14.1 Hormonal Communication

Pituitary Gland

Produces growth hormone and anti diuretic hormone

Thyroid gland

Produces thyroxine and raises metabolic rate

Adrenal gland

Produces adrenaline, prepares the body for action in fight or flight and raises metabolic rate

Pancreas

Produces insulin and glucagon, and lowers blood glucose levels

Ovaries

Produce oestrogen and progesterone, developed female secondary sex characteristics

Testes

Produce testosterone, and develop male secondary sex characteristics

What are chemical messengers?

Hormones

What are hormones often referred to as?

Chemical messengers

Example of a peptide hormone

Insulin or adrenaline

Example of a steroid hormone

Testosterone

Difference between endocrine and exocrine system

Endocrine hormones are secreted directly into the bloodstream whilst exocrine hormones are secreted into a duct.

Cells with a specific receptor for a specific hormone

Target cells

Main property of steroid hormone

Lipid soluable

Why is it important that steroid hormones are lipid soluble

Because it means that they can diffuse past the plasma membrane and bind to receptors present in the cytoplasm or nucleus.

What is the complex created when a hormone binds to a receptor?

Hormone-receptor complex.

Explain the process of a steroid hormone like oestrogen inhibiting/facilitating gene transcription .

The hormone is lipid so liable so it can pass through the target cell plasma membrane and bind to a receptor in the cytoplasm/nucleus, the hormone-receptor complex then binds to the DNA and acts as a transcription factor, inhibiting/facilitating the transcription of a specific gene

Why can steroid hormones pass through a target cell’s plasma membrane, but non-steroid hormones cannot?

Because steroid hormones are lipid soluble and non-steroid hormones are hydrophobic

Where are non-steroid hormone receptors

Outside the plasma membrane

Why do peptide hormones need external receptors?

Because the wire hydrophilic, and cannot diffuse past membrane

What is a secondary messenger and what does it do

cAMP, cyclic AMP is a secondary messenger that causes an enzyme cascade

What can steroid hormones do in terms of Transcription?

Hormone-receptor complexes are transcription factors, meaning that they can activate or regulate DNA transcription