BIO Unit 4 Review

Hormone Function

Hormones relay messages to organs and glands in the body.

Endocrine Cells

Cells responsible for chemical signaling to organs and glands.

Circulatory System Role

Transports hormones to target tissues throughout the body.

Target Cells

Cells that have specific receptors that bind to hormones.

Receptors

Locations on target cells where hormones bind.

Protein-based Hormones

Hormones that are water-soluble and cannot cross cell membranes; bind to receptors on the surface of target cells.

Steroid-based Hormones

Hormones that can cross cell membranes and have receptors inside target cells; deal with gene expression and protein production.

Insulin Action

Protein-based hormone that binds to surface receptors to increase glucose uptake in muscle cells via GLUT4 transporters.

Cortisol Action

Lipid-based hormone that binds to intracellular receptors to activate genes for gluconeogenesis in liver cells.

Negative Feedback

Regulates hormone activity by reducing secretion when the desired effect is achieved.

Positive Feedback

Amplifies a response until a specific outcome is achieved.

Thyroid Hormones

Regulate metabolism, providing negative feedback by inhibiting TSH and TRH secretion when levels are sufficient.

Spermatogenesis

The process of sperm production occurring in the seminiferous tubules of the testes.

Sertoli Cells

Support cells that provide nutrients and create the blood-testis barrier during spermatogenesis.

Leydig Cells

Cells that produce testosterone, essential for spermatogenesis.

GnRH

Gonadotropin-releasing hormone that stimulates the release of LH and FSH.

LH

Luteinizing hormone that targets Leydig cells to promote testosterone production.

FSH

Follicle-stimulating hormone that acts on Sertoli cells to stimulate spermatogenesis.

Inhibin

Hormone secreted by Sertoli cells that provides negative feedback to regulate FSH levels.