Hormones Flashcards
1
Q
What is the Endocrine System?
A
The Endocrine system facilitates the regulation and communication of the body through chemicals called hormones.
Endocrine glands secrete hormones, which travel through the body fluids such as the blood and act on specific target cells in various parts of the body to change their function
2
Q
How does an Endocrine Gland deliver its hormones to its target cell?
A
Endocrine glands have no ducts, so they release hormones directly into the bloodstream where they are delivered to their target destination
3
Q
What are the three main types of hormones?
A
- Steroids hormones
- Polypeptide hormones
- Amine Hormones
4
Q
What is a steroid hormone?
A
- NB: Synthesized from Cholesterol (Common Test Question)
- Examples:
- Estrogen
- Androgens (Such as Testosterone)
- Progesterone
- Cortisol
- Cortisone
- Aldosterone
- They are lipid soluble, so they can travel through the cell membrane to bind to receptors. (may be nuclear receptors depending on the steroid)
5
Q
What is a Polypeptide hormone?
A
- Composed of Amino Acids. (Contain C, H, O, N, S)
- Examples:
- Insulin
- Amino Acids can be aromatic, acidic, basic, polar, or nonpolar depending on the R group.
- Can be H20 or Lipid soluble depending on the R group
6
Q
How do you calculate the mass of an amino acid residue?
A
110 D is the average weight of a single amino acid in all the naturally occurring amino acid residues based on their frequency.
Remember that H20 is lost in the formation of a peptide bond, this is taken into account in the averaging.
Take 110 D * the number of amino acids in the residue to get the approximate weight of the polypeptide.
7
Q
Describe the hormone’s journey to the cell
A
The hormone is secreted from the endocrine gland into the blood stream.
The hormone travels through the blood to its target site
The hormone either binds to a receptor on the cell membrane if it’s H20 soluble, or it passes through the cell membrane and binds to a receptor within the cell either in the cytoplasm or the nucleus.
The hormone likely enters the nucleus regardless of solubility
In the nucleus, activation of mRNA synthesis occurs.
mRNA then goes into the cytoplasm to make proteins.
The whole receptor process is often called a biological cascade. This refers to a series of chemical reactions that occur from the binding of a hormone to a receptor.
8
Q
Where do H20 soluble hormones bind on their target cell? What types of hormones are H20 soluble?
A
They bind to a receptor on the cell membrane and then are often brought into the nucleus.
Amine Hormones and some polypeptide hormones are H20 soluble
9
Q
Where do lipid soluble hormones bind on their target cell? What types of hormones are lipid soluble?
A
Lipid soluble hormones pass through the cell membrane and bind to a receptor within the cytoplasm or within the nucleus. Most end up in the nucleus regardless of where they bind.
All Steroid hormones are lipid soluble, and some poplypeptide hormones (hydrophobic)
10
Q
What is an Amine Hormone?
A
- Amine Hormones are called Catecholamines
- They are made from the amino acid tyrosine.
- They are H20 soluble
- A catechol is a benzene ring with two hydroxy groups on it.
- Examples:
- Dopamine
- Epinephrine (adrenaline)
- Norepinephrine (noradrenaline)
11
Q
Describe the hypothalamus and what non-tropic hormones it makes?
A
- The Hypothalamus is the link between the nervous system and the endocrine system
- It’s located in the brain
- Makes:
- Oxytocin
- ADH (vasopressin)
- These two hormones travel along special axons to be stored in the posterior pituitary gland, and will be released from here.
12
Q
What is Oxytocin?
A
Oxytocin is a hormone created in the hypothalamus and stored in the posterior pituitary gland.
Oxytocin stimulates milk secretion and stimulates contractions in the uterus. It also stimulates feelings of emotional connection.
13
Q
What is ADH?
A
ADH (vasopressin) is a hormone created in the hypothalamus and stored in the posterior pituitary
It is an antidiuretic hormone. It is involved with H20 retention in the kidneys. This hormone helps maintain blood volume by retaining water if there is blood loss.
14
Q
Describe the positive feedback loop of oxytocin
A
The more a baby sucks milk from the mammary glands, the more oxytocin is released to stimulate milk secretion.
15
Q
What are tropic hormones?
A
Tropic hormones are hormones that stimulate other endocrine glands to release their hormones.
16
Q
What are the hormones released from the Anterior Pituitary Gland?
A
Tropic Hormones
- Growth Hormone (Somatotropin)
- FSH (Follicle Stimulating Hormone)
- LH (Leuteinizing Hormone)
- TSH (Thyroid Stimulating Hormone)
- ACTH (Adrenocorticotropic Hormone)
Non-Tropic Hormones
- Prolactin
- MSH (Melanocyte-Stimulating Hormone)
17
Q
What is the function of Growth Hormone?
A
- It is a tropic hormone released from the anterior pituitary
- Also known as somatotropin
- Growth Hormone is involved with stimulation of bone growth.
- Increases DNA, RNA, and protein synthesis
- Stimulates the liver to release IGFs (Insulin growth factors) which allow for bone and cartilage growth
- Increases blood sugar
- Abnormal amounts can result in hypersecretion (giantism) or hyposecretion (dwarfism)
- If done before puberty Growth hormone therapy can be used to treat dwarfism
18
Q
What is the function of FSH?
A
Follicle Stimulating Hormone
- It is a tropic hormone released from the anterior pituitary
- Ovarian follicle in women
- Spermatogenesis in men
19
Q
What is the function of LH?
A
Luteinizing hormone
- It is a tropic hormone released from the anterior pituitary
- Stimulates ovulation
- progesterone secretion
- corpus luteum formation in women in the ovary,
- stimulates testosterone secretion in men
20
Q
What is the corpus luteum
A
- The corpus luteum is a mass of cells that forms in the ovary during the menstruation cycle.
- The mass of cells is an endocrine gland that secretes progesterone.
- The Progesterone induces changes in the uterus that makes it suitable for the implanting of an embryo
21
Q
What is the function of TSH?
A
Thyroid Stimulating Hormone
- It is a tropic hormone released from the anterior pituitary
- Will stimulate the thyroid gland to make and release hormones
22
Q
What is the function of ACTH?
A
Adrenocorticotropic Hormone
- It is a tropic hormone released from the anterior pituitary
- Will stimulate the adrenal cortex to secrete glucocorticoids (steroid hormones) such as cortisol
23
Q
What is the adrenal cortex?
A
- The adrenal cortex is the outer portion of the adrenal gland.
- The adrenal gland is located on top of the kidneys
24
Q
What is prolactin?
A
- Prolactin is a non-tropic hormone released from the anterior pituitary gland
- Stimulates mammary gland growth and milk production in mammals
- Has cytokine-like functions involved in the immune system
- Acts as a growth factor
- In fish, it controls water and salt balance
25
What is MSH?
Melanocyte Stimulating Hormone is a non-tropic hormone released from the anterior pituitary gland
- Regulates the function of melanocytes, involved with skin, hair, eyes, etc.
- Pigmentation in humans, reptiles, amphibians, and fish
- Can suppress appetite in humans by binding to receptors in the hypothalamus
26
What is Leptin?
Leptin is a hormone made by adipose cells that acts in appetite suppression
27
What is the thyroid gland?
- The thyroid gland has two lobes on the ventral side of the trachea
- produces thyroid hormone, which is really two hormones
* T3 (Triiodothyronine) - has 3 iodine atoms
* T4 (Thyroxine) - has 4 iodine atoms
28
What are T3 and T4?
- T3 (triiodothyronine) and T4 (thyroxine) are thyroid hormones.
- They bind to the same receptor
- T4 is more abundant
- These hormones are involved in
* Growth,
* Cell Differentiation,
* Control of O2 Consumption
* Basal Metabolic Rate
29
What is hyperthoyroidism?
Hyperthyroidism is too much T3 and T4 production. It results in:
- increase in metabolism
- weight loss
- profuse sweating
- high blood pressure
- irritability
Graves disease is the most common form of hyperthyroidism
30
What is Graves disease?
Graves disease is the most common form of hyperthyroidism.
It's an autoimmune disease that often has patient's eyes protruding
31
What is hypothyroidism?
```
Hypothyroidism is too little T3 and T4 hormone
Results in:
- Feeling cold
- Gaining weight
- Feeling tired all the time
```
The body tries to compensate for this by increasing TSH from the anterior pituitary gland. It attempts to entice the thyroid to make more thyroid hormone. This is not good. Constant TSH causes the thyroid to enlarge creating a goiter.
32
What is Myxedema
Myxedema is a severe case of hypothyroidism
In myxedema we see swelling of the face, lips, eyelids, and even tongue. Heart rate and blood pressure are often quite low.
33
What is Cretinism?
Cretinism is an extreme form of hypothyroidism in fetal life through adulthood.
Mental retardation and growth failure are noted
34
What is Hashimoto's disease?
Hashimoto's disease is an autoimmune disease.
- It is the most common cause of hypothyroidism.
- It is most prevalent in middle-aged women
- Untreated Hashimotos can result in:
* Myxedema
* Heart Problems
* Goiter
* Depression
35
What is Calcitonin?
Calcitonin is a thyroid hormone that "tones down" or lowers blood calcium.
- Ca++ reabsorption by the kidneys is lessened
- inhibits osteoclast activity and promotes bone formation by osteoblasts, decreasing Ca++ levels as bones are formed.
36
What is the parathyroid gland?
The parathyroid gland is four lobes located on the posterior of the thyroid.
- It secretes PTH (parathyroid hormone)
37
What is PTH?
Parathyroid Hormone is secreted from the parathyroid
It causes:
- an increase in blood calcium concentration
It influences 3 organ types:
- Bone: Indirectly causes Osteoclast activity to increase and Osteoblast activity to decrease
- Kidney: reabsorption of Ca++ increases. Some kidney cells release an enzyme that allows Vitamin D to be activated
- Intestine: The intestine uses the activated Vitamin D to absorb Ca++ from food.
38
What happens if you don't have enough Vitamin D?
Without enough Vitamin D, the body is not allowed to absorb enough calcium or phosphorus, thus bone development is retarded.
In children the pathology is called rickets
39
What occurs in hypoparathyroidism?
In hypoparathyroidism, calcium concentrations are low
Tetany often occurs. We see sporadic contractions of skeletal muscles and generalized convulsions
40
What occurs in hyperparathyroidism?
In hyperparathyroidism, blood calcium concentration is high, and can cause damage to organs such as kidney and arteries
41
What is the pancreas?
The pancreas is a gland that is both endocrine (ductless) and exocrine (has ducts, secretes enzymes)
Contains Alpha and Beta cells
- Alpha Cells (20%): Secrete Glucagon which causes glycogen breakdown, hence blood sugar rises.
- Beta Cells (70%): Secrete Insulin which lowers blood sugar, as well as enhancing the synthesis of fats and proteins, and transport of amino acids
- Delta Cells (10%): Secrete Somatostatin which is an inhibitory hormone that inhibits the secretion of insulin and glucagon.
42
What is Glucagon?
Glucagon is a hormone secreted from the alpha cells in the pancreas
- It increases blood sugar levels by inducing the breakdown of glycogen
43
What is Insulin?
Insulin is a hormone secreted from the beta cells in the pancreas
- It decreased blood sugar levels by pulling the glucose into glycogen
- It also enhances the synthesis of fats and proteins, and the transport of amino acids.
44
What is Somatostatin?
Somatostatin is an inhibitory hormone that inhibits the secretion of insulin and glucagon in the pancreas
45
What are the islets of langerhans?
The islets of langerhans are clusters of alpha, beta, and delta cells in the pancreas that make up the endocrine portion of the pancreas (only about 2% of the total mass of the pancreas)
46
Other than produce hormones, what else does the pancreas do?
The Pancreas makes digestive enzymes (proteases, amylases, and lipases), in addition to bicarbonate ion (HCO3-) secretion.
47
What is diabetes mellitus?
Diabetes mellitus is an insulin deficiency that prevents glucose from being imported into cells.
Glucose is instead peed out.
48
What is type I diabetes?
Type I diabetes is an autoimmune disorder.
Beta cells are destroyed by white blood cells.
Insulin is injected manually to control blood sugar levels
49
What is type II diabetes?
Type II diabetes is a cell resistance to insulin.
Insulin levels are close to normal, but the target cells fail to respond normally to insulin, thus glucose uptake is compromised.
Obesity, Age, lack of exercise, are all contributing factors.
Top 10 leading cause of death in USA. The exact cause is unknown.
50
What are the adrenal glands?
The adrenal glands sit on top of your kidneys and consist of an outer portion (adrenal cortex) and a central portion (adrenal medulla).
- Like the pituitary gland, this gland also has endocrine and neuroendocrine functions.
51
What is the Adrenal Medulla?
The Adrenal medulla is the central portion of the adrenal gland. It produces the catecholamines:
- Epinephrine (80%)
- Norepinephrine (20%)
52
What are epinephrine and norepinephrine?
Epinephrine and Norepinephrine are catecholamine hormones produced by the adrenal medulla
- Differ in one CH3 group
- The two hormones are involved in short-term stress responses such as increased blood pressure, increased heart rate, increased glycogenolysis, and increased metabolic rate
- Norepinephrine is released continuously and epinephrine is released when the body is stressed
Catecholamines can either dilate or constrict blood vessels
- Dilation: Blood is increased to areas of the heart, brain, and skeletal muscles
- Constriction: Blood is decreased to areas such as skin, kidneys, and digestive organs (constriction)
53
What is the Adrenal Cortex?
The Adrenal Cortex is the outer portion of the adrenal gland located on top of the kidneys. It has three layers:
- Zona Glomerulosa: Produces mineralocorticoids
- Zona Fasiculata: Produces glucocorticoids
- Zona Reticularis: Produces androgens
54
What is a glucocorticoid?
A glucocorticoid is a type of hormone produced in the zona glomerulosa of the adrenal cortex of the adrenal gland.
There are two types of glucocorticoids:
- Cortisol
- Corticosterone
Glucocorticoids raise the glucose levels of the blood by:
- Stimulating gluconeogenesis particularly in the liver. Glucose is made from amino acids and glycerol
- Fatty acid breakdown for energy production
- Causing breakdown of skeletal muscle where the amino acids are made into glucose when needed
They can be used as an anti-inflammatory agent to treat things like arthritis
55
What is Cushing Syndrome?
Cushing syndrome is too much cortisol
56
What is Addison's disease?
Addison's disease is too little cortisol
57
What is Aldosterone?
Aldosterone is a mineralcorticoid hormone produced by the zona fasciculata in the adrenal cortex of the adrenal gland.
Aldosterone stimulates kidney cells to reabsorb sodium along with water. This increases blood volume, hence increases blood pressure.
58
What are gonads?
Gonads are sex organs in males and females that secrete sex hormones and gametes.
Males: Testes
Females: Ovaries
The gonads secrete three different types of sex hormones:
- Estrogens
- Progestins
- Androgens
59
What are Estrogens?
Estrogens are a type of hormone produced by the gonads.
There function is:
- Development of female sex characteristics
- Growth
- Egg cell maturation,
- Preparing the Uterus for pregnancy and its maintenance
60
What is Estradiol?
Estradiol is a type of estrogen.
- It controls the way fat is distributed in females
- triggers the luteal surge to release an egg (2° oocyte)
Females: Made in the ovaries
Males: Made in the testes and adrenals (In much lower amounts than in women)
61
What are progestins?
Progestins include progesterone
- Involved with preparing and maintaining the uterus for pregnancy.
- Directly effects breast development in the female.
- Regulates mucus produced by the glands of the uterine cervix
62
What are Androgens?
Androgens include the male sex hormone testosterone
- Male secondary sex characteristics
- Muscle building
- Sperm formation
- Growth and development
63
What Tropic Hormones does the Hypothalamus create?
The Hypothalamus creates the following Tropic hormones:
- GnRH (Gonadotropin-releasing hormone): Stimulates the release of FSH and LH from the anterior pituitary gland
- Thyrotropin-releasing hormone: stimulates TSH release
- Growth hormone-releasing hormone: stimulates GH release
- Corticotropin-releasing hormone: Stimulates ACTH release
- Dopamine (Prolactin-inhibiting hormone): Inhibits prolactin release and also promotes pleasurable feelings
64
What is the Adrenal Cortex?
The Adrenal Cortex is the outer portion of the adrenal gland located on top of the kidneys. It has three layers:
- Zona Glomerulosa: Produces mineralocorticoids
- Zona Fasiculata: Produces glucocorticoids
- Zona Reticularis: Produces androgens
65
What is a glucocorticoid?
A glucocorticoid is a type of hormone produced in the zona glomerulosa of the adrenal cortex of the adrenal gland.
There are two types of glucocorticoids:
- Cortisol
- Corticosterone
Glucocorticoids raise the glucose levels of the blood by:
- Stimulating gluconeogenesis particularly in the liver. Glucose is made from amino acids and glycerol
- Fatty acid breakdown for energy production
- Causing breakdown of skeletal muscle where the amino acids are made into glucose when needed
They can be used as an anti-inflammatory agent to treat things like arthritis
66
What is Cushing Syndrome?
Cushing syndrome is too much cortisol
67
What is Addison's disease?
Addison's disease is too little cortisol
68
What is Aldosterone?
Aldosterone is a mineralcorticoid hormone produced by the zona glomerulosa in the adrenal cortex of the adrenal gland.
Aldosterone stimulates kidney cells to reabsorb sodium along with water. This increases blood volume, hence increases blood pressure.
69
What are gonads?
Gonads are sex organs in males and females that secrete sex hormones and gametes.
Males: Testes
Females: Ovaries
The gonads secrete three different types of sex hormones:
- Estrogens
- Progestins
- Androgens
70
What are Estrogens?
Estrogens are a type of hormone produced by the gonads.
There function is:
- Development of female sex characteristics
- Growth
- Egg cell maturation,
- Preparing the Uterus for pregnancy and its maintenance
71
What is Estradiol?
Estradiol is a type of estrogen.
- It controls the way fat is distributed in females
- triggers the luteal surge to release an egg (2° oocyte)
Females: Made in the ovaries
Males: Made in the testes and adrenals (In much lower amounts than in women)
72
What are progestins?
Progestins include progesterone
- Involved with preparing and maintaining the uterus for pregnancy.
- Directly effects breast development in the female.
- Regulates mucus produced by the glands of the uterine cervix
73
What are Androgens?
Androgens include the male sex hormone testosterone
- Male secondary sex characteristics
- Muscle building
- Sperm formation
- Growth and development
74
What Tropic Hormones does the Hypothalamus create?
The Hypothalamus creates the following Tropic hormones:
- GnRH (Gonadotropin-releasing hormone): Stimulates the release of FSH and LH from the anterior pituitary gland
- Growth hormone-releasing hormone: stimulates GH release
- Corticotropin-releasing hormone: Stimulates ACTH release
- Dopamine (Prolactin-inhibiting hormone): Inhibits prolactin release and also promotes pleasurable feelings
75
What is the Pineal Gland?
The Pineal Gland is the located in the brain. It is pinecone shaped.
Produces Melatonin which helps you sleep when in dark environments.
Involved in other biological rhythms.
76
What is GnRH?
GNRH(Gonadotropin-releasing hormone) is a tropic hormone produced by the hypothalamus: Stimulates the release of FSH and LH from the anterior pituitary gland
77
What is Growth Hormone Releasing Hormone?
Growth Hormone Releasing Hormone is a tropic hormone produced in the hypothalamus. It stimulates the release of GH from the anterior pituitary
78
What is Thyrotropin-releasing hormone?
Thyrotropin-Releasing Hormone is a tropic hormone produced in the hypothalamus that stimulates the release of TSH from the anterior pituitary gland
79
What is corticotropin releasing hormone?
Corticotropin-releasing hormone is a tropic hormone produced in the hypothalamus that stimulates the release of ACTH (Adrenocorticotropic Hormone) from the anterior pituitary
80
What is dopamine?
Dopamine is a hormone produced by the hypothalamus that aids in learning and pleasurable feelings.
Dopamine is also known as Prolactin-inhibiting hormone. It acts as a Prolactin release inhibitor
81
What is Melatonin?
Melatonin is a hormone produced by the pineal gland in dark environments. It helps put the body to sleep.
82
What is the placenta?
```
The Placenta is an organ that exchanges solutes between mother and fetus without bloodstreams mixing.
Produces:
- Progesterone
- Estrogen
- Human Chorionic Gonadotropin (hCG
- Relaxin
```
83
What is hCG?
Human Chorionic Gonadotropin (hCG) is a hormone produced by the placenta that is produced only when a woman is pregnant. It is used to detect pregnancies in at home pregnancy tests
84
What is relaxin?
Relaxin is a hormone produced by the placenta that:
- Works with progesterone to help maintain pregnancies
- Helps relax the pelvic ligaments at the end of gestation
- Helps dilate and soften the cervix in preparation for birth
85
What hormone does the heart produce?
The heart produces ANP (Atrial Natriuretic Peptide)
| - lowers blood pressure by relaxing the arterioles, and inhibiting the reabsorption of Na+ by the kidney
86
What is ANP?
ANP (Atrial Natriuretic Peptide) is a hormone made by the heart
- lowers blood pressure by relaxing the arterioles, and inhibiting the reabsorption of Na+ by the kidney
87
What hormones does the kidney produce?
The kidney produces:
- EPO (Erythropoetin)
- Renin
88
What is EPO
EPO (erythropoetin) is a hormone that is produced in the kidney.
- EPO binds with bone marrow receptors to stimulate the production of red blood cells
89
What is renin?
Renin is a hormone made in the kidneys
- It is involved in blood pressure regulation
- It causes an increase in blood pressure
90
Describe the hormone negative feedback loop
Some hormones are produced when levels of something are low. They will stop producing hormones when that level reaches it homeostasis
91
What is ecdysone?
ecdysone is an insect hormone
- involved with molting and metamorphosis
- It is a steroid hormone made by glands in the thorax
92
What is JH
JH (Juvenile Hormone) is a hormone made in insect brains
| - involved with larva growth
93
What are prostaglandins?
Prostaglandins are modified fatty acids, with hormone lik effects in animals.
- Made by many cells
- Involved in promoting fever and inflammation.
- Produced by almost all nucleated cells
- Inhibit platelet aggregation in blood, acting as vasodilators
- They contribute to the cardinal signs of inflammation:
* redness
* heat
* swelling
* pain
94
What is down regulation?
Down regulation is a decrease in cellular components in response to a stimuli
Ex: Too much insulin causes the receptors for insulin on cells to be decreased, causing type II diabetes.
95
What is up regulation?
Up regulation is an increase in cellular components in response to a stimuli.
Ex: When liver cells are exposed to dioxin, they will increase their production of cytochrome p450 enzymes to help break down the toxins.
96
What are the maJor endocrine organs of the body?
The maJor endocrine organs of the body are:
- Pituitary Gland
- Pineal Gland
- Thyroid Gland
- Adrenal Gland
- Pancreas
- Ovary
- Testis
