Endocrine system

Question 1

Endocrine organs:

Answer 1

Organs that release chemical signals that circulate in the blood: Hormones and neurohormones.

Question 2

Major classes of hormones:

Answer 2

Steroid hormones

Protein & peptide hormones

Amine hormones.

Question 3

Steroid hormones:

Answer 3

Derived from cholesterol.

Not stored within secretory cells and are synthesized on demand.

Question 4

Hormone-receptor complex:

Answer 4

A transcription factor that regulates the transcription of particular genes.

They regulate protein synthesis.

Question 5

Protein & Peptide hormone:

Answer 5

Composed of amino acids.

Each P&P hormone is encoded by a gene.

After synthesis, they are modified into pre-prohormones.

Question 6

Pre-prohormone:

Answer 6

A new synthesized structure that contains a signal peptide that directs synthesis to the endoplasmic reticulum rather than to the cytosol.

Question 7

What happens if the signal peptide is removed:

Answer 7

The hormone becomes an inactive prohormone.

Question 8

Inactive prohormone:

Answer 8

They are processed into active hormones within the vesicles and stored inside vesicles until they are released via exocytosis.

Question 9

Receptors for protein & peptide hormone:

Answer 9

They are embedded in target cell membranes.

Binding activates a secondary messenger inside the target cell.

Question 10

Receptors for steroid hormones:

Answer 10

Located in the ICF of target cells.

Question 11

Signal transduction:

Answer 11

Binding activates events inside the cell.

EX: Protein & Peptide hormone.

Question 12

Amine Hormones:

Answer 12

Derived from either tyrosine or tryptophan.

They are stored (in vesicles) after synthesis, and when the endocrine cell is stimulated.

Question 13

What determines the strength and response of the target cell:

Answer 13

The concentration of the hormone in the ECF is a primary determinant.

Question 14

How can you achieve a graded response:

Answer 14

1.) By keeping receptor number constant and changing the hormone concentration. *[more common]

2.) By changing receptor numbers and keeping hormone concentration constant.

Question 15

Hormone concentration can be changed by:

Answer 15

1.) Altering the rate of release from endocrine cells. This normally varies.

2.) Altering the rate of degradation in the ECF. [Degradtion is normally constant].

Question 16

The ECF is filled with:

Answer 16

Enzymes that degrade hormones.

Question 17

Hormone Half-life:

Answer 17

A measure of hormone persistence in the ECF.

The amount of time it takes for half of the hormone molecules to be removed from the ECF.

Question 18

What can affect the half-life of a hormone:

Answer 18

Carrier proteins can extend the half-life of proteins considerably.

Question 19

Carrier proteins:

Answer 19

Binds to hormones in the ECF and transports them in the blood.

They prolong hormone half-life, as they protect the from degradation.

Increase the solubility of non-polar hormones in the blood.

Question 20

Hypothalamus:

Answer 20

A small region within the inferior part of the brain.

Question 21

Pituitary gland:

Answer 21

Divided into the anterior and posterior lobe.

Question 22

What connects the hypothalamus to the pituitary gland:

Answer 22

The infundibulum.

Question 23

Anterior lobe:

Answer 23

Made up of endocrine cells.

Produces 6 different hormones.

Question 24

Posterior lobe:

Answer 24

Made up of neural tissue.

Question 25

The posterior lobe consists of:

Answer 25

Axon terminal & capillaries associated with the axon terminal.

Question 26

The cell bodies of the neurosecretory cells are located:

Answer 26

Within the hypothalamus and are localized in two clusters

Question 27

Two clusters of the cell bodies:

Answer 27

Supraoptic nucleus [SON]. Paraventricular nucleus [PVN].

Question 28

PVN & SON produce:

Answer 28

Two peptide hormones: 1.) Anti-diuretic hormones [Vasopressin] 2.) Oxytocin.

Question 29

ADH & Oxytocin are released:

Answer 29

From the axon terminal within the posterior lobe.

Question 30

ADH & Oxytocin are made up of:

Answer 30

9 amino acids on chromosome 20.

Question 31

Direct acting hormone:

Answer 31

Exert their effects on non-endocrine organs. EX: Prolactin & Growth hormone.

Question 32

Tropic hormone:

Answer 32

Regulate hormones produced by other endocrine organs.

Question 33

Growth Hormone:

Answer 33

Regulate metabolism & nutrient utilization.

Question 34

Prolactin:

Answer 34

Acts on the breast. Promotes milk synthesis.

Question 35

LH and FSH affect:

Answer 35

Affects sex hormone and gamete production in the gonads. Testis & Ovary.

Question 36

The adrenocorticotropic hormone [ACTH] affects:

Answer 36

Glucocorticoid hormone production in the adrenal cortex.

Question 37

Thyroid stimulating hormone:

Answer 37

Affects thyroid hormone production in the thyroid glands.

Question 38

What regulates the hormone production in the anterior lobe:

Answer 38

The hypothalamus. They are released by neurosecretory cells whose cell bodies are located in the PVN.

Question 39

Hormones of neurosecretory cells that are located within the hypothalamus are:

Answer 39

Released into a special capillary network that drains into portal veins that carry blood directly to the anterior lobe.

Question 40

How many hormones are produced in the hypothalamus:

Answer 40

7 hormones, each produced by different neurosecretory cells. Each neurohormone affects the release of a specific hormone from the anterior lobe.

Question 41

A high TSH level means:

Answer 41

There are low thyroid hormones.