endocrine glands Flashcards
– stimulates growth of bones, muscles and organs by increasing gene expression
GH
-resists protein breakdown and favor fat breakdown during periods of starvation
GH
↓GH, young person, small but normally proportioned
PITUITARY DWARF
- ↑GH present before bones finish growing in length
- exaggerated bone growth
- abnormally tall
GIANTISM
↑GH after completion of bone growth in length
-abnormally large facial features and hands
GIANTISM
PERIODS OF INCREASED GH SECRETION
↑GH after completion of bone growth in length
-abnormally large facial features and hands
somatomedins
- influences part of the effect of GH
- similar in structures to insulin and can bind to insulin receptors
- secretion from tissues is increased by GH
insulin-like growth factors
- binds to MBR on cells in cortex of adrenal glands
- increases the secretion of cortisol/hydrocortisone
- required to keep adrenal cortex from degenerating
Adrenocorticotropic hormone (ACTH)
-bind to melanocytes in skin and increase skin pigmentation
Adrenocorticotropic hormone (ACTH)
– bind to MBR on cells of gonads
-regulate growth, development, and functioning of gonads
Gonadotropins
cause the ovulation of oocytes and secretion of estrogen and progesterone
luteinizing hormone
-stimulates interstitial cells of the testes to secrete testosterone
Interstitial Cell-stimulating hormone
stimulates development of follicles in ovaries and sperm cells
Follicle-stimulating hormone (FSH) –
binds to MBR in cells of breast
-helps promote development of breast during pregnancy
prolactin
-stimulates the production of milk following pregnancy
prolactin
binds to MBR on melanocytes
- causes MBR on melanocytes to synthesize melanin
- structure is similar to ACTH
Melanocyte-stimulating hormone (MSH)
- increases water reabsorption by kidney tubules (result: less water lost as urine)
- causes blood vessels to constrict
ADH VASOPRESSIN
– caused by lack of ADH secretion
-production of large amount of dilute urine
DIABETES INSIPIDUS
causes contraction of smooth muscle cells of uterus
-causes milk letdown from breasts of lactating women
OXYTOCIN
- made up of 2 lobes connected by isthmus
- lobes are located on each side of trachea
- one of the largest endocrine glands
- appears more red because it is highly vascular
- surrounded by a connective tissue capsule
THYROID GLAND
secrete hormone calcitonin
C Cells or parafollicular cells
enlargement of thyroid gland
-excess TSH
GOITER
– lack of thyroid hormones
HYPOTHYROIDISIM
– hypothyroidism in infants
-mental retardation, short stature, abnormally formed skeletal structure
cretinism
hypothyroidism in adults
-decreased metabolic rate, sluggishness, reduced ability to perform routine tasks
myxedema
elevated rate of thyroid hormone secretion
-metabolic rate, extreme nervousness, chronic fatigue
hyperthyroidism
• Graves disease – results when immune system produces abnormal proteins that are similar in structure and function to TSH
-often accompanied by exophthalmia (bulging of eyes)
graves disease
required to synthesize thyroid hormones
-taken up by thyroid follicles
IODINE
secreted if blood concentration of Ca becomes too high
-binds to MBR of osteoclasts and reduces rate of Ca resorption by inhibiting osteoclasts
Calcitonin
- embedded in posterior wall of the thyroid gland
- secrete parathyroid hormone
PARATHYROID GLANDS
Binds to MBR of renal tubule cells – increases active vitamin D formation (Vit D – increase Ca absorption)
Parathyroid Hormone
Binds to receptors on osteoblasts, increase osteoclast activity, cause resorption of bone tissue, release of Ca
Parathyroid Hormone
Binds to receptors on renal tubules – decreases rate at which Ca is lost in urine
Parathyroid Hormone
Acts on target tissues to raise blood Ca levels to normal
Parathyroid Hormone
abnormally high rate of PTH secretion
hyperparathyroidism
- increase in bone resorption and elevated blood Ca levels
- bones become soft, deformed, easily fractured
- nerve and muscle cells are less excitable = fatigue and muscle weakness
hyperparathyroidism
– abnormally low rate of PTH secretion
hypoparathyroidism
- low levels of Ca, decrease bone resorption
- nerve and muscle cells are more excitable = muscle cramps or tetanus = severe tetanus = breathing stops
hypoparathyroidism
fight-or-flight hormones
Epinephrine and Norepinephrine
type of steroid hormone of the adrenal cortex
helps regulate blood volume and blood levels of K and Na
Mineralocorticoids
- binds to receptor molecules in kidneys
- affects intestine, sweat glands, salivary glands
- causes Na and H2O to be retained in the body
- increases the rate at which K is eliminated
aldosterone
release is caused by low blood pressure
renin
causes smooth muscle in blood vessels to constrict
-acts on adrenal cortex to increase aldosterone secretion
Angiotensin II
class of steroid hormone of adrenal cortex
helps regulate blood nutrient levels
-major hormone: cortisol
Glucocorticoids
– increases fat and protein breakdown
- increases fat and protein conversion to usable forms of energy
- causes proteins to be broken down to amino acids
- reduces inflammatory and immune responses
- secreted in large amounts in response to stressful conditions so it aids the body by providing energy sources for tissues
CORTISOL
reduces inflammation cause by injuries
-reduces immune and inflammatory responses resulting from allergic reactions or abnormal responses
CORTISONE
– regulate secretion of cortisol from adrenal cortex
ACTH
– stimulate the development of male sexual characteristics
ANDROGENS
secrete insulin (beta cells) and glucagon (alpha cells) which help regulate blood levels of nutrients
PANCREATIC ISLETS
nervous system’s main source of energy
glucose
– reduced pH of body fluids below normal condition
-result of low blood glucose levels, which causes the breakdown of fats, which causes the release of fatty acids and ketones
acidosis
– respond to elevated blood glucose levels and increased parasympathetic stimulation associated with digestion of a meal
-respond to blood levels of certain amino acids
insulin
- binds to MBR receptors and increases the rate of glucose and amino acid uptake
- glucose is converted to glycogen or fat, amino acid to protein
insulin
– too little insulin secreted
-tissues cannot take up glucose effectively
Type 1 Diabetes Mellitus
too much insulin present, no glucose, brain malfunctions (no energy source)
-causes disorientation, convulsions, loss of consciousness
Insulin shock
– insufficient numbers of insulin receptors on target cells
-defective receptors
Type 2 Diabetus Mellitus
– released from alpha cells when blood glucose are low
-binds to MBR in liver, causing glycogen → glucose
Glucagon
male sex hormone, secreted by testes
-growth and development of male reproductive structures, muscle enlargement, growth of body hair, etc
Testosterone –
– development and function of female reproductive structures
- enlargement of breasts and distribution of fat
- menstrual cycle
Estrogen & Progesterone
stimulate secretion of hormones from ovaries and testes
-also has a negative feedback
LH & FSH –
- upper part of thoracic cavity
- important in the function of immune system
- secretes thymosin
- most important early in life
Thymus
aids the development of T cells (WBC)
thymosin
help protect body against infection
T cells –
- small, pine-cone shaped structure
- located superior and posterior to the thalamus
- produces melatonin
PINEAL GLAND
– function as intercellular signals, widely distributed throughout the body
- not transported long distances
- cause contraction and relaxation of different smooth muscles
- used medically to initiate abortion
- inflammation: released by damaged tissues and cause blood vessel dilation, localized swelling, pain
- necessary for normal blood clotting
prostaglandins
secreted by kidneys
- respond to reduced O2 levels in kidney
- acts on bone marrow to increase production of RBC
Erythropoietin
– similar in structure and function to LH
Human chorionic gonadotropin
important source of hormones that maintain pregnancy and stimulate breast development
Placenta
