Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT - Biology > Chapter 5 - The Endocrine System > Flashcards

Chapter 5 - The Endocrine System Flashcards

1
Q

What does Endocrine singling involve?

A

The secretion of hormones directly into the bloodstream. The hormones travel to distant target tissues, where they bind to receptors and include a change in gene expression or cell function.

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

What are Peptide Hormones?

A

Composed of amino acids and are derived from larger precursor proteins that are cleaved during post translational modification.

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

Are Peptide hormones Polar or NonPolar?

A

Polar; cannot pass through the plasma membrane.

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

What do Peptide Hormones bind to?

A

Extracellular receptors, where they trigger the transmission of a second messenger.

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

What does each step of the Signalling Cascade induce?

A

Amplification of the signal.

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

What kind of effects do Peptide Hormones exert?

A

Rapid onset but short-lived.

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

Peptide Hormones are water soluble: what does this mean?

A

They travel freely in the bloodstream and do not require a special carrier.

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

What are Steroid Hormones derived from? Are they Polar or Non Polar?

A

Derived from cholesterol. They’re minimally polar and can pass through the plasma membrane.

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

What is the relationship between Steroid Hormones and Cytosolic/Intracellular Receptors?

A

Steroid Hormones bind to and promote a conformational change in cytosolic or intracellular receptors; the hormone-receptor complex binds to DNA, altering the transcription of a particular gene.

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

What kind of effects to Steroid Hormones exert?

A

Slow onset but long-lasting.

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

Steroid Hormones are lipid soluble: what does this mean?

A

They cannot dissolve in the bloodstream and must be carried by specific proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are Amino-Acid Derived Hormones?

A

Modified amino acids; their chemistry shares some features with peptide hormones and some with steroid hormones. Different amino acid derived hormones share different features with the other hormone classes.

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

What are some common examples of Amino-Acid Derived Hormones? (4)

A

Epinephrine, norepinephrine, triiodothyronine, and thyroxine.

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

Hormones be classified by their target tissues: what is the difference of effects between Direct Hormones and Tropic Hormones?

A

Direct: have major effects on non-endocrine tissues and secrete to target tissues via bloodstream.
Tropic: have major effects on endocrine tissues and cause secretion of another hormone.

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

What role does the Hypothalamus serve?

A

The hypothalamus is the bridge between the nervous and endocrine systems.

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

What mediates the release of hormones by the Hypothalamus?

A

A number of factors, including projections from other parts of the brain, chemoreceptors/baroreceptors in the blood vessels, and negative feedback from other hormones.

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

In negative feedback what does the final hormone (or product) of a pathway inhibit?

A

Hormones (or enzymes) earlier in the pathway, maintaining homeostasis.

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

How does the hypothalamus stimulate the Anterior Pituitary Gland?

A

Through paracrine release of hormones into the hypophyseal portal system, which directly connects the two organs.

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

What are the 5 Hypothalamic Releasing Hormones?

A
  1. Gonadotropin-releasing hormone (GnRH)
  2. Corticotropin-releasing factor (CRF)
  3. Thyroid-releasing hormone (TRH)
  4. Dopamine
  5. Growth hormone-releasing hormone (GHRH)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which hormones do the Gonadotropin-releasing hormone (GnRH) promote the release of?

A

Follicle-stimulating hormone (FSH) *ovulation/spermatogenesis
luteinizing hormone (LH)
*ovulation and testosterone production

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

What is the target organ of Gonadotropin-releasing hormone (GnRH)? What hormones does the target organ release?

A

Gonads (testes or ovaries); releases testosterone or progesterone/estrogen

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

What is the target organ of Corticotropin-releasing factor (CRF)? What hormones does the target organ release?

A

Adrenal Cortex; Glucocorticoids (cortisol and cortisone)

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

Which hormones do the Corticotropin-releasing factor (CRF) promote the release of?

A

Adrenocorticotropic hormone (ACTH)

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

What is the target organ of Thyroid-releasing hormone (TRH)? What hormones does the target organ release?

A

Thyroid; Triiodothyronine (T3), thyroxine (T4); Calcitonin

25
Q

Which hormones do the Thyroid-releasing hormone (TRH) promote the release of?

A

Thyroid-stimulating Hormone (TSH)

26
Q

What is the target organ of Dopamine? What hormones does the target organ release?

A

Breast tissue; NA

27
Q

Which hormones does Dopamine promote the release of?

A

Prolactin *results from a DECREASE in dopamine

28
Q

What is the target organ of Growth hormone-releasing hormone (GHRH)? What hormones does the target organ release?

A

Bone and muscle; NA

29
Q

Which hormones do the Growth hormone-releasing hormone (GHRH) promote the release of?

A

Growth hormone

30
Q

What inhibits the release of Prolactin?

A

Prolactin-Inhibiting Factor (PIF or dopamine)

31
Q

How do interactions with Posterior Pituitary occur?

A

Anti-diuretic hormones (ADH or vasopressin) and oxytocin are synthesized in the hypothalamus and then travel down to the posterior pituitary where they are released into the bloodstream.

32
Q

Which hormones are Tropic (4)? Which are Direct (3)?

A

Tropic: FSH; LH; ACTH; and TSH
Direct: Prolactin; Endorphins; and Growth Hormone

33
Q

What does Prolactin do?

A

Promotes milk production *Mammary Glands

34
Q

What do Endorphins do?

A

Decrease perception of pain and can stimulate euphoria.

35
Q

What does Growth Hormone (GH) do?

A

Promotes growth of bone and muscle and shunts glucose to these tissues. It also raises blood glucose concentrations.

36
Q

What response is required for Antidiuretic Hormone (ADH or Vasopressin) to be released?

A

Low blood volume or increased blood osmolarity, and increased reabsorption of water in the collecting duct of the nephron, increase in blood blood volume and decrease in blood osmolarity.

37
Q

When is Oxytocin recreated?

A

During childbirth and promotes uterine contractions. It also promotes milk ejection and may be involved in bonding behaviour. Has a positive feedback loop.

38
Q

What do T3 (Triiodothyronine) and T4 (Thryoxine) do?

A

Produced by follicular cells and contain iodine. They increase basal metabolic rate after the utilization of glucose and fatty acids. Required for proper neurological and physical development in children.

39
Q

What does Calcitonin do?

A

Produced by parafollicular (C) cells. It decreases plasma calcium concentration by promoting calcium excretion in the kidneys, decreases calcium absorption in the gut, and promotes calcium storage in bones.

40
Q

What do the Parathyroid Glands do?

A

Release parathyroid hormone (PTH) which increases calcium concentration.

41
Q

What is the role of Parathyroid Hormone (PTH)?

A

Decreases calcium in kidneys and increases blood calcium concentration. It activates Vitamin D, which is necessary for calcium and phosphate absorption from the gut. PTH promotes reabsorption of phosphate from bone and decreases reab. of phosphate in kidneys, but vitamin D promotes absorption. These two effects of phosphate concentration somewhat cancel each other out.

42
Q

What are the three classes of Steroid Hormones produced by the Adrenal Cortex?

A
  1. Gluconoids
  2. Mineralocorticoids
  3. Cortical Sex Hormones
43
Q

What do Gluconoids do?

A

Gluconoids, such as cortisol and cortisone, increase blood glucose concentration, reduce protein synthesis, inhibit the immune system, and participate in the stress response.

44
Q

What stimulates Gluconoid release?

A

ACTH

45
Q

What do Mineralocorticoids do?

A

Mineralocorticoids, such as Aldosterone, promote sodium reabsorption in the distal convoluted tubule and collecting duct, thus increasing water reabsorption.

46
Q

What is an additional function of the Mineralocorticoid Aldosterone? What regulates Aldosterone activity?

A

Increases potassium and hydrogen ion excretion. Aldosterone activity is regulated by the renin-angiotensin-aldosterone system, not ACTH.

47
Q

What are Corticoid Sex Hormones?

A

Includes Androgens (like testosterone) and estrogen in both males and females.

48
Q

What does the Adrenal Medulla do?

A

Derived in the nervous system and secretes catecholamines into the bloodstream.

49
Q

What are Catecholamines? What do they promote?

A

Include norepinephrine and epinephrine, which are involved in the fight-or-flight response. They promote Glycogenolysis, increase the basal metabolic rate, increase heart rate, dilate the bronchi and alter blood flow.

50
Q

What is the role of the Pancreas?

A

Produces hormones that regulate glucose homeostasis; Glucagon and Insulin.

51
Q

What does Glucagon do?

A

Produced by alpha-cells; raises blood glucose levels by stimulating protein and fat degradation, glycogenolysis and gluconeogenesis.

52
Q

What does Insulin do?

A

Produced by beta cells; decreases blood glucose levels by stimulating glucose uptake by cells and promoting anabolic processes, like glycogen, fat, and protein synthesis.

53
Q

What does Somatostatin do?

A

Produced by delta-cells; inhibits insulin and glucagon secretion.

54
Q

What is the function of the Gonads?

A

Produce hormones that are involved in the development and maintenance of reproductive systems and secondary sex characteristics.

55
Q

What is the function of the Pineal Gland?

A

Releases melatonin, which helps to maintain circadian rhythms.

56
Q

How do the Stomach and Intestines support Endocrine functions?

A

Produce hormones like secretin, gastrin and cholecystokinin.

57
Q

How do the Kidneys support Endocrine function?

A

Secrete erythroprotein, which stimulates bone marrow to produce red blood cells in response to low oxygen levels in blood.

58
Q

How does the Heart support Endocrine function?

A

The atria of the heart produces atrial natriuretic peptide (ANP) to promote excretion of salt and water in kidneys in response to stretching of the atria (high blood volume).

59
Q

How does the Thymus support Endocrine function?

A

secretes Thymosin, which is important for proper T-cell development and differentiation.

MCAT - Biology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions