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Lab #8: Endocrine System
Terms in this set (80)
The disease diabetes mellitus is caused by either the hyposecretion or the hypoactivity of which hormone?
Diabetes mellitus is caused by a problem with the hormone insulin.
What is the role of insulin?
reduce blood sugar levels
The role of insulin is to reduce blood glucose levels after a meal. Insulin does this by stimulating glucose uptake into cells and stimulating glycogen formation in the liver.
Label Endocrine Organs
How do endocrine hormones reach their target cells?
Hormones are transported through the blood stream to target cells.
The blood stream allows hormones to be distributed throughout the body.
Water-soluble hormones affect target cells by binding to __________.
plasma membrane receptors
Water-soluble hormones bind to specific receptors in the plasma membrane, whereas steroid hormones bind to cytoplasmic receptors.
The magnification of the signal from a water-soluble hormone is achieved through an increase in _______.
cAMP in the cytoplasm
Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.
What is the role of activated protein kinases?
Phosphorylation can activate different proteins causing the response of the cell to water-soluble hormone.
Which of the following enzymes is important in the deactivation of cAMP and termination of signalling?
Phosphodiesterase degrades cyclic AMP into AMP. The increase in cAMP levels is usually short-lived because the enzyme phosphodiesterase is constantly present in the cytoplasm of the target cells.
Which of the following hormones has intracellular receptors?
Yes, cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble
What is the mechanism of action of lipid-soluble hormones?
activation of genes, which increases protein synthesis in the cell
Yes, lipid-soluble hormones diffuse into the nucleus or they diffuse into the cytoplasm and then move into the nucleus, where they affect transcription and translation.
After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?
acts as a transcription factor and binds to DNA, activating a gene
Yes, then mRNA is synthesized. Please note: the animation mistakenly said the mRNA then "transcribes" a protein. If you remember from ANPS19, transcription is when an mRNA molecule is made from a DNA molecule. Translation is the process by which the code from an mRNA molecule is used to produce a protein (on a ribosome). Hormones that act as transcription factors turn on genes in the nucleus, which leads to transcription of mRNA in the nucleus, and the production of new proteins in the cytoplasm.
What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?
chaperone proteins (chaperonins)
Yes, each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site.
Hypothalamus and Pituitary Gland
primary bed capillary
anterior pituitary: (adenohypophysis)
secondary capillary bed
hypohyseal portal veins
Hypothalamus and Pituitary Gland
Which lobe of the pituitary gland is made up of neural tissue instead of glandular tissue?
The pituitary gland is attached to the hypothalamus by a stalk called the
The stalk like structure that suspends the pituitary gland from the hypothalamus is called the infundibulum.
All of the following hormones are released from anterior pituitary cells EXCEPT:
TRH (thyrotropin releasing hormone) is released from the
Adrenocorticotropic hormone (ACTH), also known as corticotropin, stimulates the release of _______________ from the __________________.
cortisol (glucocorticoids); adrenal cortex
Adrenocorticotropic hormone (ACTH) is also known as corticotropin because it stimulates the release of glucocorticoids from the cortex of the adrenal gland. Cortisol is the most abundant glucocorticoid in humans.
GnRH or gonadotropin releasing hormone is released from the hypothalamus and regulates the release of _____________________ from anterior pituitary cells.
FSH and LH (follicle stimulating hormone and luteinizing hormone)
CRH (corticotropin releasing hormone) causes the release of ____________________________ .
ACTH from the anterior pituitary.
Which hormones are released from the posterior pituitary?
oxytocin and vasopressin (ADH)
Where is oxytocin produced?
Oxytocin is produced in the nerve cell bodies of the paraventricular nucleus of the hypothalamus and is transported to the posterior pituitary through the long axons of the hypothalamo-hypophyseal tract, where it is released when needed.
Which hormone is required for the full adult height of the skeleton?
The secretion of which of the following anterior pituitary hormones can be regulated by both a releasing hormone and a release-inhibiting hormone?
growth hormone (GH)
How can you tell the anterior pituitary from the posterior pituitary in a schematic image?
The anterior pituitary image shows two capillary beds connected by portal veins.
Anterior pituitary hormones
Where are the hormones oxytocin and antidiuretic hormone (ADH) stored?
The axon terminals of neurons of the hypothalamic-hypophyseal tracts store and secrete ADH and oxytocin in the capillaries of the inferior hypophyseal artery.
What hormone released into the blood by the posterior pituitary helps to maintain water balance by preventing loss of water in the kidney?
antidiuretic hormone (ADH)
Antidiuretic hormone (ADH) targets the kidneys and modulates how much water is lost in the urine.
Hypersecretion of what hormone can produce the effects of gigantism in the individual in the center of this image?
Growth hormone has effects on metabolism as well as growth. Hypersecretion can lead to gigantism.
What gland secretes growth hormone?
The anterior pituitary secretes a variety of hormones, including growth hormone.
hypothalamic hormones with the pituitary hormone targets
bones & marrow
Prolactin--> mammary glands
Follicle stimulating hormone-->
testes or ovaries
Thyroid stimulating hormone-->
Adrenocorticotropic hormone--> adrenal cortex
Homeostasis -- Regulating Blood Sugar
When blood glucose levels are high
The pancreas releases insulin
The pancreas responds to high blood glucose levels by releasing insulin.
A liver cell responds to insulin by
Taking in glucose and converting it to glycogen.
What cells in the body respond to glucagon by breaking down glycogen and releasing glucose?
Body cells that respond to insulin include
Liver cells, as well as most other cells of the body.
When blood glucose levels are low
The pancreas releases glucagon, which eventually causes blood glucose levels to increase.
The body's tendency to maintain relatively constant internal conditions is called
Homeostasis -- High Blood Glucose
1. blood glucose becomes high
2.pancreas releases insulin
3. insulin binds to receptors on target cells
4.cells take in glucose
5. blood glucose returns to normal
Homeostasis -- Low Blood Glucose
1. low blood glucose
2. cells in the pancreas
4. liver cells
5. glycogen breakdown; glucose released into blood
in_________ diabetes, target cells do not respond normally to insulin.
In _________diabetes, no insulin is produced.
In ___________diabetes, glucose levels remain higher than norm
both type 1 and type 2
what triggers the release of glucagon?
a decrease in blood glucose levels
Glucagon acts to stimulate release of glucose into the blood to counteract falling levels.
The clusters of endocrine cells in the pancreas are known as the pancreatic islets, or Islets of Langerhans. Which is the cell type that secretes insulin?
Beta cells secrete insulin when blood glucose levels are high.
Glucose is stored in the human body as _______.
Which hormone stimulates the breakdown of polymerized glucose (stored glucose)?
Higher than normal levels of glucose in the blood indicates __________________.
type 1 and type 2 diabetes mellitus
Excess glucose can be found in the urine _______.
when the transport maximum for reabsorption in the kidney tubules is exceeded, as a result of type 1 diabetes or as a result of type 2 diabetes
In this experiment, what was the purpose of the glucose standard curve?
It provides a point of reference to convert optical density readings to glucose readings.
In this experiment, optical density is measured using a
Using this assay, glucose concentration is ________________________.
directly proportional to optical density
According to the experimental results, FPG (Fasting Plasma Glucose) levels between 110 and 126 mg/dl indicate
impairment or borderline impairment of insulin-mediated glucose uptake by cells.
what was the purpose of adding heparin to the test tube?
to prevent blood clots
Identify the pancreas.
The pancreas occupies a retroperitoneal position partially behind the stomach.
All of the following are secreted from the thyroid gland EXCEPT
Which cells produce thyroid hormone (TH)?
All of the following are roles of thyroid hormone EXCEPT:
stimulating storage of glucose
Which cells release calcium from bone?
Where are the parathyroid glands located?
In the neck, on the posterior surface of the thyroid gland
Which hormone is the MOST important for regulating blood calcium levels?
Parathyroid hormone (PTH)
Parathyroid hormone (PTH) increases blood calcium levels by all of the following EXCEPT:
inhibits the activity of osteoclasts and the activity of calcitriol
What stops parathyroid hormone secretion?
blood calcium levels increase
Identify the thyroid gland.
The thyroid gland is located in the lower anterior throat superficial to the trachea at the level of the cricoid cartilage.
What is the target organ of thyroid hormones' metabolic effects?
cells of the body
Thyroid hormones secreted by the thyroid gland target cells of the body to modulate metabolism.
The adrenal gland(s) is/are located
attached to the superior pole of the kidneys.
The outer part of the adrenal gland is called the adrenal cortex. The cells of the adrenal cortex are arranged into three zones that secrete steroid hormones called corticosteroid hormones or corticosterones. All of the following hormones are secreted from the adrenal cortex EXCEPT:
the catecholamines, epinephrine and norepinephrine
What is the role of the mineralocorticoid aldosterone?
It regulates electrolyte balance by causing sodium retention in the kidney.
Cells of the zona fasciculata and zona reticularis secrete
the glucocorticoid cortisol.
A major role of cortisol is to
regulate the immune system and facilitate the stress response.
What is secreted from the adrenal medulla?
the catecholamines epinephrine and norepinephrine
What is the role of the adrenal medulla?
It facilitates the sympathetic nervous system "fight and flight" response.
Which of these glands is responsible for regulating minerals in the body but is also part of the sympathetic division of the autonomic nervous system?
The adrenal glands have a medulla that contains postganglionic neurons of the sympathetic division of the autonomic nervous system. Its cortex helps regulates mineral levels in the body, along with other functions.
The size and shape of a pea; produces hormones that stimulate other endocrine glands.
Pituitary gland (hypophysis)
Is part of the sympathetic nervous system.
Produces hormones that regulate glucose levels in the body.
Primary regulators of blood calcium levels
Produces the body's major metabolic hormones.
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