Untitled Deck

Question 1

What is the primary function of the endocrine system?

Answer 1

Facilitate communication across multiple organs to maintain whole body homeostasis

The endocrine system uses hormones as chemical messengers to achieve this.

Question 2

Define a hormone.

Answer 2

A chemical messenger that brings information from one cell to another to change the function of the recipient cell

Hormones travel through fluids, usually blood, to act on target cells.

Question 3

What are the three types of hormone signaling?

Answer 3

• Endocrine
• Paracrine
• Autocrine

Each type has a different mechanism of action based on the distance between the signaling and target cells.

Question 4

What is the role of the hypothalamus in hormone regulation?

Answer 4

Acts as a major control center that influences multiple body systems, including metabolism and growth

It receives neural input and regulates hormone release.

Question 5

How are hormones typically removed from circulation?

Answer 5

• Irreversible binding to target cell receptors
• Liver metabolism
• Renal excretion

These processes ensure that hormone levels are regulated in the bloodstream.

Question 6

True or false: Peptide hormones are stored in advance for rapid release.

Answer 6

TRUE

Peptide hormones are synthesized as prohormones and stored in vesicles until needed.

Question 7

What distinguishes steroid hormones from peptide hormones?

Answer 7

• Lipid-based
• Derived from cholesterol
• Not stored in cells

Steroid hormones are synthesized and secreted upon demand.

Question 8

Fill in the blank: Hormonal control occurs when one gland releases a hormone that acts on another gland to release another hormone. An example is the _______ gland secreting ACTH.

Answer 8

pituitary

This process illustrates the interconnectedness of endocrine glands.

Question 9

What is pulsatile hormone release?

Answer 9

A pattern where hormone is released in pulses or waves

This release pattern is essential for maintaining target cell receptiveness.

Question 10

What are the two major classes of hormones?

Answer 10

• Peptide hormones
• Steroid hormones

Amines are a subtype of peptide hormones with unique characteristics.

Question 11

What is the half-life of a hormone?

Answer 11

The time in which the plasma concentration of a hormone decreases to 50% of its initial concentration

Hormones with a longer half-life have a longer duration of action.

Question 12

How do peptide hormones elicit rapid responses?

Answer 12

By binding to receptors on the cell surface

This leads to activation of secondary messengers and rapid physiological changes.

Question 13

What is the role of intracellular receptors for steroid hormones?

Answer 13

Alter gene transcription in response to binding

This can either promote or repress transcription of target genes.

Question 14

What is negative feedback in hormone regulation?

Answer 14

An inhibitory signal that leads endocrine cells to stop releasing their hormone

This process helps maintain homeostasis in the body.

Question 15

What is the significance of glycosylation in peptide hormones?

Answer 15

Increases specificity for cell surface receptors and extends half-life in circulation

This modification helps protect the hormone from degradation.

Question 16

What is an example of a hormone that follows a circadian rhythm?

Answer 16

Cortisol

Cortisol levels peak in the morning to help with waking up after sleep.

Question 17

What happens to hormone levels during stress?

Answer 17

They may increase due to the body’s response to stressors

Stress can influence the secretion patterns of various hormones.

Question 18

What is the half-life of steroid hormones compared to peptide hormones?

Answer 18

Steroid hormones have a longer half-life

This is due to their binding to plasma proteins, which protects them from metabolic clearance.

Question 19

Peptide hormones have a rapid onset of action due to their ability to travel _______ in plasma.

Answer 19

free

Peptide hormones are not bound to plasma proteins.

Question 20

What are the two major classes of hormones discussed?

Answer 20

• Peptide hormones
• Steroid hormones

Each class has distinct characteristics regarding their action and metabolism.

Question 21

True or false: Steroid hormones are synthesized when released upon demand.

Answer 21

TRUE

They are lipid-based hormones that travel bound to plasma proteins.

Question 22

What is the concept of dynamic equilibrium in hormone binding?

Answer 22

The percentage of protein-bound versus free hormone stays consistent

This is maintained under normal circumstances despite fluctuations in free hormone levels.

Question 23

What factors can influence the percentage of free hormone in circulation?

Answer 23

• Nature of the hormone
• Amount of plasma protein available
• Presence of other pathologies

These factors can affect the binding dynamics of hormones.

Question 24

What is the equation for total hormone in circulation?

Answer 24

Total hormone = Free hormone + Bound hormone

This equation accounts for both active and inactive forms of the hormone.

Question 25

What are the two main types of **hormone assays** used clinically?

Answer 25

* Radioimmunoassay (RIA) * Enzyme-linked immunosorbent assay (ELISA) ## Footnote Both assays are quick and easy to perform for measuring hormone levels.

Question 26

Dynamic testing involves examining multiple time points or assessing responses due to a _______.

Answer 26

stimulus or inhibitor ## Footnote This approach helps in understanding hormone dynamics over time.

Question 27

What is the purpose of **stimulation tests** in hormone testing?

Answer 27

To evaluate the endocrine organ's ability to release its hormone ## Footnote These tests are used when baseline hormone levels are low.

Question 28

What happens to hormone levels during a **suppression test**?

Answer 28

Baseline hormone levels are measured, then an inhibitor is given to reduce hormone levels ## Footnote This tests the organ's ability to respond to negative feedback.

Question 29

In the normal thyroid axis, TRH stimulates the anterior pituitary to secrete _______.

Answer 29

thyroid stimulating hormone (TSH) ## Footnote TSH then stimulates the thyroid gland to release thyroid hormones.

Question 30

If the anterior pituitary gland is damaged, what happens to TSH secretion?

Answer 30

TSH levels would be decreased ## Footnote This results in decreased thyroid hormone release due to lack of stimulation.

Question 31

What occurs if the thyroid gland is damaged?

Answer 31

T3 and T4 levels would be decreased ## Footnote This leads to a lack of negative feedback on the hypothalamus, causing increased TRH levels.

Question 32

The endocrine system is described as being very _______.

Answer 32

dynamic ## Footnote Changes in one part of the system can affect multiple other components.