Exam 3 Flashcards
● Some mediators can be both a neurotransmitter and
a hormone
Norepinephrine
Epinephrine
Oxytocin
Explain Oxytocin as a neurotransmitter and hormone
Neurotransmitter: released throughout the brain and
expressed by neurons
Hormone: released from the pituitary gland into blood,
acting on breast and uterine tissue
Secrete hormones into interstitial fluid and blood surrounding the secretory cells (TSH for example)
ENDO- “Within”
Secrete their product into ducts that release into body cavities, lumen of organs, or to outer surface (skin) Sudoriferous (sweat), sebaceous (oil), mucous, salivary, mammary, ceruminous, lacrimal
EXO- “Outside”
Hormone Receptors are ____ (composition)
cellular proteins
Occurs when too much hormone present
Reduction of receptors means less sensitivity to the circulating hormone
If not enough receptors, some of the hormone will get metabolized unused…not as effective
Receptor Down-regulation
Occurs when not enough hormone present Increase of receptors means more sensitivity to the circulating hormone
If more receptors present, better chance at all of the circulating hormone being used
Receptor Up-regulation
Endocrine Action
● The hormone is distributed in blood and binds to distant target cells (most, but not all hormones)
● Example: _____ pituitary releases thyroid stimulating hormone (TSH) which binds to receptors on cells of the thyroid as no other cells in the body should have receptors for this hormone
Anterior
Circulating vs Local Hormones
● Circulating hormones (the majority) – pass from secretory cells to the interstitial fluid into the blood stream
● Local hormones- act on a neighboring cell or the same cell without entering the bloodstream
(the majority) – pass from secretory cells to the interstitial fluid into the blood stream
● Circulating hormones
- act on a neighboring cell or the same cell without entering the bloodstream
● Local hormones
the majority of hormones are circulating or local?
circulating
hormones that act on neighboring cells
hormones that act on same cell
Paracrines
Autocrines
hormones that act on neighboring cells
Paracrines-
hormones that act on same cell
Autocrines-
– tend to linger in blood stream minutes to hours
Circulating hormones
Local hormones act….
quickly
Lipid-soluble hormones: Most use….
transport proteins (synthesized in the liver)
Lipid-soluble hormones: Most use transport proteins (synthesized in the liver)
Make the hormone temporarily ______
Retard the passage of smaller hormone molecules through the kidney filter therefore _______
water-soluble
reducing the amount lost in urine
Lipid-soluble hormones: Most use transport proteins (synthesized in the liver)
Provide a ready reserve of hormone in the bloodstream or free fraction which is:
Free fraction- 0.1-10% are not bound to a transport protein;
these diffuse from capillaries, bind to receptors immediately
transported in their free (unbound) form in blood
Water-soluble hormones
Control of Hormone Secretion
● Regulated by
Signals from nervous system
Ex: Nerve impulses to adrenal medullae regulate release of epinephrine
Chemical changes in the blood
Ex: Blood Ca2+ level regulates secretion of parathyroid hormone
Other hormones
Ex: Release of a hormone (ACTH) from the anterior
pituitary stimulates release of cortisol by adrenal cortex
Control of Hormone Secretion
● Regulated by
Signals from nervous system
Chemical changes in the blood
Other hormones
Reverses a change in the controlled condition
Hormone “A” secreted by anterior pituitary
Blood levels of hormone “A” increase
Sends signal to anterior pituitary to stop/slow production of Hormone “A”
Negative Feedback
Strengthens or reinforces the change in the controlled condition
EX:
Oxytocin causes uterine contractions
Uterine contractions cause oxytocin to be released
Positive Feedback
Types of Hormones
● Divided into three major groups based on chemical
structure
Proteins and Polypeptide hormones
Steroid hormones
Tyrosine derivative hormones
Types of hormones Divided into three major groups based on…
chemical structure (in this class)
Numerous other ways to classify hormones though
By solubility
By gland
By function
The majority of the hormones in the body fall into this
category
Proteins and Polypeptides
Proteins and Polypeptides are made from
the joining of three or more amino acids
100+ amino acids joined together
EX’s:
Human Growth Hormone
Prolactin
Protein
3-99 amino acids joined together
Ex’s:
Thyrotropin releasing hormone
Polypeptides
Are all water soluble
Can travel unbound in blood
Finds their receptors on the cell membrane
Proteins and Polypeptides
Refer to slide 28, 29, and 30 of the ppt
stellar
Cholesterol Hormones are known as….
steroid hormones
● Derived from cholesterol
● Very little concentration of these are stored
Steroid Hormones
____ are lipid-soluble
Have to be bound to transport proteins while in blood (because blood is water-based)
Can freely pass through cell membrane
Binds to receptors on the inside of the cell
Steroid hormones
Promotes development of male reproductive system and male secondary sex characteristics
Testosterone from testes
Promotes growth and development of female reproductive system, female breasts, female secondary sex characteristics
Estrogen
Helps to produce “uterine milk” that nourishes growing embryo, helps develop secretory apparatus of breast
Progesterone
ovary hormones
estrogen and progesterone
adrenal cortex hormones
cortisol and aldosterone
kidney hormone
calcitrol
● Derived from some form of tyrosine (amino acid)
Thyroid hormones
Triiodothyroinine (T3)
Thyroxine (T4)
Adrenal medullary hormones (catecholamines)
Epinephrine
Norepinephrine
Prolactin Inhibiting Hormone (PIH)
Also known as dopamine
Tyrosine Derivative Hormones
Tyrosine Derivative Hormones
thyroid hormones
adrenal medullary hormones (catecholamines)
Prolactin Inhibiting Hormone (PIH) also known as
dopamine
dopamine other name
Prolactin Inhibiting Hormone (PIH)
Name all of the Tyrosine Hormones then look at page 36 of the PDF
Good little nerd
Controls the autonomic nervous system through neural and hormonal approaches
Hypothalamus
Location of Hypothalamus:
anterior and inferior to the thalamus
Hypothalamus Connected to the posterior pituitary gland by the….
infundibular stalk (axons)
There is a partial sheath that wraps up the infundibular stalk from the anterior pituitary gland called the
pars tuberalis
These two things entwined become the infundibulum
Pars tuberalis and the infundibular stalk
Every hormone synthesized in the hypothalamus is
transported to the pituitary gland where it will either __ or __?
Be stored (ADH, oxytocin)
Cause another hormone to be synthesized
Hypothalamus + Pituitary gland =
regulation of growth, development, metabolism, and homeostasis
Hypothalamus Responds to signals from internal AND external environment like…
Temperature, hunger, satiety, blood pressure, levels of hormones, stress
Controls daily bodily rhythms such as melatonin secretion
from pineal gland, cortisol secretion, body temperature
Hypothalamus
Collects and combines information from the body and makes changes to correct any imbalances
Hypothalamus
Hypothalamic Hormones are Those that have action on the…
and those that get stored in the …
Anterior Pituitary Gland
Posterior Pituitary Gland
Anterior (APG) think
action
Posterior (PPG) think
storage
From hypothalamus to anterior pituitary gland
Hormones produced in hypothalamus, placed into pituitary portal system (capillaries), transported via portal system down to anterior pituitary gland
Once at anterior pituitary gland, these hormones….
CAUSE other hormones to be synthesized in the anterior pituitary
- These hormones are metabolized once their message is received at the anterior pituitary
- Made in small quantities, made only at the request of the body and its feedback systems
Hypothalamic Releasing Hormones Function is to…
STIMULATE release of particular anterior pituitary hormones
Hypothalamic Releasing Hormones include:
● GHRH: growth hormone-releasing hormone ● TRH: thyrotropin-releasing hormone ● CRH: corticotropin-releasing hormone ● GnRH: gonadotropin-releasing hormone ● PRH: prolactin-releasing hormone
Hypothalamic Inhibiting Hormones
● Function is to….
INHIBIT release of particular anterior pituitary hormones
● Hypothalamic inhibiting hormones include:
● GHIH: growth hormone-inhibiting hormone AKA somatostatin
● PIH: prolactin-inhibiting hormone
AKA dopamine
another name for somatostatin
GHIH or growth hormone-inhibiting hormone
another name for dopamine
PIH or prolactin-inhibiting hormone
Transport to Posterior Pituitary Gland is From hypothalamus to posterior pituitary gland. Where are these hormones produced vs stored?
Hormones produced in hypothalamus, but stored in the posterior pituitary gland
Posterior Pituitary Glan hormones Once produced, these hormones are sent via ____ from the hypothalamus down through the ______, into the posterior pituitary gland, where they are stored for future use
axons
infundibular stalk
Examples of Hormones synthesized in the hypothalamus but stored in the posterior pituitary gland
● Oxytocin
● Antidiuretic hormone (ADH/Vasopressin)
The Pituitary Gland (aka: _____)
hypophysis
The Pituitary Gland
● A small, pea-sized endocrine gland located within the
sella turcica of the sphenoid bone
sella turcica of the sphenoid bone holds the
pituitary gland
Posterior pituitary gland is connected to the hypothalamus
via the
infundibular stalk
Has two separate glandular portions, one intermediate
portion
pituitary gland
Anterior pituitary
AKA: _______
adenohypophysis or pars distalis
Posterior pituitary
AKA: ________
neurohypophysis or pars nervosa
neurohypophysis or pars nervosa aka…
Posterior pituitary
adenohypophysis or pars distalis aka….
Anterior pituitary
comprises ~ 75% of the total weight of the pituitary gland
The anterior segment of the pituitary gland\
The anterior segment of the pituitary gland is composed of:
Pars distalis: glandular tissue (the largest portion)
Pars tuberalis: partially covers the infundibulum (like a sheath)
when you see Pars tuberalis think….
Anterior pituitary gland
● The anterior pituitary gland produces ____ from 5 specific cell types within the gland
tropic hormones
● Once anterior pituitary hormones are synthesized they are….
released into general circulation (venous)
● Four of the tropic hormones released from the anterior
pituitary gland exert their effect on another endocrine gland… the exception is?
-The exception to this is human growth hormone as it acts directly on almost all tissues found in the body, not a particular gland
HGH (somatotropin) secreted by these cells
Somatotrophs
TSH (thyrotropin) secreted by these cells
Thyrotrophs
FSH and LH secreted by these cells
Gonadotrophs
PRL (prolactin) secreted by these cells
Lactotrophs
ACTH (corticotropin) secreted by these cells
Corticotrophs
MSH (melanocyte) secreted by these cells
Corticotrophs
Hormones made in the anterior pituitary
GOLF TAMPA - ADH and OXY
Also known as somatotropin
Human Growth Hormone (hGH)
Most abundant anterior pituitary hormone
Human Growth Hormone (hGH)
Secreted by somatotrophic cells (most abundant cell)
Usually secreted in bursts every few hours
Human Growth Hormone (hGH)
Starts to decline production after adolescence
Found to be approximately 25% production after age of 70
Human Growth Hormone (hGH)
Is produced and released in a pulsatile manner
Characteristic increase during the first two hours of deep sleep
Human Growth Hormone (hGH)
increases during first TWO HOURS of DEEP SLEEP
Human Growth Hormone (hGH)
Main function is to promote synthesis and secretion of
small protein hormones called Insulin-like Growth Factors (IGF’s; also known as somatomedins)
Human Growth Hormone (hGH)
somatomedin also known as….
Insulin-like Growth Factors (IGF’s; also known as somatomedins)
In response to hGH, cells in the liver, skeletal muscle, cartilage, bones synthesize and secrete _____
Enters bloodstream via the liver or may act locally as autocrines or paracrines
IGF’s
It is believed that all of the changes seen in the body are due to the presence of these IGF’s, not hGH directly
This means that…
someone can have a normal hGH level but if there is a deficiency in the production of IGF’s, they will have some abnormalities
IGF’s
Increases protein synthesis
-Increases uptake of amino acids into cells
Decreases protein catabolism
-Decreases breakdown of proteins by limiting use of amino acids for ATP production and instead uses free-fatty acids
Stimulates growth in childhood
-Especially of bone, and muscle
Enhances lipolysis (break down of adipose tissue) - Releases free-fatty acids (FFA’s) into the bloodstream for use as a source of energy in cells rather than glucose
Tis True
Increases protein synthesis Decreases protein catabolism Stimulates growth in childhood Enhances lipolysis (break down of adipose tissue) Influences carbohydrate metabolism
Insulin-like Growth Factors (IGF’s; also known as somatomedins)
Insulin-like Growth Factors (IGF’s; also known as somatomedins)
Influences carbohydrate metabolism by…
Decreasing glucose uptake into the cells (leaving it in the blood for neurons) & increase glycogenolysis
explain the decreasing glucose….
Decreases glucose uptake into cells (to an extent), leaving it in the bloodstream readily available for neurons to use (if needed)
With increased FFA’s, cells will use these as their main energy source
Insulin-like Growth Factors (IGF’s; also known as somatomedins)
Influences carbohydrate metabolism by…
Decreasing glucose uptake into the cells (leaving it in the blood for neurons) & increase glycogenolysis
explain glycogenolysis
Also stimulates the liver to release glucose (glycogenolysis) into the blood if serum levels are low (hypoglycemia)
IGF’s attempt to keep glucose available for neurons at all times during states of hypoglycemia
While doing this, they mobilize glucose stores from liver to increase blood glucose levels
Insulin secreted in abundance in high blood glucose situations
IGF’s produced and secreted in abundance in low blood glucose situations and -This starts a chain reaction to release more glucose in blood stream from various methods
Insulin-like Growth Factors (IGF’s; also known as somatomedins)
_____ stimulates GHRH secretion and inhibits GHIH secretion (hypothalamus) resulting in
Hypoglycemia
Anterior pituitary increases secretion of hGH resulting in increased IGF concentration
-Carbohydrate metabolism and liver glycogenolysis increase blood glucose
Hyperglycemia does the opposite of hypoglycemia because it Stimulates the hypothalamus to secrete
Reduced levels of hGH result which also reduces the IGF action… this causes?
GHIH
– plasma glucose levels reduce because the IGF’s are no longer working to keep integral glucose in the blood stream for neurons (there is enough already there)
Factors that stimulate hGH secretion: name all 9
come up with mnemonic
Hypoglycemia
Sympathetic nervous system stimulation (stress, strenuous exercise)
Deep sleep
Decreased serum fatty acids
Increased serum amino acids
Starvation/fasting or protein deficiency
Increased levels of:
- Testosterone
- Estrogen
- Ghrelin – hormone secreted by stomach right before meals
Factors that inhibit hGH secretion: name all 9
Hyperglycemia
Increased serum fatty acids
Decreased serum amino acids
Emotional deprivation
Obesity
When plasma T3 and T4 levels are low (thyroid)
hGH (somatotropin) itself (negative feedback)
GHIH (somatostatin)
Aging
Describe hypoglycemia’s effect on the body followed by hyperglycemia’s… look at ppt slide 70 image
draw it out on the board to reinforce
ACTH stands for…
Adrenocorticotropic Hormone
ACTH (Adrenocorticotropic Hormone ) Secretion is stimulated by:
Corticotropin-releasing hormone (CRH) from hypothalamus which is usually induced by:
Stress-related stimuli:
- Low blood glucose
- Physical trauma
ACTH controls production of ____, other glucocorticoids and certain _____ produced by
the cortex of adrenal glands
cortisol
androgens
(PRL) stands for
Prolactin
Prolactin (PRL)
Secretion is controlled by:
● Prolactin-releasing hormone (PRH)
● Prolactin-inhibiting hormone (PIH) (AKA
dopamine)
(PRH) stands for
● Prolactin-releasing hormone
Prolactin-inhibiting hormone (PIH) AKA….
dopamine
prolactin helps cause two things:
These together cause milk production in pregnant women
Ejection of milk is caused by oxytocin (posterior pituitary)
Low levels of estrogen and progesterone just prior to
menstruation inhibits secretion of ____ and
stimulates _____ secretion (this likely accounts for
breast tenderness at this time)
PIH (dopamine); prolactin
During the rest of the female cycle: as _____ secretion
increases, ______ secretion increases
estrogen increases
PIH (dopamine) increases
Prolactin secretion is reduced at this point
Prolactin Hypersecretion Is most commonly caused by a
prolactinoma (a benign pituitary adenoma)
Consider this diagnosis if a non-pregnant, non- breastfeeding female complains of a milky breast discharge
Consider this diagnosis in a male with erectile dysfunction with no obvious cause (older, HTN, obese) or a male with milky breast discharge
When you hear thyroid hormones in this class think….
T3 / T4
iodide issue not making
T3 / T4
peroxidase issue… not making iodide to iodine so no
T3 / T4
thyroglobulin (TGB) is…
the glue that binds the MIT, DIT, T3, and T4
resorption vs reabsorption is PROBABLY on the test
watch out for these key words and differentiate between on the exam
FSH
Follicle Stimulating Hormone
Gonadotropin-Releasing Hormone (GnRH) from the
hypothalamus stimulates the anterior pituitary to secrete
FSH
___ initiates follicle production in women monthly
& Also stimulates ovarian follicular cells to produce estrogen
& stimulates production of sperm cells in me
FSH
FSH is inhibited by negative feedback, seen as
increased serum levels of estrogen (females)
Increased serum levels of testosterone (males)
LH
Luteinizing Hormone
Gonadotropin-Releasing Hormone (GnRH) from the
hypothalamus stimulates the anterior pituitary to secrete _____
LH
What stimulates the AP to secrete LH?
Gonadotropin-Releasing Hormone (GnRH) from the
hypothalamus
What stimulates the AP to secrete FSH?
Gonadotropin-Releasing Hormone (GnRH) from the
hypothalamus
_____ triggers ovulation in women as well as formation of the corpus luteum and therefore the secretion of progesterone by the corpus luteum… also with FSH stimulates release of estrogen by follicular cells
LH
With FSH, LH triggers secretion of estrogen by ovarian
follicular cells
LH stimulates cells in the testes to produce and secrete
testosterone in male… T or F
True
● Collective name for group of peptide hormones produced in the skin, the anterior pituitary and other parts of the brain
● Dopamine (PIH) inhibits MSH release from anterior
pituitary only
Melanocyte Stimulating Hormones
● In humans, MSH is involved with:
- Pigmentation of skin cells (i.e. increased melanin causing tanned skin) (This MSH is made locally in the skin)
- Possible suppression of appetite
Melanocyte Stimulating Hormones
______ inhibits MSH release from anterior
pituitary only
Dopamine (PIH)
TSH
Thyroid Stimulating Hormone
Release of _____ from the hypothalamus stimulates the release of Thyroid Stimulating Hormone (TSH) from the anterior pituitary
Thyrotropin Releasing Hormone (TRH)
TRH is inhibited by increased levels of ____ in the bloodstream which when reduced, causes a reduced amount of TSH to be produced in the anterior pituitary
T3 and T4; This reduction in TRH and subsequently TSH reduces the amount of T3/T4 to be made
(negative feedback loop)
Posterior Pituitary aka…
neurohypophysis