Lab 26: Nervous System Flashcards
Nervous System (NS) Components
- made up of 2 divisions
1. Central Nervous System(CNS): brain and the spinal cord
2. Peripheral Nervous System(PNS): crainal and spinal nerves
Autonomic Nervous System
- involuntary function
- responsible for control of breathing and heartrate
- parasympathetic: controls homeostatsis and the body at rest
- sympathetic: responsible for the bodys response to threat and the “fight or flight” response
Somatic Nervous System
- voluntary function
- part of the PNS
- repsonsible for movement of muscle
Neuron
- basic unit of the nervous system
- contains: axon, dendrites, cell body, myelin sheath, Schwann cells, Node of Ranvier, and Synaptic Cells
- surrounded by glial cells
Axon
-sends signals from the cell body through the axon to other cells
Dendrites
-receives signals through the dendrites from other cells to the cell body
Myelin Sheath
-increases speed of nerve impulses
Schwann Cells
- cells on the axon of the nerve
- support the neuron
Node of Ranvier
-impulse travels from node to node along the axon
Synaptic Cells
- located at the ends of the axon
- transfer electrical impulse from one cell to another
Afferent Neurons
-send signals from the body to the CNS
Efferent Neurons
-send signals from the CNS to the body
Basic Neuron Structure
Motor Neurons
-located in the spinal cord
Neuromuscular Junction
- located in skeletal muscle
- motor neurons allow voluntary movement
Spinal Cord Slide
-contains gray matter, white matter, and central canal
Brain Lateral View
Cerebrum
- largest portion of the brain
- controls motor functions, sensory impulse, speech, emotion, etc.
- divided into right and left hemispheres and 4 lobes
Cerebral Cortex
- outermost layer of the cerebrum
- composed of grey matter
Gyri
-bumps in the cerebral cortex
Sulci
-groove in the cerebral cortex
Right Hemisphere
-visual and intuitive processing
Left Hemisphere
-language and logical processing
Longitudinal Cerebral Fissure
-separates the two hemispheres of the brain
Frontal Lobe
- front portion of brain
- thought, memory, judgement
Parietal Lobe
- middle portion of brain
- processing of sensory input
Temporal Lobe
- side portion of brain
- auditory reception and interpretation
- expressed behavior and speech
Occipital Lobe
- back portion of brain
- visual reception
Cerebellum
- located in back of the brain
- voluntary movement and balance
Pons
- beginning of the brain stem
- relays information between the cerebrum and the cerebellum
- regualtes respiration
- controls arousal
Medulla Oblongata
- located underneath the pons
- regulates respiration and circulation
Brain Midsagittal View
Corpus Callosum
- connects the two hemispheres internally
- integrates motor, sensory, and cognitive signals between the two hemispheres
Thalamus
- structure in the middle of the brain
- processes sleep, consciousness, and sensory interpretations
Pituitary
-endocrine system gland that produces hormones
Brain Inferior View
Olfactory Nerve
- cranial nerve
- responsible for sense of smell
Optic Chiasm
- X-shaped structure on the underside of the brain
- contains the optic nerve responsible for vision
Photoreceptors
- specialized neurons located in the retina
- responsible for transferring light into signals
Chemoreceptors
- receptors of the PNS located in blood vessels
- sense change in chemical concentration
Human Eye Diagram
Cornea
- outermost lens of the eye
- protects the eye and transmitts light
Iris
- colored part of the eye
- controls the amount of light that enters the eye by changing the size of the pupil
Lens
- structure located behind the iris
- focuses light onto the retina
Pupil
- opening in the center of the iris
- changes size depending on the amount of light
Optic Nerve
- located in the back of the eye
- transmits impulses from the retina to the brain
Anterior Chamber
-fluid filled space behind the iris
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Suspensory Ligament
- series of fibers that connect the ciliary body to the lens
- provides support
Ciliary Body
-structure that releases transparent liquid
Posterior Cavity
- space in the eye behind the lens
- filled with a watery filled called aqueous humor
Sclera
- outermost layer of the eye
- fibrous and protective
Choroid
- middle layer of the eye
- vascular layer containing connective tissue
Retina
- sensitive inner layer of the eye
- trigger nerve impulses that pass through the optic nerve
Fovea Centralis
- small depression in the retina of the eye
- highest location of visual activity
Blind Spot (optic disc)
- raised disc on the retina located at the opening of the optic nerve
- lacks visual receptors
Tapetum Lucidium
- extra layer of tissue in the eyes of animals
- allows for night vision
Eye Tissue Slide
Snellen Eye Chart
- tests vision
- the first 20 represents the distance in feet the person is standing away from the chart
- 20/15 is great vision
- 20/40 is bad vision
Astigmatism
- irregularities in the cornea or lens
- affect how the light rays enter the eye
- vision will be blurred when focusing of a single point
Farsightedness
- inability to focus on objects nearby
- also called hyperopia
Nearsightedness
- inability to focus on distant objects
- also called myopia
Anatomy of the Human Ear
-made up of three parts: outer, middle, and inner
Structures of the Outer Ear
-contains the pinna (auricle), external auditory canal, and the tympanic membrane (eardrum)
Pinna (Auricle) Function
-collects and amplifies sounds
External Auditory Canal Function
- contains a waxy substance which aids in cleaning and lubricating and protecingthe ear canal
- carries sound from the pinna to the middle ear
Tympanic Membrane (Eardrum) Function
-transmits and amplifies sounds from the air to the sounds in fluid to the middle ear
Structures of the Middle Ear
-contains the malleus (hammer), incus (anvil), and stapes (stirrup)
Malleus (Hammer) Function
-transmits the sound vibrations from the eardrum to the incus
Incus (Anvil) Function
-transmits sound vibrations from the malleus to the stapes
Stapes (Stirrup) Function
-transmits sound vibrations from the incus to the inner ear membrane
Structures of the Inner Ear
-contains the oval window, semicircular canals, cochlea, and eustachain (auditory) tube
Oval Window Function
-intersection opening between the middle and inner ear
Semicircular Canals Function
- provides sensory input
- filled with fluid called endolymph with motor neurons
Cochlea Function
- filled with perilymph liquid which moves in response to vibrations
- transfers vibrations in the liquid to neural messages
Eustachain (Auditory) Tube Function
- links the nasopharynx to the middle ear
- equalizes pressure and drains mucus from the middle ear
Organ of Corti
- structure in the cochlea
- produces nerve impulses in response to sound vibrations
Conduction
- amplification of sound waves in the middle ear (ossicles)
- allows us to hear and distingusih sound
Stimulation of Receptors
-stimulation of hair cells in the organ of Corti in the cochlea allow us to hear and disgusih sounds
Transmittance
- transmitting of the resulting action potential from the cochlear nerve to the auditory centers of the brain
- allows us to hear and distinguish sounds
Reflex
- autonomc response of a muscle to a stimulus
- measured by an EKG
- can be reinforced by slight voluntary contractions of other muscles
