Endocrine System - Chapter 20 Flashcards
Do endocrine glands have ducts or no ducts?
Endocrine glands are ductless
What is the function of the endocrine system?
secrete hormones into the bloodstream to bring about homeostasis
In order for hormones to affect a cell or organ what must they have?
a specific receptor for that hormone
What are the 3 major classes of hormones?
- peptide hormones
- steroid hormones
- biogenic amines
peptide hormones are also known as what?
growth hormones
steroid hormones are also known as what?
estrogen hormones
biogenic amines are also known as what?
thyroid hormones
What is the function of a feedback loop?
regulates hormone secretion
What are the 2 types of feedback loops?
negative feedback loop and positive feedback loop
This feedback loop leads to a decrease in a reaction
negative feedback
This feedback loop accelerates the process
positive feedback
What is the function of the hypothalamus?
controls and oversees most endocrine functions
Where is the hypothalamus located?
superior to pituitary gland
The hypothalamus controls endocrine activity in what 3 ways?
- control release of regulatory hormone from anterior pituitary gland
- secrete oxytocin and antidiuretic hormone
- controls stimulation and secretion activities of adrenal medulla
What hypophysis is also known as the what?
pituitary gland
The pituitary land gland is connected to the hypothalamus by what?
infundibulum
What 2 parts is the hypophysis divided into?
anterior and posterior lobes
What anterior pituitary is also known as the what?
adenohypophysis
What are the 3 areas of the adenohypophysis called?
- pars distalis
- pars intermedia
- pars tuberalis
The hypothalamo-hypophyseal portal system does what?
where regulatory hormones travel through a blood vessel
What are the 5 types of anterior pituitary cells?
- somatotrophs
- thyrotrophs
- gonadotrophs
- lactotrophs
- corticotrophs
Human growth hormone (hGH) is secreted what what anterior pituitary cells?
somatotrophs
What does hGH stimulate?
tissues to secrete insulin-like growth factors
What do thyrotrophs secrete?
thyroid-stimulating hormone (TSH)
What does thyroid-stimulating hormone (TSH) do?
controls secretions from thyroid gland
Follicle-stimulating hormone (FSH) and Luteinizing Hormone (LH) is secreted by what?
gonadotrophs
Gonadotrophs stimulates the secrete of what?
estrogen and progesterone
Estrogen and progesterone serves what function? (2)
- maturation of oocytes in ovaries
- stimulate sperm production and secretion of testosterone of testes
Prolactin (PRL) is secreted by which anterior pituitary cell?
lactotrophs
What is the function of PRL (Prolactin)?
initiate milk production in mammary glands
Which hormones do corticotrophs secrete? (2)
Adrenocorticotropic Hormone (ACTH) and Melanocyte-stimulating Hormone (MSH)
What is the function of ACTH?
stimulate adrenal cortex to secrete corticoids
What is the hormone that influences other endocrine glands?
tropic hormone
What does Melanocyte-stimulating Hormone (MSH) stimulat?
synthesis of melanin and distribution of melanocytes
What are the 2 regions of the posterior pituitary called?
- pars nervosa
- infundibular stalk
What is the hypothalamo-hypophyseal tract?
the neural connection between the hypothalamus and posterior pituitary
What is the function of Oxytocin (OT)?
stimulate uterine contraction and milk ejection from mammary glands
Which hormone increases blood pressure via water reabsorption in kidneys and vasocontraction?
Antidiuretic Hormone (ADH)
Largest Gland in endocrine system
Thyroid Gland
The thyroid follicle is composed of which cells?
simple cuboid ells
What do thyroid follicles produce?
thyroglobulin (TGB)
Where are parafollicular cells loctated?
between thyroid follicles
What do parafollicular cells secrete?
calcitonin
What is the function of calcitonin?
regulate serum calcium
where are the parathyroid glands located?
posterior surface on posterior surface of thyroid galnd
What are the 2 types of cells found in parathyroid glands are called what?
chief cells and oxyphil cells
What hormone do chief cells secrete?
parathyroid hormone (PTH)
What is the function of parathyroid hormone (PTH)?
increase blood calcium levels through bone reabsorption
Adrenal glands are also called what?
suprarenal glands
The 2 functional parts of the adrenal gland are named what?
outer adrenal cortex and inner adrenal medulla
What are the 3 distinct layers of the adrenal cortex called?
- zona glomerulosa
- zona fasciculata
- zona reticularis
which layer of the adrenal cortex is the most superficial?
zona glomerulosa
which layer of the adrenal cortex is the most deep?
zona reticularis
This layer of the adrenal cortex is responsible for producing what?
mineralocorticoids (such as aldosterone)
Aldosterone determines how the kidney deals with what?
sodium and potassium
Glucocorticoids are produced what which layer of the adrenal gland?
zona fasciculata
cortisol and corticosterone are the main glucocorticoids, which is their function?
help body deal with physiological distress
What hormone is produced by the zona reticularis?
weak androgens (which are estrogen and testosterone related hormones)
estrogen and testosterone related hormones have what function?
weak sex hormones, until puberty
The inner core of the adrenal gland forms what?
adrenal medulla
The adrenal medulla consist of what cells?
chromaffin cells
What do chromaffin cells secrete?
norepinephrine and epinephrine
The pancreas is both what?
a exocrine gland and endocrine gland
98 - 99% of the pancreatic cells as what?
pancreatic acini
What do pancreatic acini produce?
alkaline pancreatic secretions into ducts
1 - 2% of pancreatic cells are small clusters of endocrine cells called what?
pancreas islets
What is the function of islet cell hormones?
regulate level of blood glucose
The pancreas islet (Islet of Langerhans) is composed of 4 different types of endocrine cells, what are they?
- Alpha cells
- Beta cells
- Delta cells
- F cells
Alpha cells secrete what hormone?
glucagon
Beta cells secrete what hormone?
insulin
Delta cells secrete what hormone?
somatostatin
F cells secrete what hormone?
pancreatic polypeptides
The secretion of glucagon is stimulated by what?
low blood glucose
The secretion of insulin is stimulated by what?
high blood glucose
High nutrient load stimulates the secretion of what hormone?
somatostatin
The secretion of pancreatic polypeptides are stimulated by what?
protein digestion
What is the pineal gland primarily composed of?
pinealocytes
pinealocytes secrete what?
melatonin
What is the function of melatonin?
maintaining 24-hour circadian cycle
Which hormones do the Thymus produce?
thymopoietin and thymosin
What is the function of the thymus in association with the lymphatic system?