Endocrine: Pituitary Gland Flashcards
Also known as hypophysis: Master gland
Pituitary gland
All pituitary hormones are characterized with
Circardian rhythms
Release other hormones
Tropic hormones
Feedback loop
Pulsatile secretion
Diurnal Rhythms
Environmental and External modification
Features of pituitary gland
Hormones secreted in the morning:
ACAI
ACTH
Cortisol
Aldosterone
Iron
Hormones secreted or high in the Evening:
PTAG
PTH
TSH
ACP
GH
Peak at: 4-6 am or 6-8am
Low: 8-12am
Cortisol
Peak at: 4-8am & 8-10pm
Prolactin
Subject to external modulation and generally influenced or modified by higher neutral input
Open-Loop Negative Feedback System
Open-Loop Negative Feedback System (3)
Short Feedback Loop - Pituitary
Long Feedback Loop - Hypothalamus
Ultra-Short Loop - Hypothalamus and Pituitary
Pituitary Hormones classification (2)
Tropic - stimulates activity of other endocrine glands
Direct Effector - direct effect in pheripheral tissue
Anatomy: Three (3) Major Parts of Pituitary
- Anterior Pituitary /Adenohypophysis
- Intermediate lobe / Pars Intermediate
- Posterior or Neurohypophysis
Considered not true endocrine gland
Posterior Pituitary gland
Pituitary tumors
<1 cm
Microadenoma
Pituitary Hormone
> 1cm
Microadenomas
ANTERIOR LOBE:
Five types of cell by Immunological Test
- Somatotrophs (GH)
- Gonadotrophs (LH, FSH)
- Thythroph (TSH)
- Lactotrophs /Mammotroph (Prolactin)
- Corticotrophs (ACTH, B-endorphins, B-lipoproteins)
Ovary Ovulation and Progesterone production
Testosterone synthesis by Testes
LH
Ovaries (Estrogen synthesis and Oogenesis)
Testis (Spermatogenesis)
FSH
Thyroid Function
TSH (T3 and T4)
Glucocorticoid synthesis; adrenal steroidgenesis
ACTH
IGF-1 Synthesis; metabolism in numerous tissues to produce growth factors
GH (Direct Effector)
Lactation
Prolactin (Direct Effector)