4. Hypothalamus
• Part of brain
– Regulates ANS,
emotions,
feeding/satiety,
thirst, body
temperature, etc.
– Hormones related to
these functions
• “Releasing hormones”
• Axonal transport to
posterior lobe
5. Anterior Pituitary
• “Releasing” hormones
regulate AP aka
adeno hypo physis
“glands” “under” “growth”
• All proteins
– TSH (thryoid stimulating
hormone/thyrotropin)
– ACTH (adrenocorticotropic hormone)
– FSH (gonadotropin)
– LH (gonadotropin)
• Tropins/tropic hormones
– GH (growth hormone)
– Prolactin-releasing H
Hypothalamic Pituitary Axis Animation : IP Web
8. Anterior P. Homeostatic Imbalances
Growth hormone (GH or hGH)
– Promotes mitosis, cell division
– Elongation of long bones, etc.
– Healing of wounds Lack of hGH
retards growth
– Hypersecretion in youth produces
giantism
– Hyposecretion in childhood
produces pituitary dwarfism
– Hypersecretion in adult produces
acromegaly
10. Pituitary—Posterior lobe
• Oxytocin
– Stimulates smooth
muscle contraction
of uterus &
mammary glands.
• Antidiuretic H.
– Stimulates water
reabsorption in
collecting ducts.
– Stimulates
vasoconstriction
(vasopressin)
– Lack diabetes
insipidus
11. Posterior Pituitary Homeostatic
Imbalances
ADH
– Hyposecretion produces
diabetes insipidus “tasteless”
– Excessive thirst and urination
• central or neurogenic DI
• gestagenic or gestational DI
• nephrogenic DI
• dipsogenic DI
Diabetes Insipidus Foundation, Inc.
12.
13. Thyroid Gland
• Location in neck
– Inferior to larynx
– Anterior & lateral to
trachea
• Composed of follicles
– Follicle cells produce
thyroglobulin
• Thyroxin (T4)
• Triiodothyronine (T3)
– Both “thyroid hormone”,
body’s major metabolic
hormone
• Parafollicular/ C cells
• Calcitonin
– Decreases blood Ca2+ by
depositing it in bones
14. Homeostatic imbalances
• Hypothyroidism results
– Myxedema (in adults)
– Goiter—low levels of iodine
– Cretinism (in children)
• Hyperthyroidism results
– Graves disease
15. Parathyroid Glands
• Four small glands
embedded in posterior
of thyroid
– Parathyroid hormone
(PTH)
– Stimulates osteoclasts
to free Ca2+ from bone
– Stimulates Ca2+ uptake
from intestine & kindey
Hormonal Regulation of Calcium
16. Parathyroid Homeostatic
Imbalances
• Severe
hyperparathyroidism
causes massive bone
destruction
• If blood Ca2+ fall too
low, neurons become
overactive, resulting in
tetany
17. Feedback Loop
• Negative feedback in calcium
homeostasis. A rise in blood
Ca2+ causes release of
calcitonin from the thyroid
gland, promoting Ca2+
deposition in bone and
reducing reabsorption in
kidneys.
• A drop in blood Ca2+ causes
the parathyroid gland to
produce parathyroid hormone
(PTH), stimulating the
release of Ca2+ from bone.
• PTH also promotes
reabsorption of Ca2+ in
kidneys and uptake of Ca2+ in
intestines.
18. Adrenal Glands
One on top of each
kidney
• Cortex
– Corticosteroid
– glandular
• Medulla
– Catecholamines
– neurohormonal
• Epinephrine
• Norepinephrine
19. Adrenal Cortex
• Cortex
– Activity stimulated by ACTH
– Controls prolonged responses
by secreting corticosteroids.
– Mineralcorticoids
• Aldosterone regulate salt and water
balance
– Glucocorticoids
• Cortisol regulate glucose metabolism
and the immune system.
– Gonadocorticoids
• Androgens
• Estrogens
20. Adrenal Cortex Imbalances
• Hypersecretion leads
to Cushing’s disease
– ACTH-releasing tumors
or side effects of
corticoid drugs.
• Hyposecretion leads to
Addison’s Disease
– Deficits in
glucocorticoids and
mineralcorticoids
21. Adrenal Medulla
• Medulla
– The adrenal medulla mediates
short–term responses by secreting
catecholamine hormones.
– Cells are modified neurons (lack
axons)
• Epinephrine (adrenaline)
• Norepinephrine (noreadrenaline)
– enable a rapid ( fight-or-flight )
responses to stress by increasing
blood glucose and blood pressure
and directing blood to the heart,
brain, and skeletal muscles.
22.
23. Pancreas
• Consists of two major
types of secretory tissues
which reflects its dual
function
– Exocrine gland
• secretes digestive juice
• localized in the acinar cells
– Endocrine gland
• releases hormones
• localized in the islet cells
(islets of Langerhans)
24. Pancreatic Islets
• “About a million”
embedded in pancreas
• Control centers for blood
glucose
– Insulin from beta cells
– Glucagon from alpha cells
26. Islets of Langerhans
• Insulin stimulates
glucose uptake,
glycogenesis
• Glucagon
stimulates
glycogenolysis,
glucose release
from liver (vs
gluconeogenesis)
27.
28. Feedback Loop
•A rise in blood glucose
causes release of insulin
from beta cells the
pancreas, promoting
glucose uptake in cells
and storage as glycogen
in the liver.
•A fall in blood glucose
stimulates alpha cells in
the pancreas to secrete
glucagon, which causes
the liver to break down
glycogen and release
glucose.
30. Gonads
• Ovaries
– Estrogens
– Progesterone
• Testes
– Testosterone
• Reproductive functions
when we study
reproductive system.
31. Pineal gland
• Melatonin
– ? Inhibits early puberty
– ? Day/night cycles
• Timing of sleep, body
temperature, appetite
• Secretes melatonin during
darkness
– Participates in setting the
body’s clock
• Melatonin is a potent
antioxidant
• Melatonin is high when young
and is reduced as we age
32. Thymus
• Thymus gland
• Thymopoietins,
thymic factor,
thymosins
– Influence development
of T lymphocytes
34. Functions regulated by the
Endocrine System
• Growth
• Healing
• Water balance & Blood Pressure
• Calcium Metabolism
• Energy Metabolism
• Stress
• Regulation of other Endocrine
Organs
