Endocrine System Flashcards Preview

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Flashcards in Endocrine System Deck (26):
1

How hormones work

Hormones are secreted into the circulatory system
Hormones reach all parts of the body, but only affect cells that have a receptor for that hormone

2

Nervous system vs. endocrine system

Nervous system: fast and wired (ex-muscle contraction)
Endocrine system: slower and wireless (ex- growth and reproduction)

3

Endocrine signaling

Hormones are released into the blood and trigger signals anywhere

4

Paracrine signaling

Molecules trigger cells nearby

5

Autocrine signaling

Molecule triggers itself

6

Synaptic signaling

Neurotransmitter released from synapse triggers cell

7

Neuroendocrine signaling

Neurohormones released into blood from nerves trigger cells anywhere

8

Difference between endocrine and exocrine glands

Endocrine: ductless organs, release into bloodstream
Exocrine: ducts, release into a lumen

9

Tropic hormone

Causes release of other hormone

10

Path of hormone secretion

1. Neurosecretory cells of hypothalamus secrete first hormone
2. First hormone travels down portal vessels to anterior pituitary gland
3. Endocrine cells of anterior pituitary gland release second hormone
4. Second hormone travels out of anterior pituitary and into general circulation
5. Second hormone triggers target cells to release their hormones
6. Hormones from target cells take effect

11

3 major classes of hormones

Polypeptides and peptides (water soluble)
Amines (water soluble)
Steroids (lipid soluble)

12

Water soluble secretion pathway

Hormone is released from cell by exocytosis -> travels through bloodstream on its own (no carrier needed) -> binds to signal receptor on outside of target cell -> cytoplasmic response or gene regulation

13

Lipid soluble secretion pathway

Hormone diffuses through plasma membrane -> travels through bloodstream via protein carrier -> binds to signal receptor inside target cell -> gene regulation -> cytoplasmic response

14

Positive feedback

Reinforces stimulus, but must have end point
Example: oxytocin causes stretching of cervix -> more oxytocin -> more cervix stretching (endpoint: baby born)

15

Negative feedback

Decreases stimulus
Example: high glucose in blood causes release of insulin -> insulin causes decrease of glucose in blood

16

Insulin

Decreases blood glucose (causes body cells to take up glucose and causes liver to store glucose as glycogen)
Produced in pancreatic beta cells
Peptide

17

Glucagon

Increases blood glucose (causes liver to break down glycogen and release glucose into blood): opposite of insulin
Produced in pancreatic alpha cells
Peptide

18

Diabetes mellitus

Caused by deficiency of insulin or a decreased response to insulin in target tissues
Problem: elevated blood glucose levels
Damage to capillaries in kidneys, eyes, and feet
Become dehydrated

19

Type 1 diabetes mellitus

Autoimmune disorder: immune system destroys pancreatic beta cells
Juvenile onset
Treatment: insulin injections

20

Type 2 diabetes mellitus

Insulin deficiency or reduced response of target cells due to change in insulin receptors
Adult onset
Obesity is common cause
Treatment: diet and exercise (cells take up glucose)

21

Thyroid hormone

Pair of hormones: Triiodiothyronin (T3; 3 iodine atoms) and Thyroxine (T4; 4 iodine atoms)
Controls body metabolism
Steroid

22

Thyroid hormone cascade

TRH (thyrotropin-releasing hormone; hypothalamus) -> TSH (thyroid stimulating hormone; anterior pituitary) -> TH (thyroid hormone)
TH inhibits TSH and TRH

23

Hypothyroidism

Too little thyroid function
Symptoms: weight gain, lethargy, cold intolerance

24

Hyperthyroidism

Excessive production of thyroid hormone
Symptoms: high temperature, sweating, weight loss, irritability, high blood pressure

25

Graves' Disease

Form of hypothyroidism caused by autoimmunity
Symptom: protruding eyes

26

Goiter

Enlarged thyroid gland caused by insufficient dietary iodine