classifications of hormones - target
1) paracrine: group of cells secrete hormones that take effect on neighboring cells
2) autocrine: only cells that secrete got effect
3) endocrine: cells secrete hormone that travel to other sites of the body and take effect
classifications of hormones - composition
1) peptide/proteins (hydrophilic)
- FSH/LH, TSH
- insulin, glucagon
- inhibin
- hCG
2) fatty acid derivatives
3) steroid (hydrophobic)
- testosterone, progesterone, estrogen/estradiol
4) tyrosine/amino acid derived
- T3/T4 (hydrophobic)
classifications of hormones - transport
1) endocrine: no duct, straight to blood
2) exocrine: duct, to surrounding tissue
classifications of hormones - effect
1) direct action on non-endocrine tissues e.g. GH, prolactin, ADH
2) modulatory effect on endocrine tissue e.g. TSH, ACTH, FSH, LH
general endocrine gland
- rich blood supply
- cuboidal/columnar epithelium cell: secretory
- cords/clusters
- connective tissue: supportive framework
pituitary gland - general
- hypothalamus + pituitary gland = neuroendocrine unit
- X control pancreas, adrenal cortex, parathyroid gland
pituitary gland - anterior pituitary - general
darker colour
pituitary gland - anterior pituitary - components - Pars Tuberalis
- undifferentiated (gonadotroph)
- chromophobe
- acidophil, basophil
pituitary gland - anterior pituitary - components - Pars Intermedia
- melanotroph: melanocyte stimulating hormone (MSH) -> melanocyte in epidermis
pituitary gland - anterior pituitary - components - Pars Distalis - chromophils
- secretory cells, hormones stored in cytoplasmic granules
pituitary gland - anterior pituitary - components - Pars Distalis - types of chromophils
1) acidophils
- somatotrophs: growth hormones to all body tissue
- mammotroph: prolactin -> mammary gland, testes
2) basophils
- gonadotroph: FSH, LH
- corticotrophs: ACTH/corticotropin
- thyrotroph: TSH
pituitary gland - anterior pituitary - components - Pars Distalis - chromophobes
- pale colour
- X store or secrete hormones
- degranulated chromophil cells
pituitary gland - posterior pituitary gland - general
- lighter colour
pituitary gland - posterior pituitary gland - components
1) large amt of capillaries
2) Pars Nervosa
- pituicytes nuclei
- herring body: granules that store hormones
- unmyelinated axons
pituitary gland - posterior pituitary gland - hormones released
- stored in neurohypophysis as granules in axons
- ADH
- Oxytocin (uterine contraction during labour)
thyroid - types of cells - follicular cells
- cuboidal to tall columnar
- contains thyroglobulin
- under TSH control
- secrete T3/T4
thyroid - type of cells - parafollicular cells
- develop from neural crest
- larger than follicular cell
- secrete calcitonin: Regulate Ca2+ levels
parathyroid - types of cells - oxyphil cell
- more acidophilic
- degenerated chief cells
- more common in old people
parathyroid - types of cells - chief cells
- small polygonal cells w round nuclei
- pale staining cytoplasm
- main cell to make parathyroid hormone
parathyroid - effects of parathyroid hormone (PTH)
low Ca2+ levels -> chief cells secrete PTH
1) increase osteoclastic activity in bone = release calcium into blood
2) increase in calcium reabsorption in distal convoluted tubule
3) increase in Vit D absorption in small intestine
adrenal gland - main function
homeostasis
adrenal gland - adrenal cortex - general
- develop from mesoderm
- contain steroid secreting cells
- rich in lipid droplets w central nuclei
- more SER & mitochondria w enzymes for cholesterol synthesis
adrenal gland - adrenal cortex - components
1) Zona gomerulosa
- mineralocorticoids (aldosterone)
2) Zona fasciculata
- glucocorticoid (cortisol)
3) zona reticularis
- dehydroepiandrosterone (androgen)
adrenal medulla - general
develop from neural crest
