Endocrine Flashcards
(45 cards)
What is a hormone
chemical messengers transported by bloodstream that stimulate physiological responses in cells of another tissue or organ
*redo definition
Similarities between endocrine and nervous system
- chemicals bind to receptors on target cells
- E and NE are both neurotransmitters and hormones
- regulated by negative feedback
- preserves homeostasis
Differences between endocrine and nervous system
Nervous: action potentials and neurotransmitters control specific cells or groups; specific and quick signals
Endocrine: hormones reach almost every cell in the body; wide-spread effects for longer
Differences between endocrine and exocrine glands
Exocrine:
- secretes products into ducts which empty onto epithelium. Ex: sweat
- cause extracellular effects. Ex: digestion of food in lumen
Endocrine:
- releases products into bloodstream
- cause intracellular effects; alters cell metabolism
Major organs of the endocrine system and their hormone
Pineal gland - melatonin
Hypothalamus - ADH, OCT, regulatory hormones
Pituitary gland - ACTH, TSH, GH, PRL, FSH, LH, MSH, OXT, ADH
Thyroid gland - T, T3, CT
Parathyroid gland - PTH
Pancreas - insulin, glucagon
Adrenal glands - E, NE, cortisol, corticosterone, cortisone, aldosterone, androgens
Mechanisms of intercellular communication
direct, paracrine, autocrine, endocrine, and synaptic communication
Direct communication
Transmission: gap junctions
Chemical mediators: ions, small solutes, lipid-soluble materials
Distribution of effects: usually limited to adjacent cells of the same type that are interconnected by connexons
Paracrine communication
Transmission: extracellular fluid
Chemical mediators: paracrines
Distribution of effects: primarily limited to a local area, where paracrine concentrations are relatively high; target cells must have appropriate receptors
Autocrine communication
Transmission: extracellular fluid
Chemical mediators: autocrines
Distribution of effects: limited to the cell that secretes the hormone
Endocrine communication
Transmission: bloodstream
Chemical mediators: hormones
Distribution of effects: target cells are primarily in other tissues and organs must have appropriate receptors
Synaptic communication
Transmission: across synapses
Chemical mediators: neurotransmitters
Distribution of effects: limited to very specific area; target cells must have appropriate receptors
What major processes are affected by hormones?
- growth and development
- reproduction
- regulation of cell metabolism
- regulation of body water content and levels of electrolytes and organic nutrients
- mobilization of body defenses
Adrenocorticotropic hormone (ACTH) function
stimulates adrenal cortex to secrete glucocorticoids
Antidiuretic hormone (ADH) function
water regulation and reabsorption, regulates blood volume and pressure
Corticotropin-releasing hormone (CRH) function
stimulates the anterior pituitary to release ACTH
Calcitonin (CT) function
regulate calcium blood levels, opposite PTH effects, support bone metabolism
Cortisol function
stress response regulation, metabolic process control, anti-inflammatory response, energy mobilization
Dehydroepiandrosterone (DHEA) function
precursor to sex hormones, supports prenatal reproductive tract development, stimulates pubic and axillary hair growth, enhances libido
Erythropoietin (EPO) function
stimulates erythrocyte production in bone marrow, regulates body’s oxygen carrying capacity
Follicle-stimulating hormone (FSH) function
females: stimulates follicle development in ovaries, promotes estrogen production
males: stimulates sperm production, supports spermatogenesis
Growth hormone (GH) function
stimulate tissue growth, enhance bone and muscle development, regulate metabolism
Growth hormone releasing hormone (GHRH) function
stimulates the anterior pituitary to release GH
Gonadotropin-releasing hormone (GnRH) function
stimulates anterior pituitary to release gonadotropins, triggers production of FSH and LH
Insulin-like growth factors (IGFs) function
stimulate tissue growth, support developmental processes
