Intro to Endocrinology Flashcards

1
Q

What is a hormone?

A

A chemical substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What secretes hormones?

A

A gland or group of glands, or a tissue into body fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do hormones do?

A

They have a physiological control effect on other cells of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define endocrine and exocrine.

A

Endocrine: secretes within the body
Exocrine: secretes outside of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the various time frames in which hormonal control can take place?

A

Seconds (epinephrine/ norepinephrine)
several days/weeks
Months ( thyroxine/ growth hormone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

True or False. The nervous system can interact with hormonal system.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The sympathetic nervous system can stimulate which glands?

A

the adrenal glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The central nervous system can control which gland?

A

the pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

True or False. The nervous system can control all hormones

A

False. It can control some but not all

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What metabolic functions of the body does the endocrine system control?

A

Chemical reaction rate of cells
Transport of substances through cell membrane
Growth of body
Secretion of other hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the 9 endocrine glands and tissues.

A
  1. Pituitary
  2. Adrenal
  3. thyroid
  4. Parathyroid
  5. Islets of Langerhans
  6. ovaries
  7. Testes
  8. Placenta
  9. duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the anterior pituitary primarily controlled by?

A

Controlled by other hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What hormones does the anterior pituitary gland secrete? (6)

A

Growth hormone
Adrenocorticotropin
thyroid-stimulating hormone
Follicle-stimulating hormone
Luteinizing hormone
Prolactin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The posterior pituitary is primarily under what control?

A

Neuronal control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What hormones does the posterior pituitary secrete?

A

Oxytocin
antidiuretic hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The adrenal glands can be separated into two parts. What two parts are these?

A

The adrenal cortex and the adrenal medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The adrenal cortex is primarily under what control?

A

Hormonal control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What hormones does the adrenal cortex secrete?

A

Cortisol
Aldosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The adrenal medulla is under what control?

A

Neural control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What hormones does the adrenal medulla secrete?

A

Secretes two catecholamine hormones:
adrenaline (epinephrine) (major secretion)
Noradrenaline (norepinephrine) (minor secretion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is the thyroid gland located?

A

Located up in the sternal and mediastinal area of the thorax. Situated above the thymus which sits above the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What hormones does the thyroid secrete?

A

Thyroxine
Triiodothyronine
Calcitonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is the parathyroid gland considered separate from the thyroid gland even though it is located within it?

A

Due to its function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What hormone does the parathyroid gland secrete?

A

Parathyroid hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The parathyroid gland consists of what?

A

Four small blobs located within the thyroid gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Where are the Islets of Langerhans found?

A

In the pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Are the Islets of Langerhans considered glands or endocrine tissue

A

Endocrine tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What hormones do the Islets secrete?

A

Insulin
Glucagon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

True or False. The ovaries are considered to be an endocrine gland.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What hormones do the ovaries produce?

A

Estrogen
Progesterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

True or False. The testes are an endocrine tissue.

A

False. They’re a gland

32
Q

What hormone does the testes produce?

A

Testosterone

33
Q

The placenta is considered to be an endocrine tissue during certain times. What are those times?

A

During menstruation, conception, gestation

34
Q

What hormones does the placenta secrete?

A

Human chorionic gonadotropin
estrogen
Progesterone
Somatomammotropin

35
Q

What glands does the duodenum contain?

A

Brunner’s Glands

36
Q

What do the Brunner’s glands do?

A

Secretin hormone signals to the pancreas
Coordinates digestion

37
Q

What is the purpose of brown adipose tissue?

A

Receives hormonal input to help regulate body temperature

38
Q

Is brown adipose tissue an endocrine tissue?

A

No, because it does not secrete hormones.

39
Q

What categories can hormones be classified into according to their range of effect?

A

Local hormone or general hormone

40
Q

What are local hormones?

A

Hormones that have specific local effects on specific tissues. (not based on where it comes from but where it has effect)

41
Q

What are three examples of local hormones?

A

Secretin (Released from duodenal (intestinal) wall, transported in blood to pancreas, cause pancreas secretions for digestion)

Cholecystokinin (Released in small intestine, transported to (1) gallbladder cause gallbladder contraction,(2) pancreas cause secretion of digestive enzyme.)

Adrenocorticotropin (Released from anterior pituitary gland, stimulates adrenal cortex to secrete adrenocortical hormones)

42
Q

What are general hormones?

A

Hormones that have effects on many parts of the body and cause many different reactions

43
Q

Describe Epinephrine and Norepinephrine

A

Secreted by the adrenal medulla under sympathetic stimulation
Secreted by sympathetic nerves
Cause constriction of blood vessels and increase in arterial pressure
Has effects on most organs and tissues of the body (general hormones)

44
Q

Give 4 examples of general hormones.

A

Epinephrine
Norepinephrine
Growth hormone: secreted from anterior pituitary, cause growth in all body parts
Thyroid hormone (T3 & T4): secreted from thyroid gland, increases reaction rates in almost all cells of the body

45
Q

Hormones can also be classified by their chemical structures. What are the three different classifications?

A

Steroid, protein and tyrosine

46
Q

Steroid-based hormones are based from what?

A

Cholesterol

47
Q

Why are steroid hormones called as such?

A

Because testosterone is built from cholesterol and many anabolic steroids are made from testosterone

48
Q

The adrenal cortex can turn cholesterol into what?

A

many hormones including aldosterone and cortisol

49
Q

What can the placenta and ovaries turn cholesterol into?

A

Estrogen

50
Q

What can the testes turn cholesterol into?

A

testosterone

51
Q

Where are the receptors for steroid hormones found and why?

A

Usually found within the cell cytoplasm or nucleus. This is due to the fact that steroid hormones are hydrophobic and lipophilic

52
Q

What is the mechanism of steroid hormone action?

A

Steroid hormones enter cytoplasm of cell ==> bind with receptors* ==> diffuse or transported into nucleus ==> bind to and activate DNA strands ==> initiate transcription process of genes to form RNA messenger ==> RNA goes into cytoplasm through nuclear pore complex ==>promote functions inside the cells.

53
Q

What can the thyroid gland turn tyrosine into?

A

Thyroxine (T4) and triiodothyronine (T3)

54
Q

What can the adrenal medullae turn tyrosine into?

A

epinephrine and norepinephrine

55
Q

How does the thyroid gland make T3 and T4 from tyrosine?

A

It adds iodine molecules to tyrosine which in turn makes T3 and T4 lipophilic.

56
Q

How does the adrenal medulla turn tyrosine into epinephrine and norepinephrine?

A

It hydroxylates tyrosine which makes the molecules lipophobic.

57
Q

What is the chain of action for thyroid hormones?

A

Thyroid hormones ==> bind with receptor in cell nucleus* ==> bind and activate DNA ==> initiate transcriptions of specific genes to form RNA messenger ==> RNA goes into cytoplasm through nuclear pore complex ==> new proteins (enzymes) are formed and become the controller to promote metabolic activities in all cells of body
*In some cases the receptors are found within the nucleus not the cytoplasm.

58
Q

What is the chain of action for epinephrine, norepinephrine and acetylcholine

A

E or NE ==> bind with receptors on the cell membrane ==> cause conformational change of proteins structure of the receptor ==> open or close channels for ions (Na or K) (change of membrane permeability) ==> change of cell membrane potential ==> cause cell excitation or inhibition

59
Q

What is the chain of action for protein and peptide-based hormones?

A

Protein or peptide-based hormones bind receptors on membrane (protrudes to exterior of cell) ==> structure change in receptor ==> receptor becomes activated enzyme “adenyl cyclase” ==> activate the formation of “cyclic adenosine monophosphate” (cAMP) ==> second messenger activates a cascade of enzymes ==> cause powerful effects on cells

60
Q

Why do peptide-based and protein hormones bind to receptors on the cell membrane?

A

Because they are lipophobic (hydrophilic)

61
Q

What are second messengers?

A

they are cell-signaling pathways that communicate with the receptors on the cell surface and the inside of the cell.

62
Q

What is the pathway of cyclic adenosine monophosphate (cAMP) as a second messenger

A

Hormones ==> receptor ==> activate enzyme “adenyl cyclase” ==> activates the formation of cAMP ==> activate a cascade of enzymes ==> cause different effects on cells.

63
Q

what is the pathway of Ca2+-Calmodulin as second messenger

A

Hormones ==> receptor ==> open channels for Ca2+ ions ==> Ca2+ diffused into cell and bind with calmodulin ==> calmodulin is activated by conformational change ==> activated calmodulin can cause multiple effects inside the cell in the same way that cAMP does

64
Q

what is the pathway of IP3 and diacylglycerol as second messenger

A

Hormones ==> receptor ==> activates enzyme phospholipase C attached to the inside projection of the receptor ==> cause phospholipids in the cell membrane to split into small substances such as inositol trisphosphate (IP3) and diacylglycerol that serve as “second messenger”

65
Q

What factors make it hard to measure hormones?

A

Blood hormone concentration is very low. The rate of secretion of hormones is extremely small. Hormones are very small chemical molecules that defy conventional measuring techniques

66
Q

How can hormones be measured?

A

By method of radioimmunoassay or mass spectrometry

67
Q

What is the advantage of controlling the secretion rate of hormones?

A

The body can control how much effect the hormone is having and can shut it off if the secretion becomes too much

68
Q

What are two types of ways to control hormones and which one is the more common?

A

Negative and Positive feedback. Negative feedback is the most common way.

69
Q

What is direct negative feedback?

A

when the hormone inhibits its own secretion when it reaches a high enough level.

Gland secretes hormone ==> hormone accumulates in blood ==> hormone gets back to gland ==> hormone inhibits its own secretion.

70
Q

What is indirect negative feedback?

A

When the effect of the hormone inhibits the secretion of the hormone

Gland secretes hormone ==> hormone accumulates in blood ==> hormone stimulates a tissue ==> the tissue produces some effects, for example, heat is produced ==> the effects, in this example heat, will go back to the gland and inhibit the secretion of the hormone.

71
Q

Why is positive feedback less common?

A

It’s hard for the body to control

72
Q

What is direct positive feedback?

A

Gland secretes hormone ==> hormone accumulates in blood ==> the hormone goes back to the gland and promotes the secretion of the hormone.

73
Q

What is indirect positive feedback?

A

Gland secretes hormone ==> hormone accumulates in blood ==> the hormone stimulates a tissue ==> the gland and produces some effect which then promotes the secretion of the hormone.

74
Q

How are hormone receptors regulated?

A

The number of receptors in the target cell varies depending on time
Receptors can be activated or deactivated by altering their second messenger cell signaling pathway, or by altering their location in the cell.
Receptors can be destroyed by enzymes
Receptors can be created by synthesis

75
Q

What does chronic over stimulation of a receptor lead to?

A

Leads to a deactivated or destroyed receptor. so the hormone will not have an effect until the receptor is reproduced.