Endocrine System Flashcards
Who is Arnold Adolph Berthold?
Founder of Endocrinology
Studied chickens
What was Berthold’s Conclusion?
- A secretory, blood-borne product of the transplanted testes is responsible for the normal development of the birds in the second and third groups.
- Today, this product is called TESTOSTERONE
- A slight problem… it is not know why Berthold performed these experiments in the first place. He never provided a clear rationale for it.
Part 1 Berthold’s Experiment Consisted of what?
To establish that castration would keep the castrated male from developing the four adult factors (aggression, a pronounced crown that attracted females, wattles “beard”, they do not sign the stereotypical “cock-a-doodle-do”)
Part 2 of Berthold’s Experiment
He castrated a set of male chicks and then with a small surgical incision, put the excised testes back into the abdominal wall area of the bird and then sutured the incision site. The bird in this part of the study DID develop those four characteristics described above (aggression, crown, wattle, and song).
Part 3 Berthold’s Experiment
He again castrated a set of male chicks but instead of putting the testes back into the abdominal wall area…. He instead swapped one chick’s testes with that of another chick’s tests and then implanted those swapped testes into a castrated bird. Like in Part 2, the birds in this part of the study DID develop those four characteristics described above (aggression, crown, wattle, and song).
What is Endocrinology?
Chemical communication
What is the Nervous System?
“Electrical” communication
What are the 2 Broad Classes of Hormones?
Steroidal Hormones
- can have a “direct effect”
- some cells have receptors for steroidal hormones that will cause a 2nd messenger protein
Created in endocrine gland
Non-Steroidal Hormones
- have an “indirect effect”
- the hormone DOES NOT enter the cell
- instead the cell stimulated by the hormone releases a 2nd messenger signal that causes change
Created in nervous tissue
How can the Endocrine Gland be regulated?
Hurmonal
- some signal in the blood will regulate a gland
- parathryoid gland
Neural
- a nerve impulse can regulate a gland
- Adrenal gland
(spinal nerve that runs into it- adrenal medulla) and (begins to pump out hormones)
Hormonal
- a hormonal signal will regulate a gland
- pituitary gland
What does the Pineal Gland do?
Produces Melatonin
- regulated sleep/wake cycles
- circadian rhythms
What is the purpose of the Hypothalamus?
Neural site; keeps the body stable: homeostasis
What is the purpose of the Pituitary Gland?
Anterior Pituitary
Posterior Pituitary
Pars Intermedia
- MSH; malochore stimulating hormone
- increae in MSH–> increase in melanin production
Development of the Pituitary and Hypothalamus prenatally is critical for successful growth and development of humans.
What are the 6 Primary Hormonal Signals Produced by the Anterior Pituitary Gland
Growth Hormone (GH)
Follicle Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Thyroid Stimulating Hormone (TSH)
Prolactin (PRL)
Adrenocorticotropic Hormone (ACTH)
Growth Hormone Details
GH
growth and development especially of the muscles and skeleton
Follicle Stimulating Hormone
FSH
a gonadotropin that is going to stimulate the gonads
Luteinizing Hormone Details
LH
a gonadotropin that is going to stimulate the gonads
FSH + LH are known as Gonadotropins
Thyroid Stimulating Hormone Details
TSH
stimulated the thyroid gland
Prolactin Details
PRL
stimulates the production of milk in the mammary glands and production in the sebaceous glands
Adrenocorticotropic Hormone Details
ACTH
stimulates the production of hormones in the adrenal cortex (outer layer of the adrenal medulla)
What are the 2 Hormones of the Posterior Pituitary Gland?
Oxytocin and Antidiuretic Hormone
What is the purpose of Oxytocin?
- ejection reflexes (mammary glands, sebaceous gland, orgasms)
- milk
What is the purpose of the Antidiuretic Hormone (Vasopressin)?
ADH
- water retention in the body
Purpose of Thyrotropin Releasing Hormone
TRH
- promotes secretion of thyroid stimulating hormone (TSH) and prolactin (PRL)
Hypothalamic Releasing and Inhibiting Hormones that regulate the Anterior Pituitary
Thyrotropin Releasing Hormone
Corticotropin Releasing Hormone
Gonadotropin Releasing Hormone
Growth hormone Releasing Hormone
Purpose of Corticotropin Releasing Hormone
CRH
- promotes secretion of adrenocorticotropic hormone (ACTH)
Purpose of Gonadotropin Releasing Hormone
GnRH
- promotes secretion of follicle stimulating hormone (FSH) and luteinizing hormone (LH)
Purpose of the Growth Hormone Releasing Hormone
GHRH
- promotes secretion of the growth hormone (GH)
Hypothalamus Inhibiting Hormones
Thyrotropin Inhibiting Hormone (TIH)
Corticotropin Inhibiting Hormone (CIH)
Gonadotropin Inhibiting Hormone (GnIH)
Growth Hormone Inhibiting Hormone (GHIH)
What is the purpose of the Hypothalamus?
It is the master control brain region
HPA–> Hypothalamic–> Pituitary Axis
What is the purpose of the Pituitary Gland?
Master control for the endocrine gland
What is the role of the Thymus Gland?
produces Thymosin
- which serves a vital role in stimulating the development of T-lymphocytes or T cells an extremely important cell in immune responses in the body
- T-cells are a type of lymphocyte (white blood cell) that plays a central role in cell-mediated immunity
Thymus Gland is quite large in newborn
Characteristics of Autoimmune Disorders
Overly active thymus gland in adulthood
- Lupus
- Fibromyalgia
- Rheumatoid Arthritis
- Myasthenia Gravis
Purpose of the Thyroid Gland
- Regulates metabolism
- Calcitonin embeds minerals into bone
T3 (Triiodothyranine)
T4 (Thyroxine) - High levels or T 3 or 4 will increase metabolism
What will Excessive T3 or T4 lead to? And what will be experienced?
Hyperthyroidism
- feel ‘hot’
- thin
- behaviors are hyperkinetic–> hyperactive
What is an extreme form of hyperthyroidism? How to treat it?
Graves Disease
- to treat; radioactive isotope of Iodine
- leading many to become hypothyroid
What will under production of T3 or T4 lead to? Symptoms?
Hypothyroidism
- feel ‘cold’
- prone to obesity
- sluggish
- treated with exogenous ‘thyroid’ supplements–> Synthroid
Who was Done Knotts?
An actor
Had untreated hyperthyroidism
- symptoms shown; very thin, protruding eyes, behavioral movement and spastic typical patterns of movement
Who was the “Runaway Bride” Jennifer Willbanks
- Individual who created a national media frenzy in 2005 when she disappeared shortly before her wedding date; had “cold feet”
- Had untreated hyperthyroidism
- Symptoms: very thin, protruding eyes, spastic typical behavioral movements
What does increase in PTH lead to?
Demineralization of bone
What is the outer layer of the adrenal gland known as and what does it do?
The Adrenal Cortex
- activated humorally/hormonally via productions of ACTH by the anterior pituitary
- hormones secreted by the cortex are
mineral corticoids
- aldosterones
glucort corticoids
- cortisols
What is the inner layer of the adrenal gland known as and what the purpose?
Adrenal Medulla
- neurally controlled via spinal nerve
- hormones secreted by the medulla are: known as adrenaline
- epinephrine (Epi)
- norepinephrine (Nor)
What was Waler Bradford Cannon known for?
“Fight or Flight”
Adrenal Glands will…
produce different hormones related to the stress response of the body.
Characteristics of Short Term Stress Response
We have the adrenal medulla producing the catecholamines (epinephrine and norepinephrine)
- increased heart rate
- increased blood pressure
- liver converts glycogen to glucose and released glucose to blood
- dilation of bronchioles
- changes in blood flow patterns leading to decreased digestive system activity and - reduced urine output
- increased metabolic rate
Characteristics of Long Term Stress Response
The production of the mineralocorticoids (Aldosterones) and the glucocorticoids (Cortisols) and their five physiological effects
- retention of sodium and water by kidneys
- increased blood volume and blood pressure
- proteins and fats converted to glucose or broken down for energy
- increased blood glucose
- suppression of immune system
What does the pancreas control?
The production of insulin and glucagon to help maintain glucose homeostasis in the body. The pancreas delivers these hormones through the pancreatic ducts and releases them into the duodenum.
High levels of insulin=
lower blood sugar
High levels of glucagon=
higher blood glucose (stimulates liver to break down glycogen)
What are the Pancreatic Islets?
Alpha, Beta, and Delton
What are the major factors of heart disease?
Diabetes, obesity, cancer prevalence which stimulates fight of flight
How to decrease long/short term stress?
Moderate/intense exercise
What is Down Regulation?
- the process by which a cell decreases the quantity of a cellular component, such as a protein, in response to a stimulus.
The complementary process that involves increases of such components is called upregulation.
Diabetes and Regulation Type
People with diabetes have down regulation
- Cells produce a lot insulin which leads to deminished cell response
With a lot of exercise and proper diet, people can return renal cell function (want up regulation)
- Can only change type 2 Diabetes, not 1
What is Acromegaly?And what causes it?
- face thickens in different areas after epiphyseal growth plates have closed
Acromegaly is usually caused by the pituitary gland producing excess growth hormone. In 95% of cases the excess production is due to a benign tumor known as pituitary adenoma.
How is an Endemic Goiter caused?
Not enough iodine consumed, abnormality of the thyroid, inability to produce T3 and T4
- can be treated by consumption of iodine (seafood, dark leafy greens, and veggies)
Cushing’s Syndrome Characteristics
- a collection of symptoms due to prolonged hyper exposure to cortisols
- often can occur due to overproduction of ACTH which hyper stimulates the adrenal cortex
- symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, a round red face, a fat lump between the shoulders, weak muscles, weak bones, acne, and fragile skin that heals poorly
Congenital Adrenal Hyperplasia (CAH) Characteristics
- females infants with classic CAH have ambiguous genitalia due to exposure to high concentrations of androgens in utero.
Clitoris resembles penis - males with classic CAH generally have no visible signs of CAH at birth. Some may present with hyperpigmentation, due to secretion of melanocyte-stimulating hormone (MSH). Males typically are typically diagnosed with hypervocalization in childhood.
Does the Adrenal Cortex create reproductive hormones?
All the hormones of the adrenal cortex and testes and ovaries (cortisols, alsosterones, androgents (testosterone), estrogens (estradiol) and progestins. This represents the full range of all the steroidal hormones of the body. Adrenal cortex produces androgens, progesterone, estrogens
Small amount compared to gonads but important enough for development
