PHGY 1 Flashcards

1
Q

True or False: All endocrine tissue secretes hormones

A

T

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2
Q

Define: Hormone

A

Hormone: a chemical substance that is secreted directly into the blood at low quantities, and exerts a physiological effect at a distant target tissue

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3
Q

What are the 2 categories of hormones?

A

-Hydrophilic
- Lipophilic

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4
Q

Are peptide hormones hydrophilic or lipophilic

A

hydrophilic

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5
Q

Define
Peptide:
Protein:
Amine:

A

Define
Peptide: short chains of aa
Protein: long chains of aa
Amines: hormones based on single aa

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6
Q

What are all steroid hormones synthesized from?

A

cholesterol

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7
Q

Since all the steroid hormones are produced by cholesterol how do they determine which is made?

A

The type of hormone produced depends on the specific enzymes within the cells of that tissue

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8
Q

How are steroid hormones regulated?

A

Bc steroid hormones are lipophilic, they are released as they are stored, therefore, they are controlled by synthesis

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9
Q

What is - peptide hormones - primary mode of transport

A

peptide hormone = dissolved in blood

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10
Q

What is - steroid hormones - primary mode of transport

A

steroid hormones = bound to carrier molecules or proteins

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11
Q

What is - thyroid hormones - primary mode of transport

A

thyroid hormones = bound to carrier molecules or proteins

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12
Q

What is - cactecholamines - primary mode of transport

A

catecholamines = 50% are found free in plasma, 50% are bound to protiens

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13
Q

what is required for hormones to exhibit their desired effect

A

Hormones must be unbound to interact wit a receptor

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14
Q

What do hormones bind?

A

receptors

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15
Q

what are the 2 second messenger pathways of peptide hormones and catecholamines?

A
  • cAMP
  • calcium
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16
Q

In the second messenger pathway, cAMP, what phosphorylates the target?

A

kinase A

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17
Q

In the second messenger pathway, calcium, what phosphorylates the target?

A

CaM kinase

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18
Q

Do the 2 lobes of the pituitary gland communicate with each other?

A

NO

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19
Q

Describe the 2 lobes of the pituitary gland

A

Posterior Pituitary Gland:
- Comprised of neural-like tissues and is sometimes called the “neurohypophysis’
Anterior Pituitary Gland:
- Comprised of glandular epithelial tissues and is also called the “adenohypophysis”

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20
Q

How does the hypothalamus control the:

Posterior Pituitary Lobe:

Anterior Pituitary Lobe:

A

Posterior Pituitary Lobe:
- The hypothalamus is connected to the posterior pituitary by a neural pathways
- Within the hypothalamus there are two well-defined clusters of neurons, called the supraoptic nucleus and the paraventricular nucleus
- Axons from these nuclei project down the pituitary stalk and terminate on blood vessels in the posterior pituitary

Anterior Pituitary Lobe:
- The hypothalamus is connected to the anterior pituitary by a unique vascular link: the hypothalamic-hypophyseal portal system
- The hypothalamus secretes hormones into this portal system and they are carried directly to the anterior pituitary where they either inhibit or promote the release of anterior pituitary hormones

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21
Q

The hypothalamic-hypophyseal portal system connects the hypothalamus to to ____

A

The hypothalamic-hypophyseal portal system connects the hypothalamus to to anterior pituitary lobe

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22
Q

Are hormones produced in the posterior pituitary gland?

A

No, hormones are synthesized in the neuron cells bodies located in the hypothalamus, then packaged into vesicles which are transported down the axons to the nerve endings in the posterior pituitary

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23
Q

What hormones are released from the posterior pituitary - describe

A

Vasopressin:
- Aka antidiuretic hormone (ADH) has 2 major actions:
1. Enhancing the retention of water by the kidneys
2. Causes contraction of arteriolar smooth muscle

Oxytocin:
- Two major roles:
1. Stimulating contraction of uterine smooth muscle cells during childbirth
2. Promoting milk ejection during breastfeeding

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24
Q

Name and describe the 6 hormones synthesized in the pituitary gland?

A

GH - Growth hormone
- responsible for regulating overall body growth, involved in metabolism

ACTH - Adrenocorticotrophic Hormone
- Stimulates secretion of cortisol by the adrenal cortex

LH - Luteinizing hormone
- In females
□ LH is responsible for ovulation and formation of the corpus luteum
□ Also stimulates the secretion of estrogen and progesterone from the ovaries
- In males
□ Stimulates the release of testosterone from the interstitial cells of Leydig

TSH - Thyroid Stimulating Hormone
- Stimulates the release of thyroid hormones from the thyroid gland

FSH - Follicle Stimulating Hormone
- In females
□ Stimulates growth and development of ovarian follicles and promotes secretion of estrogen by the ovaries
- In males
□ FSH is required for sperm production

PRL - Prolactin
- In females
□ Enhances breast development and milk production
- In males
□ Present but physiological purpose is not clear
- only anterior pituitary hormone that’s not trophic

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25
Q

Name the hypothalamic hormones and the anterior pituitary hormones they influence

A

○ TRH - thyrotropin-releasing hormone:
Stimulates the release of TSH and prolactin

GnRH - Gonadotropin-Releasing Hormone:
Stimulates the release of FSH and LH

○ GHIH - Growth Hormone Inhibiting hormone:
Inhibits the release of growth hormone and TSH

○ CRH - Corticotropin-Releasing Hormone:
Stimulates the release of ACTH (corticotropin)

○ GHRH - Growth Hormone Releasing Hormone
- Stimulates the release of growth hormone

○ PRH - Prolactin-Releasing Hormone
- Stimulates the release of prolactin

○ PIH - Prolactin-Inhibiting Hormone:
Inhibits the release of prolactin

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26
Q

How are hypothalamic hormones inhibited/stimulates

A

They respond to both neuronal and hormonal inputs

27
Q

Describe the general chain of command for hypothalamic hormones

A
  1. hypothalamic hormone is released into portal system
  2. travels to the pituitary gland to regulate the output of a trophic hormone
  3. Trophic hormone is transported by the systemic circulation to its target endocrine gland
  4. regulated the secretion of the third hormone which produces the physiological effect
28
Q

In response to stress the hypothalamus increases its secretion of:

A

In response to stress the hypothalamus increases its secretion of: corticotropin-releasing hormone

29
Q

Corticotropin-releasing hormone then stimulates the ___ pituitary to release ____

A

Corticotropin-releasing hormone then stimulates the anterior pituitary to release adrenocorticotrophic hormone

30
Q

ACTH acts on the adrenal _____ to release _____

A

ACTH acts on the adrenal cortex to release cortisol

31
Q

Cortisol then acts in a negative feedback fashion to reduce the secretion of regulatory hormones from the ____ and ____

A

Cortisol then acts in a negative feedback fashion to reduce the secretion of regulatory hormones from the hypothalamus and anterior pituitary

32
Q

What aa does the thyroid use?
What does it produce?

A
  • They thyroid uses the aa tyrosine to produce tetraiodothyronine (T4) and triiodothyronine (T3)
  • T4 is converted to T3
33
Q

Why is iodine important?

A

Is needed to produce thyroid hormone

34
Q

How long does it take for thyroid hormones to take effect?

A
  • hours, then lasts for days even after plasma concentrations of thyroid hormones have returned to normal
35
Q

Describe the Hypothalamic-Pituitary-Thyroid Axis

A
  • the hypothalamus secretes TRH (thyroid releasing hormone)
  • TRH acts on the anterior pituitary to secrete TSH (thyroid stimulating hormone)
36
Q

What is the most important regulator of thyroid hormone synthesis and release

A

TSH is the most important regulator of thyroid hormone synthesis and release

37
Q

What happens if there is too much/too little TSH

A

too much = thyroid gland follicles get larger and increase in number

too little/ none = TSH will directly affect the thyroid gland and the thyroid gland will shrink

38
Q

The release of both TSH and TRH are under ______ ____ control

A

The release of both TSH and TRH are under negative feedback control

39
Q

Name some symptoms of hypothyroidism

A
  • cold intolerance
  • slower reflexes
  • reduced mental alertness
  • easy to fatigue
  • slow, weak heart rate
  • weight gain due to decreased basal metabolic rate
40
Q

What are some symptoms of Hyperthyroidism

A
  • Increased heart rate
  • Excessive heat production
  • Muscle weakness due to skeletal muscle protein degradation
  • Mood swings due to increased CNS mental alertness
  • Elevated basal metabolic rate that causes weight loss even with increased caloric intake
41
Q

What symptom can arise in both hyper/hypo thyroidism? Describe

A

Goiter
- is a visibly enlarged thyroid gland
- results from any condition with increased TSH bc THS stimulates the thyroid to increase the number and size of follicles

42
Q

Describe the 2 layers of the adrenal glands and their functions

A

Cortex =
- outer layer
- secrete several steroid hormones

Medulla =
- inner layer
- secretes catecholamines

43
Q

What are the 3 zones of the adrenal cortex

A
  • zona glomerulosa
  • zona fasciculata
  • zona reticularis
44
Q

The adrenal cortex produces ____ hormones

A

The adrenal cortex produces steroid hormones

45
Q

What are the 3 main categories of adrenal cortex hormones?

A

○ Mineralocorticoids
- Influence mineral (electrolyte) balance
- Produced in the zona glomerulosa

○ Glucocorticoids
- Play a role in glucose, lipid, and protein metabolism
- Produced mainly in the zona fasciculata and the zona reticularis

○ Sex hormones
- Are identical or similar to those produced in the gonads
- Are produced in lower quantities in the zona fasciculata and the zona reticularis

46
Q
A
47
Q

Alpha and beta receptors: which are excitatory/inhibitory

A

a1 + B1 = excitatory
a2 + B2 = inhibitory

48
Q

What does Ne primarily bind?

A

Ne primarily binds a and B1 receptors near postganglionic sympathetic nerve terminals

49
Q

What does Epi usually bind

A

Epi released from the adrenal medulla can reach all receptors, but B2 is exclusively activated by Epi

50
Q

How does Epi affect metabolism?

A
  • incre gluconeogenesis
  • incre glyconeogenesis
  • promotes lipolysis to incre circulating free fatty acids for energy
51
Q

what happens if you lose an adrenal gland?

A
  • If lose one adrenal gland, the other would undergo hypertrophy and hyperplasia to increase its hormone secreting capacity
52
Q

Define: Exocrine

A

Exocrine: glands that secrete their products through ducts opening into the epithelium rather than directly into the bloodstream

53
Q

Endocrine functions of the pancreas are localized to ____ ___

A

Endocrine functions of the pancreas are localized to islets of Langerhans

54
Q

What are the major types of cells in the islets of Langerhans

A

○ Alpha cell
§ Produce and secrete glucagon

○ Beta cell
§ Produce and secrete insulin

○ Delta cell
§ Produce and secrete somatostatin

○ PP cell
§ Secrete pancreatic polypeptide, which may play a role in reducing appetite

55
Q

What is the dominant hormone in the absorptive state of metabolism?

A

Insulin - released by beta cells of pancreatic islets
- also plays major role in anabolism

56
Q

What are the primary hormones responsible for growth in males vs females

A

Both = androgens and growth hormone

females = DHEA
males = testosterone

57
Q

Which of the hormones produced by the anterior pituitary is the most abundant?

A

Growth hormone

58
Q

Define:
Osteoblasts:
Osteoclast:

A

1) Osteoblasts: deposit new bone
2) Osteoclasts : dissolve bone

59
Q

Where does bone growth occur

A

Only occurs at the ends between the epiphysis and diaphysis in the epiphyseal plate

60
Q

Which hormone promotes the thickness and length of bone?

A

Growth hormone

61
Q

What causes Larson dwarfism

A

Laron dwarfism - caused by lack of response from tissue to growth hormone, responds to IGF-I treatment

62
Q

What 3 hormones regulate the plasma [] of Calcium?

A

○ Parathyroid hormone (PTH)
○ Calcitonin
○ Vitamin D

63
Q

What is the primary action of PTH

A

The primary action of PTH is to raise plasma Ca levels by its effects on bone, the kidneys and intestines

64
Q
A