Endocrine System Flashcards
Second controlling system of the body
Endocrine system
What system is the fast-control system?
Nervous system
The endocrine system uses chemical messengers called ___ that are released into the blood.
Hormones
Hormones control which major processes?
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism
What hormones are used in reproduction?
Follicle-stimulating hormone
Luteinizing hormone
What hormone is used in growth and development?
Growth hormone
Hormones are produced by ___.
Specialized cells
Cells secrete hormones into ____.
Extracellular fluids
Blood transfers hormones to ___.
Target sites
The scientific study of hormones and endocrine organs.
Endocrinology
What are the four chemical classifications of hormones?
Amino-acid based
Steroids
Prostaglandins
Amino acid-based hormones include ___.
Proteins, peptides, and amines
Catecholamines (ex. dopamine, epinephrine, norepinephrine) are examples of what chemical classification of hormones?
Amines
What hormones are commonly used to treat inflammation?
Steroids
What hormones are examples of steroids?
Sex hormones (estrogen, progesterone, testosterone)
These type of hormones are made from cholesterol
Steroids
These are made from highly active lipids that act as local hormones.
Prostaglandins
These hormones serve as chemical mediators
Prostaglandins
Hormones act by what two mechanisms?
Direct gene activation and second messenger system
True or False: Hormones affect only certain tissues or organs.
TRUE. They are called target cells or target organs.
Target cells must have ___.
Specific protein receptors
What happens when cells are aroused by hormones?
- Changes in plasma membrane permeability or electrical state
- Synthesis of proteins, such as enzymes
- Activation or inactivation of enzymes
- Stimulation of mitosis
- Promotion of secretory activity
What is the order of direct gene activation?
- Steroid hormones diffuse through the plasma membrane of target cells
- Steroid hormones enter the nucleus
- Steroid hormones bind to a specific protein within the nucleus
- Hormone-receptor complex binds to specific sites on the cell’s DNA
- Certain genes are activated that result in…
- Synthesis of new proteins
Direct gene activation is also known as ___.
Steroid hormone action
What is the order of second-messenger system?
- Hormone (first messenger) binds to a membrane receptor
- Activated receptor sets off a series of reactions that activates an enzyme
- Enzyme catalyzes a reaction that produces a second-messenger molecule (such as cyclic AMP, or cAMP)
- Oversees additional intracellular changes to promote a specific response in the target cell
Second-messenger system is also called ___.
Nonsteroid hormone action
Hormone levels in the blood are maintained mostly by ___.
Negative feedback
What triggers the release of more hormones?
A stimulus or low hormone levels in the blood
How does hormone release stop?
Once an appropriate level in the blood is reached.
Stimuli that activate endocrine glands fall into what three major categories?
Hormonal
Humoral
Neural
What is the most common stimulus?
Hormonal
It is when endocrine organs are activated by other hormones.
Hormonal stimuli
Anterior pituitary hormones travel to target glands (ex. thyroid gland) to prompt release of a particular hormone (ex. thyroid hormone). This is an example of what endocrine stimulus?
Hormonal stimuli
It is when changing blood levels of certain ions and nutrients stimulate hormone release.
Humoral stimuli
It indicates various bodily fluids (ex. blood & bile)
Humoral
Parathyroid hormone and calcitonin are produced in response to changing levels of blood calcium levels, and insulin is produced in response to changing levels of blood glucose. This is an example of what type of endocrine stimuli?
Humoral stimuli
True or False: Nerve impulses stimulate hormone release.
TRUE
Most are under the control of what subdivision of the autonomic nervous system?
Sympathetic nervous system
The release of norepinephrine and epinephrine by the adrenal medulla is an example of what type of endocrine stimuli?
Neural stimuli
What are the major endocrine organs?
Pituitary gland
Thyroid gland
Parathyroid gland
Adrenal glands
Pineal gland
Thymus gland
Pancreas
Gonads (ovaries & testes)
Hypothalamus
They are ductless glands.
Endocrine glands
What glands are purely endocrine?
Anterior pituitary
Thyroid
Parathyroid
Adrenals
Where are hormones released?
Directly into blood or lymph
They are glands with both endocrine and exocrine functions.
Mixed glands
What are examples of mixed glands?
Pancreas and gonads
How large is the pituitary gland?
The size of a pea
The pituitary hangs by a stalk from what part of the brain?
Hypothalamus
What bone protects the pituitary gland?
Sphenoid bone
What are the two lobes of the pituitary gland?
Anterior pituitary
Posterior pituitary
The anterior pituitary is made of ___ tissue, while the posterior pituitary is made of ___ tissue.
Glandular; nervous
It is often called the “master endocrine gland”
Pituitary gland
What type of hormones are released by the hypothalamus?
Releasing & inhibiting hormones; oxytocin and antidiuretic hormone
What connects hypothalamus to anterior pituitary?
Portal circulation
Where are oxytocin and antidiuretic hormone stored?
Posterior pituitary
What carries oxytocin and antidiuretic hormone to the posterior pituitary?
Neurosecretory cells
Stimulates contractions of the uterus during labor, sexual relations, and breastfeeding
Oxytocin
Causes milk ejection (let-down reflex) in a breastfeeding woman
Oxytocin
Inhibits urine production by promoting water reabsorption by the kidneys
Antidiuretic hormone
Urine production is also known as ___.
Diuresis
True or False: In large amounts, causes vasoconstriction of arterioles, leading to increased blood pressure.
TRUE. This is why ADH is known as vasopressin.
What inhibits ADH secretion?
Alcohol
What results from ADH hyposecretion?
Diabetes insipidus
How many hormones are produced by the anterior pituitary?
Six
What are the anterior pituitary hormones?
- Growth hormone
- Prolactin
- Thyroid-stimulating hormone
- Adrenocorticotropic hormone
- Follicle-stimulating hormone
- Luteinizing hormone
Thyroid-stimulating hormone is also known as ___.
Thyrotropic hormone
What hormones of the anterior pituitary affect nonendocrine targets?
- Growth hormone
- Prolactin
These hormones stimulate other endocrine glands to release hormones.
Tropic hormones
What anterior pituitary hormones are tropic?
- Thyroid-stimulating hormone
- Adrenocorticotropic hormone
- Follicle-stimulating hormone
- Luteinizing hormone