BB physiology Flashcards
Control of drinking
Osmoreceptors in subfornical organ of 3rd ventricle
Project to medial pre optic nucleus of hypothalamus (thirst) and paraventricular and supraoptic nucleus (ADH release)
Control of eating
Lateral hypothalamus = hunger centre
Medial hypothalamus = satiety centre
Ghrelin
Produced by cells lining the stomach
Project to periventricular nucleus to inhibit satiety
Leptin
Produced by adipose tissue
Long term monitor of energy stores
Acts on hypothalamus
CCK
Released when chyme received in duodenum
Acts on arcuate nucleus to induce satiety
Broadmann area 44
Broca’s
Broadmann area 22
Wernicke’s
Broadmann area 4
Primary motor cortex
Broadmann area 1,2,3
Primary somatosensory cortex
Broadmann area 17
Primary visual cortex
Broadmann area 41 and 42
Primary visual cortex
Photoreceptor actvity
Dark = constant inward leak of sodium to keep the cell depolarised and tonically releasing sodium
Eye blood supply
Ophthalmic artery
Choroid network of capillaries
Accommodation reflex
Pupillary constriction - CN III PS
Thickening of lens - CN III PS
Convergence - CN III
Nystagmus
Cold = flick towards non-irrigated ear
Warm - flick towards irrigated ear
Glaucoma treatments
Prostaglandin analogs Beta-adrenergic receptor antagonists Alpha 2 adrenergic agonists Parasympathomimetic agonists Anticholinesterases Carbonic anhydrase inhibitors
Ear ossicles
Malleus –> incus –> stapes
Membrane of organ of Corti
3 rows of outer hair cells
1 row of inner hair cells
Cochlear frequency preference
Thin and wide at apex - best for low frequency
Thick and narrow at base - best for high frequency
Impedance matching
Relative sizes of ossicles
Tympanic membrane larger than oval window
Attenuation reflex
Slow
Stapedius muscle
Prevents damage to ear structures
Startle reflex
Facial nerve and reticular formation
Serves to protect back of neck and eyes
Fast
Cochlear nucleus
Ventral = fast and precise --> superior olivary nucleus Dorsal = complex --> lateral lemniscus
Sound localisation
Interaural time differences more useful at low frequencies
Intramural level differences more useful at high frequencies
