise blood pressure.

14. • Secreted by the middle layer of adrenal cortex.
• It regulates blood nutrient levels.

15. increases the breakdown of
protein and fat and their
conversion to form energy.
causes liver to convert amino
acids to glucose, it acts on
adipose tissue, causing fat to be
broken to fatty acids. Glucose and
fatty acids are released into the
blood, taken up by tissues, and
convert it to energy.
breaks down protein to amino
acids, which are then released
into the blood.
reduces inflammatory and
immune responses.
CORTISOL

16. • A steroid, cortisone, or other similar drug, can reduce
inflammation caused by injuries, allergic reactions,
rheumatoid arthritis and asthma.
• In stressful conditions, cortisol is secreted in larger
amount; thus, it helps the body by providing energy
sources for tissues.
• If stressful conditions are prolonged, it can be harmful
it can lead to hypertension, heart disease, ulcers, etc.
• Adrenocorticotropic hormone (ACTH) stimulates
cortisol secretion. Without ACTH adrenal cortex will be
dysfunctional and loses its ability to secrete cortisol.

18. Secreted by the inner
layer of the adrenal
cortex.
Stimulates the
development of male
sexual characteristics. in
adult males androgens are
secreted by the testes.
In adult females,
androgens influence the
female sex drive.

19. • If the secretion of sex hormones from the
adrenal cortex is abnormally high, exaggerated
male characteristics develop in both males
and females.
• This condition is most apparent in females and
in males before puberty

20. • Endocrine part of the pancreas consist of
pancreatic islets, which are dispersed among
the exocrine portion off the pancreas.
• These two islets secretes two hormones –
insulin and glucagon – which help regulate
blood levels of nutrients specially glucose.
Beta cells
secretes insulin.
Alpha cells
secretes glucagon

22. • It is very important to maintain normal blood
glucose levels. A below-normal blood glucose
level causes the nervous system to
malfunction because glucose is the main
source of energy. Other tissues rapidly break
down fats and proteins to provide an
alternative energy source.

23. converts some fatty acids to acidic
ketones which are released into
the blood.

24. • The breakdown of fats can cause release of
enough fatty acids and ketones that reduce
the pH of the body fluids below a normal
range, a condition called acidosis.
• The amino acids of proteins are broken down
and used by the liver to synthesize glucose.

25. If glucose levels are too
high, the kidneys produce
large volumes of urine
containing a lot of
glucose
Rapid loss of water in the
form of urine will occur and
dehydration can result
Insulin from beta cells is
released in response to
elevated blood glucose levels
and increased
parasympathetic stimulation
Increase in blood levels of
certain amino acids also
stimulate insulin secretion
Decreased insulin
secretion results from
decreasing blood glucose
levels and from
stimulation pancreas by
the sympathetic division
of the nervous system
Decreased insulin level
therefore allows glucose to
be conserved to provide the
brain w/ adequate glucose
and to allow other tissues to
metabolize fatty acids and
glycogen stored in the cells

26. • The major target tissues for insulin are the
liver, adipose tissue, muscles and the area of
the hypothalamus that controls appetite,
called the satiety center.
• Insulin increases the rate of glucose and
amino acid uptake in these tissues.
Glucose
Glycogen or
Fat
Amino Acids Protein

27. Diabetes mellitus – has many causes:
• Type 1 diabetes mellitus occurs when too
little insulin is secreted from pancreas. Tissues
cannot take up glucose effectively causing
blood sugar levels to become very high, a
condition called hyperglycemia.
• Type 2 diabetes mellitus is caused by
insufficient numbers of insulin receptors on
target cells or by defective receptors.

29. • Because glucose enter the cells of the satiety
center of the brain, the satiety center
responds as if there were too little blood
glucose, causing an exaggerated appetite.
• The excess glucose in the blood in excreted in
the urine, making the urine volume much
greater than normal.
• Because of this the person has a tendency to
become dehydrated and thirsty.

30. • Fats and proteins are broken down to provide an
energy source for metabolism because levels of
blood glucose is not in a normal range, thus
causing malfunction in the nervous system.
• When too much insulin is injected or when a
person is injected with insulin who has not eaten
after the injection, blood glucose levels become
very low thus making the brain malfunction
because it depends primarily on glucose for an
energy source, this condition is called insulin
shock.

31. blood glucose levels
are low
Glucagon is released
from the alpha cells
It binds with the
membrane-bound
receptors of the
liver
causing the
glycogen in the liver
to be converted to
glucose
released it into the
blood to increase
blood glucose levels
After a meal, when
blood glucose are
elevated, glucagon
secretion decreased

32. blood glucose
levels
Insulin
secretion
Glucagon
secretion
blood glucose
levels
Glucagon
secretion
Insulin
secretion

33. Target Tissues Insulin Response Glucagon Response
Skeletal muscles,
Increase glucose uptake and
Has little effect
cardiac muscles,
glycogen synthesis;
cartilage, bone
increases uptake of amino
fibroblasts, blood cells,
acids.
mammary glands
Liver Increases glycogen
synthesis; increases use of
glucose for energy
Causes rapid increase in
the breakdown of
glycogen to glucose and
release of glucose into the
blood increases the
formation of glucose from
the amino acids and to
some degree from fats;
increases metabolism of
fatty acids.
Adipose cells Increases glucose uptake,
glycogen synthesis, far
synthesis.
High concentrations cause
breakdown of fats;
probably unimportant
under most conditions.
Nervous System Has little effect except to
increase glucose uptake in
the satiety center
Has no effect

35. • Testes of the
male and ovaries
of the female
secretes sex
hormones in
addition to
producing sperm
cells and
oocytes.

36. Testosterone is the main sex
hormone in the male which is
secreted by the testes. It is
responsible for the growth and
development of the male
reproductive structures,
muscle enlargement, growth of
body hair, voice changes, and
the male sexual drive.

37. In the female, there are two sex
hormones secreted by the ovary:
estrogen and progesterone.
Together these hormones contribute
to the development of female sexual
characteristic and female
reproductive structures. Such as the
enlargement of the breast and the
distribution of fats which influences
the shape of the hips, breasts, and
thighs. Female menstrual cycle is also
controlled by the sex hormones.

38. • Luteinizing Hormone (LH) and Follicle-stimulating
Hormone (FHS) stimulate the
secretion of hormones from the ovaries and
testes. Hypothalamus controls the rate of LH
and FHS, in turn, LH and FHS controls the
secretion of hormones from the ovaries and
testes.

39. • Lies in the upper part of the
thoracic cavity. Important in the
function of the immune system.
• Secretes hormone called thymosin,
which aids in the development of
white blood cells called T cells.
White blood cells fight infections
and protects the body against
foreign organisms.
• Thymus is most important early in
life, without this a newborn cannot
develop the immune system
normally.

40. • Is a pinecone-shaped
structure
located superior
and posterior to
the thalamus of
the brain.

41. • Produces a hormone called melatonin.
• This decreases the release of hypothalamic-releasing
hormones and secretion of LH and
FHS thus melatonin inhibits the functions of
reproductive system.

42. • Animal studies show that the amount of
available light controls the rate of melatonin
secretion. In short, less light increases
melatonin secretion and more light decreases
melatonin secretion.
• Some evidence suggest that melatonin plays
an important role in the onset of puberty in
humans.