Chemical messengers synthesized and secreted by endocrine glands are called?

UPUMS Nsg officer-2023

Applied Physiology

Easy

Appeared in: UPUMS Nsg officer-2023

Explanation

Hormones are defined as chemical substances produced by endocrine glands.
They are secreted directly into the bloodstream, which transports them to target cells and organs throughout the body.
Their primary role is to act as messengers, regulating various physiological processes like growth, metabolism, mood, and reproduction.
This matches the description in the question perfectly.

Option A: Enzymes are biological catalysts, primarily proteins, that speed up biochemical reactions. They are not typically used for long-distance signaling between glands and target organs.
Option C: Neurotransmitters are chemical messengers used by the nervous system to transmit signals across a very short distance—the synaptic cleft—between a neuron and another cell (neuron, muscle, or gland). They do not travel through the bloodstream to reach distant targets.
Option D: Catalyst is a broad, general term for any substance that increases the rate of a chemical reaction without being consumed. While enzymes are biological catalysts, 'hormone' is the specific term for the signaling molecules produced by endocrine glands.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Definition and function of hormones in the endocrine system as background academic context rather than a clinical decision trigger.
Understanding the role of hormones is fundamental to nursing, as many diseases involve hormonal imbalances (e.g., diabetes mellitus, hypothyroidism, Cushing's syndrome).
Nurses are responsible for administering hormonal medications (like insulin or levothyroxine), monitoring patients for signs of endocrine dysfunction, and educating them about their conditions.
What if? - If a chemical messenger only affects cells immediately next to the secreting cell without entering the bloodstream, it's called paracrine signaling (e.g., histamine). This is a different mechanism from the long-distance endocrine signaling described in the question.

How to Approach the Question

First, identify the key terms in the question: 'chemical messengers' and 'endocrine glands'.
Recall the basic definitions related to the body's two main communication systems: the nervous system and the endocrine system.
The endocrine system is defined by its use of ductless glands that secrete substances directly into the blood.
The specific name for these substances is 'hormones'.
Evaluate the options: 'Enzymes' are catalysts, 'neurotransmitters' are for nerve synapses, and 'catalysts' is too general. 'Hormones' is the precise term for messengers from endocrine glands.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 2 pp. 16-18, 15-17

E6 Physiology Review Sembulingam 5e p. 80-82