Intro to Endocrine Flashcards
Common endocrine diseases managed by the primary care provider?
- diabetes mellitus
- thyroid diseases (hypothyroidism and hyperthyroidism)
- Hyperlipidemia
What is endocrinology?
- study of hormones and disorders of these hormones
What makes up the endocrine system?
- hypothalamus and pituitary
- thyroid and parathyroid
- adrenals
- (islets of langerhans, ovaries, testicles, placenta)
Who was the first person to use the term hormone?
- Ernest Henry Starling
How does the endocrine system maintain homeostasis?
- 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
What are hormones?
- 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
What are the functions of hormones?
- 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
What are the characteristics of hormones?
- 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
What are the 2 different functional types of hormones?
- 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
categories of chemical hormones?
- 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
Where are hormone receptors and what are their function?
- 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.
How are hormones regulated and controlled?
- 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
Relationship b/t endocrine and nervous system?
- 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.
Functions of the nervous system?
- exerts point-to-point control through nerves, similar to sending messages by conventional landline telephone. Nervous control is electrical in nature and immediate
Endocrine system functions?
- 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.
Why are cells targets for hormones?
- 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
What 2 systems are needed for proper body regulation and function?
- Nervous system and Endocrine system
Breakdown of Nervous system?
- PNS: Efferent and Afferent, efferent: Autonomic (parasympathetic and sympathetic) , and somatic
- CNS
Are the 2 main systems (endocrine and nervous system) that coordinate and regulate function mutually exclusive?
- 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
2 major regulatory systems of the body?
- 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
What does the endocrine system do?
- 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)
endocrine system?
- produces chemical messengers (hormones) that influence growth, development, and metabolic activities. There are 2 major categories of glands in the body: exocrine and endocrine