SamanthaPerez NervousSystem (Senses (Eye (Components: Tunics of the eye…
Tunics of the eye (layers)
Fibrous layer- Sclera, white part composed of Dense CT acts as an anchor for extrinsic eye muscle. Cornea, transparent part allows light into the eye focuses.
Vascular layer- choroid,pigmented part nourishes outer layers absorbs light prevents scattering, continuous with cilia body muscle that changes the shape of the lens.
inner layers- Retina, photoreceptors (axons will converge to form the optic nerve) types: rods- most abundant sensitive to light and dark
cones- gives us color vision best in bright light.
Lens- focuses light on retina
Iris- anterior to lens posterior to cornea, colored part of eye, intrinsic muscle for dilation of pupil.
Optic disc- AKA blind spot no photoreceptors
Macula Lutea- part of retina gives the clearest vision (fovea centralis)
Cornea > lens > Retina > Optic Nerve > Optic Chiasm(a) > Optic Tract > Mid brain > Thalamus > Primary visual cortex in occipital lobe
Components and Pathway:
Location roof nasal cavity
Pseudostratified Columnar Epithelium contains olfactory sensory neurons > the olfactory bulb > Olfactory tract > Limbic Region and Primary Olfactory cortex in temporal lobe.
Receptors stimulus origin:
Exterocepters- stimulus origin is our environment skin, special senses.
Interoceptors- stimulus origin is internal organs
Proprioceptors- stimulus origin is muscle, tendons, ligaments, joints.
Thermoreceptors- sense cold and warmth
Photoreceptors- sense light
chemoreceptors- sense chemicals
Nociceptors- sense pain
Mechanorecceptors- sense touch, pressure, vibration, stretch.
Baroreceptors- sensitive to blood pressure
Components and pathway:
Taste buds with receptors soak in chemicals > 3 cranial nevers- facial nerve, Glossopharyngeal, Vagus > Medulla Oblongata > Thalamus > Primary Gustatory cortex in the insula.
Components and Pathway:
Auricle- (pinna) gather Funnel sound waves amplify
Tympanic membrane- Vibrates, transmits vibration > middle ear > auditory ossicles > transmits vibrations > Cochlea (fluid filled) > cochlear Nerve + vestibular nerve = Vestibulocochlear Nerve ( sense of equilibrium)
Hearing Pathway- Impulses from cochlear Branch( Nerve) to brain
Cochlear Nerve > medulla oblongata > Pons > mid brain > Thalamus > Primary Auditory cortex in the temporal lobe.
Central Nervous System (CNS)
Structures: Brain and Spinal cord
Functions: Receives, processes and responds to sensory input.
Peripheral Nervous System (PNS)
Structures: Cranial nerves (connected to brain), spinal nerves (connected to spine) Ganglia (clusters of neuron bodies)
Function: Gathers sensory information from receptors and passes it on to the CNS.
Somatic and Autonomic Division
Motor/ Efferent OUTPUT
Somatic Motor- Mainly to skin, body wall, skeletal muscle, everything except ventral body cavity contents.
Autonomic Motor- mainly ventral body cavity content, smooth muscle, cardiac muscle, glands, arector pilli, smooth muscle of blood vessels, sweat glands.
Sensory/ Afferent INPUT
Somatic sensory- Skin, muscle, joints, hearing, equilibrium, vision.
Visceral Sensory (not called autonomic)- mainly ventral body cavity contents, gustation (Taste), Olfaction (smell).
Nerve: a bundle of neuron/ axons
insulated coating- myelin sheath (around some axons)
Endoeurium- loose CT
Bundle of neurons- Fascicle
Perineurium- fibrous CT
Epineurium- tough fibrous CT surrounds all fascicles
Glial Cells: more abundant
CNS (neuro)glial Cells
astrocytes- Most abundant, processes contact aons + capillaries, supportive, help maintain a proper chemical environment.
Microglia- Phagocyte, destroy invading microbes and damaged/dying nervous tissue.
Ependymal cells- simple cubodal spithelium with cilia and microvili ( to help circulate cerebral spinal fluid), location ventricles (spaces in brain filled with cerebral spinal fluid).
Oligodenrocytes- creates myelin sheath
PNS (neuro)glial cells
Satellite cells- surrounding neuron cell bodies in ganglia, supportive help regulate what goes in/out of neuron cell bodies.
schwann cell- creates myelin sheath, surrounding only one axon. when surrounding a bundle of axons it is non-myelinated.
Nucleolus: creates Ribosomes
Chromatophilic substance- dense region of rough ER and free ribosomes outsided of nucleus, creates plasma membrane and other protein.
Axon hillock- Where axon leaves cell body
axon collateral- Branch of axon from main axon.
axon terminals- very ends of terminal branches of axon.
Multipolar neuron- cell body, dendrites axon, many processes
Bipolar neuron- cell body and only two processes
unipolar neuron- cell body only one process.
motor- away from CNS and are multipolar
Sensory- to CNS and are unipolar
interneurons- in CNS only between neurons and are multipolar
special sensory- bipolar neurons.