Module 6 - Endocrine Flashcards
The endocrine system uses what to influence the body?
Describe these.
Hormones.
Hormones are organic molecules that are created in one part of the body and are secreted into the blood stream to influence behavior of other parts of the body.
All hormones have a specific gland of origin, a specific organ they act on, and a specific action.
They are secreted by endocrine glands.
What are the two main classes of hormones?
Peptide and Steroid
Describe peptide hormones.
Peptide hormones can be made from proteins, peptides, or catecholamines. They activate existing enzymes in the cell, act quickly and are short lived.
Describe steroid hormones.
Steroid hormones are built from cholesterol. They are lipid soluble and as such can cross the plasma membrane both out of and into a cell.
When in a new cell, they bind to another molecule and create a hormone-receptor complex, which in turn acts on genes that create new proteins.
Steroid hormones act slower than peptide hormones, because building a new protein takes longer than activating an existing enzyme. Their effects also last longer than peptide hormones.
Name and describe the two types of glands.
Endocrine glands secrete hormones and are ductless.
Exocrine glands have ducts and are found in epithelial surfaces.
What are primary endocrine organs?
Primary endocrine organs secrete hormones as their primary function. They include the hypothalamus, pituitary gland, pineal gland, thyroid gland, parathyroid glands, adrenal glands, and pancreas.
Name the three endocrine glands found in the brain.
Pituitary, Hypothalamus, Pineal
What are secondary endocrine organs?
These secrete hormones in addition to performing another bodily function. They include the heart, kidneys, gonads (testes in males, ovaries in females), and the thymus.
What it homeostasis?
The process of keeping a system at the same level of equilibrium through physiological processes.
How do most endocrine organs sense and respond to maintain homeostasis?
Through negative feedback. They sense that something has dropped too low and they excrete hormones until they sense that homeostasis has been reached again.
What is positive feedback?
When a body action causes a gland to increase its production of a hormone in response to the increased action. More produces more. The stimulus is promoted instead of negated.
Describe the hpothalamus?
The portion of the brain that regulates the internal environment and homeostasis. It helps to control heart rate, body temperature, and water balance, as well as the glandular secretions of the pituitary gland.
Describe the pituitary.
The pituitary lies just below the hypothalamus and is divided into two portions called the posterior pituitary and the anterior pituitary. The posterior pituitary is connected to the hypothalamus by means of a stalk-like structure. There are neurons in the hypothalamus that are called neurosecretory cells because they both respond to neurotransmitters and produce the hormones that are stored in and released from the posterior pituitary. The hormones pass from the hypothalamus through axons that terminate in the posterior pituitary
The hypothalamus connects to both the _______________ and the ______________
________________ gland.
Anterior and Posterior Pituitary Gland.
SaveAnother name for the posterior pituitary is:
neurohypophysis
It is made of neural tissue.
