Alexa Bain

Give examples and describe- 449

Structure

1.

Free nerve ending- Simplest, most common sensory receptors located on the surface of the body known as exteroceptors and in internal organs known as visceroceptors. Nociceptor are slender sensory fibers that are responsible for pain.Brain tissue lacks free sensory nerve endings and is incapable of sensing painful stimuli Nerve endings are also responsible for sensation and touch and also sensations of heat cold. Ex: Krause’s end bulbs & Ruffini’s corpuscles (5 450-451)

2.

root hair plexuses- delicate, weblike arrangements of free nerve endings that surround fair follicles that can detect any type of hair movement (5, 451)

3.

merkel disks- disc-shaped or flattened and are responsible for mediating sensations of light or discriminative touch that is located on surface of the skin (5, 451)

Hearing (give detailed diagram of all 3 divisions of the ear (5, 456-457)

1.

Describe Mechanism of hearing- sound is created by vibrations that can occur in air. Fluid or solid material. Ex: when we speak our vocal cords create sound waves that produces vibrations. Amplitude of a sound wave determines its loudness or volume. Number of sound waves during a specific time (frequency) determines pitch. (5, page 459)

2.

Detail Neuronal pathway of hearing- (5, page 460)

Dendrites of neurons terminate around bases of hair cells of the organ named Corti. Movement of hair cells against adherent tectorial membrane stimulates dendrites and initiates impulse conduction by cochlear nerve to the brainstem. Impulses pass through “relay stations” in the nuclei of the medulla, pons, midbrain and thalamus before reaching auditory area of temporal lobe.

JingleFree nerve endings, free nerve

endings, nociceptors are responsible for pain,Nerve endings are responsible for sensation and touch, andKrause’s end bulbs and Ruffini’s corpuscles are the names.

Delicate, weblike free endings surround follicles that are fairThese are all the characteristics that make up plexuses of the hair

Merkel discs are flattened and responsible for sensations of light, Also responsible for touch that is located on the skin and can be in plain sight

Sound waves create vibrations through fluid or solid that occur in the airAmplitude of a sound wave determines its loudness or volume so we can hear When we speak our vocal cords create sound waves in our ears

Corti is the name of the organ that dendrites of neurons terminate,Dendrites and impulses conducted by cochlear nerve to the brainstem, Is what movement of hair cells against a tectorial membrane stimulate

Impulses must pass through relay stations in the nuclei of the medulla, and pons and the rest of its adobe, before reaching the auditory area of the temporal lobe.