LS endocrine Flashcards
What are the functions of the endocrine system?
- Regulate metabolic processes
- Involve carbohydrates, proteins, and fats
- Play an important role in growth and reproduction
- Regulate water and electrolyte balance
- Help the body during infection, trauma, and stress
Functions of the endocrine system include a wide range of physiological processes necessary for maintaining homeostasis and responding to environmental changes.
Define hormone.
A hormone is a chemical messenger that influences or controls the activities of other tissues or organs.
Hormones are secreted by endocrine glands and travel through the bloodstream to target organs.
What are the three mechanisms that control the secretion of hormones?
- Feedback loops
- Biorhythms
- Control by the central nervous system
Feedback loops can be negative or positive, affecting the secretion of hormones based on physiological conditions.
Describe the relationship of the hypothalamus to the pituitary gland.
The hypothalamus controls both the anterior and posterior pituitary function through releasing and release-inhibiting hormones.
The hypothalamus secretes hormones into the hypothalamic–hypophyseal portal capillaries that connect to the anterior pituitary.
What is the main difference between the nervous system and the endocrine system?
The nervous system communicates through electrical signals (nerve impulses) for rapid, short-term effects, while the endocrine system communicates through chemical signals (hormones) for slower, longer-lasting effects.
This fundamental difference underlines their distinct roles in body regulation.
What is a negative feedback loop?
A biological response in which the effects of a reaction slow or stop that reaction.
An example is the regulation of adrenocorticotropic hormone (ACTH) and cortisol.
What hormones are secreted by the anterior pituitary gland?
- Thyrotropin (TSH)
- Adrenocorticotropic hormone (ACTH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
These hormones regulate various physiological processes including metabolism and reproductive functions.
What is the function of antidiuretic hormone (ADH)?
ADH conserves water by causing the kidneys to reabsorb water from urine back into the blood.
This action decreases urine output and helps maintain blood volume.
Fill in the blank: The thyroid gland secretes two thyroid hormones, _______ and _______.
[T3], [T4]
T3 (Triiodothyronine) is more potent than T4 (Thyroxine).
What is hyperthyroidism?
High secretion of T3 and T4, often associated with conditions like Graves disease.
Symptoms can include weight loss, increased heart rate, and exophthalmia (bulging eyes).
What does calcitonin do?
Calcitonin helps regulate blood levels of calcium and phosphate by decreasing blood calcium levels.
It stimulates osteoblastic activity in bones and increases calcium excretion in urine.
What is the main hormone secreted by the parathyroid glands?
Parathyroid hormone (PTH)
PTH increases blood calcium levels by stimulating bone resorption and renal reabsorption of calcium.
What are the two main hormones secreted by the adrenal medulla?
- Epinephrine
- Norepinephrine
These hormones are critical for the body’s stress response, elevating blood pressure and heart rate.
What is the primary function of aldosterone?
Regulates blood volume, blood pressure, and electrolyte concentration by acting on the kidneys.
Aldosterone promotes sodium retention and potassium excretion.
What are the islets of Langerhans?
The hormone-secreting cells of the pancreas, consisting of alpha cells (glucagon) and beta cells (insulin).
These cells play a crucial role in regulating blood sugar levels.
True or False: Prostaglandins act on distant organs after being secreted.
False
Prostaglandins act locally, near their site of secretion.
What is the effect of excess adipose tissue on hormone secretion?
Excess adipose tissue secretes cytokines, which can make an obese person resistant to insulin.
This can lead to various health issues, including diabetes and cardiovascular diseases.
