Lab Practical 1

external ear

funnel for conducting airborne vibrations to tympanic membrane

middle ear

bounded by the tympanic membrane; contain the ear bones which transmit airborne vibrations to inner ear and the auditory tube which helps equalize pressure in the middle ear

internal ear

contains the vestibule cochlea (organ of hearing) and the semicircular canals (sense of balance)

cochlea

sense of sound

vestibule

sense of gravity and acceleration

semicircular ducts

sense of rotation

pitch

sound frequency

frequency

measured in hertz

normal range

a person who has hearing within this range can hear sounds that have frequencies between 20-20,000 Hz (most important sounds we hear every day are in the 2050 to 6,000 Hz range)

vestibule

sense of linear acceleration and gravity

otoliths

ear stone or hair cells with overlying gelatinous matrix

utricle

otolith organ that detects head tilts in the horizontal plane

saccule

otolith organ that detects head tilts in the vertical plane

semicircular ducts

sense of rotary motion (spinning around, turning a corner, bending to pick something up), oriented in different planes, and are filled with endolymph

sclera

white part of eye, covers most of eye surface, protective, provides attachment for extrinsic muscles of the eye

cornea

protective transparent region, it refracts (bends) light rays to converge on the lens

iris

controls the diameter of the pupil, pigmented (think about eye color)

lens

bends light rays so that they can form a clear image at the back of the eye

pupil

opening of the eye that allows light to enter

choroid

deeply pigmented vascular layer of tissue behind retina

aqueous humor

serous fluid that fills area between cornea and lens

vitreous humor

jellylike fluid that fills area behind lens

retina

actually part of the brain, transparent membrane attached to the eye at the optic disc and the anterior margin contains photoreceptors (rods and cones)

pupillary dilator muscles

extend radially away from the edge of the pupil, contraction of these muscles enlarges the pupil

pupillary constrictor muscles

form a series of concentric circles around the pupil. When these sphincter muscles contract, the diameter of the pupil decreases

ciliary muscles

change shape of the lens

retina

contains photoreceptors (rods and cones), this is the neural part of the eye, and where light is converted to an electrical stimulus

blind spot

where the optic disc connects to the retina, it is an area that contains no receptor cells so it produces a blind spot in the visual field of each eye

myopia

nearsightedness, if the eyeball is too deep or the resting curvature of the lens is too great, the image of a distant object is projected in front of the retina. People see distant objects as blurry and out of focus. Vision at close range will be normal because the lens can round as needed to focus the image on the retina (corrected with a diverging concave lens)

hyperopia

farsightedness, if the eyeball is too shallow or the lens is too flat, the ciliary muscle must contract to focus even a distant object on the retina. At close range, the lens cannot provide enough refraction to focus an image on the retina. Older people become farsighted as their lenses lose elasticity, a form of presbyopia (can be corrected with a converging convex lens

peripheral nervous system

cranial nerves, spinal nerves, and their roots and branches, peripheral nerves, and neuromuscular junctions

nerve plexus

network of interwoven nerves. Nerve fibers from the ventral rami of different spinal nerves are sorted and recombined in plexuses so that all fibers going to a specific body part are put together in one nerve

cranial nerves

part of peripheral nervous system, these are 12 pairs of nerves that directly arise from the brain

olfactory

1, nose

optic

2, eye

oculomotor

3, all eye muscles except superior oblique and external rectus

trochlear

4; superior oblique muscle

trigeminal

5, face, sinuses, teeth, mastication

Abducens

6, external rectus muscle

intermediate motor

7, submaxillary and sublingual gland, anterior part of tongue and soft palate

vestibulocochlear

8, inner ear

glossopharyngeal

9, pharyngeal musculature, posterior part of tongue, tonsil, pharynx

vagus

10, heart, lungs, bronchi, gastrointestinal tract, trachea, larynx, pharynx, gastrointestinal. tract, external ear

accessory motor

11, sternocleidomastoid and trapezius muscles

hypoglossal

12, muscles of the tongue

Olfactory 1

transmits the sense of smell

optic 2

transmits visual information to the brain

oculomotor 3

innervates eye muscles

trochlear

innervates the superior oblique muscle

trigeminal 5

receives sensation from the face and innervates the muscles of mastication

abducens 6

innervates the lateral rectus

facial 7

provides motor innervation to the muscles of facial expression

vestibulocochlear 8

sense of sound, rotation, and gravity

glossopharyngeal9 9

motor, pharyngeal, musculature, posterior part of tongue braid

endocrine system

system of communication

hormones

chemical signals are released from an organ, tissue, or cell, and travel through the blood to target cells