Ch 36: Animal Endocrine Systems Flashcards
Endocrine System
A system of cells and glands that secretes hormones into the bloodstream and works with the nervous system to regulate an animal’s internal physiological functions.
Hormones
A chemical signal that influences physiology and development in both plants and animals; in animals, hormones are released into the bloodstream and circulate throughout the body.
Molting
Periodic shedding, as of an exoskeleton.
Metamorphasis
The process in some animals in which the body changes dramatically at key stages in development.
Neurosecretory cells
A neuron in the vertebrate hypothalamus and the posterior pituitary gland that secretes hormones into the bloodstream.
Pituitary Gland
An endocrine gland located at the base of the vertebrate brain that produces a number of different hormones and controls many of the other organs of the endocrine system.
Homeostasis
The active regulation and maintenance, in organisms, organs, or cells, of a stable internal physiological state in the face of a changing external environment.
Negative Feedback
The effect in which the final product of a biochemical pathway inhibits the first step; the process in which a stimulus acts on a sensor that communicates with an effector, producing a response that opposes the initial stimulus. Negative feedback is used to maintain steady conditions, or homeostasis.
Positive Feedback
In the nervous and endocrine systems, a type of feedback in which a stimulus causes a response that leads to an enhancement of the original stimulus that leads to a larger response in the same direction. The process reinforces itself until interrupted.
Peptide Hormones
A hormone that is a short chain of linked amino acids.
Amine Hormones
A hormone that is derived from a single aromatic amino acid, such as tyrosine.
Steroid Hormones
A hormone that is derived from cholesterol.
Releasing Hormones
A peptide hormone that binds to receptors on cells in the anterior pituitary gland, leading that organ to release a much larger amount of the associated hormones.
Anterior Pituitary Gland
A peptide hormone that binds to receptors on cells in the anterior pituitary gland, leading that organ to release a much larger amount of the associated hormones.
Posterior Pituitary Gland
An endocrine organ that forms the posterior lobe of the pituitary gland; it develops from neural tissue at the base of the brain and contains axons of neurosecretory cells from the hypothalamus that secrete releasing hormones.
Tropic Hormones
A hormone that controls the release of other hormones.
Oxytocin
A hormone released by the posterior pituitary gland that causes uterine contraction during labor and stimulates the release of milk during breastfeeding.
Antidiuretic Hormone/ vasopressin
A posterior pituitary gland hormone that acts on the kidneys and controls the water permeability of the collecting ducts, thus regulating the concentration of urine that an animal excretes; also known as vasopressin.
Thyroid Gland
A gland located in the front of the vertebrate neck that leads to the release of two peptide hormones, thyroxine and triiodothyronine.
Ovaries
in animals, the female gonad where eggs are produced.
Testes
The male gonad, where sperm are produced.
Adrenal Glands
Paired glands located adjacent to the kidneys that secrete cortisol in times of stress.
Parathyroid Gland
A gland adjacent to the thyroid gland that secretes parathyroid hormone (PTH), which, with calcitonin, regulates the actions of bone cells and levels of calcium in the blood.
Pineal Gland
A gland located in the thalamic region of the brain that responds to autonomic nervous system input by secreting melatonin, which controls wakefulness.
Adrenal Medula
The inner part of the adrenal gland, which is stimulated by the sympathetic nervous system to secrete norepinephrine.
Acclimitization
An adaptive change in body function to a new environment.
Pheremones
A water- or airborne chemical compound released by animals into the environment that signals and influences the behavior of other members of their species.
The two main classes of hormones are:
amine/peptide hormones and steroid hormones.
When iodine intake is too low, the anterior pituitary gland _____.
increases TSH production
Growth factors are examples of which type of chemical signal?
paracrine signals
In Type I diabetes, the body fails to produce insulin and, thus, individuals must inject themselves with insulin before eating. Based on your knowledge of the control of glucose levels in the blood, what would happen if Type I diabetics injected themselves with too much insulin?
Their blood sugar levels would drop to potentially dangerous low levels.
Oxytocin and cholecystokinin are transported through the bloodstream and arrive at the uterus at the same time. Why does oxytocin cause the uterus to contract, whereas cholecystokinin has no effect?
The uterus has receptors for oxytocin, but not for cholecystokinin.
An individual who is experiencing a prolonged period of stress would likely have _____ levels of circulating _____ than an individual who was not experiencing stress.
higher; cortisol
Chemical signals that are released by one cell and act locally on neighboring cells are referred to as:
paracrine signals.
Which insect hormone acts on the body tissues to stimulate molting and metamorphosis?
ecdysone
The same hormone stimulates gene expression in one cell, but inhibits gene expression in another cell. What is the best explanation for this difference?
The two cells have different types of receptors for the hormone.
In vertebrates, which structure frequently serves as the first intermediary between the areas of the brain that perceive sensory stimuli and the rest of the endocrine system?
the hypothalamus
_____ are chemical signals that, instead of being secreted into the bloodstream, are introduced by animals into their habitats. They can be used to attract mates and mark territories.
Pheremones
_____, which is released from _____, acts on the ovaries and testes.
Follicle-stimulating hormone; the anterior pituitary gland
T/F: The production of pheromones is seen in many different types of organisms.
True
T/F: The nervous system transmits signals between adjacent cells using neurotransmitters, whereas the endocrine system signals with hormones.
True
Receptors for _____ hormones are located on the plasma membrane and affect target cells by _____.
amine; activating protein kinase enzymes
If ACTH secretion is inhibited, what will be the result?
The adrenal glands will not release cortisol.
A botanist working in the Amazon rain forest discovers a new species of orchid. Interestingly, males, but not females, of a certain wasp species keep visiting the flowers of these orchids. Why?
The orchid might produce a pheromone similar to that produced by female wasps.
T/F: Small amounts of hormones have large effects on an organism’s physiology because the signals are amplified between glands and tissues in an endocrine axis and within the signal transduction systems of individual cells.
True
T/F: Hormone receptors evolved later than many of the hormones with which they now interact.
False
T/F: Peptide hormones can evolve through changes in their amino acid sequence.
True
Steroid hormones are derived from:
Cholesterol
