Chapter 13 Flashcards
Endocrine System
Body system that includes endocrine glands in various locations in the body that produce and secrete hormones directly into the blood.
These glands include the pituitary gland, hypothalamus, pineal gland, thyroid gland, parathyroid glands, thymus, pancreas, adrenal glands, ovaries, and testes.
Gland
Structure of the endocrine system that produces and secretes one or more hormones into the blood.
Homeostasis
State of equilibrium of the internal environment of the body. The endocrine system plays a role in homeostasis by using hormones to regulate body fluids, electrolytes, glucose, cellular metabolism, growth, and the sleep-wake cycle (circadian rhythm).
Hormone
Chemical messenger of the endocrine system that is produced by a gland and secreted into the blood. It exerts an effect on a gland or an organ that has a receptor for that specific hormone to bind to.
Pituitary gland
Endocrine gland in the brain that is connected by a stalk of tissue to the hypothalamus. The pituitary gland sits in the bony cup of the sella Turkic a in the sphenoid bone.
It is the “master gland of the body.” Also known as the hypophysis. It consists of an anterior lobe and posterior lobe, each of which has a different endocrine function.
Adrenocorticotropic Hormone (ACTH)
Hormone produced and secreted by the anterior pituitary gland. It stimulates the cortex of the adrenal gland to secrete its hormones.
Anterior pituitary gland
Lobe of the pituitary gland that produces and secretes seven hormones: thyroid-stimulating hormone (TSH), prolactin (PRL), follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), growth hormone (GH), and melanocyte-stimulating hormone (MSH).
Also known as the adenohypophysis because it is a true gland.
Follicle-stimulating hormone (FSH)
Hormone produced and secreted by the anterior pituitary gland. In females, it stimulates follicles in the ovary to produce mature ova and to secrete the hormone estradiol.
In males, it stimulates the seminiferous tubules of the testes to produce spermatozoa
Gonadotropins
Category of hormones that stimulates the male and female sex glands (gonads). It includes FSH and LH
Growth hormone (GH)
Hormone produced and secreted by the anterior pituitary gland.
It stimulates growth and protein synthesis in all cells. It increases height and weight during childhood and puberty
Luteinizing hormone (LH)
Hormone produced and secreted by the anterior pituitary gland.
In females, it stimulates a follicle in the ovary to release a mature ovum each month. It stimulates the corpus luteum (ruptured ovarian follicle) to secrete estradiol and progesterone.
In males, it stimulates the interstitial cells of the testes to secrete testosterone.
Melanocyte-stimulating hormone (MSH)
Hormone produced and secreted by the anterior pituitary gland, it is secreted in pregnant women and stimulates melanocytes in the skin to produce melanin. This causes a darkened pigmentation on the face and abdomen.
Prolactin (PRL)
Hormone produced and secreted by the anterior pituitary gland. It stimulates the development of the breasts during puberty and stimulates them to produce milk for breast feeding.
Thyroid-stimulating hormone (TSH)
Hormone produced and secreted by the anterior pituitary gland.
It stimulates the thyroid gland to grow and to secrete the thyroid hormones T3 and T4.
Antidiuretic hormone (ADH)
Hormone produced by the hypothalamus but stored in and secreted by the posterior pituitary gland.
ADH acts on the tubules of the kidneys to increase the reabsorption of sodium and water back into the blood.
This decreases urine output and helps to maintain a normal blood volume and blood pressure.
Oxytocin (OXT)
Hormone produced by the hypothalamus but stored in and secreted by the posterior pituitary gland. It stimulates the pregnant uterus to contract during labor and childbirth and causes the uterus to contract after birth to prevent hemorrhaging.
It stimulates the breasts to release milk for breastfeeding.
Posterior pituitary gland
Lobe of the pituitary gland that stores and secretes ADH and oxytocin produced by the hypothalamus; it secretes these hormones in response to a nerve impulse from the hypothalamus. Also known as the neurohypophysis.
Hypothalamus
Endocrine gland in the brain just below the thalamus. The hypothalamus secretes hormones that stimulate or inhibit the secretion of hormones from the anterior pituitary gland.
It also produces oxytocin hormone and antidiuretic hormone that are stored in the posterior pituitary gland.
Melatonin
Hormone secreted by the pineal gland.
It regulates the 24 hour sleep-wake cycle and the onset and duration of sleep.
Pineal gland
Endocrine gland between the two lobes of the thalamus. It secretes the hormone melatonin.
Calcitonin
Hormone secreted by the thyroid gland.
It regulates the amount of calcium in the blood. If the calcium level is too high, calcitonin suppresses bone breakdown and increase the excretion of calcium in the urine.
Euthyroidism
Steady state of normal functioning of the thyroid gland producing and secreting its hormones.
Triiodothyronine (T3)
Hormone secreted by the thyroid gland. Most of it is changed into T3 by the liver.
Thyroid gland
Endocrine gland in the neck that secretes the hormones T3, T4, and calcitonin when stimulated by TSH from the anterior pituitary gland.
Parathyroid glands
Four small endocrine glands on the posterior surface of the thyroid gland. They secrete parathyroid hormone.e
Parathyroid hormone
Hormone secreted by the parathyroid glands. It regulates the amount of calcium in the blood.
If the calcium level is too low, parathyroid hormone stimulates the release of calcium from the bones and into the blood.
Thymus
Endocrine gland posterior to the sternum and within the mediastinum. It secretes hormones called thymosins.
Thymosin
Secreted by the thymus. It causes immature T cell lymphocytes in the thymus to mature.
Glucagon
Hormone secreted by alpha cells in the islets of Langerhans. It stimulates the liver to convert glycogen (glucose stored in the liver) to glucose and realest it into the blood.
Glucose
A simple sugar that is the main source of energy for cellular metabolism. Glucose in the blood comes from digested foods and from glycogen when it is converted into glucose by the hormone glucagon.
Glycogen
Glucose stored in the liver. it is converted to glucose by the hormone glucagon from the pancreas and by the hormone cortisol from the adrenal cortex.
Insulin
Hormone secreted by beta cells in the islets of Langerhans. It transports glucose into the cells where it is metabolized for energy.
Pancreas
Endocrine gland posterior to the stomach. it contains the islets of Langerhans (alpha, bets, and delta cells) that secrete the hormones glucagon, insulin and somatostatin.
Somatostatin
Hormone secreted by delta cells in the islets of Langerhans.
It inhibits the secretion of glucagon and insulin from the pancreas. It inhibits the secretion of growth hormone from the anterior pituitary gland.
Adrenal cortex
Outer layer of the adrenal gland.
When stimulated by ACTH from the anterior pituitary gland, the adrenal cortex secretes three groups of hormones: mineralocoritocoids (primarily aldosterone), glucocorticoids (primarily cortisol), and androgens (male sex hormones).
Adrenal glands
Endocrine glands on top of the kidneys. the adrenal gland consists of two parts: the cortex (an outer layer) and the medulla (an inner layer), each of which is a gland that secretes to own hormones.
Adrenal medulla
Inner layer of the adrenal gland. It secretes the hormones norepinephrine, epinephrine, and dopamine.
Aldosterone
Most abundant and biologically active of the mineralocorticoid hormones secreted by the adrenal cortex.
When the blood pressure is low, aldosterone causes reabsorption of sodium and water from tubules in the kidney into the blood.
This increases the blood volume and the blood pressure.
Androgens
Group of male sex hormones secreted by the adrenal cortex and by the testes. It includes testosterone, the most abundant and biologically active of the androgens.
Cortisol
Most abundant and biologically active of the glucocorticoid hormones secreted by the adrenal cortex.
It stimulates the liver to convert glycogen to glucose to increase the level of glucose in the blood.
It decreases the formation of proteins and new tissues, and it has an anti-inflammatory effect.
Dopamine
Hormone secreted by the adrenal medulla during times of stress. It is also a neurotransmitter between the brain and spinal cord of the nervous system.
Epinephrine
Hormone secreted by the adrenal medulla in response to a nerve impulse from the sympathetic division of the nervous system during times of danger or anger.
It produces the “fight-or-flight” response.
glucocorticoids
Group of hormones secreted by the adrenal cortex, of which aldosterone is the most abundant and biologically active.
Mineralocorticoids
Group of hormones secreted by the adrenal cortex, of which aldosterone is the most abundant and biologically active.
Norepinephrine
Hormone secreted by the adrenal medulla. It is also a neurotransmitter between the brain and the spinal cord of the nervous system.
Estradiol
Most abundant and biologically active of all the female sex hormones. Estradiol is secreted by the follicles and corpus luteum of the ovary when stimulated by FSH from the anterior pituitary gland.
Ovaries
Endocrine glands near the uterus; they are the female sex glands (gonads). FSH from the anterior pituitary gland stimulates the follicles of the ovary to secrete estradiol.
LH from the anterior pituitary gland stimulates the corpus luteum to secrete estradiol and progesterone.
The cells around the follicles secrete the male sex hormone testosterone.
Progesterone
Female sex hormone secreted by the corpus luteum of the ovary when stimulated by LH from the anterior pituitary gland.
Testes
Endocrine glands on either side of the scrotum; they are the male sex glands (gonads). Also known as testicles.
FSH from the anterior pituitary gland stimulates their seminiferous tubules to produce spermatozoa. LH from the anterior pituitary gland stimulates their interstitial cells to secrete testosterone.
Testosterone
Most abundant and biologically active of the male sex hormones. Testosterone is secreted by the interstitial cells of the testes when stimulated by LH from the anterior pituitary gland.
Antagonism
Process in which two hormones exert opposite effects
Inhibition
Action of a hormone that inhibits an endocrine gland from secreting its hormones
Receptor
Structure on the cell membrane of an organ or gland where a hormone binds and exerts an effect.
Stimulation
Action of a hormone that stimulates an endocrine gland to secrete its hormones or stimulates a receptor on an organ or tissue.
Synergism
Process in which two hormones work together to accomplish an enhanced effect.
Hyperpituitarism
Hypersecretion of one or all of the hormones of the anterior pituitary gland. It is caused by a benign tumor (adenine) in the anterior pituitary gland.
Treatment: Drug therapy to suppress secretion of the hormones or surgery to remover the adenoma, with radiation therapy to destroy any remaining adenoma.
Hypopituitarism
Hyposecretion of one or more of the hormones of the anterior pituitary gland. It is caused by an injury or a defect in the anterior pituitary gland.
Panhypopituitarism is hyposecretion of all of the hormones.
Treatment: Drug therapy to replace the hormones
Galactorrhea
Hypersecretion of prolactin. It is caused by an adenoma in the anterior pituitary gland. In women, the high level of prolactin stimulates the breasts to produce milk, even though the patient is not pregnant.
Failure of lactation
Hyposecretion of prolactin. It is cause by a defect in the anterior pituitary gland. The low level of prolactin prevents the development of the lactiferous lobules.
Gigantism
Hypersecretion of growth hormone during childhood and puberty.