Biology 30 - Chapter 12

What is the lens?

A transparent, biconcave, soft, elastic disk. It changes shape to focus image on back of retina. Refracts light focussing it onto the retina.

Vibrations from sound waves cause stereocilia to bend, which?

Bending creates an action potential which is conveyed to the cochlear nerve.

What are proprioceptors?

Body orientation (semicircular canals - balance and equilibrium; receptors in joints and muscles). Detect position of parts of the body relative to the rest of the body and space.

What are cones?

Detect high intensity (bright) light; for color vision. Concentrated on the fovea centralis.

What is the eustachinan tube?

Extends from the middle of the mouth and nasal cavities, involved in equalizing pressure.

What is myopia?

Eyeball is too long. Nearsighted. Image focuses in front of the retina.

What is hypermyopia?

Eyeball is too short. Farsighted. Image focuses behind the retina.

What is the pinna?

Finnel light flap of skin, collects sound waves, directing them into the auditory canals.

What are the two main functions of the ear?

Hearing and equilibrium (balance).

What is astigmatism?

Imperfection in the cornea or lens. Makes images appear fuzzy.

What are photoreceptors?

Involved in light. Photons.

What is the retina?

Layer containing photoreceptors (rods and cones).

What is the eye stimulated by?

Light (photons).

What is the organ of corti?

Located in the cochlea. Moves and responds to movements in the fluid.

Where is the olfactory lobe?

Located in the forebrain.

What is the vitreous humour?

Maintains the shape of the eyeball and allows the transmission of light.

What is the auditory canal?

Makes ear wax. Directs sound waves towards the tympanic membrane.

What is the blind spot?

On the retina where the optic nerve inserts; no photoreceptors present.

What is the sclera?

Outer (superficial) layer of the eyeball.

What are the ossicles?

Smallest bones in the body. Vibration of sound strengthens as they pass through the 3 bones.

What is the round window?

Soft membrane on the cochlea that stops wave motion.

What is the cochlea?

Sound detection organ. Snail shaped. Fluid filled. Identifies sound and converts them to nerve impulses.

What is inside of the semicircular canals?

Stereocilia embedded in tall gelatinous (fluid like) material.

What are thermoreceptors?

Temperature.

What is sensory adaptation?

The filtering by the brain of redundant, insignificant sensory information. I.e. when you no longer notice socks on your feet.

Loudness is interpreted by?

The number of sensory neurons that respond to the stimulus.

What mechanoreceptors are located in the hear?

Tiny hairs located in the inner ear.

What is the optic nerve?

Transmits electrical impulses from the retina to the brain. Collects information from the rods and cones, sending it to the thalamus and occipital lobe.

What is the auditory nerve?

Transmits messages to the brain.

What is the auditory nerve?

Transmits nerve impulses to the auditory area (temporal lobe) of the cerebral cortex from the organ of Corti.

What are the two types of sensory systems?

Visual system and auditory system.

What is the pathway of light into the eye?

light through the eye to the cornea aqueous humor - through pupil - lens - vitreous humor - retina - optic nerve - brain - the occipital lobe.

What is binocular vision?

Allows to see 3D.

What is accommodation reflex?

Changing shape of the lens to focus light on the retina.

What are chemoreceptors?

Chemicals, taste and smell.

What are the different types of sensory receptors? Plus examples.

Chemoreceptors (taste), mechanoreceptors (muscles, hair cells), photoreceptors (rods and cones), and thermoreceptors (hot or cold).

What is the cornea?

Clear portion of the sclera that covers the front of the eye; allows light to enter the eye. Refracts light towards the pupil.

What are cataracts?

Clouding of the lens.

What is the fovea centralis?

Contains only cones.

What is the ciliary muscles?

Controls the shape of the lens. Alters the shape of the lens to allow near and far focussing "accommodation."

What are rods?

Detect low intensity (dim) light. Assist in low light conditions (black and white) located on the periphery of the retina). Contains the pigment rhodopsin.

Both olfactory and taste senses are involved in what?

Enjoying food.

What happens in change of position/motion in the semicircular canals?

Fluid bend stereocilia (sensory receptor) -> nerve impulses relay information to the brain (cerebellum) about the position and motion.

What is the semicircular canals?

Fluid filled structure providing information about body movement and position. Detect dynamic position - movement of body.

What happens with head movement in the vestibule?

Head movement -> stereocilia embedded in gel bend -> action potential sent via nerve to the brain -> brain adjusts body to maintain balance.

If an image is near, what happens with the lens?

If an image is near the accommodation reflex causes the ciliary muscles to tighten and the ligaments to relax and therefore the lens becomes rounded.

If an image is far away what happens with the lens?

If an object is far away, the ciliary muscles relax and the ligaments tighten causing the lens to flatten.

Where are taste buds located?

In different parts of the tongue.

What are olfactory receptor cells?

Located in the nasal cavity. They're activated by chemicals binding due to specific shape.

What is the choroid layer?

Middle layer between the sclera and the retina. It is vascular (full of blood vessels to nourish retina), and it contains melanin (black) to prevent light from scattering.

What are mechanoreceptors?

Monitor blood pressure, involved in hearing, touch and pressure.

What are osmoreceptors?

Monitor osmolarity of body fluids (e.g. hypothalamus- thirst).

What is the iris?

Pigmented smooth muscle, controls the pupil size. Controls the amount of light entering the eye.

What is the pathway of sound?

Pinna - auditory canal - tympani membrane - malleus,incus, and staples - oval window - cochlea (organ of corti) - auditory nerve - brain - the temporal lobe.

What is glaucoma?

Pressure build up in anterior cavity.

What is the aqueous humor?

Provides nourishment and is involved in focusing the image. Provides nutrients to the cornea and helps to refract light.

What are the 4 tastes humans can only detect?

Salty, sweet, bitter, and sour.

What is the oval window?

Separates the middle ear and the inner ear.

What is the tympanic membrane (eardrum).

Thin membrane that converts sound waves into mechanical motion, and transmits sound to the middle of the ear (through the ear bones to the oval window of the cochlea). Causes the ossicles to vibrate.

What is the vestibule.

Utricle and Saccule. Movement. Detect static position: position of head, movement along one plane (horizontal or vertical). 2 fluid filled sacs with stereocilia embedded.

What is basilar membrane?

Where stereocilia are embedded.

Different areas of the cochlea are sensitive to different pitches of _________________.

sound.