SM_171b: Introduction to the Endocrine System and Physiology / Pathophysiology Flashcards
Exocrine glands are ____ and ____
Exocrine glands are ducts and lumen / surfaces
Endocrine glands are ____ and ____
Endocrine glands are chemical messengers and blood stream
Endocrine action is ____
Endocrine action is the hormone is distributed in the blood and binds to distant target cells
Paracrine action is ____
Paracrine action is when the hormone acts locally by diffusing from its source to target cells in the neighborhood
Autocrine action is ____
Autocrine action is when the hormone acts on the same cells that produced it
Most hormones are controlled by ____
Most hormones are controlled by negative feedback
- Hormones are released in response to stimuli
- Travel through the circulatory system to reach target cells with specific receptors
Three chemical classes of hormones are ____, ____, and ____
Three chemical classes of hormones are polypeptides, steroids, and amines
Peptide / protein hormones ____ in size, are often produced as ____, and are ____ soluble
Peptide / protein hormones vary in size, are often produced as inactive precursors that are proteolytically cleaved to the active form, and are water soluble
Steroid hormones are derived from ____ and are ____ soluble
Steroid hormones are derived from cholesterol and are lipid soluble
Describe the types of steroid hormones
Types of steorid hormones
- Glucocorticoids: cortisol
- Mineralocorticoids: aldosterone
- Androgens: testosterone
- Estrogens: estradiol, estrone
- Progestogens: progesterone
- Sterols: Vitamin D
The two groups of hormones derived from the amino acid tyrosine are ____ and ____
The two groups of hormones derived from the amino acid tyrosine are thyroid hormones and catecholamines
____ occurs when the output of a system acts to oppose changes to the input of the system
Negative feedback occurs when the output of a system acts to oppose changes to the input of the system
(thermostat)
Describe the interplay between insulin and glucagon
Ibterplay between insulin and glucagon
- Increased glucose
- Insulin release from beta cells
- Fat / muscle glucose uptake (effectors)
- Decreased glucose
- Glucagon release from alpha cells
- Liver gluconeogenesis and glycogenolysis
- Cycle continues
Describe the hypothalamic-pituitary-target organ system
Hypothalamic-pituitary-target organ system
____ occurs when the output of a system acts to enhance the changes to the input of the system
Positive feedback loop occurs when the output of a system acts to enhance the changes to the input of the system
- Contraction in childbirth -> oxytocin released -> further contractions -> contractions increase in amplitude and frequency
Stress leads to a positive feedback loop in the HPA axis via ____
Stress leads to a positive feedback loop in the HPA axis via increased action of ACTH from the pituitary on the adrenal glands
____ is an example of a hormone excess syndrome
Benign adenoma producing excess hormones is an example of a hormone excess syndrome
Surgical removal of a gland, autoimmune destruction of a gland, congenital defects of glandular development, and congenital mutations of genes for hormones or enzymes involved in hormone synthesis can prompt a _____ syndrome
Surgical removal of a gland, autoimmune destruction of a gland, congenital defects of glandular development, and congenital mutations of genes for hormones or enzymes involved in hormone synthesis can prompt a hormone deficiency syndrome
____ is connected to the hypothalamus by hypothalamic-pituitary portal vessels
Anterior pituitary is connected to the hypothalamus by hypothalamic-pituitary portal vessels
Anterior pituitary produces 6 peptide hormones: ____, ____, ____, ____, ____, and ____
Anterior pituitary produces 6 peptide hormones:
- Prolactin
- Growth hormone
- Thyroid stimulating hormone
- Adrenocorticotropic hormone
- Follicle stimulating hormone
- Luteinizing hormone
Describe syndromes due to oversecretion of hormones from the anterior pituitary
Syndromes due to oversecretion of hormones from the anterior pituitary
Describe results of hypopituitarism
Hypopituitarism
Describe the anatomy of the neurohypophysis
Anatomy of the neurohypophysis
- Magnocellular neurons originate in the supraoptic and paraventricular nuclei and project through the stalk and diaphragma sella
- Regulated by neurons from osmoreceptors, baroreceptors, and emetic center
Neurohypophysis produces ____ and ____
Neurohypophysis produces ADH and oxytocin
- ADH also called vasopressin (AVP)
____ and ____ are diseases of the posterior pituitary
Diabetes insipidus and increased vasopressin secretion are diseases of the posterior pituitary
Diabetes insipidus involves _____ from the _____
Diabetes insipidus involves decreased vasopressin release from the posterior pituitary
- Causes failure of kidney to reabsorb water -> failure to concentrate urine -> increased urine volume and thirst
____ secretion from the ____ can increase kidney water retention, resulting in excessive dilution of blood solutes (hyponatremia) and water intoxication
Increased vasopressin secretion from the posterior pituitary can increase kidney water retention, resulting in excessive dilution of blood solutes (hyponatremia) and water intoxication
Adrenal glands involve two exocrine glands: ____ and ____
Adrenal glands involve two exocrine glands: adrenal cortex (outer) and adrenal medulla (inner)
Adrenal cortex secretes ____ including ____, ____, and ____
Adrenal cortex secretes lipid-based steroid hormones (corticosteroids) including mineralocorticoids, glucocorticoids, and androgens
- Mineralocorticoids: aldosterone
- Glucocorticoids: cortisol
- Androgens: androstenedione, dehydroepidandrosterone
Adrenal meulla secretes ____ and ____
Adrenal meulla secretes epinephrine and norepinephrine
Describe aldosterone
Aldosterone
- Mineralocorticoid
- Secreted by adrenal cortex in response to decreased blood volume or BP (terminal hormone in RAAS system)
- Prompts distal and collecting tubules in kidney to reabsorb more Na -> water passively follows -> blood volume increases
Describe cortisol
Cortisol
- Glucocorticoid
- Stress response: physical, psychological, physiological
- Regulates or supports important homeostatic functions including water balance
- Keeps blood glucose levels high enough to support brain activity
- Catabolic: breaks down protein
- Redirects circulating lymphocytes to lymphoid and peripheral tissues where pathogens usually are
- Depresses immune system and inflammatory response
Primary adrenal insufficiency is ____
Primary adrenal insufficiency is Addison’s disease
- Atrophy or hypocortisolism
Primary adrenal hypercortisolism is _____
Primary adrenal hypercortisolism is Cushing’s syndrome (adenoma, carcinoma)
____ results from mutations in enzymes for cortisol synthesis
Congenital hyperplasia results from mutations in enzymes for cortisol synthesis
Thyroid gland produces ____ and ____
Thyroid gland produces thyroid hormone and calcitonin
____ is a hormone produced in the thyroid gland that regulates calcium and phosphorus metabolism
Calcitonin is a hormone produced in the thyroid gland that regulates calcium and phosphorus metabolism
Thyroid is composed of ____
Thyroid is composed of spherical follicles
- Follicle cells: produce thyroglobulin (precursor of thyroxine)
- Colloid lumen contains thyroglobulin
- Parafollicular C cells produce calcitonin
The two thyroid hormones are ____ and ____ and are derived from modification of ____
The two thyroid hormones are tetraiodothyronine (T4, thyroxine) and triidothyronine (T3) and are derived from modification of tyrosine
Thyroid hormone ____ and ____
Thyroid hormone increases basal metabolic rate and affects many target cells throughout the body
- Basal metabolic rate: rate at which body uses oxygen to transform nutrients (carbohydrates, fats, proteins) into energy
- Protein synthesis, bone growth, neuronal maturation, cell differentiation
Describe calcitonin
Calcitonin
- Secreted from thyroid parafollicular C cells when blood Ca levels are high
- Lowers Ca by slowing Ca-releasing activity of osteoclasts in bone and increasing Ca excretion by kidney
- Acts mostly during childhood
- Producd in excess by medullary cancer which is a rare thyroid cancer
Hyperthyroidism is ____ and ____
Hyperthyroidism is elevated T4 and T3 levels
- Suppressed TSH level
- Hypermetabolism
- Due to thyroid stimulating IgG
Hypothyroidism is ____ and ____
Hypothyroidism is decreased T4 and T3 levels
- Increased TSH level
- Hypometabolism
- Usually autoimmune
____ are an enlarged thyroid
Goiters are an enlarged thyroid
- Diffuse
- Nodular
- Cancer
Endemic goiter results from ____ deficiency
Endemic goiter results from iodine deficiency
Parathyroid glands regulate ____ and secrete ____
Parathyroid glands regulate blood Ca levels and secrete parathyroid hormone
- Embedded or behind in thyroid gland
___ cells in parathyroid glands produce parathyroid hormone
Chief cells in parathyroid glands produce parathyroid hormone
Parathyroid hormone functions to ____
Parathyroid hormone functions to increase blood Ca concentration
- Stimulates osteoclasts to release more Ca from bone
- Decreases excretion of Ca by kidney
- Activates Vitamin D, which stimulates uptake of Ca from the intestine
Hyperparathyroidism is when ____
Hyperparathyroidism is when excess PTH from a single adenoma or 4-gland hyperplasia causes hypercalcemia
Hypoparathyroidism causes ____
Hypoparathyroidism causes hypocalcemia
- Usually due to inadvertent removal during thyroidectomy, can also be congenital embryopathic or autoimmune
Parathyroid hormone activates _____ to _____
Parathyroid hormone activates 25-OH-D to 1,25(OH)2D3 (calcitriol)
Describe effects of Vitamin D
Vitamin D effects
- Gut: increases Ca absorption
- Bone: increases Ca mobilization via increased osteoclast number and activity
- Parathyroid: decreases PTH gene transcription and PTH secretion
____ stimulate bone formation, while ____ stimulate bone resorption
Osteoblasts stimulate bone formation, while osteoclasts stimulate bone resorption
- Osteoporosis is when activity of osteoclasts outstrips osteoblasts
Adipose tissue is an endocrine organ and secretes _____
Adipose tissue is an endocrine organ and secretes adipocytokines
Normal basal glucose regulation involves the ____, ____, ____, ____, and ____
Normal basal glucose regulation involves the liver, pancreas, fat, muscle, and brain
Alpha cells secrete ____
Alpha cells secrete glucagon
- Raises blood glucose, mostly in periphery
Beta cells secrete ____
Beta cells secrete insulin
- Lowers blood glucose, mostly central
Delta cells secrete ____
Delta cells secrete somatostatin
- Inhibits glucagon and insulin
Describe the etiologic classification of diabetes
Diabetes etiologic classification
- Type 1: beta-cell destruction with lack of insulin
- Type 2: insulin resistance with insulin deficiency
- Other specific types
- Gestational: first diagnosed during pregnan
Pathogenesis of Type 2 Diabetes involves ____ and ____
Pathogenesis of Type 2 Diabetes involves insulin resistance and diminished insulin secretion
____ may result from excess insulin / nutrient intake during the treatment of diabetes
Hypoglycemia may result from excess insulin / nutrient intake during the treatment of diabetes
- Rare tumors of pancreas (insulinomas) can cause hypoglycemia
Pheochromocytoma may secrete ____ including ____ and ____ which cause hypertension
Pheochromocytoma may secrete catecholamines including epinephrine and norepinephrine which cause hypertension
