Endocrine Flashcards
Function of endocrine
Acts as nervous system to coordinate and integrate activity of body cells
How does endocrine system influences metabolic activities
Via hormones
How does the response of endocrine system compare to nervous system
Nervous system can override endocrine
Endocrine responses are slower but longer lasting And directly into blood stream
Endocrine system controls and integrates what
Reproduction
Growth
Maintenance of electrolyte, water, and nutrient balance of blood
Regulation of cellular metabolism and energy balance
Mobilization of body defense
What are major endocrine glands
Pituitary, adrenal, thyroid, parathyroid, pancreas, testes, and ovaries
What is autocrines
Chemicals that exert on the same cell
What is a paracrine
Locally acting chemicals that affect cells other than those that secrete them
What are the peptide protein hormones
Water soluble
Pancreatic, pituitary, parathyroid, GI
What are the way two hormones can act
Water soluble: act on plasma membrane receptors, act via G protein second messengers, they cannot enter cells (all amino based hormones except thyroid)
Lipid soluble: act on intracellular receptors that directly activate genes, they can enter cells (steroid and thyroid)
What is negative feedback
Hormone inhibits itself from further secretion
What is positive feedback
Effects of hormones result in further hormone secretion
Which hormones travel attached to plasma proteins
Steroid and thyroid
How can hormones be removed from the blood
Degrading enzymes
Kidneys or liver
Hypothalamus connects to the pituitary gland by what
Infundibulum
Connection maintained via hypothalamus hypophyseal tract
Describe posterior pituitary (neurohypophysis)
Made of neural tissue
Receives, stores, and releases hormones from hypothalamus
Storage tank- release in response to nerve impulses
Describe the anterior pituitary (adenohypophysis)
Glandular tissue
Synthesizes and secretes hormones
What does oxytocin trigger
Uterine contractions
Milk ejection
Sexual arousal or orgasms
Promotes nurturing and affection
How is oxytocin regulated
Positive feedback
Until stimulus stops
Where is oxytocin stored
Made by paraventricular nuclei of hypothalamus
Stored in posterior pituitary
Pitocin is artificial form
When is ADH released/stored
High solute concentration= ADH released, inhibits urine formation
Low concentration= ADH Is not released, water loss allowed
Alcohol inhibits ADH release and increases urine output
Where is ADH produced/stored
Produced by supraoptic nuclei of hypothalamus
Stored in posterior pituitary
What does ADH target
Renal tubules of kidneys
Causes ducts to reabsorb from water
ADH is regulated by what
Negative feedback
What inhibits ADH
Diuretics
Used to treat edma, high BP
ADH deficiency can result in what
Diabetes insipidus
Huge urine output, intense thirst
When does ADH hypersecretion occur
Children with meningitis
Following trauma, surgery, cancer after general anesthesia
All can lead to SIADH- headache, fluid retention, and disorientation
How is the anterior pituitary controlled
Controlled by hypophyseal portal system in hypothalamus
No direct neural connection
What is hypophyseal portal system
System of blood vessels in the brain that connects the hypothalamus with anterior pituitary
What are the 6 peptide hormones of adenohypophysis
Growth hormone Lutienizing hormone Follicle stimulating hormone Prolactin hormone Adrenocorticotrophic hormone Thyroid stimulating hormone
Which anterior pituitary hormones are trophic
TSH, ACTH, FSH, LH
regulate the secretory action of other endocrine glands
What anterior pituitary hormones are direct hormones
GH, PRL
go directly to cells and tissues
Hypersecretion of GH in kids results in what
Gigantism
Excessive GH release before the epiphysesl plate closes
Hypersecretion of GH in adults results in what
Acromegaly
After epiphyseal plate closes
Nose, jaw, internal organs, hands and feet
Excessive GH can lead to what
Hyperglycemia and can cause diabetes mellitus
Hyposecretion of GH can result into what
Adults= no problems
Kids= pituitary dwarfism, can be treated with GH injections but has risks
What is the function of TSH
Stimulates development and secretory activity of thyroid
Stimulates production of thyroid hormones via second messenger
What regulates TSH
Released in response to thyrotropin releasing hormone
Inhibited by rising blood levels of thyroid hormone, blocks release of TSH negative feedback
What is the function of adrenocorticotrophic hormone
Stimulates adrenal cortex to produce/secrete glucocorticoids
These increase blood levels of nutrient molecules
What does FSH target
Ovaries and testes
Stimulates gamete production
What does LH target
Women: ovulation, promotes synthesis and release of estrogen and progesterone from ovaries
In women LH and FSH act together for maturation of ovarian follicle
Men= stimulates interstitial cells of the testes to produce testosterone
What stimulates the release of ACTH
Triggered by corticotropin releasing hormone (CRH) in daily rhythm
Internal and external factors can alter CRH
Inhibited by increased levels of glucocorticoids negative feedback
Where is GH produced
Anterior lobe of pituitary by somatotropin cells
What is GH regulated by
Growth hormone inhibiting and releasing hormone
What is the direct gene action of GH
Stimulates liver, skeletal muscle, bone and cartilage to produce insulin like growth factors
Release increases breakdowns of fats and glycogen stores for fuel
What is the function of prolactin
Stimulate milk production
What regulates prolactin release
Primary= prolactin inhibiting hormone
Females= stimulated by estrogen and prolactin releasing hormones
What is the possible basis for the role of prolactin in men
Possible erectile dysfunction
High PRL can suppress FSH and GnRH= hypogonadism
Describe thyroid glands
2 lateral lobes in anterior neck
Connected by median mass called isthmus
Composed of follicles that produce the glycoprotein thyroglobulin
What is colloid
Thyroglobulin plus iodine
Fills lumen of the thyroid follicles and is precursor of the thyroid hormone
What are parafollicular cells
Outer edges of the follicles of the thyroid gland
Produce calcitonin hormone
How does thyroid hormone work
Via direct gene activation
2 iodine containing compounds
T4- thyroxine
T3- triiodothyronine
Function of thyroid hormone
Increase metabolic rate and body heat production by stimulating enzymes used in glucose metabolism
Plays role in- maintaining BO, regulating tissue growth, development of skeletal and muscle systems, and reproductive capabilities
How does hypothyroidism affect adults
Myxedema
Low metabolic rate, chilled, constipation, thick and dry skin, puffy eyes, edema, lethargy
Enlarged thyroid= endemic goiter
How does hypothyroidism affect infants
Cretinism
Mental retardation, short/disproportionate body, thick tongue and neck
What is Graves’ disease
Autoimmune hyperthyroidism
Goiter
Elevated metabolic rate, sweating, rapid heart beat, nervousness, weight loss, building eyes
Where is calcitonin produced
Parafollicular cells of thyroid
When is calcitonin released
When calcium levels are high
Targets skeleton, inhibits osteoclasts
Stimulates calcium uptake and deposition into bone, lowers calcium blood levels
What inhibits calcitonin
Inhibited by low blood calcium levels via negative feedback
Calcitonin is an antagonist to
Parathyroid hormone PTH
What are your parathyroid glands
4-8 tiny glands embedded in posterior thyroid
Contain oxyphil cells and chief cells that secrete PTH
PTH is most important hormone in
Calcium homeostasis
PTH stimulates what
Osteoclast activity which increases calcium and phosphate levels in the blood
What is hyperparathyroidism
Due to tumor
Bones are soften and deform
Elevated CA2+ depresses nervous system and contributes to formation of kidney stones
What is hypoparathyroidism
Caused by gland trauma, removal, or prolonged MG deficiency
Increases excitability of muscles which results in tetany, respiratory paralysis and possible death
What is rickets
Childhood bone deformation due to demineralization
Deficiency in Ca and or Vit D
What is osteomalacia
Adults equivalent to rickets
Increase risk of fracture
Describe the structure and function of adrenal glands
Triangular, 2 glands in 1
Outer= adrenal cortex, glandular tissue, makes and secretes corticosteroids, hormones made here work via direct gene activation
Inner= adrenal medulla, nervous tissue, sympathetic nervous system
What are the 3 layers of adrenal cortex and what does each produce
Zona glomerulosa= mineralcorticoids
Zona fasciculata= glucocorticoids
Zona reticularis= gonadocorticoids
Function of mineralcorticoids
Regulate electrolytes, mainly Na and K, on extracellular fluid
Na affects ECF volume, blood volume, BO and levels of other ions
K sets RMP of cells
What is the most potent mineralcorticoid and function
Aldosterone
Stimulates Na reabsorption and water retention by kidneys
Considered antidiuretic
Stimulates K excretion and elimination
Function of glucocorticoids
Keep blood sugar levels constant
MaintainBP
Most significant glucocorticoid and function
Cortisol
Released in response to ACTH
Promotes gluconeogenesis
Promotes rise in blood glucose, fatty acids, and amino acids
Most significant gonadocorticoid and what do they contribute to
Androgens
Contribute to onset puberty, secondary sex characteristics, and sex drive in females
What type of cells does the pancreas have
Exocrine= acinar cells, produce digestive juices
Endocrine= pancreatic islets or islets of langerHans
What are the type of cells in pancreatic islets
Alpha= glucagon
Beta= insulin
Gamma- somatostatin
What is glucagon
Secretes by pancreas when blood glucose is low
Major target of glucagon is what
Liver
Promotes glucaneogenesis, glycogenolysis, and release of glucose to blood from liver cells
What is insulin
Hypoglycemic agent- lower blood glucose
Functions of insulin
Lowers blood glucose levels
Enhances transport of glucose into body cells
Participates in neuronal development
Learning and memory
Inhibits glycogenolysis and gluconeogenesis
What is diabetes mellitus
Hypo secretion of insulin
3 cardinal signs of DM
Polyuria
Polydipsia-excessive thirst
Polyphagia- excessive hunger
What is hyperinsulinism
Excessive insulin secretion, resulting in hypoglycemia, disorientation, and unconscious
What are two types of diabetes
Type 1- insulin dependent, lack of
Type 2- non insulin dependent, inefficient insulin
What is function of estrogen in the body
Maturation
Secondary sex characteristics
Thickening of uterus
What is function of progesterone
Breast development
Menstrual cycle
Function of testosterone
maturation
Sex drive
Secondary sex characteristics
Sperm production
What is pineal gland and function
Small gland hanging from roof of 3rd ventricle of brain
Produce melatonin
Melatonin is involved in
Timing of sexual maturation
Day and night cycle
Body temp, sleep, appetite
What is thymus
Gland deep to sternum
Large in kids but shrinks
Hormonal production that are essential for T cell production in immune system
