Hormone Regulation

Pt. 1 and 2

What is the purpose of cell signaling

To coordinate cell activities, growth, development and internal regulationW

What is homeostasis

Maintaining a relatively stable internal environment

What is homeorhesis?

Maintaining stability along a changing developmental trajectory

What are the three stages of cell signaling?

Reception → Transduction → Response

What is a ligand

A signaling molecule that binds to a specific receptor

Where are receptors for lipid-soluble hormones located>

Inside the cell, in the cytoplasm or nucleus

Where are receptors for water-soluble hormones located?

On the plasma membrane

What is a genomic response

A cellular response involving changes in gene expression

What is a non-genomic response

A rapid change in the activity of existing cellular proteins

What is juxtacrine signaling

Communication between cells through direct contact

What is paracrine signaling?

A cell sends a signal to nearby cells

What is autocrine signaling?

A cell sends a signal to itself

What is endocrine signaling?

Hormones travel through the bloodstream to distant target cells

What is neuroendocrine signaling

Neurosecretory cells release hormones into the bloodstream

What is the hypothalamus’s endocrine function?

It regulates pituitary hormone secretion

Which pituitary lobe produces growth hormone?

Anterior pituitary (aneohypophysis)

What does the posterior pituitary do?

Stores and releases hormones produced by the hypothalamus

What are magnocellular neursecretory neurons

Large hypothalamic neurons associated with posterior pituitary hormone release

What are parvocellular neurosecretory neurons do?

Small hypothalamic neurons that regulate the anterior pituitary

What is an endocrine gland?

A ductless gland that releases hormones into the bloodstream

What is an example of follicular endocrine gland?

The thyroid gland

What hormones stimulates growth hormone secretion

Growth hormone-releasing hormone (GHRH)

What hormones inhibits growth hormone secretion?

Somatostatin

Where is the growth hormone (GH) produced?

Anterior pituitary

What are the GH’s major effects?

Promotes growth, protein synthesis, and fat mobilization

What does IGF-1 do?

Supports bone and muscle growth and protein synthesis

Which IGF is particularly important during prenatal growth?

IGF-2

What stimulates insulin secretion?

Elevated blood glucose and nutrient signals stimulate insulin release

What is insulins main function?

Promotes nutrient uptake and storage; generally lowers blood glucose

What is glucagons main function?

Mobilizes energy reserves and generally raises blood glucose

What hormones are produced by the thyroid gland?

T3 (triiodothyronine) and T4 (thyroxine)

What does TSH stimulate?

Thyroid hormone production and secretion.

What are the major effects of thyroid hormones?

Increase metabolic activity and support growth and development.

What does testosterone promote?

Skeletal development and muscle protein synthesis.

What does estrogen promote in the mammary gland?

Mammary epithelial and ductal development.

What does progesterone promote in the mammary gland?

Lobular and alveolar development.

What is a negative feedback loop?

Rising hormone levels inhibit further hormone stimulation or secretion.

What is the GH ——> IGF-1 pathway?

GH stimulates IGF-1 production, which promotes tissue growth.

What is the TRH —> TSH pathway

TRH stimulates TSH, which stimulates thyroid hormone secretion.

What is the GnRH—> FSH/LH pathway?

GnRH stimulates FSH and LH, which regulate gonadal activity.