Endocrine Flashcards
Characteristics (4) and Function (4) of Endocrine organs
Endocrine organs
Functions
- growth and development
- internal environment
- energy production/storage/use
- reproduction
Characteristics
- Epithelial in origin
- ductless
- highly vascular
- mediated by hormones
List the primary endocrine organs (6)
Primary endocrine organs
- Pituitary gland (hypophysis)
- pineal gland (epiphysis)
- thyroid gland
- parathyroid glands
- adrenal glands
- Ultimobranchial bodies (birds only)
Explain the importance of the hypothalamus.
Hypothalmus= portion of brail that links the nervous system and the endocrine system via the pituitary gland
Functions through two pathways:
- Production of releasing hormones: into portal system to target cells in the adenohypophysis
- hormones transported down axons and stored in the neurohypophysis to be released into blood to target distant sites (ex. ADH and Oxytocin)
Describe the origin of the two parts of the hypophysis.
Hypophysis= Pituitary Gland
Neurophypophysis= Posterior Pituitary
Adenohypophysis= Anterior Pituitary
Name the main parts of the adenohypophysis and the neurohypophysis.
Neurohypophysis= posterior pituitary
- infandibular stalk
- pars nervosa
- cell bodies of large neurons produce ADH and oxytocin
- axons are infundibulum and pars nervosa
- herring bodies- swellings along these axons where hormones accumulate.
- axons terminate on vessels where blood transports hormones to target organs.
Adenohypophysis= anterior pituitary
- pars distalis
- bulk of the adenohypophysis and secretes majority of hormones
- chromophils= acidophils and basophils
- chromophobes= dont stain well
- bulk of the adenohypophysis and secretes majority of hormones
- pars intermedia
- pars tuberalis
Name the cells of the adenohypophysis and the hormones produced by them. (6)
Adenohypophysis= Anterior Pituitary
Bulk of hormones produced by cells in pars distalis
- Acidophils
- Somatotroph—> GH= growth hormone
- Lactotroph—> prolactin
- Basophils
- Thyrotropes—> TSH= thyrotropin
- Gonadotropes—> FSH= follicle stim hormone
- Gonadotropes—> LH= leutenizong hormone
- Adrenocorticotropes—> ACTH
Explain function of the hypothalamic-hypophyseal portal system.
hypothalamic-hypophyseal portal system
= system of blood vessels connecting the hypothalmus to the anterior pituitary. allows for efficient transport of hormones between the glands.
Give the location and function of the pineal gland.
Pineal gland= Epiphysis
Location: back/base of brain above hypothalmus
Function: regulates daily rythem of bodily activity
- Pinealocytes- produce melatonin hormone. stimulated by darkness=secretion of melatonin.
Melanin is important in SEASONAL REPRODUCTION
List the common types of hormones and their intracellular method of action.
Hormones:
- Proteins, glycoproteins or polypeptides
- Amino Acids
- T3,T4
- catecholamines (E and NE)
- Steroids
- testosterone, estrogen, cortisol, aldosterone
Most hormones trael via blood stream, then bind to receptors on target cells, and produce slow, sustained responses.
Steroids pass through plasma membrane and bind nucleus!
Trace a releasing hormone from the hypothalamus to the acidophils/basophils of the adenohypophysis, then to the appropriate target organ for each, and the production of the third hormone of each (where applicable) and state the effect of the terminal hormone.
Tracing hormones
- hypothalmic neurons produce releasing hormones into portal vessels
- releasing hormones tracel to adenohypophysis and stimulate acidophils or basophils in pars distalis
- second hormone produced by stimulated cells and travle to target endocrine organ where third hormone is produced.
- third hormone has effect on target organ/cell
- see chart of the organs and specific effects
Trace the production of oxytocin from the hypothalamus to its target cells and action on the mammary gland.
produced in posterior pituitary= Neurohypophysis- pars nervosa
- Oxytocin= stimulate milk (positive feedback loop!)
- endocrine loop
- hypothalmus–>neurohypophysis–>oxytosin stored in nerve terminal–>released into blood–> stimulates milk let down and milk production of mamary gland
- neural loop
- claf stimulates mamary gland–>impulse travels to spinal cord–>pathway to hypothalmus–>back to endocrine loop
- endocrine loop
Trace the production of antidiuretic hormone (ADH) from the hypothalamus to its target cells and action on the kidney.
produced in posterior pituitary= Neurohypophysis- pars nervosa
- ADH= stimulates water retention (increased blood volume)
- high blood osmoticity–> hypothalmus–> stimulates neurohypophysis–> ADH to kidney–> increased water reabsorption and concentration of urine
List the hormone-producing cells of the thyroid gland and their basic actions on the body.
Thyroid Gland=
- Cells lining follicles produce thyroglobulin which is stored in colloid
- converted to thyroxine (T3/T4)
- Parafollicular cells (C-cells)
- secrete calcitonin in response to high calcium–> targets kidneys and bone–> lowers serum calcium
List the hormone-producing cells of the parathyroid gland and their basic actions on the body.
Parathyroid gland=
- chief cells
- low calcium–>secrete PTH–> targets bone, stomach and kidney–> increased calcium resorption–> increased calcium levels
List the regions of the adrenal gland, the hormones produced there, and their general action on the body.
Adrenal gland
Cortex- produces corticosteroids
- zona glomerulosa–> Aldosterone= increase blood volume
- zona fasciculata–> Cortisol= stress hormone
- zona reticularis–> Weak Androgens=sex
Medulla- produces catecholamines
- Epinephrine + Norepinephrine= fight/flight
Identify
Identify
Identify
Thyroid Gland
