Endocrine System Flashcards
Glands secrete ____ that travel through blood to ____ cells which have specific ____
hormones, target, receptors
What are the 2 general chemical categories of hormones?
Hydrophilic & lipophilic
What are the 2 types of hydrophilic hormones?
Peptide hormones & catecholamines
Peptide hormones are chains of ____ ____ while catecholamines are ____
amino acids, cholesterol
What are the 2 types of lipophilic hormones?
Steroid & thyroid hormone
What are the 3 methods that hormones can influence other hormones?
- Permissiveness
- Synergism
- Antagonism
Describe permissiveness
One hormone must be adequately present for full exertion of another hormone’s effect
Describe synergism
- Complimentary action of several hormones
- Combined effect > sum of separate effects
Describe antagonism
Hormones working against each other
The posterior pituitary gland is also known as ___hypophysis while the anterior is also known as ___hypophysis
neuro, adeno
The posterior pituitary gland is composed of what type of tissue?
Nervous
What 2 hormones does the posterior pituitary gland store & release?
ADH (vasopressin) & oxytocin
What is the function of ADH?
Conserve water during urine formation
What is the function of oxytocin?
Stimulates uterine contraction during birth + milk secretion during breast-feeding
The anterior pituitary gland is composed of what type of tissue?
Glandular epithelial
What 6 hormones does the anterior pituitary gland secrete?
- TSH
- ACTH
- Growth hormone
- LH
- FSH
- Prolactin
What are the 2 pituitary glands regulated by?
Hypothalamus
What are 2 disorders related to ADH secretion?
SIDAH & diabetes insipidus
Diabetes insipidus is ___secretion of ADH while SIDAH is ___secretion of ADH
hypo, hyper
Where is the thyroid gland?
In the neck
Describe the structure of the thyroid gland?
2 lobes joined in the middle
The thyroid is made of ____ cells and _ cells
follicular, C
What 2 thyroid hormones do the follicular cells produce?
§ Tetraiodothyronine (T4 or thyroxine) & Tri-iodothyronine (T3)
What do C cells secrete?
Calcitonin
Thyroid hormone is ___philic
lipo
What is the general function of thyroid hormone?
Alter protein synthesis in target cell
What are 4 specific effects of thyroid hormone?
- Effect metabolic rate & heat production (calorigenic)
- Body growth (GH)
- Nervous system growth & normal function
- Sympathomimetic effect
What are 4 abnormalities of thyroid function?
- Hypothyroidism
- Cretinism
- Myxedema
- Hyperthydroidism
What are 3 potential causes of hypothyroidism?
- Primary failure of thyroid gland
- Secondary deficiency of TRH and/or TSH
- Insufficient supply of iodine
What causes cretinism?
Hypothyroidism from birth
What is the treatment for myxedema?
Replacement therapy + dietary iodine
What causes hyperthyroidism?
Grave’s disease
What ion does parathyroid hormone increase levels of in the plasma?
Calcium
What are the effects of parathyroid hormone of the bones, kidneys and intestine
- Bones: bone dissolution
- Kidneys: conserve Ca2+ & eliminate PO4
- Intestine: promotes absorption of Ca + PO4
Where are the adrenal glands?
Above each kidney in a capsule of fat
What are the 2 components of an adrenal gland from outer most to inner most?
Adrenal cortex & adrenal medulla
What are the 3 layers of the adrenal cortex?
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
What does the zona glomerulosa secrete?
Aldosterone (mineralocorticoids)
Aldosterone is synergistic with which other hormone?
ADH
What does the zona fasciculata secrete?
Cortisol (glucocorticoids)
What are 4 metabolic effects that cortisol has?
- Survival during fasting
- Stimulates gluconeogenesis
- Stimulates protein degradation
- Facilitates lipolysis
Hypersecretion of cortisol can lead to:
Cushing’s syndrome
Hyposecretion of cortisol can lead to:
Addison’s disease
What does the zona reticularis secrete?
DHEA (dehydroepiandrosterone)
What is DHEA?
An adrenal sex hormone
Is DHEA significant in males or females?
Females
What is the function of DHEA in females?
- Growth of pubic + axillary hair
- Enhancement of pubertal growth spirt
- Development & maintenance of female sex drive
In general, what type of hormone does the adrenal cortex secrete?
Steroid hormones
What hormone does the adrenal medulla secrete?
Catecholamines (epinephrine + norepinephrine)
What are the 3 functions of catecholamines?
- Fight-or-flight responses
- Maintenance of arterial BP
- Increases blood glucose and blood fatty acids
Where is the pancreas?
In the abdomen, behind the stomach
What are the 4 endocrine cells (islets of langerhans) found in the pancreas?
- Beta cells
- Alpha cells
- Delta cells
- PP cells
What is the function of the B cells?
Site of insulin synthesis + secretion
What is the function of A cells?
Produce glucagon
What is the function of D cells?
Site of somatostatin synthesis
What event is a release of D cells in direct response to?
Increase of blood sugar + amino acids during absorption of meal
What is the function of PP cells?
Secrete polypeptide
What is the function of insulin?
Promotes absorption of glucose
Diabetes insipidus is an insufficiency of ___ while diabetes mellitus is an insufficiency of ___
ADH, insulin
Where is the pineal gland located?
Epithalamus
Where is the thymus gland located?
Upper front part of the chest, behind the sternum and in front of the heart
What is the function of the thymus gland?
Site of T cell maturation (adaptive immune system)
What is the function of the pineal gland?
Produces melatonin (regulates sleep cycles)
