BIOL 1412 > TOPIC 7 - ENDOCRINE SYSTEM > Flashcards

TOPIC 7 - ENDOCRINE SYSTEM Flashcards

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1
Q

What does the endocrine system regulate?

(Overview)

A
  • Growth
  • Reproduction
  • Metabolism
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2
Q

Glands and tissues secrete hormones which travel in blood to____?

(Overview)

A

Glands and tissues secrete hormones which travel in blood to target cells where they will bind to receptors and change cell activity

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3
Q

What are target cells?

(Overview)

A

Cells of an effector tissue/organ that have specific receptors for that hormone

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4
Q

Where are receptors (proteins) found?

(Overview)

A
  • On cell membrane
  • Intracellular (nuclear)
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5
Q

What are the 2 hormone types?

(Hormone Types & Actions)

A
  • Water soluble hormones
  • Lipid soluble hormones
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6
Q

T or F:

Water soluble hormones are able to cross the hydrophobic areas of the phospholipid bilayer naturally.

(Hormone Types & Actions)

A

FALSE
* Water soluble hormones are NOT able to cross the hydrophobic areas of the phospholipid bilayer, so they must bind to receptors on the cell membrane

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7
Q

What do water soluble hormones include?

(Hormone Types & Actions)

A
  • Peptides
  • Proteins
  • Catecholamines

That act as ‘1st messengers’ in a signalling cascade

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8
Q

Describe the mechanism of action for water soluble hormones.

(3)

(Hormone Types & Actions)

A

1) Hormone binds to cell membrane receptors (doesnt enter cell)
2) Hormone-receptor complex activates membrane proteins
3) Membrane proteins then activate 2nd messenger systems

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9
Q

Using cAMP (cyclic adenosine monophosphate) as second messenger, describe the mechanism of action for water soluble hormones.

(5)

(Hormone Types & Actions)

A

1) Hormone binds to cell-surface receptor and activates G-protein
2) G-protein activates adenylate cyclase (membrane protein)
3) Adenylate cyclase converts ATP to cAMP (2nd messenger) therefore the concetration of cAMP in cytosol ↑
4) cAMP activates protein kinases (in cytosol)
5) Protein kinae acts on other proteins to alter their activity, which changes cell activity

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10
Q

Using cAMP, describe epinephrine action on liver cells.

(3)

(Hormone Types & Actions)

A

1) cAMP activates protein kinase A
2) Protein kinase A activates metabolic proteins (enzymes) that cause breakdown of glycogen to glucose
3) Glucose is released into blood

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11
Q

Why do we use 2nd messenger systems?

(4)

(Hormone Types & Actions)

A

1) Hormone cant enter cell (cuz water soluble)
2) Rapid acting bc enzymes are already present (just need activating)
3) 1 hormone molecule activates many enzyme molecules (cascade) which multiplies signal
4) Limited - messenger broken down or removed

e.g. cAMP broken down after use

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12
Q

What are lipid soluble hormones?

(Hormone Types & Actions)

A

Steroids

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13
Q

What do lipid soluble hormones trigger?

(Hormone Types & Actions)

A

Protein synthesis

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14
Q

T or F:

Lipid soluble hormones cause quick, short responses

(Hormone Types & Actions)

A

FALSE
* Response is slow but long lasting

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15
Q

Describe the mechanism of action for lipid soluble hormones.

(3)

(Hormone Types & Actions)

A

1) Enter target cell & bind to intracellular (nuclear) receptors in cytosol/nucleus
2) Hormone-receptor complex binds to specific region on DNA (activates genes) → starts gene transctiption → produces mRNA
3) mRNA attaches to ribosomes to produce proteins (translation)

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16
Q

Stimuli acting on an endocrine gland may be____?

(3)

(Regulation of Hormone Secretion into Blood)

A
  • Humoral stimulus
  • Neural stimulus
  • Hormonal stimulus
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17
Q

What is a humoral stimulus?

(Regulation of Hormone Secretion into Blood)

A

Stimulus for hormone relase is changes in the concentration of of a particular ion or nutreint in the blood

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18
Q

An ↑ in blood glucose & a ↓ in blood Ca++ is what kind of stimulus?

(Regulation of Hormone Secretion into Blood)

A

Humoral stimulus

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19
Q

What occurs after an ↑ in blood glucose?

(Regulation of Hormone Secretion into Blood)

A

Pancreatic β-cells (islets of langerhans) detect glucose and realse insulin = ↓ blood glucose

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20
Q

What happens when there is a ↓ in blood Ca++ levels?

(Regulation of Hormone Secretion into Blood)

A

Parathyroid gland detects ↓ Ca++ and releases parathyroid hormone (PTH) = ↑ bone reabsorption
* ↑ osteoclast activity
* ↓ osteoblast activity
* = ↑ blood Ca++

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21
Q

Give 2 examples of a neural stimulus

(Regulation of Hormone Secretion into Blood)

A
  • Heart rate
  • Uterine contractions
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22
Q

Illustrate how uterine contractions are a neural stimulus.

(Regulation of Hormone Secretion into Blood)

A

Unterine contraction → hypothalamus → posterior pituitary (NS)
↓
Oxytocin
↓
Begin again (postive feedback loop)

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23
Q

Illustrate how HR is a neural stimulus.

(Regulation of Hormone Secretion into Blood)

A

Resting HR
↓”suprise”
SNS - preganglionic directly to
↓ nt=ACh
Adrenal medulla
↓ Epinephrine + NE
=↑ HR + force of contraction

(moving out of homeostasis in a controlled manner)

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24
Q

Give an example of a hormonal stimulis

(Regulation of Hormone Secretion into Blood)

A

Metabolism

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25
Illustrate how metabolism is a hormonal stimulus ## Footnote (Regulation of Hormone Secretion into Blood)
Low metabolism ↓ Hypothalamus: **thyrotropin-releasing hormone (TRH)** ↓ Ant. Pituitary: **throid-stimulating hormone (TSH)** ↓ Thyroud gland: **Thyroxin (T4)** (inhibits TRH & TSH) ↓ T4 to T3 (in target tissue/liver) ↓ =↑ metabolism
26
What is stress? ## Footnote (Physiological Response to Stress)
Any extreme external/internal stimulus | e.g. surgery, infections, strong emotions, exams
27
What does stress trigger? ## Footnote (Physiological Response to Stress)
A set of body changes called **General Adaptation Syndrome**
28
The General adaptation syndrome is co-ordinated indirectly/directly bt the____? ## Footnote (Physiological Response to Stress)
Hypothalamus
29
What are the 3 phases of general adaptation syndrome? ## Footnote (Physiological Response to Stress)
1) Alarm reaction 2) Resistance Reaction 3) Exhaustion
30
Illustrate the immediate (NS) response of the alarm reaction phase (phase 1) ## Footnote (Physiological Response to Stress)
CNS (Sensory input - detect change) ↓ Hypothalamus (RAS; ↑ Alertness) ↓ ----------SNS ------↙--------↘ Organs--------Adrenal medulla ----------------------------↓ --------------------------E+NE
31
What are the 5 effects of SNS + endocrine system during phase 1 of GAS? ## Footnote (Physiological Response to Stress)
1) ↑ blood glucose (SNS inhibits insulin release, E+NE trigger conversion of glycogen to glucose in liver) 2) ↑ HR 3) ↑ Respiratory rate 4) ↓ blood flow to skin + abdominal viscera (so more is availible to brain, skel. + card. muscle 5) ↓ digestion + urine production
32
What occurs during the resistance reaction (phase 2)? ## Footnote (Physiological Response to Stress)
* Long term = endocrine * Permits recovery from the effects of phase 1 **OR** response to longer term stress (e.g. starvation)
33
What hormones initaite the resistance reaction phase (2)? ## Footnote (Physiological Response to Stress)
Hypothalamic hormones
34
Illustrate the resistance reaction phase (2). ## Footnote (Physiological Response to Stress)
Hypothalamus GHRH↓↓CRH -----Ant. Pit. ---↙---------↘ACTH GH-----Adrenal cortex ----------------↓ -------------Cortisol (gluticorticoid) ## Footnote Growth hormone releasing hormone (GHRH), corticotropin releasing hormone (CRH), growth hormone (GH), adrenocorticotropic hormone (ACTH)
35
What does GH do? ## Footnote (Physiological Response to Stress)
Stimulates growth (protein production), cell reproduction
36
When is cortisol released? When does the response? ## Footnote (Physiological Response to Stress)
* Released within 30s of the stress * Response is not for hours (steroid hormone)
37
What does cortisol do? ## Footnote (Physiological Response to Stress)
Inhibits insulin release
38
What hormones are released during the resistence reaction phase? What releases them? ## Footnote (Physiological Response to Stress)
* **Hypothalamus:** GHRH, CRH * **Ant. Pit.:** GH, ACTH * **Adrenal cortex:** Cortisol
39
What are the 3 effects due to the release og hormones during the resistance reaction phase (2)? ## Footnote (Physiological Response to Stress)
1) ↑ blood glucose 2) Inhibition of immune system, bone formation, formation of CT 3) Release of aldosterone and antidieretic hormone (ADH) (reduces salt + water loss @ kidney to maintain blood volume)
40
Why is there an ↑ of blood glucose during phase 2? ## Footnote (Physiological Response to Stress)
* Liver is stimulated to produce new glucose from fats + proteins * Little insulin due to inhibition so glucose isnt taken up well by muscle * Glucose is spared for NS * Non-NS tissue uses fats + protein for energy * Overall: ↑ blood FA + AA = energy (except for brain) | TLDR: For NS to use best energy source over other tissues
41
Why is there an ↑ for type 2 diabetes after experiencing lots of stress? ## Footnote (Physiological Response to Stress)
Bc of all the ↑ in blood glucose during phase 2
42
What are the long term effects of phase 2? | (6) ## Footnote (Physiological Response to Stress)
* ↓ weight * ↑ BP * ↑ HR * Immune system suppression * ↓ bone density * ↑ risk of type 2 diabetes
43
What is phase 3 of GAS? ## Footnote (Physiological Response to Stress)
Exhaustion
44
What does pahase 3 result from? | (3) ## Footnote (Physiological Response to Stress)
* Depletion of body respurces (i.e. lipid reserves) * Loss of K+ * Damage to organs (heart, kidneys, liver)
45
What is the aldosterone effect? ## Footnote (Physiological Response to Stress)
The loss of K+ during phase 3 due to stress
46
Illustrate male hormones after puberty, including what releases them. ## Footnote (Testicular Hormones)
**Hypothalamus:** Gonadotropin releasing hormone (GnRH) ---------------↓-----------------↓ **Ant. Pit.:** LH --------------FSH ---------------↓------------------↓ **Testes:** Testosterone----Spermatogenesis | Luteinizing hormone (LH), follicle stimulating hormone (FSH)
47
What are the 4 functions of testosterone? ## Footnote (Testicular Hormones)
1) Development of organs in reporductive tract + secondary sex characteristics 2) Stimulates bone growth at epiphyseal plate 3) Promotes protein anabolism 4) Directly stimulates spermatogenesis
48
# T or F: Testosterone is converted to estrogen in the epiphyseal plate to stop growth and close the plate. ## Footnote (Testicular Hormones)
**TRUE**
49
Illustrate female hormones after puberty, including what releases them. ## Footnote (Ovarian Hormones)
**Hypothalamus:** GnRH ----------------------↙-------↘ **Ant. Pit.:** ----LH-→→------FSH -------------------↓-------↓→-----↓ **Ovaries:** Ovulation ---↓----Follicles Develop ------------------------------→→→→→↓ ---------------------------------------Estrogen
50
What is the function of FSH? ## Footnote (Ovarian Hormones)
Stimulates 1º to become 2º follicles
51
What is FSH inhibited by? ## Footnote (Ovarian Hormones)
Progesterone * Therefore FSH ↑ when progesterone ↓ & vice versa
52
What does LH stimulate? ## Footnote (Ovarian Hormones)
**Estrogen production** from **theca** & **granulosa** cells of follicle
53
What does a surge of LH cause? ## Footnote (Ovarian Hormones)
**Ovulation** & then formation of **corpus luteum** from remanents of follicle
54
What does LH do during the follicular & luteal phases? ## Footnote (Ovarian Hormones)
* **Folliclular:** Estogen from 2º follicle rises for a few days → LH release (via GnRH) → Stim. follicle to ↑ E secretion (positive feedback) → Lh surge * **Luteal:** progesterone inhibits LH release
55
What is estrogen required for? ## Footnote (Ovarian Hormones)
* Ovulation * Development of 2º sex characteristics
56
What does estrogen stimulate? ## Footnote (Ovarian Hormones)
* Growth & maintains the endrometrium * Bown growth during puberty & later in life; closure of epiphyses
57
What is progesterone formed from? ## Footnote (Ovarian Hormones)
Corpus luteum
58
What does progesterone prepare the uterus for? ## Footnote (Ovarian Hormones)
Pregnancy
59
How many days total are Ovarian/Uterine Cycles? ## Footnote (Ovarian/Uterine Cycles)
~28 days
60
What occurs during days 1-14 for the ovary? ## Footnote (Ovarian/Uterine Cycles)
* Early on: P low; LH + FSH secreted - some 1º follicles → 2º follicles * Follicles secrete E → blood E rises * Later on: one 2º follicle becomes vesicular follicle | P = progesterone
61
What occurs during days 1-14 for the uterus? ## Footnote (Ovarian/Uterine Cycles)
* Menstral phase (1-5) * Proliferative phase (6-14)
62
What occurs during the menstral phase? ## Footnote (Ovarian/Uterine Cycles)
* Stratum functionalis shed (outer layer of endometrium) & denuded areas bleed * Menstrual flow = blood, cells, & secretions
63
What occurs during the Proliferative phase? ## Footnote (Ovarian/Uterine Cycles)
E → repair + proliferation of stratum functionalis (due to mitosis in statum basalis
64
What occurs on day 14? ## Footnote (Ovarian/Uterine Cycles)
Ovulation
65
Ovulation (day 14) is due to what? ## Footnote (Ovarian/Uterine Cycles)
**LH surge**, which triggers: * Completion of meiosis 1→2º oocyte * Rupture of vesicular follicle with relase of 2º oocyte
66
What happens to the ovary during days 15-28? ## Footnote (Ovarian/Uterine Cycles)
**Luteal phase** * High P from corpus luteum inhibits GnRH = no follicles develop
67
What happens to the uterus during days 15-28? ## Footnote (Ovarian/Uterine Cycles)
**Secretory phase**
68
What does progesterone from corpus luteum do to the uterus during the secretory phase (days 15-28)? ## Footnote (Ovarian/Uterine Cycles)
* Prepares endometrium for implantation - becomes bascular, thick, & stores glycogen * Inhibits uterine contractions
69
If fertilization occurs during the Ovarian/Uterine Cycle, what happens? | (3) ## Footnote (Ovarian/Uterine Cycles)
* Placenta secretes **human chorionc gonadotropin** (hCG) - hCG maintains corpus luteum (similar structue to LH) * Corpus luteum → secretes P, E for about **6 weeks**, then placenta takes over (secretes P & E) * FSH, LH inhibited by high P (no new follicles)
70
# T or F: If progesterone is high, new follicles develop slowly. ## Footnote (Ovarian/Uterine Cycles)
**FALSE** * **NO** new follicles develop
71
What occurs if no fertilization occurs during the Ovarian/Uterine Cycle? | (2) ## Footnote (Ovarian/Uterine Cycles)
* Corpus luteum → **corpus albicans** (no hCG, low LH) * ↓ P & E = no longer inhibit LH & FSH = ↑ LH & FSH; no longer inhibit menstruation = menstruation
72
What are the 3 Endocrine Contraceptives? ## Footnote (Endocrine Physiology of Contraceptives)
* Oral contraceptives * Implants * Moring after pill
73
How do oral contraceptives work? ## Footnote (Endocrine Physiology of Contraceptives)
High P & E = inhibit GnRH secretion → low FSH & LH * No follicle maturation, no ovulation
74
Which contraceptives mimic the luteal phase? ## Footnote (Endocrine Physiology of Contraceptives)
Oral contraceptives
75
What is an example of an implant secretion? ## Footnote (Endocrine Physiology of Contraceptives)
Progestin - similar mechanism to oral contraceptives
76
How does the morning after pill work? ## Footnote (Endocrine Physiology of Contraceptives)
* High E & Progestin or Progestin only * Prevents implantation, ovulation, or fertilization
77
What is the placenta formed from? ## Footnote (Physiological Role of the Placenta)
Chorion (fetus) & Endometrium (maternal)
78
# T or F: Due to the close proximity of the Fetus' & Mother's blood, they mix to share nutients & antibodies. ## Footnote (Physiological Role of the Placenta)
**FALSE** * **NO** blood mixing, just close proximity
79
What are the functions of the placenta? ## Footnote (Physiological Role of the Placenta)
* Exhcange site * Secretes nutrients
80
What can be exchanged at the placenta? | (7) ## Footnote (Physiological Role of the Placenta)
* Gases * Nutrients * Wastes * Hormones * Antibodies * Drugs (Alchohol, morphine) * Viruses (measles, polio)
81
What is secreted by the placenta? ## Footnote (Physiological Role of the Placenta)
* E & P * hCG
82
What does the secretion of hCG at the placenta do? ## Footnote (Physiological Role of the Placenta)
* Maintains corpus luteum for ~6 weeks post fertilization * Is what is detected by pregnancy tests * Stimulates testosterone secretion by fetal testes
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