Anatomy. the joint of the leg that allows for movement between the femur and tibia and is protected by the patella; the central area of the leg between the thigh and the lower leg. 2. Zoology. the corresponding joint or region in the hind leg of a quadruped; stifle. 3. a joint or region likened to this but not anatomically homologous with it, as the tarsal joint of a bird, the carpal joint in the forelimb of the horse or cow, etc.
The special sense which interprets the position of the head permitting the CNS to maintain stability and posture when the head and body are not moving; it is detected by mechanoreceptors in the vestibule of the inner ear, the utricle and saccule, which each contain a macula with the receptors for static equilibrium; when the head moves with reference to gravity, the otolithic membrane shifts and the mechanoreceptors (hair cells) in the macula detect this movement and send the information ...
With the middle ear acting as an impedance-matching device, a majority of the energy of a sound wave moves on to the inner ear. In the case of a sound that is too loud, muscles attached to the ossicles can tense to decrease the proportion of the sound that is transferred and help to prevent damage to the inner ear. Connecting the middle ear to the throat s a short, narrow passage called the eustachian tube (Figure 1).