Flashcards in 18.6-18.9 Deck (26):
Pituitary gland (hypophysis)
The master endocrine gland that controls other glands. Pea shaped structure that lies in hypophyseal fossa and has two regions: anterior and posterior pituitary.
Controls the pituitary gland. Major link between nervous and endocrine system. Synthesizes 9 different hormones.
Funnel. Composed of anterior and posterior pituitary.
75% of pituitary weight.
Secretes hormones to regulate growth and reproduction.
Composed of epithelial tissue.
composed of two parts:
2) pars tuberalis
Part of anterior pituitary. Forms sheath around infundibulum.
Composed of neural tissue. Consists of two parts.
2) pars intermedia
Hypophyseal portal system flow of order
Superior arteries>primary plexus>veins>secondary plexus
Synthesize the hypothalamic releasing and inhibiting hormones
Tropic hormones (tropins)
Anterior pituitary hormones that act on other endocrine glands
Hormones of the anterior pituitary:
Secrete HGH, Aka somatotropin. Which then stimulates release of insulin growth factors (iGF)
Thyroid stimulating hormone, aka thyrotropin.
Aka gonadotropins, 2 kinds-
1) follicle stimulating hormone (FSH)
2) luteinizing hormone (LH)
Produce estrogen in ovaries and testosterone in testes.
Secrete prolactin (PRL) which starts milk production in mammary glands.
Secrete adrenocorticotropic hormone (ACTH) aka corticotropin . Stimulates secretion on cortisol or melanocyte-stimulating hormone (MSH).
Functions of IGF
1) increase uptake of amino acids accelerating protein synthesis
3) increase carb metabolism by decreasing glucose uptake
Low blood glucose concentration
High blood glucose concentration , stimulates hypothalamus to secrete GHRH
Does not synthesize hormones, but stores and releases two hormones: oxytocin (OT) & antidiuretic hormone (ADH)
Blood flow of posterior pituitary
Inferior hypophyseal arteries>capillary plexus of infundibular process> posterior hypophyseal veins>distribution to target cells
Affects uterus and breasts. Allows for smooth muscle to contact during labor and for lactation for breast feeding.
Decreases urine production . Causes kidneys to return more water to the blood.
Fun fact: alcohol inhibits secretion of ADH.
An antidiuretic which raises blood pressure
Neurons in Hypothalamus that monitor blood osmotic pressure
Blood carries ADH to three target tissues
Kidneys, sweat glands, smooth muscle in blood vessel walls