HR Lesson 1- general principles, pineal gland

How do hormones travel through the body to reach target cells?

through the bloodstream

what are steroid hormones derived from?

cholesterol

what are peptide hormones derived from?

amino acids

What are endocrine glands composed of?

ductless glandular epithelial cells that secrete hormones directly into the bloodstream.

what is autocrine signaling?

signaling that binds to receptors on its own surface

what is paracrine signaling?

signaling molecules that affect nearby cells

how does the way a hormone is transported in the blood affect its half-life?

Hormones transported bound to proteins generally have a longer half-life than those that are free in the bloodstream, as protein binding protects them from degradation.

how do water-soluble hormones travel in the blood?

travel freely in the blood

how do lipid soluble hormones travel in the blood?

They are transported bound to plasma proteins.

What type of hormone will need a transporter to cross a plasma membrane?

peptide hormones

What type of hormone usually involves second messengers?

peptide hormones

What type of responses can a target cell elicit when acted upon by a hormone?

metabolic changes, gene expression, cell division and differentiation.

How is hormone signaling terminated?

negative feedback loops, hormone degradation, reduction in the number of receptors

What are eicosanoid hormones derived from?

fatty acids, particularly arachidonic acid.

What stimulates exocytosis of peptide hormones?

Calcium or cAMP

What is the first step in steroid hormone synthesis?

Conversion of cholesterol to pregnenolone by 3B- HSD in the mitochondria

Where does the hormone-receptor complex bind in the mechanism of steroid hormones?

to specific DNA sequences in the nucleus

What is a response driven configuration mechanism in the endocrine system?

A regulatory process where hormone levels adjust based on feedback from physiological responses, ensuring homeostasis.

What is the hypothalamic-pituitary-endocrine axis?

A complex set of interactions between the hypothalamus, pituitary gland, and endocrine glands that regulates various bodily functions through hormone signaling.

what are tropic hormones?

released by the pituiatary gland that stimulate other endocrine glands to release their hormones.

where is the pineal gland located?

caudel end of the roof of the third ventricle in the brain

what produces melatonin?

pineolocytes

what is melatonin derived from?

serotonin

How does the pineal gland function?

acts as a functional neuroendocrine transducer by translating environmental changes into neural impulses which coordinate endocrine responses in males and females

How does melatonin affect horses?

when melatonin is low in long days, reproduction hormones are stimulated