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64 Cards in this Set
- Front
- Back
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Where can you find the Integumentary system? What does it consist of? |
outer surface of the body
skin, hair, nails, glands & sensory receptors |
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What are 5 functions of skin? |
1.Protects the body from dehydration, impact & friction injuries, mold & bacterial invasion, UV light damage
2. Acts as a receptor organ for sensory input 3.Regulates body temp 4. Secrete some waste (urea sats & water) 5. Synthesizes vit D
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what are the 2 layers of the skin
what is located underneath them? |
outer, thinner layer = epidermis
inner thicker layer = dermis subcutaneous layer is found underneath the dermis |
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how many major cell types and layers are there in the epidermis?
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four major cell types and five cell layers
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what are the four epidermal cell types and their relative abundance
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Keratinocytes (90%)
Melanocytes (8%) Langerhans cells Merkel cells |
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What are the characteristics of keratinocytes
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-produce keratin
-protect skin & underlying tissues from heat, microbes & chemicals -surface cells are dead and contain only keratin . |
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what are the characteristics of melanocytes? |
-spider-shaped
-secrete and transfer pigment melanin to keratinocytes -found near basal surface & their cell projections extend between keratinocytes
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what are the characteristics of langerhans cells |
arise from red bone marrow & migrate to epidermis involved in immune response
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what are the characteristics of merkel cells? |
least numerous contact sensory neurons & function in touch sensations located deep in epidermis |
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What are the five epidermal layers? |
Stratum basale stratum spinosum stratum granulosum stratum lucidum stratum corneum |
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what is intraocular pressure? what is the common disease called that causes an excessive intraocular pressure? |
-the pressure of the fluids of the three chambers, responsible for maintaining the shape of the eye -glaucoma |
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what does the lens do? |
the lens is responsible for focusing light onto the retina, accomodation is the term referring to the adaptation of shape that occurs in the lens |
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what keeps the lens in shape? |
zonule fibres pull on the edges of the lens and connect it to the choroid |
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what muscles are used to keep the lens in shape? |
ciliary muscles |
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what happens to the lens when the ciliary muscles are relaxed? |
the zonule fibres pull on the lens and it takes on a flat/weak state |
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what happens to the lens when the ciliary muscles contract? |
they oppose the pull of the zonule fibres and the lens thickens |
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what are the two types of photo receptors? |
rods and cones |
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what do the rods and cones communicate with in the eye |
retinal ganglion cells |
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what is the blind spot? |
also called the optic disk, where the retinal ganglion cells send their signals through the back of the eye to the brain, there are no photo receptors in this area. |
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what is the fovea |
where the axis of the eye passes through, a higher concentration of cones is found at the fovea and there are no rods here, this is where the central vision is |
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detects many wavelengths, is responsible for visual acuity |
cones |
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is sensitive in low light, caries little sensitivity for varying wavelengths of light |
rods |
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what is it called when a photopigment molecule absorbs a photon and changes from 11-cisretinal to all-transretinal |
photoisomerization |
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how long does it take for your eyes to become fully adapted to the dark? |
30 mins
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how long does it take (approximately) to reach the rod cone break? |
around 8 minutes |
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at which point of the dark adaptation curve are the cones more sensitive than the rods? |
the first eight minutes, after this period the rods take over |
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what is photopigment regeneration |
the process of photopigment molecules switching from all-transretinal back to 11-cisretinal |
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what is the result of a high convergence RGC |
high sensitivity to dim light, low acuity |
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describe on centre receptive field |
cells that increase firing when the centre is brighter relative to the surround |
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describe off centre receptive field |
cells that increase firing when the surround is brighter relative to the centre |
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if both the centre and the surround of a receptive field are exposed to light what will happen to the firing rate |
it will remain the same |
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myopia |
nearsightedness |
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hyperopia |
farsightedness |
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presbyopia |
old-sightedness |
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glaucoma |
high intraocular pressure, blockage to openings that allow aqueous humor to drain from the anterior chamber |
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phosphenes |
breif tiny bright flahses in the persons field of view not caused by light |
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wet macular degeneration results from what> |
new blood vessels growing nderneath the retina scar and leak fluid etc and damage photo receptors |
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describe retiontopic mapping. |
An arrangement of neurons in the visual system whereby signals from retinal ganglion cells with receptive fields that are next to each other on the retina travel to neurons that are next to each other in the visual area of the brain |
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funcional specialization |
the specialization of different neural pathways and different areas of the brain for representing different kinds of informtaion |
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what is the optic chiasm |
where the nerves from the two eyes split in half, half o fthe axons cross over to the other hemisphere of the brain |
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What is the optic tract? Which area of the eye would send signals to the right optic tract? |
continuation of the nerve past the optic chiasm, axons from the RGCs on the right side of each retina |
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Explain contralateral organization |
simulation on one side of the body results in activity on the opposite sides of the brain |
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What is the LGN a part of ? |
the thalamus |
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what are the three different layers of the LGN called and how many layers of each are there? |
Magnocellular 2 Parvocellular 4 koniocellular 6 |
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which kind of ganglion cells do each layer in the LGN receive signals from? |
magnocellular - parasol ganglion cells parvocellular- midget ganglion cells koniocellular- bistratified ganglion cells |
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which properties of sight are the magno cellular layers responsible for? |
dynamic visual properties motion and flicker
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which properties of sight are parvocellular layers responsible for? |
static visual properties ie colour and texture |
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what are the koniocellular layers thought to be responsible for? |
colour |
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what is the purpose of the LGN? |
thought to be attention |
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what is the superior colliculus |
structure near the top of the brain stem, principle function is to help control eye movements |
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what are the two categories of cells in the area V1 of the brain? |
simple cells and complex cells |
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what does an end stopped cell do? |
specially tuned to lines of a certain length |
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define cortical column |
small volume of neural tissue running through layers of cortex perpendicular to its surface |
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describe ocular dominance columns |
cortical columns consisting of neurons that recieve signals from the left or the right eye only |
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descrive orientation columns |
cortical columns consisting of neurons with the same orientation tuning |
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dorsal pathway |
where or how |
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ventral pathway |
what |
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where does information from the parasol cells go? |
magno cellular layer of LGN, MT brain area (motion) on to parietal cortex |
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Where does info from the midget cells go> |
parvocellulr layer, V4 (form, colour), Inferotemporal cortex |
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where does info from bistratified cells go |
koniocellular layer, V4 (form, colour), inferotemporal cortex |
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which areas are involved in the dorsal pathway? |
the how pathway, magnocellular layer (parasol cells), MT and parietal lobe |
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which areas are involved in the ventral pathway? |
what pathway parvo cellular (midget cells) konio cellular (bistratified cells) V4 and inferotemporal lobe |
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what is v4 known for |
colour and curvature |
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what is area mt known for |
motion |
