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Flashcards in Intro to Endocrine Deck (56)
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1
Q

Common endocrine diseases managed by the primary care provider?

A
  • diabetes mellitus
  • thyroid diseases (hypothyroidism and hyperthyroidism)
  • Hyperlipidemia
2
Q

What is endocrinology?

A
  • study of hormones and disorders of these hormones
3
Q

What makes up the endocrine system?

A
  • hypothalamus and pituitary
  • thyroid and parathyroid
  • adrenals
  • (islets of langerhans, ovaries, testicles, placenta)
4
Q

Who was the first person to use the term hormone?

A
  • Ernest Henry Starling
5
Q

How does the endocrine system maintain homeostasis?

A
  • hormones act on distant target cells to maintain the stability of the internal environment
  • secretion of the hormone was evoked by a change in the milieu and the resulting action on the target cell restored the milieu to normal. The desired return to the status quo results in the maintenance of homeostasis
6
Q

What are hormones?

A
  • any substance normally produced by specialized cells in some part of the body, carried by the blood stream to another part, where it effects the body as a whole
  • vehicles for intracellular and extracellular communication
7
Q

What are the functions of hormones?

A
  • maintain homeostasis
  • regulate growth and development
  • promote sexual maturation, sexual rhythms and facilitate reproduction
  • regulate energy production
  • adapt/adjust body to stressful/emergency situations
  • promote/inhibit production or release of other hormones
8
Q

What are the characteristics of hormones?

A
  • specificity: only target cells respond
  • multiple actions
  • varibale half life: often depends on solubility properties
  • variable forms: depends on wt
  • excretion rates: diurnal variation, cyclic patterns, and stimulus response
9
Q

What are the 2 different functional types of hormones?

A
  • tropic: originate from anterior pituitary gland
    specific for another endocrine gland
  • non-tropic or direct effector: secreted by non-pituitary endocrine glands, act directly on peripheral tissue. Exert a feedback effect on hypothalamus or anterior pituitary gland
10
Q

categories of chemical hormones?

A
  • peptides/proteins: polypeptides or glycoproteins, soluble in plasma, interact with target cell membrane receptors to trigger a 2nd messenger to complete the specific action of the hormone, short term effects
  • Amines: AA derivatives, poorly soluble in plasma, interact with membrane receptors of target cells, provide long and short term effects
  • steroids: composed of lipids (cholesterol), can transverse through the cell membrane, produced by ovaries, testis, placenta, and adrenal cortex, insoluble in water, and long-lasting
11
Q

Where are hormone receptors and what are their function?

A
  • located on cell membrane or within cell cytoplasm.
  • binding of hormone to receptor initiates a signal, results in changes in gene expression, ultimately causes a biological response.
12
Q

How are hormones regulated and controlled?

A
  • occurs by controlling rate of synthesis rather than rate of degradation
  • primary control: hypothalamus - small gland next to pituitary gland, and is connected to pituitary by “pituitary stalk”
  • pituitary gland: releases both tropic and effector hormones
13
Q

Relationship b/t endocrine and nervous system?

A
  • 2 major communication systems in the body
  • integrate stimuli and responses to changes in external and internal environment
  • both are crucial to coordinated functions of highly differentiated cells, tissues, and organs
  • unlike the nervous system, the endocrine system is anatomically discontinuous.
14
Q

Functions of the nervous system?

A
  • exerts point-to-point control through nerves, similar to sending messages by conventional landline telephone. Nervous control is electrical in nature and immediate
15
Q

Endocrine system functions?

A
  • broadcasts its hormonal messages to essentially all cells by secretion into blood and extracellular fluid. Like a radio broadcast, it requires a receiver to get the message, in the case of endocrine messages, cells must bear a receptor for the hormone being broadcast in order to respond.
16
Q

Why are cells targets for hormones?

A
  • becausae it has a specific receptor for the hormone
  • most hormones circulate in blood, coming into contact with essentially all cells. However, a given hormone usually affects only a limited number of cells, which are called target cells, a target cell responds to a hormoned because it bears receptors for the hormone
17
Q

What 2 systems are needed for proper body regulation and function?

A
  • Nervous system and Endocrine system
18
Q

Breakdown of Nervous system?

A
  • PNS: Efferent and Afferent, efferent: Autonomic (parasympathetic and sympathetic) , and somatic
  • CNS
19
Q

Are the 2 main systems (endocrine and nervous system) that coordinate and regulate function mutually exclusive?

A
  • NO!
  • one example of 2 systems working together: sympathetic flight or fight response - direct stimulation of effector site by neuron -> stimulation of medulla results in release of epi and norepi in the blood which: greatly prolongs sympathetic stimulation, and this can affect all cells of the body, even those not innervated directly by sympathetic neurons
20
Q

2 major regulatory systems of the body?

A
  • endocrine and nervous system
  • ** Because there is so much overlap with coordination of function with the nervous system, there are several sxs of endocrine disorders that mimic pathology seen in other organ systems
21
Q

What does the endocrine system do?

A
- controls numerous body processes:
growth and development
metabolism
reproduction
homeostasis
- involves numerous organs and tissues located throughout the body, and it works in conjunction with the nervous system (and to lesser extent with the immune system)
22
Q

endocrine system?

A
  • produces chemical messengers (hormones) that influence growth, development, and metabolic activities. There are 2 major categories of glands in the body: exocrine and endocrine
23
Q

What are hormones?

A
  • chemical messengers that are released in one tissue and transported by bloodstream to reach target cells in their tissues
24
Q

What are exocrine glands?

A
  • produce secretions which are released to the outside; the sweat, salivary, mammary, and digestive gland systems are examples of this.
25
Q

Endocrine glands?

A
  • hormones are secreted directly into the blood and are carried throughout the body where they influence the appropriate receptor sites for that hormone.
26
Q

What are mixed glands?

A
  • (both exocrine and endocrine), some glands have non-endocrine regions that have functions other than hormone secretion. For example, the pancreas has a major exocrine portion that secretes digestive enzymes and an endocrine protion that secretes hormones
27
Q

Components of the endocrine system?

A
  • hypothalamus
  • pineal gland
  • pituitary gland
  • thyroid gland
  • thymus
  • parathyroid glands
  • adrenal glands
  • gonads
  • pancreas
28
Q

Function of the hypothalamus?

A
  • primary link b/t endocrine and nervous systems
  • regulates activities of nervous and endocrine systems in 3 ways: 1- acts as an endocrine organ and releases hormones ADH and oxytocin
    2 - secretes regulatory hormones (releasing hormones or inhibiting hormones)
    3- control endocrine cells in the adrenal medulla
29
Q

Pituitary gland structure?

A
  • AKA hypophysis
  • small oval gland seated in sella turcica of sphenoid bone
  • consists of 2 lobes (anterior and posterior)
    anterior: adenohypophysis (made up of glandular cells)
    posterior: neuroypophysis (cells are non-secretory, resemble neurological tissue)
30
Q

Function of adenohypophysis?

A
  • can be divided into anterior pars distalis and posterior pars intermedia
  • contains endocrine cells surrounded by an extensive capillary network (hypophyseal portal system)
  • secretes 7 important hormones, and 6 are produces by the pars distalis
31
Q

Hormones of adenohypophysis?

A
  • thyroid-stimulating hormone (TSH)
  • Adrenocorticotropic hormone (ACTH)
  • follicle-stimulating hormone (FSH)
  • luteinizing hormone (LH)
  • Prolactin( PRL)
  • Somatotrophin (GH)
  • melanocyte-stimulating hormone (MSH)
32
Q

What does the neurohypophyis (posterior lobe of pituitary gland) produce?

A
  • contains the axons of hypothalamic neurons

- nuclei of hypothalamus produce ADH and oxytocin

33
Q

Which lobe secretes more hormones?

A
  • anterior lobe (adenohypophysis)
34
Q

WHat is the pineal gland, fxn?

A
  • lies in the roof of the thalamus (3rd ventricle), under teh posterior end of the corpus callosum
  • it contains neurons, glial cells, and secretory cells that synthesize the hormones melatonin
35
Q

Where is the thyroid gland, function?

A
  • lies anterior to trachea and just below thyroid cartilage, which forms most of anterior surface of larynx
  • Has 2 lobes (butterfly shape) united by isthmus
  • has an extensive blood supply
  • produces the hormones T3, T4, and calcitonin
36
Q

Where are parathyroid glands located and what are their functions?

A
  • 2 pairs of parathyroids embedded in the posterior surface of thyroid gland
  • there are 2 different types of cells within parathyroid glands (chief cells and oxyphil cells)
  • Chief cells produce parathyroid hormone (parathormone) -> stimulates osteoclasts, inhibits osteoblasts, increases intestinal absorption, and reduces urinary exretion of calcium ions
  • Oxyphil cell function: unknown, but appears at onset of puberty
37
Q

Where is the thymus and what is the function?

A
  • embedded in the mediastinum, usually posterior to the sternum
  • organized in 2 lobes separated by septa. Each lobe consists of dense outer cortex and central medulla
  • cortex consists of epithelial cells that secrete thymic hormones (Thymosins= T cells), which play key role in development and maintenance of immunological defenses
  • medulla has thymic corpuscles (Hassall’s corpuscles): unknown function
38
Q

Adrenal gland location and function?

A
  • AKA suprarenal glands
  • lie along superior borders of kidneys
  • pyramid shaped glands
  • can be subdivided on histological grounds into an outer cortex and inner medulla
    Adrenal cortexL produces steroid hormones called corticosteroids, contains 3 distinct zones, and has yellowish color due to presence of stored lipids
39
Q

Where are corticosteroids produced?

A
  • adrenal cortex -> of adrenal glands
40
Q

What are the zones of adrenal cortex?

A
  • zona glomerulosa (outermost and relatively narrow layer, secretes mineralocorticosteroids: aldosterone)
  • zona fasciculata: extends toward the capsule in a series of radiating cell columns. Produces glucocorticoids (cortisol, corticosterone, and cortisone)
  • zona reticularis: surrounds adrenal medulla, produces androgens
  • adrenal medulla: contains 2 populations of secretory cells, one produce epi (75-80%) and the other NE (20-25%)
41
Q

pancreas function?

A
  • contains exocrine and endocrine cells
  • endocrine cells are found within pancreatic islets (islets of langerhans)
    alpha cells: secrete glucagon - released when glucose levels are too low
    beta cells: produce insulin - released when glucose levels too high
42
Q

Gonads males and females?

A
  • testes: male gonads, located in scrotum
    each testicle is made up of seminiferous tubules which produce spermatozoa, b/t tubules are interstitial cells that secrete steroid hormones known as androgens (testosterone)
  • ovaries: female sex organs, located in pelvic cavity, follicle cells in the ovaries produce steroid estrogens while eggs are developing. After ovulation the cells reorganize into a corpus luteum that produces progesterone. If a pregnancy occurs, the placenta will gradually develop endocrine functions on its own.
43
Q

What are the non-endocrine organs that produce hormones?

A
  • brain
  • heart
  • lungs
  • kidneys
  • liver
  • skin
  • placenta
    also produce and release hormones
44
Q

How are diseases and disorders of the endocrine system characterized?

A
  • hypo or hyper hormone release
  • inappropriate response to signaling
  • absence of a gland
  • structural enlargement
45
Q

How are diseases and disorders of endocrine system classified?

A

primary: inhibits action of downstream glands
secondary: indicative of problem with pituitary gland
tertiary: dysfunction of hypothalamus

46
Q

What are the adrenal insufficiency disorders?

A
  • addison’s disease (primary adrenal insufficiency)

- mineralocorticoid deficiency

47
Q

What are the adrenal hormone excess disorders?

A
  • conn’s syndrome (aldosterone producing adenoma)
  • cushing’s syndrome (high levels of cortisol in the blood by a tumor or systemic steroids)
  • GRA/glucocorticoid remediable aldosteronism (cause of primary hyperaldoesteronism)
  • congenital adrenal hyperplasia
  • adrenocortical carcinoma
48
Q

What are the pancreas disorders?

A
  • diabetes mellitus: type 1, type 2, and gestational diabetes
  • hypoglycemia: idiopathic hypoglycemia, insulinoma (tumor of the b-cells in the pancreas)
  • Glucagonoma: tumor of the iselt cell in the pancreas
49
Q

Thyroid disorders?

A
  • goiter (iodine deficiency)
  • hyperthyroidism: graves disease, and toxic multinodular goiter
  • hypothyroidism
  • thyroiditis: hashimoto’s thyroiditis
  • thyroid cancer
50
Q

Parathyroid disorders?

A
  • parathyroid gland disorders: primary hyperparathyroidism, secondary hyperparathyroidism, tertiary hyperparathyroidism, and hypoparathyroidism (pseudohypoparathyroidism)
  • osteoporosis
  • osteitis deformans (Paget’s disease of the bones)
  • Rickets and osteomalacia
51
Q

Pituitary gland disorders?

A
  • posterior pituitary: diabetes insipidus
  • anterior pituitary: hypopituitarism, pituitary tumors: pituitary adenomas, prolactinoma (hyperprolactinemia), acromegaly, gigantism, cushing’s disease
52
Q

categories of sex hormone disorders?

A
  • disorders of sex development

- hypogonadism (gonadotropin deficiency)

53
Q

Disorders of sex development?

A
  • hermaphroditism
  • gonadal dysgenesis
  • androgen insensitivity syndromes
54
Q

Hypogonadism disorders?

A
  • inherited (genetic and chromosomal disorders): kallmann syndrome, klinefelter syndrome, turner syndrome
  • disorders of puberty: delayed puberty, precocious puberty
  • menstrual function or fertility disorders: amenorrhea, and polycystic ovary syndrome
55
Q

Tumors of endocrine glands?

A
  • Multiple endocrine neoplasia:
    MEN 1: parathyroid, pancreatic, and pituitary
    MEN 2: thyroid, pheochromocytoma, parathyroid
    MEN 3: medullary thyroid cancers, pheochromocytoma, neuroma
  • carcinoid syndrome
56
Q

What disorders of the endocrine system does an Endocrinologist treat? (more complicated disorders)

A
  • diabetes (brittle DM, complex, insulin pumps)
  • thyroid disorders (initial eval)
  • metabolic disorders
  • lipid disorders (refractory cases)
  • infertility
  • deficiency of growth hormones
  • cancers of endocrine glands