Homeostasis & Physiological Control Flashcards
What is feed-forward control?
Occurs when the ANTICIPATION of a change brings about an effector response BEFORE the change actually occurs or is sensed.
E.g.
- HR & RR increases prior to exercise
- Increases in gastric juices before food has entered the GI tract
What are the main stages of feedback pathways?
Sensors Afferent pathways Integrating centres Efferent pathways Effectors
What are the main endocrine glands?
Hypothalamus Pituitary Thyroid & parathyroid Adrenal cortex & medulla Testes Ovaries
What X2 types of hormones does the hypothalamus produce?
What do these do?
Releasing hormones = cause further hormone release from the anterior pituitary gland
Inhibitory hormones = inhibit hormone release from the anterior pituitary gland
What is the technical name for the pituitary gland?
The hypophysis
How does posterior pituitary hormone production and release differ from anterior pituitary hormone production and release?
Anterior pituitary hormones are endocrine only and are synthesised in the anterior pituitary, and are regulated in their release through the secretion of releasing and inhibitory hormones (neuroendocrine) produced in the hypothalamus which are released into the hypophysesl portal system (blood vessels). It is the presence of these in the blood stream which regulate anterior pituitary hormone release.
Posterior pituitary hormones in comparison are neuroendocrine and are synthesised in the hypothalamus and transported to the posterior pituitary and stored in herring bodies ready for release.
What are the releasing hormones produced in the hypothalamus?
GHRH (growth factor…)
CRH (corticotrophin…)
TRH (thyrotrophin…)
GnRH (gonadotrophin…)
What are the inhibiting hormones produced in the hypothalamus?
What does each one inhibit?
Dopamine = inhibits prolactin
Somatostatin = inhibits growth hormone
What are the anterior pituitary hormones?
Growth hormone Prolactin Follicle stimulating hormone Luteinizing hormone Thyroid stimulating hormone Adrenocorticotrophin hormone
What are the posterior pituitary hormones?
Oxytocin and ADH.
What are the X3 types of molecular structure the hypothalamic and pituitary hormones can take?
Which hormones are examples of each?
Peptides (both posterior pituitary hormones)
= ADH
= Oxytocin
Polypeptides
=Growth hormone only (Anterior pituitary)
Glycoproteins
=All the rest!
What are X2 hormone examples of derivatives of the amino acid tyrosine?
Where are each of these synthesised?
Adrenaline (in the adrenal medulla)
Thyroxine (in the thyroid gland)
What structure are all steroid hormones derived from?
What is the first molecule produced in this reaction pathway?
Cholesterol
Pregnenolone
Name X4 steroid hormones.
Estrogen
Testosterone
Cortisol
Aldosterone
What family is the hormone cortisol part of?
The glucocorticoids
