Anatomy and Physiology / Unit 7: The Endocrine System
7.2 Hypothalamus and Pituitary
Notes
The hypothalamus links the nervous and endocrine systems and controls the pituitary gland.
- Posterior pituitary (neural tissue) stores and releases two hormones made in the hypothalamus: antidiuretic hormone (ADH) (kidneys retain water) and oxytocin (uterine contractions, milk ejection).
- Anterior pituitary (glandular tissue) makes hormones controlled by hypothalamic releasing and inhibiting hormones: growth hormone (GH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin (PRL), and the gonadotropins FSH and LH.
- GH excess in childhood causes gigantism, in adults acromegaly; deficiency in childhood causes pituitary dwarfism. Low ADH causes diabetes insipidus (large volumes of dilute urine, intense thirst).
- Example: a dehydrated person has higher ADH, so urine becomes more concentrated and less in volume.
Practice
Which hormone is released by the posterior pituitary and causes the kidneys to conserve water?
ADH increases water reabsorption in the kidney collecting ducts.
A person produces large amounts of dilute urine and has constant thirst due to low ADH. This condition is:
Lack of ADH prevents water reabsorption.
Which pituitary hormone stimulates the thyroid gland?
Thyroid-stimulating hormone is released from the anterior pituitary.
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