Question | Answer |
Sclera of the eye | The outermost layer; thick, opaque; white of they eye |
Choroid layer of the eye | Under the sclera, dark pigmented area that reduces reflection in the eye; supplies retina with blood |
Retina | Innermost layer; contains photoreceptors that sense light |
Cornea | Transparent front part of the eye that bends and focuses light rays |
Pupil | The small opening behind the cornea through which light passes after cornea |
Iris | Muscle that controls the diameter of the pupil. The more light=more constricted pupil |
Lens | Located behind the pupil and focuses light after it passes through the pupil into the lens. |
Ciliary muscles | Control the shape and focal length of lens |
Cones | located in the retina and respond to high intensity light and is sensitive to color, specifically the Red, Green, and Blue wavelengths |
Rods | Located in the retina and contain different pigments that absorb specific wavelengths of light. contains pigment Rhodopsin which absorbs 1 wavelength. |
Optic nerve | Photoreceptor cells merge into bipolar cells which merge into ganglion cells. The axons of the ganglion cells bundle to form the optic nerve. Sends visual information to the brain. |
Blindspot | The part of the eye that does not contain any photoreceptors and through which light impulse passes when exiting the eye. |
Vitrous humour | The jelly-like substance that maintains the shape of the eye |
Aqueous humour | The watery substance that fills the aqueous chamber that maintains the convex shape of the cornea. This must continuously be drained and refilled. It exits through ducts to join venous blood. |
Outer ear constituents | Auricle (ext ear), Auditory canal |
Middle ear constituents | Tympanic membrane (eardrums); Ossicles (3bones-malleus, incus, stapes:amplify stimulus); Oval window |
Inner Ear | Cochlea; vestibular apparatus; Cochlear nerve |
Sound energy pathway | Auricle-Auditory canal-tympanic membrane-malleus, incus, stapes-oval window-cochlea (perilymph until round window bulges and back)- Organ of Cort-tympanic membrane-cochlear branch |
3 semicircular canals of the ear | maintain dynamic equilibrium; positions at right angles to each other |
Eustacian tube | connection between ear canal and nasopharynx; functions in maintaining pressure on both sides of the tempanic membrane. |
Nerve impulse pathway | Dendrites-Soma (cell body)-Axon- Nodes of Ranvier- Terminal buttons/Synaptic terminals- Neurotransmitter exits |
Dendrites | Cellular extensions of nueron that recieve information. Always the entrance of nerve impulses in a neuron |
Soma | Cell body of a neuron; contains nucleus and controls the cell's metabolic activities |
Axon | Transmits impulses away from the body and most are sheathed by myelin making impulse faster |
Nodes of Ranvier | Gaps b/w the myelin sheathed axon. site of saltatory conduction bc it is the only site of permeability on myelin sheathed axon so impulse jumps from node to node |
Neuroglia | 2nd type of nerve cell. mostly present in CNS and serve to support neurons and some have phagocytic properties. |
Astrocytes | One type of neuroglia. "star cell". serve as supporting network in brain and spinal cord. attach nerve cells to blood vessels |
Oligodendrocytes | One type of neuroglia. support neurons by forming a semi-rigid connective tissue mesh. engulf neurons in CNS to produce the myelin sheath. |
Microglial cells | "small" "glue" small cells with few processes; migrate to injure area if tissues is damaged; engulf and destroy microbes and cellular debri. |
Perikaryon | aka Soma or cell body of neuron. Contain nucleus, mitochondria, nissl bodies, |
Nissl bodies | specialized rough endoplasmic reticulum studded with ribosomes that create proteins for neurons. |
Schwann cells | Myelinate the PNS neurons by encircling the axons many times until the Schwann cytoplasm and nucleus are pushed to the periferi. |