Bio of Psychology: The Endocrine System

Question 1

The ____ is fast-acting with relatively short term effects

Answer 1

nervous system

Question 2

The ____ takes longer to communicate signals but has generally longer lasting effects

Answer 2

endocrine system

–> regulates physiology (especially metabolism) over a period of hours to days

Question 3

Can neurons signal the release of hormones from endocrine glands?

Answer 3

Yes

Question 4

Primary connection btw the nervous and endocrine systems (axis)

Answer 4

Hypothalamic-pituitary axis

Question 5

Hormone

Answer 5

Signal of the endocrine system, secreted into the bloodstream by an endocrine gland, and has effects on distant target cells possessing the appropriate receptor

Question 6

Endocrine Gland

Answer 6

Ductless gland whose secretory products are picked up by capillaries supplying blood to the region

Question 7

Exocrine glands

Answer 7

Secrete their products into the external environment by way of ducts, which empty into the gastrointestinal lumen or the eternal world

Question 8

Hormone receptor (what is it?)
What happens when ligand (hormone) binds?

Answer 8

A polypeptide that has a ligand-specific binding site

When hormone binds to the site it causes the receptor to modify target cell activity

Question 9

2 classes of hormones:

Answer 9

Hydrophilic hormones: peptides and amino-acid derivatives-must bind to receptors on the cell surface
Hydrophobic hormones: steroid hormones-bind to receptors in the cellular interior

Question 10

Peptide Hormones

Answer 10

Synthesized in rough ER, modified in golgi
Stored in vesicles until needed and then released by exocytosis
Hydrophilic, so dissolve in plasma in bloodstream
Communicate with interior of target cell by second messenger cascades

Question 11

What activates the second messenger cascade?

Answer 11

The polypeptide receptor with a domain on the inner surface of the plasma membrane

Question 12

End result of 2nd messenger activation?

Answer 12

The function of proteins in the cytoplasm has changed

Question 13

Key feature of 2nd messenger cascade?

Answer 13

Signal amplification, which allows a few activated receptors to change the activity of many enzymes in the cytoplasm

Question 14

What do peptide hormones do and how long are their effects?

Answer 14

They modify modify the activity of existing enzymes in the cytoplasm, so their effects are exerted rapidly, minutes to hours from the time of secretion and duration of effects is brief

Question 15

2 subgroups of peptide hormones:

Answer 15

Polypeptides and amino acid derivatives

Question 16

Ex. Insulin

Answer 16

• Polypeptide Hormone
• Complex tertiary structure involving disulfide bridges
• Secreted by B cells of the pancreatic islets of langerhans in response to elevated blood glucose and binds to a cell-surface receptor with a cytoplasmic domain possessing protein kinase activity

Question 17

Amino Acid derivatives

Answer 17

Derived from a single amino acid and contain to peptide bonds

Question 18

Ex. Catecholamines (includes epinephrine) and thyroid hormones

Answer 18

• Tyrosine is parent amino acid for these

- Catecholamines act like peptide hormones and thyroid hormones are more like steroid hormones

Question 19

Epinephrine

Answer 19

Small cyclic molecule secreted by the adrenal medulla upon activation of the sympathetic nervous system; binds to cell-surface receptors to trigger a cascade of events that produces the 2nd messenger cAMP and activates protein kinases in the cytoplasm

Question 20

Thyroid hormones

Answer 20

Incorporate iodineinto structure

Enter cell, bind to DNA, and activate transcription of genes involved in energy mobilization

Question 21

Steroid hormone

Answer 21

• Hydrophobic
• Synthesized from cholesterol in the smooth ER
• Freely diffuse through biological membranes
• Not stored and diffuse into bloodstream as soon as they are made (if it’s not needed it won’t be made)
• Hydrophobic, so can NOT be dissolved in the plasma, so they journey through bloodstream stuck to proteins in the plasma, such as albumin
• Steroid stays bound to plasma protein by hydrophobic interactions, no bonds
• Exerts effects by diffusing through plasma membrane to bind to receptor in the cytoplasm
• Once it binds ligand, the steroid hormone-receptor complex is transported to the nucleus, where it acts as a sequence-specific regulator of transcription

Question 22

What do steroid hormones do and how long are their effects?

Answer 22

They modify transcription by changing the amount and/or type of proteins in the cell
Their effects are exert slowly, over a period of days, and persist for days to weeks

Question 23

Steroids regulating sexuality, reproduction, and development are secreted by:

Answer 23

The testes, ovaries, and placenta

Question 24

Steroids regulating water balance and other processes are secreted by”

Answer 24

The Adrenal Cortex

Question 25

All other endocrine glands secrete:

Answer 25

Peptide hormones | **Thyroid hormone is derived from an amino acid but behaves more like a steroid hormone

Question 26

Regulation of the endocrine system is not preplanned or structured but: (and type of regulation)

Answer 26

Automatic - Hormone levels rise and fall according to physiological needs - Feedback regulation

Question 27

Ex. of feedback regulation with calcitonin and serum [Ca2+]

Answer 27

- Function of calcitonin is to prevent serum [Ca2+] from peaking above normal levels - The amount of calcitonin secreted is directly proportional to increases in serum [Ca2+] above normal - When Ca2+ become elevated, calcitonin is secreted - Then when Ca2+ levels fall, calcitonin secretion stops - Falling Ca2+ levels (that which is regulated) feeds back to the cells which secrete calcitonin (regulators) - Ca2+ levels is a physiological endpoint which must be maintained at constant levels - ->This demonstrates the role of the endocrine system in maintaining homeostasis, or physiological consistency

Question 28

Tropic Hormones

Answer 28

Hormones that regulate hormones Meta-Regulators, superimposed upon the hormonal regulation of physiological endpoints Feedback regulation applies to tropic hormones, ex. level of ACTH is influenced by the level or cortisol; when cortisol is needed, ACTH is secreted, and when the serum [cortisol] increases enough, ACTH secretion slows

Question 29

Tropic Hormone ex. ACTH

Answer 29

- Secreted by the anterior pituitary - Role is to stimulate increased activity of the adrenal cortex, which is responsible for secreting cortisol - This is a tropic hormone because it does not directly affect physiological endpoints, but regulates another regulator (cortisol)

Question 30

Cortisol

Answer 30

Regulates physiological endpoints, including cellular responses to stress and serum [glucose]

Question 31

Hypothalamus

Answer 31

Controls much of the endocrine system; located at the center of the brain Controls the endocrine system by releasing tropic hormones that regulate other tropic hormones-->called releasing and inhibiting factors/hormones Ex. hypothalamus secretes CRH, whose role is to cause increased secretion of ACTH ACTH secretion is regulated by feedback inhibition from cortisol, and CRH secretion is also inhibited by cortisol --> Controls the anterior pituitary which controls most of the endocrine system

Question 32

Hypothalamic-pituitary control axis

Answer 32

The hypothalamus exerts its control of the pituitary by secreting hormones into the bloodstream, just like any other endocrine gland

Question 33

Hypothalamic-pituitary portal system

Answer 33

Special mini circulatory system provided for efficient transport of hypothalamic releasing and inhibiting factors to the anterior pituitary Blood supply

Question 34

Pressure drops or increases in the capillaries??

Answer 34

DROPS

Question 35

Hepatic Portal System

Answer 35

Form gastrointestinal tract to the liver

Question 36

Anterior Pituitary also known as:

Answer 36

Adenohypophysis

Question 37

Posterior pituitary also known as:

Answer 37

Neurohypophysis

Question 38

Anterior Pituitary

Answer 38

-Normal endocrine gland controlled by hypothalamic releasing and inhibiting factors (tropic hormones)

Question 39

Posterior Pituitary

Answer 39

- Composed of axons which descend form the hypothalamus - Hypothalamic neurons that send axons down to the posterior pituitary are an example of neuroendocrine cells, which are neurons that secrete hormones into the bloodstream

Question 40

Hormones of the posterior pituitary

Answer 40

ADH (or vasopressin)-causes the kidney to retain water in times of thirst Oxytocin-causes milk let-down fro nursing as well as uterine contractions during labor

Question 41

All hypothalamic and pituitary hormones are what kind of hormone?

Answer 41

Peptides

Question 42

Thyroid Hormone

Answer 42

- Produced from AA tyrosine in thyroid gland and comes in 2 forms, with 3 or 4 iodine atoms per molecule - Production of thyroid hormone is increased by TSH from the anterior pituitary, which is regulated by the hypothalamus and the CNS - Thyroid hormone binds to receptor in cytoplasm of cells and then regulates transcription in the nucleus

Question 43

Effect of regulation of thyroid hormone on transcription in nucleus?

Answer 43

To increase overall metabolic rate and body temp, and in children to stimulate growth --> exposure to cold can increase the production of of thyroid hormone

Question 44

Cortisol

Answer 44

- Secreted by the adrenal cortex in response to ACTH from the pituitary - The effects of cortisol help the body deal with stress - Also helps to mobilize glycogen and fat stores to provide energy in times of stress and also increases the consumption of proteins fro energy

Question 45

What effect does an inhibitor of protein synthesis have on thyroid hormone?

Answer 45

Effects would not be seen because TH binds to a receptor that regulates transcription , and the mRNA stimulated by TH receptor in the nucleus must be processed and translated before effects of TH are seen