For MLS Students studying HISTOLOGY

1. ACTIVITY 15
ENDOCRINE SYSTEM
PREPARED BY: KABARKADS NOTES Maker
Please be aware that there are
notes written in some slides.

2. GENERAL FEAUTURE OF THE ENDOCRINE
SYSTE,
• Endocrine glands are ductless
• Have rich blood supply
• Hormones, produced by the endocrine
glands are secreted into the bloodstream
• Hormones travel in the blood to target cells
close by or far away from point of secretion
• Hormones receptors are specific binding
sites on target cells.

5. GLAND LOCATION Hormone Secreted
Pituitary Gland
(Hypophysis)
located at the base of the
brain, just below the
hypothalamus, to which it is
attached via nerve fibers.
Thyroid Stimulating Hormone
(TSH)
Follicle-Stimulating Hormone
(FSH)
Luteinizing Hormone (LH)
Prolactin (PRL)
Growth Hormone (GH)
Alpha Melanocyte-Stimulating
Hormone (α-MSH)
Vasopressin.
Oxytocin.
Adrenal Gland located on top of each kidney Cortisol
Aldosterone
Pancreatic Islets behind the lower part of the
stomach
Insulin
Glucagon
Thyroid Gland lies below your Adam's apple,
along the front of the
windpipe.
Triiodothyronine (T3)
Thyroxine (T4),
Parathyroid located in the neck behind the
thyroid
Parathyroid hormone (PTH)
Pineal Gland Located deep in the center of
the brain
Melatonin

6. Gland Endocrine cells Major hormone
Adrenal Cortex • cells of zone
glomerulosa
• cells of zone fasiculata
• cells of zone reticularis
• mineral-corticoid
• gluco-corticoid
• weak androgens
Adrenal Medulla Chromaffin cells • epinephrine
• norepinephrine
Pancreatic Islets • Alpha,
• Beta
• Delta
• PP cells
• glucagon
• insulin
• somatostatin
• pancreatic polypeptide
Thyroid Glands • follicular cells
• Parafollicular cells
• Thyroid hormones
• Calcitonin
Parathyroid
Glands
Chief cells Parathyroid hormones
Pineal Gland Pinealocytes Melatonin

7. Hormone Function
Glucagon • Acts on several tissues to make energy
stored in glycogen and fat available through
glycogenolysis and lipolysis
• Increase blood glucose
Insulin • Causes entry of glucose into cell
• Promotes decrease blood glucose content
Somatostatin • Inhibits release of other islet cell hormones
through local paracrine action
• Inhibits release of GH and TSH in anterior
pituitary and HCl secretion by gastric pits
Thyrotropin-releasing
hormone (TRH)
Stimulates release of thyrotropin (TSH)
Gonadotropin-releasing
hormone (GnRH)
Stimulates the release of both FSH and LH
Somatostatin Inhibits release of both somatotropin and TSH
Growth hormone-releasing
hormone
Stimulates release of GH
Dopamine Inhibits release of prolactin

8. Corticotropin-releasing
hormone (CRH)
Stimulates synthesis of pro-opiomelanocortin
Vasopressin Increases water permeability of renal
collecting ducts
Oxytocin Stimulates contraction of mammary gland
myoepithelial cells and uterine smooth muscle
Mineralocorticoids Stimulate renal absorption of water and
sodium to maintain salt and water balance
Glucocorticoids Influences carbohydrate metabolism; suppress
immune cell activities
Weak androgens Precursor for testosterone or estrogen
Epinephrine Increases heart rate and constrict vessels
Norepinephrine Dilates vessels and increases glucose release

9. Hormone Function
Glucagon Raises blood glucose levels
Insulin Lowers blood glucose level
Somatostatin Inhibits secretion of insulin. Glucagon, and somatotropin
Pancreatic
polypeptide
Inhibits secretion of pancreatic enzymes and HCO3-
Thyroid hormone Increase metabolic rate
Parathyroid
hormone
Lowers blood calcium levels by inhibiting osteoclast
activity
Melatonin Regulates circadian rhythms

10. Pituitary Gland
It is called the master gland because it produces hormones that
control other glands and many body functions including growth.
The pituitary consists of the anterior and posterior pituitary.

11. Pituitary Gland
Anterior Pituitary OIO
(Pars Distalis)
Posterior Pituitary OIO
Basophils
Acidophil
Chromophobe
Sinusoidal Capillaries
Darkly stained (blue)
Darkly stained (red)
Lightly stained (blue)
Contains RBC
Herring Bodies
Blood Vessel
Glial Cells
HERRING BODIES - Represent
the terminal end of the axons
from the hypothalamus, and
hormones are temporarily
stored in these locations

12. Adrenal Gland
100x
Capsule
Medulla
Starts with from
the lumen
Zonae
Glomerulosa
Zonae Fasiculata
Zonae
Reticularis

13. Adrenal Gland (a closer look sa zones) OIO
Zonae ReticularisZonae Glomerulosa Zonae Fasiculata
Clue: Identify the capsule ang
sa dalom yah na glomerulosa
na dyun.
Clue: if sa tunga gn point
siya na si fasi.
Clue: dalom ya lumen (sunod
yah na medulla diba?). Sa
babaw (lumen) lng na si reti
• Makes
glucocorticoids
• Column of cells
• Makes androgen
• Deep angstroming
of darker cells
• Makes aldosterone
• Cells arranged in
clusters
• Separated by a septa
(line in between)

14. Pancreatic Islets
LPO
HPO
OIO
Exocrine Duct
Pancreatic Islets??
Note: Fenestrated Capillaries can be seen here
Captured during lab
activity.
Alpha- cell
Location: periphery (red)
Beta-cell
Location: centrally blue
PP cells?

16. Thyroid Gland OIO
THIS TAKEN FROM THE INTERNET.REFERENCE NI
INCASE I ASK KUNG ANO NA SIYA NG GLAND SA AMO
NI NGA OBJECTIVES.
Parafollicular Cells (C-cells)
Follicle with Colloid
Follicular Cells
Thyrocyte
sClue: smaller size and dark
staining
- Secretes calcitonin

17. Parathyroid Gland
LPO HPO
OIO
Oxyphil cells
-for old parathyroid
- Acidophilic and non-
functional
Chief cells
- Smaller and numerous
- Produces parathyroid
hormone

18. Pineal GlandHPO
Legit Look of Pineal Gland
Blood Vessel
Corpus arenaceum
Astrocyte?
Pinealocyte
Interstitial glial cells
- Or brain sand
- Forms as extracellular protein
deposit become mineralized
(ephiphysis cerebri)
Secretes melatonin
Corpus arenaceum