Endocrine System Hormone Regulation

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Questions and Answers

Which of the following glands is NOT directly controlled by humoral stimuli, according to the text?

Heart

Adrenal medulla (correct)

Parathyroid gland

Pancreas

What type of stimulus triggers the release of hormones from the anterior pituitary gland?

Neural stimuli only

A combination of hormonal and neural stimuli (correct)

Hormonal stimuli only

Humoral stimuli only

Which of the following is NOT a characteristic of regulatory hormones produced by the hypothalamus?

They are peptide hormones

They bind to intracellular receptors (correct)

They regulate the activity of the anterior pituitary gland

They are transported via the hypothalamic-hypophyseal portal system

Which of the following statements about the pituitary gland is TRUE?

The posterior lobe releases hormones synthesized by the hypothalamus (B) Signup and view all the answers

Which of the following BEST describes the function of portal vessels in the hypothalamic-hypophyseal portal system?

To transport regulatory hormones from the hypothalamus to the anterior pituitary gland (B) Signup and view all the answers

Which of the following BEST describes the mechanism by which negative feedback regulates hormone secretion?

Increased hormone levels act on target cells to reduce the initial stimulus (B) Signup and view all the answers

Which of the following is NOT a direct function of hypothalamic regulatory hormones?

Directly controlling hormone release from the posterior pituitary gland (B) Signup and view all the answers

Based on the text, which of the following is TRUE about the mechanism of action of hormones released by the anterior pituitary gland?

They bind to extracellular receptors and use cAMP as a second messenger (D) Signup and view all the answers

Which structure, according to the text, is primarily responsible for synthesizing and releasing hormones that directly control the release of hormones from the anterior pituitary gland?

Hypothalamus (A) Signup and view all the answers

Which statement BEST describes the relationship between the hypothalamus and the posterior pituitary gland?

The hypothalamus synthesizes and releases hormones that are stored and released by the posterior pituitary gland (B) Signup and view all the answers

Which hormone is primarily responsible for stimulating the production of androgens in males?

Luteinizing hormone (LH) (D) Signup and view all the answers

Which hormone is primarily responsible for stimulating the release of thyroid-stimulating hormone (TSH)?

Thyroid-stimulating hormone (TSH) (B) Signup and view all the answers

What is the primary function of somatomedins, released by liver cells in response to growth hormone (GH)?

Promoting the uptake of amino acids by skeletal muscle fibers (A) Signup and view all the answers

Which of the following conditions is directly associated with a low production of gonadotropins?

Hypogonadism (C) Signup and view all the answers

Which of the following conditions would likely lead to an increased production of MSH (melanocyte-stimulating hormone)?

Pregnancy (B) Signup and view all the answers

Which of the following hormones is primarily involved in regulating fluid balance by acting on the kidney and initiating thirst?

Antidiuretic hormone (ADH) (A) Signup and view all the answers

What is the primary action of oxytocin (OXT) related to childbirth?

Contracting the uterus during labor (B) Signup and view all the answers

Which of the following hormones is released due to the release of corticotropin-releasing hormone (CRH)?

Adrenocorticotropic hormone (ACTH) (D) Signup and view all the answers

What is the name of the tissue that comprises the posterior lobe of the pituitary gland?

Neural tissue (B) Signup and view all the answers

Which of the following hormones directly inhibits the release of prolactin (PRL)?

Prolactin-inhibiting hormone (PIH) (D) Signup and view all the answers

Study Notes

Hormone Secretion Control

Hormone secretion is primarily regulated by negative feedback.
A stimulus triggers hormone production, then the hormone reduces the stimulus's intensity.
This process may involve one or more hormones.
Humoral stimuli: changes in extracellular fluid.
Hormonal stimuli: arrival or removal of a hormone.
Neural stimuli: neurotransmitters.
Humoral stimuli affect hormone secretion in organs like the heart, pancreas, parathyroid gland, and digestive tract.
Hormonal stimuli can involve multiple intermediate steps.
Neural stimuli are controlled by the hypothalamus.

Pituitary Gland

The pituitary gland is located in the sella turcica.
It's isolated from the cranial cavity by the sellar diaphragm.
Connected to the hypothalamus by the infundibulum.
Releases nine peptide hormones.
These hormones bind to extracellular receptors and use cAMP as a second messenger.

Hypothalamus

The hypothalamus regulates the pituitary gland.
It synthesizes and transports ADH and OXT to the posterior pituitary.
It secretes regulatory hormones to control the anterior pituitary's activity.
The hypothalamus has direct control over the adrenal medulla.
It's divided into anterior and posterior lobes (adenohypophysis and neurohypophysis).

Anterior Pituitary

The anterior lobe of the pituitary is also called the adenohypophysis.
Formed from epithelial tissue.
Hormones stimulate or support other endocrine glands.
Hormones "turn on" other endocrine glands, or support other organs.

Hypothalamic Control of Anterior Lobe

The hypothalamus controls the anterior pituitary using releasing and inhibiting hormones.
Releasing hormones stimulate hormone production in the anterior lobe.
Inhibiting hormones prevent hormone secretion.

Anterior Pituitary Hormones

Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Prolactin (PRL)
Growth hormone (GH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Functions of hormones:
TSH: stimulates thyroid hormone secretion.
ACTH: stimulates adrenal cortex hormone secretion.
PRL: stimulates milk production.
GH: stimulates growth and metabolism.
FSH: stimulates egg or sperm production.
LH: regulates sex hormone production.

Growth Hormone (GH)

GH stimulates liver cells to release somatomedins.
Somatomedins stimulate tissue growth by increasing uptake of amino acids.
Stem cells divide in epithelia and connective tissues.
Breakdown of triglycerides in adipocytes (glucose-sparing effect).
Breakdown of glycogen in liver cells (diabetogenic effect).

Posterior Pituitary

The posterior lobe is also called the neurohypophysis.
Made from neural tissue.
Stores and releases neurohormones (ADH and OXT) synthesized in the hypothalamus.
ADH (antidiuretic hormone): regulates fluid balance by affecting the kidneys and initiating thirst.
Oxytocin (OXT): stimulates uterine contractions during labor and milk ejection.

Portal Vessels

Blood vessels that link two capillary networks, for hormone transport.
The hypothalamus-hypophyseal portal system transports regulatory hormones to the anterior pituitary before entering general circulation.

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Description

This quiz covers the control of hormone secretion, focusing on the roles of negative feedback, humoral, hormonal, and neural stimuli. It also explores the anatomy and function of the pituitary gland and hypothalamus in hormone regulation. Test your knowledge on how these systems work together to maintain body homeostasis.