Free nerve endings
Movement of otoliths
Substances in solution
Photons of light
The basilar membrane vibrates more intensely
Action potentials from hair cells are blocked
Sound wave amplitude decreases
Sound wave frequency decreases
Saccule and utricle
Organ of Corti
Are less sensitive in low light conditions
Provide colour vision
Provide greater visual acuity (sharpness of detail)
Are more responsive in the daylight
All of these correctly describe cones.
Alter the activity of an enzyme
Alter the rate of synthesis of an enzyme
Alter the permeability of cell membranes
All of the above are correct
Are derived from cholesterol
Are lipid molecules
Are not water soluble
Include the sex hormones and corticosteroids
All of these describe steroid hormones.
Triiodothyronine (T3) and tetraiodothyronine (T4)
Catecholamines (epinephrine and norepinephrine)
Binding to an intracellular carrier protein
Initiation of gene transcription
Dimerisation of receptors
Binding to a hormone response element
Bind to membrane receptors.
Diffuse easily through the plasma membrane.
Act by activating cAMP.
Are inactivated by second messengers.
The activating hormone interacts with a receptor site on the plasma membrane
The activating hormone activates an enzyme, most often adenylate cyclase
Activated adenylate cyclase catalyses the transformation of AMP to cyclic AMP
Cyclic AMP causes the activation of protein kinase
Anterior pituitary to the hypothalamus.
Posterior pituitary to the hypothalamus.
Hypothalamus to the anterior pituitary.
Hypothalamus to the posterior pituitary.
LH and FSH
GH and ACTH
TSH and prolactin
Oxytocin and ADH
GnRH and dopamine
TRH and CRH
GnRH and GHRH
Dopamine and somatostatin
Aldosterone and other mineralocorticoids
Sex steroids: weak androgens and some estrogens
Cortisol and other glucocorticoids
Adrenaline and some noradrenaline
Increased calcitonin secretion
Increased thyroid hormone production
Increased TSH production
Increased serum potassium levels
Is secreted by the alpha cells of the pancreas
Promotes the entry of glucose and amino acids into tissue cells
Promotes the breakdown of glycogen (glycogenolysis) and fat (lipolysis)
Levels fall immediately after a meal is eaten
Involves substances bound to carrier proteins in the blood
Involves the secretion of a substance to act locally without entering the circulation
Involves secretion via ducts into the lumen of the gastrointestinal tract
Never occurs in a normal healthy organism