Endocrine System Flashcards
What is prolactin (PRL)?
acts on the mammary glands to stimulation milk production; sustains breast feeding
What body systems facilitate cellular communication? Describe how each works.
the nervous system and the endocrine system
NS vs ES:
- NS rapidly affects specific tissues to which neurons directly connect it
- ES uses chemical messengers, hormones, which circulate in the blood stream and have broad, long-lasting effects
What happens when the brain detects sustained danger (long term stress response)?
- the hypothalamus triggers the anterior pituitary to secrete ACTH
- this hormone targets the adrenal cortex (outer portion)
- Cortisol is released into the blood which raises blood glucose levels
What is dwarfism?
deficiency of the growth hormone (or even a genetic mutation)
- results in unusual, short stature
What is acromegaly?
overproduction of growth hormone which causes body tissues and bones to grow more quickly
- increase in thickness of bones in face hands, feet
How does glucose imbalance lead to diabetes mellitus? What is diabetes mellitus?
- diabetes mellitus: a serious chronic condition that results when the pancreas does not make enough insulin or the body does not respond properly to insulin
- levels of blood glucose tend to rise sharply after meals (hyperglycemia) and remain at significantly high levels
~ without insulin, cells remain relatively impermeable to glucose and cannot obtain enough from the blood - the body switches to protein and fat metabolism for energy (releases acetone as a toxic byproduct)
- kidneys cannot rebsorb all the glucose that is filtered through them from the blood, causing there to be glucose in urine
What happens after a meal?
- digestive system releases glucose into the blood stream, increasing blood sugar level
- this increase is detected by the islets of Langerhans
- the BETA cells of the pancreas release insulin into the blood
- it acts on two target cells: body cells to use glucose in respiration and liver cells that convert glucose into glycogen
- as glucose levels drop, insulin secretion slows
What are hormones?
chemical messengers distributed by the blood stream to target cells
What happens during fasting or skipping meals?
- blood glucose levels drop
- this drop is detected by the islets of Langerhans
- the alpha cells of the pancreas release glucagon into the blood
- it acts on the liver cells to convert glycogen back into glucose, which raises sugar levels in the blood and slows the release of glucagon
What are the two parts of the pituitary gland? What does each do?
the anterior pituitary - produces a variety of hormones
the posterior pituitary - stores and releases hormones produced by the HYPOTHALAMUS
What are most of the tropic hormones released by?
released by the hypothalamus & the anterior pituitary and are controlled by a negative feedback loop
What is antidiuretic hormones (ADH)?
acts on the kidney to increase WATER REABSORPTION into the blood
- decreases urine output when dehydrated
What is thyroid stimulating hormone (TSH)?
acts on the thyroid gland to produce thyroxine
- increases metabolism rate of fats, proteins, carbs for energy
- stimulates many cell types (heart, skeletal, kidney)
- assists growth and development in childhood by organizing cells into tissues and organs
What hormones are involved in LONG TERM STRESS RESPONSE?
- Glucocorticoids (Cortisol - increases metabolism)
- Mineralocorticoids (aldosterone - raises blood pressure
- Gonadocorticoids - supplement sex hormones
What is long term stress response?
- occurs in adrenal cortex (outer portion of adrenal glands)
produce stress hormones that trigger sustained physiological responses
What is oxytocin?
stimulate uterine contractions during child-birth & the mammary glands to produce milk for initial breastfeeding (positive feedback)
What is adrenocorticotropic hormone (ACTH)?
acts on the adrenal glands (outer cortex) and causes the release of stress hormone, cortisol
- cortisol raises blood glucose levels by breaking down muscle proteins into amino acids
- stimulates breakdown of fats
- chronic stress causes sustained high cortisol leading to high BP, heart damage, etc.
What is the role of the hypothalamus in the endocrine system?
- links the nervous system to the endocrine system
- produces hormones or electrical messages and sends them to pituitary gland through neurohormones via the pituitary stalk
What is hyperthyroidism?
high thyroxine levels
- symptoms: anxiety, insomnia, irregular heartbeat, weight loss
- severe state = Grave’s disease
What are the negative impacts of a sustained release of cortisol on the body?
can cause many health problems, can impair thinking, damage the heart, cause high BP, lead to diabetes, increase risk to infections and even cause early death
What is the thymus gland
gland between lungs in the chest (part of the immune system when young; produces thymosin which stimulates production & maturation of T lymphocytes
- disappears after puberty & regulated by the pituitary gland
what are neurosecretory cells?
cells in the hypothalamus that receive neural messages and convert them to hormone secretions
- secretions to the anterior pituitary = stimulate release or inhibit release of hormones
- secretions to the posterior pituitary = ADH, oxytocin
what happens in response to a stress for SHORT TERM STRESS RESPONSE?
- the hypothalamus triggers the adrenal medulla to secrete two related hormones: epinephrine and norepinephrine
- these trigger an increase in breathing rate, heart rate, blood pressure, and conversion of glycogen to glucose
~ pupils also dilate & blood flow to extremities is decreased
What is prolactinoma?
tumor causing the pituitary gland to overproduce prolactin
- symptoms: infertility, irregular periods, breast tenderness
