Endocrine Flashcards
What hormone is released by the kidneys that stimulates the absorption of calcium ions from the digestive tract?
calcitriol
Blood passes in a direct route from the hypothalamus to the anterior pituitary gland through the…
hypophyseal portal veins
Either a deficiency of insulin production by the pancreas, or defects in insulin receptors on target cells, result in the disease of..
diabetes mellitus
For the formation of thyroxine to occur, it is essential that _____ be present
iodine
If you drank a liter of water very quickly, what would happen?
decreased secretion of antidiuretic hormone
Target cells for hypothalamic releasing hormones are in the
anterior pituitary
The cell bodies of the axons of the posterior pituitary gland are actually located in the
hypothalamus of the brain
The concentration of calcium ions and phosphates in the blood is regulated by
Parathyroid hormone
The posterior pituitary gland stores and secretes
oxytocin and antidiuretic hormone
The release of cortisol is stimulated by
Adrenocorticotropic hormone (ACTH)
The _____ cells of the islets of Langerhans secrete insulin.
beta
The ____________ is the major integrating link between the nervous and endocrine systems.
hypothalamus
What stimulates the release of parathyroid hormone (PTH) from the parathyroid gland?
low levels of calcium ion in the blood
What organ has both exocrine and endocrine functions?
Pancreas
Which hormone requires a releasing hormone from the hypothalamus for its secretion?
prolactin
Which three hormones have a direct effect on the urinary system in terms of adjusting rate of water loss and ions in the urine?
- antidiuretic hormone
- aldosterone
- atrial natriuretic peptide
Adrenal hormones useful in treating chronic inflammatory disorders such as rheumatism are
glucocorticoids
What do Adrenocorticotropic hormone stimulate?
Stimulates the adrenal cortex to secrete glucocorticoids
Hypersecretion of glucocorticoids results in the following clinical symptoms: redistribution of body fat, hyperglycemia, osteoporosis, weakness, hypertension, ‘moon face’ and ‘buffalo hump’, excessive bruising, and poor wound healing. These symptoms are associated with
Cushing’s syndrome
Why can’t insulin be administered by the mouth and must be injected?
it is a protein and would be digested by the enzymes of the stomach
Where is the pineal gland located?
In the brain
Type II diabetes most often occurs in humans who are overweight and…
over 35 years in age
Which chemicals acts both as a neurotransmitter in some locations and as a hormone in other locations?
- Adrenaline (epinephrine)
- Noradrenaline (Norepinephrine)
What is associated with diabetes mellitus?
- glycosuria
- polyuria
- ketosis
- hyperglycaemia
What is classified as a glucocorticoid?
cortisol
What gland is known as the ‘Master gland’ and why?
- Pituitary gland
- Because it secretes hormones and most of these control other endocrine glands
What lobes can the Pituitary gland be broken into?
- Posterior lobe
- Anterior lobe
What hormones does the posterior lobe contain?
- Oxytocin hormone
- Antidiuretic hormone
What hormones does the Anterior lobe contain?
- Growth hormone (GH)
- Thyroid stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Follicle stimulating hormone (FSH)
- Luteinising hormone (LH)
- Prolactin
How are hormones in the posterior lobe released?
Caused by an action potential from the hypothalamus
How are hormones in the anterior lobe released?
Is a result of specific releasing hormones from the hypothalamus, which travels to the anterior lobe
What two types of solubles can hormones be?
- Water soluble
- Lipid soluble
What is an example of a Water soluble hormone and how do they get in the body?
- Adrenaline is an example
- Must be injected into the body
What is an example of a Lipid soluble hormone and how do they get into the body?
- Progesterone is and example
- Taken orally
Which hormone acts to lower blood calcium levels and where is it produced?
- Calcitonin
- Produced in the thyroid gland
What are the three stages of the stress response?
- Fight or Flight
- Resistance
- Exhaustion
Describe the Fight or Flight response and what hormones are released
Automatic physiological reaction to an event that is perceived as stressful or frightening (increases heart rate etc)
- Adrenaline and Cortisol (increases sugars in the bloodstream, enhances the brains use of glucose and increases the availability of substances that repair tissues)
Describe the Resistance response
After the Initial fight or flight response, the body acts to help us cope with longer term effects of the stressful event. Secretion of Adrenaline decreases, but cortisol remains at elevated levels and levels of growth hormone and thyroxine also increase. With help of these 3 hormones, the body returns back to normal
Describe the Exhaustion response
Occasionally the body is unable to cope with the stressor and exhaustion results, which is due to an unrelenting exposure to high levels of cortisol which continues to suppress the immune system.
What are 4 aged-related changes to the endocrine system?
- Growth hormone decreases, allowing for muscle atrophy
- Falling levels of oestrogen in females middle aged leads to menopause
- Rising levels of parathyroid hormone (PTH) can result in decreased bone density in the elderly, condition called osteoporosis
- Pancreas releases insulin more slowly & cells are not as responsive to insulin
State five ways that the endocrine system maintains homeostasis
- Altering metabolism
- Regulating growth and development
- Regulating reproduction
- Regulate circadian rhythms
- Regulate activity of smooth and cardiac muscles as well as glands
What do Paracrine hormones activate?
Paracrine hormones activate neighbouring cells
What do autocrine hormones activate?
Autocrine hormones activate the cell that produced them
Explain the difference in receptor location for both water soluble hormones and lipid soluble hormones
- Water soluble hormones circulate freely in the blood and they bind to receptors on cell membrane then alter the activity of intracellular enzymes
- Lipid soluble hormones diffuse through the cell membrane and bind to receptors within target cells. Most of these hormones are carried in blood by transport proteins which prevent them being activated
Explain why water soluble hormones cannot be administered via the oral route
Water soluble hormones are destroyed by digestion
What do lipid soluble hormones activate?
Genes in cell which results in the formation of new proteins which alter the cell’s activity
Describe the difference between endocrine & exocrine glands
- Exocrine glands secrete their products (eg. Sweat, pancreatic enzymes) into ducts. The ducts then carry the secretion to the target site
- Endocrine glands secrete into interstitial fluid, then diffuse into the blood
Name the organ that has both endocrine & exocrine functions
Pancreas
Explain how hormones are inactivated and excreted from the body
- Inactivated by the liver
- Excreted by the kidneys or in the faeces
Describe the three stimuli that trigger hormone secretion
- Signals from the nervous system
- The levels of a chemical in the blood
- Another hormone
Describe the structure and location of the pituitary gland
- Located in the brain, connected to the hypothalamus by the infundibulum
- This gland consists of a larger anterior lobe & a smaller posterior lobe
Name the two hormones released from the posterior pituitary and state where they are produced
- Oxytocin hormone
- Antidiuretic hormone
- Produced in the hypothalamus
How are the oxytocin and antidiuretic hormones released?
When an action potential travels down the axon of the neurosecretory cells
How are the Anterior pituitary gland hormones released?
- Stimulated by a releasing hormone from the hypothalamus
- Hypothalamus sending its controlling hormones through portal veins to the anterior pituitary
- Stimulates the release of hormones synthesised in the -anterior pituitary
Describe three clinical situations that arise from alterations to secretion of Growth Hormone (GH)
- Hyposecretion during growth years results in dwarfism
- Hypersecretion in childhood results in giantism
- Hypersecretion in adulthood results in acromegaly
Describe the two clinical conditions associated with alterations in the secretion of thyroxine
- Hypothyroidism
- Hyperthyroidism
What is Hypothyroidism?
Low levels of thyroxine and this results in lower BMR
What is Hyperthyroidism?
High levels of thyroxine and this results in higher BMR - can cause acute symptoms that need treatment
State the mineral needed by the body to produce thyroxine
Iodine
State the location of the adrenal glands
Located on top of the kidneys
State the two areas of the adrenal glands
Adrenal Cortex and Adrenal Medulla
What hormones does the Adrenal Cortex secrete?
Cortisol and aldosterone
What hormones does the Adrenal Medulla secrete?
Adrenaline and Noradrenaline
Describe three effects/actions of cortisol
- Anti-inflammatory effect that suppresses the immune system but this slows tissue repair and wound healing
- Raised blood glucose by gluconeogenesis
- Raise levels of fatty acids and amino acids in the blood to provide non carbohydrate source of energy
State a clinical situation where glucocorticoids (cortisol) might be prescribed
To suppress the inflammatory response in chronic conditions and also prescribed for organ transplant patients to avoid organ rejection
Name two situations that would cause the release of adrenaline
- Stressful situations & exercise
- Sympathetic stimulation - Fight or flight response
State six effects/actions of adrenaline
- Increases cardiac output
- Increases blood pressure
- Increases rate and force of heart contraction
- Dilate airways
- Increase blood glucose levels
- Increase blood flow to the myocardium, liver and skeletal muscles
State the main effect/action of noradrenaline
Stress situations
Name the two hormones that control blood calcium levels
- Parathyroid hormone (PTH) increases blood calcium levels
- Calcitonin decreases blood calcium levels
State three uses for calcium in the body
- Blood clotting
- Transmission of nerve impulses
- Muscle contraction
Describe three actions of parathyroid hormone (PTH)
- Stimulates osteoclasts to resorb bone and raise blood calcium
- Enhances reabsorption of calcium by the kidneys
- Activates vitamin D to become calcitriol which is needed to absorb calcium from food
Describe two actions of calcitonin
- Produced when blood calcium levels are raised, it lowers the levels by inhibiting osteoclast activity
- Calcium is absorbed from the GI tract under the influence of calcitriol
What is calcitriol also known as?
Active Vitamin D
State two effects of calcitriol
- Increasing absorption of calcium and phosphate from the intestine
- Enhances the actions of parathyroid hormone which resorbs bone
Name the two hormones that specifically regulate BGL’s
- Insulin (Lowers)
- Glucagon (Raises)
Name the specific cells that secrete insulin and glucagon
- Beta cells secrete Insulin
- Alpha cells secrete Glucagon
Describe the actions or function of Insulin and Glucagon
- Insulin (dominant hormone after eating) lowers blood glucose levels.
- Glucagon (dominant hormone of the fasting state) raises blood glucose levels.
State the stimulus for secretion of Insulin and Glucagon
- Insulin is secreted when blood glucose levels are high
- Glucagon is secreted when blood glucose levels are low
Name three other hormones that raise BGL’S and why?
- Adrenaline (so that glucose is available for an emergency)
- Growth hormone (by stimulating lipolysis so that lipids are available for growth leaving glucose to be available for the brain)
- Cortisol (which makes additional glucose available to deal with stress situations)
Name the hormone that is produced from the pineal gland
Melatonin
Where is the pineal gland located?
Attached to the roof of the 3rd ventricle of the brain (epithalamus)
State the main function of melatonin
Contributes to the natural body clock. (Convey information concerning the daily cycle of light and darkness to body structures)
Name the three stages of the stress response
- Initial fight-or-flight response
- Resistance reaction
- Exhaustion
Name the main hormone for stage 1 of the stress response
Adrenaline
Name the hormones for stage 2 of the stress response
- Cortisol
- Growth hormone
- Thyroxine
Describe the long term effects of prolonged cortisol
Causes wasting of muscle, suppression of the immune system, ulceration of the gastrointestinal tract, failure of the pancreatic beta cells which produce insulin
Name two health implications of stress
- Dying prematurely
- Greater risk of developing chronic disease
Which hormone requires a releasing hormone from the hypothalamus for its secretion?
prolactin
What stimulates the release of PTH from the parathyroid gland?
low levels of calcium in the blood
The target cells for hypothalamic releasing hormones are in the…
anterior pituitary
Tropic hormones are secreted by the…
anterior pituitary
The concentration of Ca2t ions in the blood is regulated by..
PTH
What is associated with diabetes mellitus?
glycosuria, polyuria, ketosis & hyperglycaemia
Which chemical acts as both a neurotransmitter in some locations and a hormone in other locations?
Adrenaline
Which three hormones have a direct effect on the urinary system to adjust the rate ion & water loss in the urine?
antidiuretic hormone, aldosterone & atrial natriuretic peptide
What is the major integrating link between the nervous & endocrine systems
Hypothalamus
Where are the cells bodies of the neurosecretory axons of the posterior pituitary gland are actually located?
Hypothalamus
The release of cortisol is stimulated by…
Adrenocorticotropic hormone (ACTH)
