Transcript The Major endocrine glands 3.

Endocrine Disorders 1.
Goiter
CH0576: The Biology of Disease-Dr Richard N. Ranson
Historical Perspectives 1: the first
endocrine experiment
A. A. Berthold 1849 – Concluded that
testes secreted something that
conditioned blood
Historical Perspectives 2: “Sexual
Rejuvenation”
1889- Charles Brown-Sequard
Extract of Testes
dissolved in H2O
Steroid
Hormones Lipid
Soluble
Placebo effect
Intuitive
observations
Hormone replacement therapy
Basic definitions:
Endocrinology:
• Hormones
• Receptors
• Signalling pathways
• Diseases/pathophysiology
Hormone: (hormon = to excite or get moving):
• Molecule secreted from endocrine cells that
regulates activity of target cells
Young, T-Cells
Location of
Endocrine
Glands
Other hormone secreting cells located in:
Leptin
• Kidneys
• Stomach
e.g. Gastrin
• Liver
• Small Intestine
• Heart
e.g. ANP
Decreased
Appetite
signal
• Skin
• Adipose
Tissue
• Placenta
e.g. Progesterone
Leptin
Hormone synthesis:
Post-translational modification
Enzyme
Fig 7.3-Silverthorn
Catecholamine, Peptide and thyroid hormones
Used as measure of insulin production
C-peptide
Hormone release - Local or circulating.
Fig 18.2 Tortora & Derrickson
Effects: Mins to hrs
Rapid inactivation
● Example Local Hormone NO (Nitric Oxide) – Blood Vessel
endothelial cells
● Acts on Smooth muscle – Vasodilatation
● Viagra enhances NO effects – Role in penile erection
Importance of receptors:
For hormone to be active ‘Target cell’ must express
specific receptor
Upregulation
Down-regulation
Hyperinsulinemia
- diabetes
Hormone excess
Homeostasis
Receptor
Blocking
Hormone deficient
E.g. RU486 (mifepristone) –
Induces Abortion
Blocks progesterone receptors
Prevents uterine conditions
embryo nurturing
Types of Hormones 1: Water Soluble
hormones
Amines
Peptides & Proteins
Norepinephrine
Posterior
Pituitary
Vasopressin
Adrenal medulla
Urine
Output
Increased
Glucose
uptake
Insulin
Pineal Gland
Eicosanoids
Pancreas
Blood
Glucose
All Cell Types
Except RBC
Local Hormones
Various effects
e.g.
vasodilatation
Types of Hormones 2: Lipid Soluble
Hormones
Testosterone
Steroid Hormones
Testes, Adrenal Cortex
Progesterone, Oestrogen
(Ovaries)
Thyroid Hormones
Thyroid Gland
Nitric Oxide - Endothelial Cells
HRT-Oral administration-cross intestinal lining
Transport of Hormones in Blood
Water soluble circulate in blood plasma in ‘free’ form
Lipid Soluble bound to transport proteins
(synthesized in liver)
● Makes lipid hormones ‘water soluble’
● Increases half life of hormone by protecting from
enzyme degradation
● 0.1-10% hormone is unbound – “Free fraction” –
leaves blood to react with cells
Mechanisms of Hormone Action 1. Steroid
and thyroid hormone receptors
Fig 7.7 From
Silverthorn
Mechanisms of Hormone action 2; Water
soluble hormones
NE, ACTH,
FSH, LH etc.
Activates Protein
Kinases
Fig 9.1. E.N. Marieb.
The Major Endocrine Organs in adults 1 The
Pituitary Gland 1.
Posterior
Fig 20-8 McCance
The Major Endocrine Organs 1 The Pituitary
Gland 2- Pituitary-hypothalamo relationship
. CRH,
GnRH
Anterior
Posterior
The Major endocrine glands 2. The Pineal gland
Pinealocytes
Decreased
Light
Melatonin
Melanopsin
Circulation
Brainstem
Body target
cells
Metabolic
rate
Antioxidant?
Promotes Sleep
The Major endocrine glands 3. : The thyroid gland
T3, triiodothyronine
T4, thyroxine
Colloid
TYr
Iodine
Stimulate metabolic rate
Increase protein synthesis etc.
Lack of Iodine in Diet (seafood) results in goiter
The Major endocrine glands 4. : The Parathyroid
gland 1.
The Major endocrine glands 4. : The Parathyroid
gland 2.
PTH
The Major endocrine glands 5. : The Pancreas
The Major endocrine glands 5. : The Pancreas
cont…
Raises Blood
Glucose
Lowers Blood
Glucose
Paracrine-inhibits
glucagon & Insulin
Inhibits SOM,
gallbladder contraction
Pathophysiology- Diabetes Mellitus
The Major endocrine glands 6. : The Adrenal gland 1
The Major endocrine glands 6. : The Adrenal gland 2
Stress &
Exercise
Metabolism
● Increased HR
● Increased CO
● Blood to Muscles
● Dilate Airways
Adr, NA
Promotes Gluconeogenesis
Anti-inflammatory
Immunosuppressive (transplants)
Cortisol
The Major endocrine glands 7. : The Gonads
Estrogens & Progesterone
● Menstrual Cycle
● Maintain pregnancy & Prep Mammary glands
● Female 20 Sex Characteristics
Ovary
Relaxin
Dilates uterine cervix
Testosterone
● Stimulates testis descent
● Regulates spermatogenesis
Testis
● Male 20 Sex Characteristics
Inhibin – Inhibits FSH from Anterior Pituitary (negative feedback)
References
Hadley, M.C. & Levine J.E. (2007). Endocrinology. 6th Edit, Pearson
International.
McCance, K. L. & Huether, S. E. (2006). Pathophysiology. (The
Biologic Basis for Disease in Adults and Children). 5th Edit. Elsevier
Mosby.
Marieb, E. N. (2009) Essentials of Human Anatomy & Physiology. 9th
Edit, Pearson International
Purves, D et al (2008). Neuroscience. 4th Edit. Sinauer.
Tortora G. J. & Derrickson B.(2006). Principles of Anatomy and
Physiology. 11th Edit, Wiley.
Unglaub Silverthorn D. (2007) Human Physiology (An integrated
approach), 4th Edit, Pearson International.