Endocrinology Flashcards
What body processes does the endocrine system control?
- Growth and development.
- Metabolism.
- Reproduction.
- Homeostasis.
Name some of the organs and tissues of the endocrine system identified in class.
- Pituitary Glands.
- Thyroid Gland.
- Parathyroid Glands.
- Adrenal Glands.
- Pancreas.
- Ovaries and Testes.
What is the endocrine system?
A communication system including glands and hormones.
What are hormones?
Chemical substances used for intracellular and extracellular communication.
How do receptors work in the endocrine system?
Hormone works by binding to specific receptors on surfaces of cell or inside the cell.
What are tropic hormones?
Tropic hormones actions are specific for another endocrine gland.
E.g. Anterior pituitary releases Adrenocorticotropic Hormone (ACTH) that acts on adrenal glands.
What are direct effector hormones?
Direct effector hormones act on peripheral tissues.
E.g. Growth hormone.
What substance whose levels in blood regulates insulin release?
Glucose levels in blood affect insulin release.
What is the link between the nervous system and the endocrine system?
Hypothalamus is the nervous system component that links with the endocrine system.
List some tropic hormones (3) of the anterior pituitary gland.
LH
FSH
TSH
What is negative feedback?
Think of an analogy to the thermostat & furnace. As temp falls, thermostat sends electrical impulse to furnace to come on and restore heat. But when temp is high enough the thermostat turns off signal and furnace stops.
What is an open-loop negative feedback system?
An open-loop negative feedback system is influenced or modified by neural input or other hormones.
Give an example of an open-loop negative feedback system?
TRH (Thyrotropin-Releasing Hormone) produced by hypothalamus and causes anterior pituitary to secrete TSH
TSH travels to thyroid stimulates release of thyroxine (FT4)
Thyroxine (FT4) in blood circulates to hypothalamus and suppresses the pituitary from further TRH and TSH production
What is positive feedback?
In response to a hormone increasing in levels another hormone (or other response) also increases in levels.
E.g. Menstrual cycle:
Estrogen –> Increased & LH –> Increased
What endocrine gland does the hormone ACTH (Adrenocorticotropic Hormone) impact and the effect?
ACTH –> Adrenal Cortex.
Effect: Produced in times of stress. Stimulates secretion of glucocorticoids.
What endocrine gland does the hormone TSH (Thyroid Stimulating Hormone) impact and the effect?
TSH –> Thyroid Gland
Effect: Stimulates secretion of thyroid hormones. Increases metabolism by cells in body.
What endocrine gland does the hormone LH (Luteinizing Hormone) & FSH (Follicle Stimulating Hormone) impact and the effect?
LH & FSH –> Ovaries and Testes
Effect: Control of reproductive function (menstrual cycle and leads to sperm production).
What hormone impacts the liver and other tissues to stimulate cell development, growth and regeneration?
Growth Hormone.
What hormone stimulates milk production in what glands?
Prolactin impacts the mammary glands for milk production.
What hormone is released by the posterior pituitary but produced by the hypothalamus in birth? To do what? What else does it do?
Oxytocin to stimulate uterine contractions.
It also is released during mom/baby bonding and during milk production.
What is the effect of ADH (Antidiuretic Hormone or Vasopressin) and what does it act on & why?
Acts on kidneys and blood vessels to reduce blood pressure for:
- The conservation of body water by increasing reabsorption of water by the renal tubules.
- Released with decreased blood volume or an increase in sodium.
What hormone plays a role in diabetes insipidus? What are the resulting symptoms?
Diabetes in insipidus is an imbalance of fluids due to decreased production or a decreased response to ADH. Results in extreme thirst and large amounts of urine production.
List the various zones of the adrenal glands and the hormones they release.
Slide 10.
At what times does ACTH and cortisol levels show diurnal peaks & troughs at?
Slide 11
How is ACTH specimen to be collected?
- Collected in a chilled EDTA tube and put on ice.
2. Collect between 0800 and 1000h, record exact time of collection.
What are the adult reference ranges for ACTH and cortisol including time ranges?
Slide 11.
What does ACTH do?
Slide 11 - reminder.
What is Cushing’s syndrome?
Excess cortisol over a prolonged period of time
Symptoms: fatty hump between your shoulders, a rounded face, and pink or purple stretch marks on your skin.
Cushing syndrome can result in high blood pressure and bone loss
What is Addison’s disease? What hormones impact it, the symptom’s and its treatment?
Addison’s Disease (or Primary Adrenal Insufficiency):
↓cortisol and N or ↑ ACTH
Adrenal glands produce too little cortisol and aldosterone
Result of damage, underactive, infection, cancer
Symptoms: fatigue, weight loss, salt craving, vomiting, dehydration, and diarrhea
Treatment: life-long gluco- and mineralocorticoids
What produces thyrotropin-releasing hormones and what do they do?
Thyrotropin-releasing hormones is produced by neurons in the hypothalamus. Stimulates the release of thyroid-stimulating hormone from the anterior pituitary.