Endocrine histology and anatomy week3 Flashcards
anterior pituitary is also known as?
adenohypophysis
posterior pituitary is also known as?
neurohypophysis
what does the anterior pituitary develop from?
dorsal outgrowth of embryonic pharynx
what does the posterior pituitary develop from?
ventrally orientated down growth from the diencephalon
of the anterior and posterior pituitary, which one stains more darkly in histology?
Anterior pituitary stains more darkly
from which tissue does the thin fibro-elastic capsule surrounding the pituitary develop?
meninges
what are the 2 types of secretory cells in anterior pituitary?
Chromophobes and chromophils
what is the difference between chromophobes and chromophils ?
Chromophobes = pale staining, exhausted secretory cells chromophils = strong staining, active secretory cells
Somatotrophs secrete _____?
Growth hormone
Lactototrophs secrete _____?
prolactin
corticotrophs secrete _____?
ACTH, Beta-lipotropin, alpha-melanocyte stimulating protein and Beta-endorphin
thyrotrophs secrete _____?
TSH
Gonadotrophs secrete _____?
FSH and LH
which endocrine cell types are acidophils?
Somatotrophs and lactotrophs
which endocrine cell types are basophils?
thyrotrophs, gonadotrophs and corticotrophs
what is the target organ and effect of Somatotrophin?
Body tissues + hepatocytes - secrete IGF-1
Metabolic actions - growth Increased protein synthesis increased growth of cartilage Increased fatty acid production Increased insulin production
what is the target organ and effect of Prolactin?
mammary gland in breast
Stimulates lactation
Renal na/water reabsorption
Steroidogenesis
Stimulates T cells
what is the target organ and effect of thyroid hormone?
Increases thyroid hormone secretion (T4 has minimal effect on metabolism but T3 increases metabolism, growth and development, potentiates catecholamine effect)
what is the target organ and effect of FSH and LH?
female = ovaries male = testes
Female: growth of follicle, maturation of follicle, oestrogen secretion, formation of corpus luteum
male: stimulates seminiferous epithelium, stimulates leading cells to secrete testosterone
what is the target organ and effect of ACTH?
adrenal cortex
synthesis and release of cortisol principally form zone fasciculata
what is the diameter of an erythrocyte?
6-8 micrometers
where does the thyroid gland develop form?
endodermal downgrowth from floor of developing pharynx
what makes the site of the down growth (development of thyroid gland) and what can sometimes remain in adults?
foramen caecum at back of tongue
Cyst like remnants
when thyroid follicles are inactive what cell shape are they? what shape do they becomes when active
simple cuboidal or squamous
become columnar
what is involved in the exocrine stage of thyroid hormone synthesis?
Exocrine secretion of colloid - rich in thyroglobulin (which is an iodinated glycoprotein) and is a storage form of thyroxine
which cell organelle produces protein part of thyroglobulin?
rough ER
where is the sugar component of thyroglobulin added?
Golgi apparatus
which enzyme enables iodide to be converted to iodine?
thyroid peroxidase
what is hashimoto’s thyroiditis and what causes it?
autoimmune disease which causes hypothyroidism
Caused by anti thyroid peroxidase antibodies
what histological staining characteristics can be seen in someone with hashimoto’s thyroiditis?
many blue nuclei due to lymphocyte infiltration
fibrosis, no follicles left
what are signs of hyperphosphataemia ?
severe itching of skin and weakening of bones
what hormone do C cells secrete? what is its function?
calcitonin
lowers serum calcium levels by inhibiting osteoclast activity and reduces renal calcium reabsorption
how many parathyroid glands do we have?
4 (2 upper, 2 lower)
what are the two types of secretory cells in parathyroid glands? which are acidophilic and which are basophilic ?
Chief cells - basophilic
Oxyphil cells - acidophilic
