Chapter 18: The Endocrine System - Practice Flashcards

A comprehensive set of practice questions (Q&A flashcards) covering key concepts from the Endocrine System notes, including intercellular communication, endocrine vs nervous systems, hypothalamic-pituitary axis, gland-specific hormones, and metabolic regulation.

Name the modes of intercellular communication mentioned in the notes.

Direct communication, paracrine communication, autocrine communication, endocrine communication, and synaptic communication.

What distinguishes nervous regulation from endocrine regulation in terms of speed and duration?

Nervous regulation is faster but short-lived; endocrine regulation is slower but longer-lasting.

What is a target cell?

A cell that has receptors for a specific hormone.

Where do hormones travel to reach distant target cells?

In the bloodstream (blood).

What are hormones?

Chemical messengers that travel in the blood to reach distant target cells.

How do hormones differ from neurotransmitters in terms of release location?

Hormones are released into the bloodstream; neurotransmitters are released across a synapse.

What is the difference between endocrine and exocrine secretions?

Endocrine secretions are released into extracellular fluid/blood; exocrine secretions are released onto epithelial surfaces via ducts.

Name the major physiological processes regulated by hormones.

Growth and development; Reproduction; Cell metabolism and energy balance; Body water content and levels of electrolytes and nutrients.

Are hormones typically released in large or very small quantities?

Very small quantities.

How do hormones reach their target cells (general movement)?

Movement through diffusion in plasma or transport in the bloodstream.

Where do lipophilic (steroid) hormones bind receptors?

In the cytosol or the nucleus.

Where do hydrophilic (peptide) hormones bind receptors?

On the cell membrane (plasma membrane).

Which hypothalamic hormone stimulates the release of TSH from the anterior pituitary, and what gland does it target?

Thyrotropin-releasing hormone (TRH) stimulates TSH release; targets the thyroid gland.

What are the two lobes of the pituitary gland?

Anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis).

Which hormones are released by the posterior pituitary?

Oxytocin (OXT) and antidiuretic hormone (ADH, vasopressin).

What is the hypophyseal portal system?

A capillary network that carries hypothalamic regulatory hormones to the anterior pituitary.

Name the hypothalamic releasing hormones that stimulate the anterior pituitary.

TRH (thyrotropin-releasing hormone), PRH (prolactin-releasing hormone), CRH (corticotropin-releasing hormone), GnRH (gonadotropin-releasing hormone), and GHRH (growth hormone-releasing hormone).

Name the hypothalamic inhibiting hormones that regulate the anterior pituitary.

PIH (prolactin-inhibiting hormone) and SS (somatostatin).

What are the main hormones released by the anterior pituitary?

ACTH, TSH, GH, PRL, FSH, LH, MSH.

What is the function of TSH?

Stimulates the thyroid to release thyroid hormones T3 and T4.

What is the function of ACTH?

Stimulates the adrenal cortex to release glucocorticoids (e.g., cortisol).

Which hormones stimulate ovarian follicle development and estrogen production in females?

Follicle-stimulating hormone (FSH) for follicle development and estrogen; luteinizing hormone (LH) also supports estrogen production. LH also triggers ovulation.

Which hormone stimulates milk production in the mammary glands?

Prolactin (PRL).

What is the primary effect of Growth Hormone (GH)?

Promotes cell growth and division, especially in muscles and bones; stimulates liver to produce somatomedins (IGFs).

What does Melanocyte-stimulating hormone (MSH) do?

Stimulates melanin production; secreted by the pars intermedia in certain conditions (fetal development, young children, pregnancy, some diseases).

Where are the hypothalamic releasing and inhibiting hormones released to reach the anterior pituitary?

Into the hypophyseal portal system, which carries them to the anterior pituitary.

What hormones are produced by the posterior lobe of the pituitary and their general functions?

Oxytocin—stimulates uterine contractions and milk ejection; ADH (vasopressin)—stimulates kidneys to retain water.

Where is the thyroid gland located and what are its structural features?

Lies inferior to the thyroid cartilage; consists of two lobes connected by an isthmus and contains thyroid follicles filled with colloid.

What hormones does the thyroid gland produce and what stimulates their release?

T3 (triiodothyronine) and T4 (thyroxine) increase metabolic rate; Calcitonin lowers blood calcium. Release is stimulated by TSH from the anterior pituitary.

What is the role of calcitonin and which cells secrete it?

Calcitonin lowers blood calcium and is secreted by parafollicular (C) cells of the thyroid.

Where are the parathyroid glands located and what do they secrete?

Located on the posterior surface of the thyroid; secrete parathyroid hormone (PTH) which increases blood calcium.

What are the three zones of the adrenal cortex and their main products?

Zona glomerulosa — mineralocorticoids (aldosterone); Zona fasciculata — glucocorticoids (cortisol, corticosterone); Zona reticularis — androgens.

What hormones are produced by the adrenal medulla?

Catecholamines: epinephrine and norepinephrine.

What hormones does the pancreas release in its endocrine function, and what are their roles?

Insulin (beta cells) lowers blood glucose; Glucagon (alpha cells) raises blood glucose.

What is diabetes mellitus and its major clinical features?

Characterized by hyperglycemia, glycosuria, and polyuria due to inadequate insulin or insulin receptor dysfunction.

Differentiate Type 1 and Type 2 diabetes mellitus.

Type 1: inadequate insulin production; Type 2: insulin resistance with normal or high insulin, often associated with obesity; treatment differs.

What hormone does the Pineal gland produce and what is its function?

Melatonin; helps regulate circadian rhythms.

What hormone is produced by the thymus and what is its general role?

Thymosins; involved in immune development and function (immune system modulation).

What is the clinical note about diabetes insipidus?

A disease characterized by excessive thirst and urination due to low ADH levels.

Which organ is primarily involved in the endocrine regulation of water balance and the stress response via glucocorticoids and mineralocorticoids?

The adrenal glands (cortex for corticosteroids and medulla for catecholamines).