The Pituitary Gland Flashcards
What are some key integrative functions of the hypothalamus and pituitary?
What kinds of hormones does the hypothalamus release?
Neurohormones
What kind of hormones does the posterior pituitary release?
Neurohormones (from hypothalamus)
What kind of hormones does the anterior pituitary release?
Endocrine hormones
What are 5 examples of tropic hypothalamic hormones?
Thyrotropic releasing hormone (TRH)
Corticotropin releasing hormone (CRH)
Growth hormone releasing hormone (GHRH)
Gonadotropin releasing hormone (GRH)
Prolactin releasing hormone (PRH)
What are 2 inhibiting tropic hypothalamic hormones?
Growth hormone inhibiting hormone (GHIH)
Dopamine
What is dopamine also known as?
Prolactin inhibiting hormone (PIH)
What is the classification of all of the tropic hypothalamic hormones?
Peptides, except for dopamine which is an amine
How are hormones transfered from hypothalamus to anterior pituitary?
Through hypothalamo-hypophyseal portal system (network of tiny vessels)
Contrast the anterior and posterior pituitary in terms of:
type of tissue
connections via
also called
size
Is the anterior or posterior pituitary larger?
Anterior makes up 2/3 of gland, posterior 1/3
What are the 6 hormones released by the anterior pituitary gland?
Thyroid stimulating hormone (TSH)
Adrenocorticotrophic hormone (ACTH)
Follicle stimulating hormone (FSH)
Luteinising hormone (LH)
Growth hormone (GH)
Prolactin
What is the classification of anterior pituitary hormones?
All are peptides, and 5 are also tropic hormones
What does prolactin do?
Stimulates milk production from the breast during lactation
What is the target organ of prolacin?
Mammary glands
What is the target organ of GH?
Musculoskeletal system
What is the target organ of TSH
Thyroid gland
What is the target organ of ACTH?
Adrenal cortex
What is the target organ of gonadotropins?
Gonads (ovary/testes)
What does TSH cause?
Thyroid hormone (TH) release from thyroid
What does addrenocorticotropic hormone cause?
Cortisol release from adrenal cortex
What tropic and what direct effects does GH have?
Tropic - IGF-1 release from liver
Direct - tissue metabolism
What tropic and what direct effect does luteinising hormone have?
Tropic - sex hormone release
Direct - regulation of reproductive function
What are the 3 integration centres involved in the feedback control of the anterior pituitary?
Hypothalamus
Anterior pituitary
Target endocrine cell
What are the 2 neurohormones stored and released from the posterior pituitary?
Vasopressin
Oxytocin
Are the hormones released from the posterior pituitary formed there?
No, they are formed in the hypothalamus but stored and released fromt he posterior pituitary
What are vasopressin and oxytocin synthesised in?
Magnocellular neurones in hypothalamus
How does vasopressin and oxytocin get from hypothalamus to posterior pituitary?
1) Axons project down infundibulim to posterior pituitary
2) Do not synapse with other neurons, terminals end directly on capillaries
What classification of hormones do posterior pituitary hormones behave as?
Typical peptide hormones, so:
synthesis and storage in vesicles
acts on cell surface receptors
For Vasopressin and Oxcytocin compare the:
- Function
- Trigger
- Mode of action
