Endocrine System Flashcards
Where to endocrine glands secrete hormones?
Directly into the blood
What are the three classes of hormones?
Proteins
Steroids
Amino acid/ metabolite derivatives
Where to glands develop from?
Epithelial cells
Example of simple tubular gland?
intestinal glands of Lieberkühn
Example of simple coiled tubular gland
Sweat glands in skin
Example of simple tubular branched gland
Glands of the stomach and uterus
Example of simple acinar or alveolar gland
Sebaceous gland
What are the four types of exocrine glands?
Simple tubular gland
Simple coiled tubular gland
Simple tubular branched gland
Simple acinar or alveolar gland
What is paracrine secretion?
Communication over very small distance
Example of paracrine signalling
Neurotransmitters
Where is paracrine secretion very important?
Embryogenesis
What growth factors are involved in embryogenesis?
Fibroblast growth factor
Hedgehog family
WnT family
TGF-beta superfamily
What are the main endocrine glands in your body?
Pineal
Hypothalamus
Pituitary
Thyroid
Parathyroid
Thymus
Adrenal
Pancreas
Ovary
Testis
How do steroid and thyroid hormones travel in the blood?
Transported by specific carrier and binding proteins
What do specific carrier proteins do for hormones?
Improves solubility
Increases half life
Provides a reserve in the blood
Where are hormone receptors found?
On the cell membrane for peptide, protein and amino acid derivatives/ catecholamines hormones
Intracellular receptors in the nucleus for steroids and thyroid hormones
Where does the anterior pituitary develop from?
Epithelium of the mouth
Where does the posterior pituitary develop from?
Downgrowth of the hypothalamus
What is the outcome of an endocrine cascade?
Amplification of the signal
Example of an endocrine cascade?
Hypothalamus secretes hormones that control the secretion and release of pituitary hormones
What are the two functions of the hypothalamus?
Controls release of anterior pituitary hormones
Secretes hormones that are stored and released by the posterior lobe of the pituitary gland
Where is oxytocin and antidiuretic hormone stored?
Posterior lobe of pituitary gland
What is prolactin controlled by?
Hypothalamic inhibiting factor
What is the anterior lobe of the pituitary gland also known as?
Adenohypophysis
What six hormones are released by the anterior lobe of the pituitary gland?
Growth hormone
Thyroid stimulating hormone
Adrenocorticotropic hormone
Follicle stimulating hormone
Luteinising hormone
Prolactin
What is the posterior lobe made from?
Neural tissue
What is the posterior lobe also known as?
Neurohypophysis
Function of oxytocin
Contraction of myoepithelial cells for lactation
Contraction of uterine myometrium during birth
Function of ADH
Prevents water dieresis- retaining water volume
Function of GH
Increases overall growth
Function TSH
Regulates thyroid secretion
Function of prolactin
Simulates milk production in females
Function of ACTH
Regulates secretion of glucocorticoids formal adrenal glands
Function of LH and FSH
Stimulating synthesis of sex steroids
Describe the hypothalamo-hypophysis-gonadal axis
Hypothalamus secretes GnRH
GnRH stimulates secretion of pituitary FSH
FHS stimulates gonads to secrete oestrogen or testosterone
Example of negative feedback control
Sex steroids inhibit the release of GnRH in the hypothalamus
What is an adenoma?
Benign tumour
What effect does an adenoma on endocrine glands
Cause dysregulation of secretion
What is acromegaly?
Excessive release of GH
What is the symptom of acromegaly pre puberty?
Gigantism
What is the symptoms of acromegaly post puberty?
Increased bone mass
What is the thyroid gland formed from?
Downgrowth of tongue epithelium
What three cells make up the thyroid?
Follicle
Follicular cells
Colloid
What do follicular cells secrete?
Tri-iodothyronine and thyroxine
Where are tri-iodothyronine and thyroxine stored?
Colloid (thyroglobulin)
What does thyroxin regulate?
Energy use- rate of metabolism
Protein and production
Regulates sensitivity of cells
What produces calcitonin?
Parafollicular cells
Function of calcitonin?
Regulates calcium homeostasis
What can goitres be caused by?
Hyper or hypothyroidism
What are symptoms of hyperthyroidism?
Staring eyes- eyes move further forward
What are symptoms of hypothyroidism?
Lethargic
Brittle hair
Cretinism
Where does the parathyroid glands develop from?
Wall of pharynx
What is produced in the parathyroid?
Parathyroid hormone
what is the function of the parathyroid hormone?
Regulates calcium homeostasis by stimulating osteoclasts
Where are the adrenal glands found?
Superior poles of kidneys
What are the two layers of the adrenal glands?
Cortex and medulla
What are the three layers of the cortex?
Zona glomerulosa
Zona fasciculata
Zona reticularis
What hormones are produced in the zona glomerulosa?
Mineralocorticoids
e.g aldosterone
What hormones are produced in the zona fasciculata?
Glucocorticoids
e.g cortisol
What hormones are produced in the zona reticularis?
Sex steroids
e.g androgens
What is the function of aldosterone?
Regulating sodium absorption and secretion in the kidneys
What is the function of cortisol?
Regulating metabolism
Anti-inflammatory responses
What does the adrenal medulla form from?
From the neural crest cells
Neuroectoderm
What cells are found in the adrenal medulla?
Chromaffin cells which produce catecholamines
What are the catecholamines?
Epinephrine
Norepinephrine
Dopamine
What does the adrenal medulla have direct connection with?
SNS
What is Cuhing’s syndrome caused by?
Increased cortisol release causing laying down of more fat
What hormone does the GI tract secrete?
Gastrin
What hormone does the kidney produce?
Renin
What hormone does the ovaries produce?
Oestradiol and progesterone
