Equilibrium: Sense of Balance (Nursing)

00:01 Equilibrium is also going to be controlled by the ear.

00:05 Equilibrium or balance exist in two forms.

00:10 We have static equilibrium which is the maintenance of the body's position relative to the force of gravity and we have dynamic equilibrium which is the maintenance of the body's position and response to sudden movements.

00:26 If we take a look at the structures responsible for maintaining equilibrium, we start at the vestibular apparatus of the ear.

00:37 These organs are necessary for maintaining equilibrium and include the saccule, utricle and the semicircular canals.

00:48 In these structures, we have otoliths which are calcium carbonate crystals found on the surface of the otolithic membrane of the macula.

01:00 The macula is located on the walls of both the utricle and the saccule.

01:07 The two maculae have receptors for static equilibrium.

01:13 The otolithic membrane sits on top of the macula and the otolithic membrane is attached to the hair cells in the macula.

01:23 Movement of the head causes this membrane to move down over the hair cells and the macula.

01:31 The hair cells then synapse with neurons in the vestibular branch of the vestibulocochlear nerve sending an impulse to the brain about our position in relation to gravity.

01:45 When it comes to sudden movements of the head, the semicircular canals are going to be responsible for our dynamic equilibrium.

01:55 These ducts lie at right angles to each other and allow for rotational acceleration and deceleration.

02:04 Within these structures, we have an ampulla which contains the cristae with a group of hair cells.

02:13 Movement of the head is going to affect the endolymph in this area and the hair cells.

02:20 The movement is going to generate an action potential, leading to nerve impulses that travel along the vestibular branch of the vestibulocochlear nerve.

02:33 As we age, sometimes our special senses are going to change.

02:38 Around the age of 50, smell and taste are going to be affected by aging as the receptor start to be gradually lost and the regeneration is going to occur at a much slower rate.

02:52 Around the age of 40, the lens of the eye begins to lose its elasticity and has a difficult time focusing on close objects.

03:02 This is referred to as presbyopia.

03:05 Also, the muscles of the iris can weaken and react more slowly to light and dark which results in difficulty adjusting to changes in lighting.

03:20 Also in the eye, retinal diseases such as macular disease, detached retina and glaucoma are going to occur more frequently as we age.

03:32 When it comes to the ears, at about age 60, approximately a quarter of individuals will experience a noticeable hearing loss also known as presbycussis.