What is the stimulus for the Kinesthetic and Vestibular Senses?
The kinesthetic sense involves being aware of position, weight, tension and body movement. This sense grants the ability to feel movements throughout the limbs and the body. Information regarding movement is communicated throughout the sensory systems by means of tension and compression of the muscles. The kinesthetic Sense involves physical activity such as dance, gymnastics, or any other athletic sport. The neurons associated with the kinesthetic sense are found within the muscles, tendons and joints. They work with one another with the cortex by means of cortical neurons as the body moves.

The vestibular sense is the sense of balance. It is the primary organ that deals with equilibrium; playing a major role in the sensation of both motion and spatial orientation. This sense involves areas of the nervous system that control motor movement and adjust muscle activity. The vestibular sense provides input to regions within the nervous system, working to control eye movement, which in turn, helps stabilize the eyes while the head is in motion. This sense reduces the movement of a fixed object the eye is seeing. The fluid in the semicircular canals that resides inside the ear detects whether or not an organism is upright. The movement of fluid stimulates the firing of receptor neurons which tells the brain the position an organism is in.

What Function do the Kinesthetic and Vestibular senses serve in regards to survival and how do they work with other senses?

The vestibular sense allows predator and prey to have the ability to have a sense of balance without thinking about it. This sense also allows organisms to become aware of the position their body is in, even when their eyes are closed or they have no sight. This allows an organism to move their body without having to remember where each body part is. These two senses allow a organism to move freely in body movement and have a sense of balance without having to think of how to move their body. For example, when an organism is running, it does not have to think or physical look at their legs to make move back and forth while being able to balance its body movements.

How is the sensory information processed and transmitted in the brain?

The word “kinesthesia” translates as “the sense that determines how you feel and where your body parts are”, and is therefore pretty self explanatory in its function, as it aids in the body’s ability to do just that--determine sensation. The kinesthetic system works to send messages throughout body parts, providing a direct connection to the sensory cortex of the brain, specifically the parietal lobe. Without the kinesthetic system, we would not feel as if our body parts were attached to our bodies, but would feel as if they were just taking up space around us, without feeling (Kinesthesia). Neuron receptors work to make this process possible. These specialized nerve endings are located within the muscles, joints, and ligaments throughout the body and are designed to communicate sensations and signals. They are vital in order to maintain movement. Therefore, a person who suffers from the loss of their kinesthetic system would suffer from severe movement difficulty, moving very slowly and with a “slumped effect” (Wikipedia).

The Vestibular system on the other hand, allows us to stand upright, maintain balance, and move through space by means of its direct connection to the brain. The vestibular system coordinates information from all of the vestibular organs. These organs include the inner ear, the eyes, the muscles and joints, the fingertips, the palms of the hands, the soles of the feet, pressers of the jaw, and lastly; gravity receptors (which are located on the skin and work to adjust a number of things including heart rate, blood pressure, muscle tone, limb position, immune responses, arousal and balance) (Brain Training). A person therefore, that suffers from dysfunctions within the vestibular system can cause anxiety or panic attacks, a need for self-stimulation, abnormalities in muscle tone, teeth grinding and chin tapping, hand flapping, academic problems, and drooling.

Vision is an important component of the vestibular system, as is the auditory system--which is highly involved in vestibular functions. The vestibular and auditory nerves join in the auditory canal and become the eighth cranial nerve of the brain. In addition, the pressers on the soles of the feet provide information used to calculate weight and posture adjustments that in turn allow balance and movement to take place.

The inner ear is the sensory organ of balance and motion and is part of both the vestibular sense and the three semicircular canals in the ear which respond to rotation which is a part of the kinesthetic senses.
Vision takes an important role in the sensory information that detects body movement because one who walks up a set of stairs may not be able to take the step unless they are looking at where they are walking.
The absolute threshold comes into play because it can be determined with sensory information from the vestibular, kinesthetic and visual senses but varies with age.
For an animal, the absolute threshold would be detected in the ear because they have better hearing than humans.
A dog has a lower absolute threshold because they can hear a car in the driveway before we can hear a knock on the door

Absolute Threshold The minimum amount of sensory stimulation that can be detected 50% of the time

The vestibular nerve in the inner ear located in the cochlear and semicircular canals, tells the brain a sense of balance. For example, when a person spins around, the vestibular system tells the brain whether or not a person is balanced or not when a person stops spinning.

http://www.enotes.com/gale-psychology-encyclopedia/kinesthetic-sense mk
http://academics.tjhsst.edu/psych/oldPsych/senses/kinesthesia/intro.html ak
http://en.wikipedia.org/wiki/Sense#Kinesthetic_sense ak
http://www.braintraining.com/vestibular.htm ak