Endocrine System Flashcards
What are the two types of secretions of the endocrine system?
Steroid hormones and Non Steroid hormones
Steroid hormones can pass through the target cell’s membrane, while non-steroid hormones bind at receptors.
How does the nervous system respond compared to the endocrine system in maintaining homeostasis?
Nervous system responds quickly through electrical impulses, while the endocrine system responds slowly with hormones released into the bloodstream
The nervous system’s response is short-lived, whereas the endocrine response is longer lasting.
How do steroid hormones affect target cells?
Steroid hormones can pass through the target cell’s membrane, altering the action of the cell.
How do nonsteroid hormones affect target cells?
Nonsteroid hormones bind at receptors since they cannot pass through cell membranes.
What is the role of negative feedback mechanisms in hormonal secretions?
Negative feedback mechanisms stop or lower the input.
Where is the anterior pituitary located?
In front of the posterior pituitary.
List the hormones secreted by the anterior pituitary and their functions.
- TSH (Thyroid Stimulating Hormone) - stimulates the thyroid
- ACTH (Adrenocorticotropic hormone) - stimulates the adrenal glands
- GH (Growth Hormone) - stimulates growth (bone/muscle)
- MSH (Melanocyte-Stimulating Hormone) - stimulates melanocytes (melanin)
- Prolactin - stimulates milk production
- Gonadotrophs - stimulates sex hormones (testes, ovaries)
Where is the posterior pituitary located?
Behind the anterior pituitary.
List the hormones secreted by the posterior pituitary and their functions.
- AH (Antidiuretic hormone) - increases water retention in the kidneys, decreasing urination
- Oxytocin - stimulates breast milk production and labor contractions
How is the secretion of each pituitary hormone regulated?
All are regulated by the hypothalamus.
Where is the thyroid gland located?
In the neck.
List the hormones secreted by the thyroid gland and their functions.
- Calcitonin - decreases calcium levels in the blood
- T3 & T4 (Thyroxine & Triiodothyronine) - regulate metabolism, body temperature, oxygen levels, blood pressure
How is the secretion of thyroid hormones regulated?
By the hypothalamus through a negative feedback loop.
Where are the parathyroid glands located?
On the posterior part of the thyroid.
What hormone do the parathyroid glands secrete and what is its function?
- PTH (Parathyroid hormone) - increases calcium levels in the blood.
How is the secretion of parathyroid hormone regulated?
By the hypothalamus.
Where are the adrenal glands located?
Above the kidneys.
List the hormones secreted by the adrenal glands and their functions.
- Glucocorticoids - regulate levels to recover (return back to level)
- Epinephrine & norepinephrine - regulate fight/flight response, blood flow, heart rate, oxygen levels, body temperature
How is the secretion of adrenal hormones regulated?
By the hypothalamus.
Where is the pancreas located?
In the abdominal cavity.
List the hormones secreted by the pancreas and their functions.
- Insulin - lowers blood glucose levels
- Glucagon - increases blood glucose levels
How is the secretion of pancreatic hormones regulated?
- Insulin - regulated by beta cells through negative feedback
- Glucagon - regulated by alpha cells through negative feedback
Where is the pineal gland located?
In the posterior half of the brain.
What hormone does the pineal gland secrete and what is its function?
- Melatonin - regulates sleep/wake cycle (circadian rhythm).
Where is the thymus located?
In the upper chest behind the breastbone.
List the hormones secreted by the thymus and their functions.
- Thymopoietin - development of immune system
- Thymic factor - development of immune system
- Thymosin - development of immune system
What hormones do the ovaries secrete and their functions?
- Estrogen - maturation of sex organs, secondary sex characteristics
- Progesterone - controls menstruation, contributes to breast development (ability to produce milk)
What hormone do the testes secrete and its function?
- Testosterone - maturation of sex organs, secondary sex characteristics, sperm production.
How is the secretion of the hormones from the pineal, thymus, and other endocrine glands regulated?
By negative feedback loops and the hypothalamus.
Hormonal Stimulus
glands are stimulated by a hormone secreted by the other glands
ex.) hypothalamus triggers pituitary
Humoral stimulus
Levels of nutrients or ions in the gland trigger hormones to secrete
ex.) Ca+ levels increase/decrease from expected level trigger the parathyroid
Neural stimuli
Nerve impulse causes a gland to secrete
ex.) sympathetic nervous System triggers adrenal glands (when stressed)
