Endocrine Glands Flashcards
Endocrine Glands
- ductless glands
- dense networks of capillaries and parenchymatous cells
- secretes hormones that regulate the functions of target organs
Hypophysis, or Pituitary Gland
- Adenohypophysis
2. Neurohypophysis
Adenohypophysis Components
- Pars distalis
- Pars intermedia
- Pars tuberalis
Pars Distalis
- Acidophils
- Basophils
- Chomophobes
- Acidophils*
- Somatotrophs
2. Lactotrophs, or prolactin cells
Somatotrophs
- production of somatotrophin, or Growth Hormone (GH)
Lactotrophs, or prolactin cells
- induces the secretion of the mammary glands
- > lactogenic activity
Basophils
- Thryotrophs
- Gonadotrophs
- Corticotrophs
Thryotrophs
- produces thyroid stimulating hormone (TSH)
- > induces the thyroid gland to release thyroxin
Gonadotrophs
- produces follicle stimulating hormone (FSH) and Luteinizing Hormone (LH)
Corticotrophs
- produce adrenocorticotropic hormone (ACTH)
- > acts on the adrenal cortex
Chromophobes
- are considered to be temporarily resting
degranulated chromophils
Pars Intermedia
- closely associated with the neurohypophysis
- completely separated from the pars distalis by the hypophyseal cleft
Pars Intermedia
- produces melanotropes
Melanotropes
- most abundant cells that may surround colloid-filled follicles
- produce melanocyte-stimulating hormone (MSH)
Pars Tuberalis
- believed to play a role in the seasonal-reproductive cycle of some domestic mammals
- a few gonadotrophs and thyrotrophs are present
Pituicytes
- glial cells of the neurohypophysis
- modified astrocytes
Neurohypophysis
- microglial cells are present
Hypothalamo-Neurohypophyseal System Components
- Supraoptic Nuclei
2. Paraventricular Nuclei
Supraoptic Nuclei
- secrete ADH, or vasopressin
Paraventricular Nuclei
- secretes oxytocin
Supraoptic Nuclei and Paraventricular Nuclei
- these nuclei have large neuronal bodies containing neurosecretory granules
Neurosecretory granules
- produce oxytocin and vasopressin, or antidiuretic hormone (ADH)
Neural Lobe
- in this, enlarged axon terminals store and release neurosecretory granules in the perivascular space of sinusoidal capillaries
Herring Bodies
- enlarged axon terminals containing neurosecretory granules in the neural lobe
Astrocytes
- strongly basophilic
with elongated nuclei and long cytoplasmic processes
Pinealocyte
- slightly basophilic with large irregular shaped nuclei
Pinealocyte
- secretes melatonin