Chapter 16 Part A Flashcards

(69 cards)

1
Q

What is the primary function of the endocrine system?

A

To coordinate and integrate activity of body cells via hormones.

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

What is endocrinology?

A

The study of hormones and endocrine organs.

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

What are the main functions controlled by the endocrine system?

A
  • Reproduction
  • Growth and development
  • Maintenance of electrolyte, water, and nutrient balance of blood
  • Regulation of cellular metabolism and energy balance
  • Mobilization of body defenses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between exocrine and endocrine glands?

A

Exocrine glands produce nonhormonal substances and have ducts; endocrine glands produce hormones and lack ducts.

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

Name some major endocrine glands.

A
  • Pituitary gland
  • Thyroid gland
  • Parathyroid glands
  • Adrenal glands
  • Pineal gland
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What role does the hypothalamus play in the endocrine system?

A

It is considered a neuroendocrine organ.

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

What are the two main classes of hormones?

A
  • Amino acid–based hormones
  • Steroids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are autocrines and paracrines?

A
  • Autocrines: Chemicals that exert effects on the same cells that secrete them
  • Paracrines: Locally acting chemicals that affect cells other than those that secrete them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the role of target cells in hormone action?

A

Target cells are tissues with receptors for a specific hormone that are affected by the hormone.

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

How do water-soluble hormones act on target cells?

A

They act on plasma membrane receptors and use G protein second messengers.

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

How do lipid-soluble hormones act on target cells?

A

They act on intracellular receptors that directly activate genes.

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

What is the cyclic AMP (cAMP) signaling mechanism?

A

A hormone binds to a receptor, activating a G protein that activates adenylate cyclase, converting ATP to cAMP, which then activates protein kinases.

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

What is the role of calcium ions in hormone signaling?

A

Calcium ions act as a second messenger that alters enzyme activity and channels.

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

True or False: Calcium ions can bind to regulatory proteins to amplify cellular response.

A

True.

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

What initiates the release of hormones in the endocrine system?

A

Hormone release is triggered by endocrine gland stimuli, nervous system modulation, and negative feedback systems.

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

What is the function of humoral stimuli in hormone release?

A

Changing blood levels of ions and nutrients directly stimulate secretion of hormones.

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

Fill in the blank: The three types of endocrine gland stimuli are _______ stimuli, _______ stimuli, and _______ stimuli.

A

humoral, neural, hormonal.

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

What is a humoral stimulus?

A

Hormone release caused by altered levels of certain critical ions or nutrients.

Example: Declining blood Ca2+ concentration stimulates parathyroid glands to secrete PTH.

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

What triggers the secretion of parathyroid hormone (PTH)?

A

Low concentration of Ca2+ in capillary blood.

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

What is a neural stimulus?

A

Hormone release caused by neural input.

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

How do sympathetic nervous system fibers affect hormone release?

A

They stimulate adrenal medulla to secrete catecholamines.

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

What is a hormonal stimulus?

A

Hormone release caused by another hormone (a tropic hormone).

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

What role do hypothalamic hormones play in the endocrine system?

A

They stimulate the release of most anterior pituitary hormones.

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

What is the feedback loop involving hypothalamic, pituitary, and target endocrine organs?

A

Hypothalamic hormones stimulate anterior pituitary hormones, which in turn stimulate target organs to secrete hormones.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the three factors that determine target cell activation?
* Blood levels of hormone * Relative number of receptors on/in target cell * Affinity of binding between receptor and hormone
26
What is up-regulation in hormone signaling?
Target cells form more receptors in response to low hormone levels.
27
What is down-regulation in hormone signaling?
Target cells lose receptors in response to high hormone levels.
28
What is the half-life of a hormone?
Time required for the level of hormone in blood to decrease by half.
29
What factors influence the concentration of circulating hormones?
* Rate of release * Speed at which it is inactivated and removed from the body
30
How can hormones be removed from blood?
* Degrading enzymes * Kidneys * Liver
31
What are the typical response times for hormones?
Ranges from immediate responses to those that take hours to days.
32
What is permissiveness in hormone interaction?
One hormone cannot exert its effects without another hormone being present.
33
What is synergism in hormone interaction?
More than one hormone produces the same effects on a target cell, causing amplification.
34
What is antagonism in hormone interaction?
One or more hormones oppose the action of another hormone.
35
What is the function of the hypothalamus in relation to the pituitary gland?
It controls the release of hormones from the pituitary gland.
36
What are the two major lobes of the pituitary gland?
* Posterior pituitary * Anterior pituitary
37
What type of tissue makes up the posterior pituitary?
Neural tissue.
38
What hormones are secreted by the posterior pituitary?
* Oxytocin * Antidiuretic hormone (ADH)
39
What is the primary capillary plexus?
A network of capillaries in the hypophyseal portal system connected to the hypothalamus.
40
What hormones does the anterior pituitary secrete in response to hypothalamic stimulation?
* Growth hormone (GH) * Thyroid-stimulating hormone (TSH) * Adrenocorticotropic hormone (ACTH) * Follicle-stimulating hormone (FSH) * Luteinizing hormone (LH) * Prolactin (PRL)
41
What is the role of oxytocin during childbirth?
It is a strong stimulant of uterine contractions.
42
What triggers the secretion of antidiuretic hormone (ADH)?
High solute concentrations in the blood.
43
What condition results from ADH deficiency?
Diabetes insipidus.
44
What is the syndrome of inappropriate ADH secretion (SIADH)?
Retention of fluid, headache, and disorientation.
45
What is the function of osmoreceptors in the hypothalamus?
They monitor solute concentrations in the blood.
46
What is vasopressin another name for?
Antidiuretic hormone (ADH) when in high concentrations.
47
What is diabetes insipidus?
ADH deficiency due to damage to hypothalamus or posterior pituitary ## Footnote Must keep well hydrated
48
What are the symptoms of the syndrome of inappropriate ADH secretion (SIADH)?
Retention of fluid, headache, disorientation ## Footnote Treatment includes fluid restriction and blood sodium level monitoring
49
How many hormones are secreted by the anterior pituitary?
Six hormones ## Footnote All are peptide hormones
50
Which hormone is not a tropic hormone among anterior pituitary hormones?
Growth hormone (GH) ## Footnote All but GH activate target cells via cAMP second-messenger system
51
What does growth hormone (GH) do?
Has direct actions on metabolism and indirect growth-promoting actions ## Footnote Also called somatotropin
52
What are the direct actions of growth hormone (GH) on metabolism?
Glucose-sparing actions, triggers liver to break down glycogen into glucose, increases blood levels of fatty acids, encourages protein synthesis ## Footnote GH decreases the rate of cellular glucose uptake and metabolism
53
What are insulin-like growth factors (IGFs)?
Produced by liver, skeletal muscle, and bone under stimulation from GH; stimulate cellular uptake of nutrients, formation of collagen, and deposition of bone matrix ## Footnote Major targets of GH are bone and skeletal muscle
54
What regulates the secretion of growth hormone (GH)?
Hypothalamic hormones on somatotropic cells ## Footnote GHRH stimulates GH release; GHIH inhibits release
55
What triggers the release of growth hormone-releasing hormone (GHRH)?
Low blood GH or glucose, or high amino acid levels ## Footnote Ghrelin also stimulates GH release
56
What is the effect of hypersecretion of GH in children?
Gigantism ## Footnote Can reach heights of 8 feet
57
What is the effect of hypersecretion of GH in adults?
Acromegaly ## Footnote Results in overgrowth of hands, feet, and face
58
What is the effect of hyposecretion of GH in children?
Pituitary dwarfism ## Footnote May reach a height of only 4 feet
59
What is thyroid-stimulating hormone (TSH) also called?
Thyrotropin ## Footnote Produced by thyrotropic cells
60
What triggers the release of TSH?
Thyrotropin-releasing hormone (TRH) from hypothalamus ## Footnote Inhibited by rising blood levels of thyroid hormones
61
What is adrenocorticotropic hormone (ACTH) also called?
Corticotropin ## Footnote Secreted by corticotropic cells
62
What does ACTH stimulate?
Adrenal cortex to release corticosteroids ## Footnote Triggered by hypothalamic corticotropin-releasing hormone (CRH)
63
What are gonadotropins?
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) ## Footnote Secreted by gonadotropic cells of anterior pituitary
64
What is the role of FSH?
Stimulates production of gametes (egg or sperm) ## Footnote In females, LH helps mature follicles of egg
65
What is the role of LH in males?
Stimulates production of testosterone ## Footnote LH promotes production of gonadal hormones
66
What regulates the release of gonadotropins?
Gonadotropin-releasing hormone (GnRH) ## Footnote Suppressed by gonadal hormones
67
What is prolactin (PRL) primarily responsible for?
Stimulates milk production in females ## Footnote Role in males is not well understood
68
What inhibits prolactin release?
Prolactin-inhibiting hormone (PIH), which is dopamine ## Footnote Decreased levels lead to lactation
69
What is hyperprolactinemia?
Most frequent abnormality of anterior pituitary tumors ## Footnote Clinical signs include inappropriate lactation, lack of menses, infertility in females, and impotence in males