Download I. Endocrine System A. Gross Anatomy of Endocrine Glands 1

I. Endocrine System
A. Classification of Glands
1. Endocrine Glands
a. Hormones
b. Target Cells
c. Negative Feedback
2. Exocrine Glands
B. Pituitary Gland (Hypophysis)
1. Gross Anatomy
a. Infundibulum
b. Anterior Lobe – Adenohypophysis – Pars
Distalis
c. Posterior Lobe– Neurohypophysis – Pars
Nervosa
d. Pars tuberalis
e. Pars Intermedia
2. Histology
a. Posterior Pituitary Lobe
1) Unmyelinated Axons
2) Pituicytes (Glial cells)
b. Anterior Pituitary Lobe
1) Chromophobes - ?
2) Chromophils
a) Acidophil Cells
(1) GH
(2) PRL
b) Basophil Cells
(1) TSH
(2) ACTH
(3) FSH
(4) LH
Pituitary gland 4X
Pituitary gland 10X
Pituitary gland 40X
3. Hormones
a. Anterior Lobe of Pituitary Gland
1) Pars Distalis
a) Growth Hormone (GH)
(1) Clinical Application - Acromegaly
b) Prolactin (PRL) – Milk Production
c) Tropic Hormones – Master Gland
(1) Hypothalamic – Hypophyseal Portal
System (Blood Vessel Plexus)
(a) Regulatory Hormones
{1} Releasing Hormones
{2} Inhibiting Hormones
(2) Gonadotropins
(a) Follicle-stimulating
Hormone (FSH)
(b) Luteinizing Hormone
(LH) / Interstitial Cellstimulating Hormone (ICSH)
(3) Adrenocorticotropic
Hormone (ACTH)
(4) Thyroid-stimulating
Hormone – Thyrotropic Hormone (TSH)
2) Pars Intermedia
a) Melanocyte-stimulating Hormone (MSH)
b. Posterior Pituitary Gland
1) Storage ONLY – No Production – Hormones are
Produced in the Hypothalamus
a) Oxytocin – Paraventricular Neuron
(1) Labor Contractions, Milk Ejection,
Contractions of Ductus Deferens and
Prostate Gland
(2) Positive Feedback
b) Antidiuretic Hormone (ADH) – Supraoptic
Neuron
(1) Water Retention
2) Clinical Application
a) Diabetes insipidus
C. Thyroid Gland
1. Gross Anatomy
a. Lateral Lobes
b. Isthmus
2. Histology
a. Thyroid Follicles
(1) Follicle (Follicular) Cells – T4 & T3
(2) Thyroid Colloid – Thyroglobulin
b. Parafollicular (C) cells – CT
3. Hormones
a. Thyroxine (T4) – Regulate Metabolic Rate
b. Triiodothyronine (T3) – Regulate Metabolic Rate
c. Calcitonin (CT) – Decreases Blood Calcium Levels
4. Clinical Application
a. Hyperthyroidism
1) Graves’ Disease – Autoimmune Response
a) Goiter
b) Exophthalmos
b. Hypothyroidism
1) Myxedema
Thyroid gland 4X
Thyroid gland 10X
Thyroid gland 40X
D. Parathyroid Glands
1. Gross Anatomy
a. Embedded in Posterior Thyroid
b. Possibly some in Neck or Thorax
c. Parathyroid Capsule
2. Histology
a. Principal (Chief) Cells – PTH
b. Oxyphil Cells - ?
3. Hormone
a. Parathyroid Hormone (PTH) – Increases Blood
Calcium Levels
4. Clinical Application
a. Tetany
Parathyroid gland 4X
Parathyroid gland 10X
Parathyroid gland 40X
E. Thymus Gland
1. Gross Anatomy
a. Lobes (2 Main)
1) Septae – Fibrous Connective Tissue
2) Lobules
a) Cortex
b) Medulla
2. Histology
a. Thymic (Hassall’s) Corpuscle
b. T Lymphocytes (T Cells)
3. Hormones
a. Thymosin
b. Thymopoietin
Thymus gland 4X
Thymus gland 10X
Thymus gland 40X
F. Adrenal (Suprarenal) Glands
1. Gross Anatomy
1) Adrenal Capsule
2) Adrenal Cortex
3) Adrenal Medulla
2. Histology
a. Adrenal Cortex
1) Zona glomerulosa – Oval clusters
a) Mineralocorticoids
2) Zona fasciculata – Tight columns
a) Glucocorticoids
3) Zona reticularis – Chainlike structures
a) Sex Hormones
b. Adrenal Medulla – many blood vessels
1) Chromaffin Cells – Epi & NE
3. Hormones
a. Corticosteroids (Adrenocortical Steroids)
1) Mineralocorticoids – Regulates
Electrolytes in Body Fluids
a) Aldosterone – Sodium
Reabsorption
2) Glucocorticoids – Fight Stress, Increase
Glucose Metabolism & Prevent
Inflammation
a) Cortisol (Hydrocortisone)
b) Corticosterone
3) Androgens – Male Sex Hormones
a) Clinical Application - Hirsutism
b. Adrenal Medulla – Sympathetic Fight-or-Flight
1) Epinephrine (Epi) 80%
2) Norepinephrine (NE) 20%
Adrenal gland 10X
Adrenal gland 40X
G. Pancreas
1. Gross Anatomy
a. Heterocrine Gland
2. Histology
a. Pancreatic Islets – Islets of Langerhans
1) Alpha Cells – Glucagon
2) Beta Cells – Insulin
3) Delta Cells – Somatostatin/Growth HormoneInhibiting Hormone (GH-IH)
4) F cells – Pancreatic Polypeptide (PP)
b. Pancreatic Acini (Acinar cells) – Exocrine Function
3. Hormones
a. Insulin – Lowers Blood Sugar Concentration
b. Glucagon – Raises Blood Sugar Concentration
4. Clinical Application
a. Diabetes mellitus
1) Type I Diabetes – Beta Cells
2) Type II Diabetes
b. Hypoglycemia
Pancreas 4X
Pancreas 10X
Pancreas 40X
H. Testes – Male Gonads
1. Gross Anatomy
a. Scrotum
2. Histology
a. Interstitial Cells (Leydig Cells) - Testosterone
b. Seminiferous Tubules – Spermatozoa – Gamete
c. Nurse Cells (Sustenacular or Sertoli) - Inhibin
3. Hormone
a. Testosterone
b. Inhibin
4. Clinical Application
a. Steroid Abuse
1) Androstedione
Testis 4X
Testis 10X
Testis 40X
I. Ovaries – Female Gonads
1. Gross Anatomy
a. Pelvic cavity
2. Histology
a. Follicles – Oocyte (Gamete) Development & Estrogen
1) Primordial Follicles
2) Primary Follicles
3) Secondary Follicles
4) Vesicular (Graafian or Tertiary) Follicle
b. Ovulation
c. Corpus luteum
1) Mostly Progesterone
3. Hormones
a. Estrogens – Prepares Uterus for Implantation
b. Progesterone – Promotes Thickening of Uterine Wall
Ovary 4X
Ovary 10X
Ovary 4X
J. Pineal Gland (Body) – Epiphysis cerebri
1. Gross Anatomy
a. Posterior Roof of the Third Ventricle
2. Histology
a. Pinealocytes
b. Brain Sand
3. Hormone
a. Melatonin
Pineal gland 40X