Endocrine System Flashcards
are glandular secretory
cells that release hormones directly into the interstitial fluids, lymphoid system, or blood
Endocrine cells
alter the metabolic activities of many different tissues and organs
Hormones
where do endocrine cells release hormones directly?
- interstitial fluids
- lymphoid system
- blood
“pure” endorcine glands
pituitary, pineal, thyroid, parathyroid, and adrenal
Other organs containing endocrine cells
- Pancreas
- Thymus
- gonads
- Hypothalamus
acts as an endocrine organ, releasing the hormones ADH and oxytocin into the circulation at the neurohypophysis
(posterior lobe)
Hypothalamus
what do hypothalamus release?
ADH and Oxytocin
where do Hypothalamus release the hormones?
Circulation at the Neurohypophysis
have direct neural control over the endocrine cells of the adrenal gland.
Autonomic centers
- important homeostatic control center
– Regulates water balance, hunger and satiety, body temperature, water balance
– Controls the pituitary gland
Hypothalamus
resembles a golf club with a stalk (or infundibulum) that extends from the hypothalamus and the head of the club as the gland
Pituitary gland
2 lobes of pituitary gland
Adenohypophysis
Neurohypophysis
anterior lobe
adenohypophysis
posterior lobe
neurohypophysis
Hormones released by Neurohypophysis
ADH and Oxytocin
Hormones released by Adenohypophysis
ACTH
TSH
GH
PRL
FSH
LH
ACTH
adrenocorticotropic hormone
TSH
thyroid-stimulating hormone
GH
growth hormone
PRL
prolactin
FSH
follicle-stimulating hormone
LH
luteinizing hormone
Stores ADH and oxytocin which are actually produced in the hypothalamus
Posterior pituitary
inability to produce ADH
Diabetes insipidis
causes uterine contractions and milk letdown in lactation
Oxytocin
It is controlled by hypothalamus by hypothalamic-releasing hormones
Anterior pituitary
Three anterior pituitary hormones that have effect on other glands
- TSH
- ACTH
- Gonadotrophic hormone
thyroid stimulating hormone stimulates thyroid gland to produce thyroid hormone
TSH
adrenocorticotrophic hormone stimulates the adrenal cortex to produce glucocorticoids
ACTH
stimulate the gonads to produce estrogen and testosterone
Gonadotrophic hormones
3 anterior pituitary hormones do not affect other glands
- MSH
- GH
- Prolactin
melanocyte stimulating hormone stimulates the melanocytes in the skin
MSH
stimulates bone and muscle growth, increases protein synthesis and fat metabolism
Growth Hormone
stimulates the mammary glands to synthesize milk
Prolactin
Effect of GH on childhood
Lack of GH: pituitary dwarfism
Excess: Gigantism
Effect of GH on Adulthood
Acromegaly
Sits on thyroid cartilage of the larynx
- butterfly-like appearance
Thyroid gland
from pituitary stimulates thyroid to produce thyroxine (T4) and triiodothyronine (T3)
TSH
What does TSH do?
- increase metabolic rate
- stimulate all body cells
- more glucose is utilized to form ATP
secreted by the follicular cells
T3 and T4
where is T3 and T4 stored
colloid
Hypothyroidism in adults-lethargy, weight gain, loss of hair
Myxedema
- Causes exophthalmic goiter-edema behind eyes causes bulging
- Hyperactivity, arrythmias
Grave’s disease hyperthyroidism
The Parathyroid Glands
Parathormone
can result if parathyroids are removed or destroyed
Hypocalcemia
- Secretes many chemicals that help T cells of the immune system develop (thymosins)
- Atrophies as one ages
Thymus
What does thymus produce?
Melatonin
structure of adrenal gland
Outer cortex
Inner medulla
is under the control of ACTH
Cortex
is a neurosecretory structure
Medulla
– Long-term stress response
– Produces 2 main groups of hormones
Adrenal cortex
2 main groups of hormones produced by Adrenal cortex
- Mineralocorticoids
- Glucocorticoids
– Regulate salt and water balance
– Aids in regulation of blood volume and pressure
Mineralocorticoids
– Under control of ACTH
– Regulates carbohydrate, protein, and fat metabolism » Causes increase in blood glucose
– Anti-inflammatory
Glucocorticoids
Malfuntions of Adrenal cortex
- Addison’s disease
- Cushing’s syndrome
- ACTH accumulates and causing bronzing of the skin from stimulation of melanocytes
- Without cortisol, there is no mobilization of glucose under stress
Addison’s disease
most serious in addisons disease
Hyposecretion of aldosterone
elevated blood potassium
Hyperkalemia
- Hypersecretion of the adrenal cortex
- Excess cortisol is primary problem
Cushing’s syndrome
Contains endocrine and exocrine cells
Pancreas
form most of the gland
- secrete digestive enzymes into the small intestine
Exocrine acinar cells
are contained in spherical bodies
- pancreatic islets or islets of Langerhans
- about 1 million scattered among the exocrine cells
Endocrine cells
4 major cells of each islets
- Alpha cells
- Beta cells
- Delta cells
- F cells
cells for glucagon
Alpha cells
Cells for insulin
Beta cells
Cells for somatostatin
Delta cells
growth-hormone inhibiting hormone
Somatostatin
cells for – pancreatic polypeptide (PP)
F cells
– Released after eating
– Stimulates uptake of glucose by cells
Insulin
- Released before eating when glucose is low
- Targets liver and adipose tissue
- Increases blood glucose
Glucagon
- Insulin-resistant
- Obesity- adipose tissue produces a substance that impairs insulin receptor function
- Insulin levels are often low, and cells may not have sufficient insulin receptors
- Controlled by diet, exercise, medications
Type 2 Diabetes mellitus
Long term complications of diabetes
- Blindness
- Kidney disease
- Cardiovascular disorders
- Small pine-cone shaped gland (or epiphysis cerebri) - part of the epithalamus
Pineal gland
Pineal gland, contains neurons, glial cells, and special secretory cells called
pinealocyte
