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Extra:
B10.Summary (Eye problems (Cataract (milky lens)
Lens lets…
Extra:
B10.Summary
Hemeostasis
Definition
- Regulation of internal cellular/organism conditions
- Maintain optimum functional conditions
- Response to internal/external changes
Importance
- Proper functioning, cells require optimum enzyme temp
- Correct H2O, mineral conc. in blood; no osmosis problems
- Glucose for cellular respiration
- Remove waste products which affect pH, poison system
Animal
Processes
Statements
- Many processes in the body,
are controlled by hormones
- NS allows you, to react to your
surroundings and co-ord. behaviour
- Cell that are sensitive to light,
are found in the eyes
- Hormones are chem. substances,
secreted by glands
- Muscles and glands are known as,
effector organs
- Bundles of neurones are known as,
nerves
Nervous
System
Purpose
- Enables reaction to surroundings
- and co-ordination of behaviour
Complimentary
- Light - Eye + Sound - Ear
- Temperature - Skin
- Touch - Skin
Reflex arc
- Stimulus - Receptor - Sensory neurone -
Relay neurone - Motor neurone - Effector -
Response
Neurones
Neurone vs. Nerve
- Neurone = individ. nerve cell
- Nerve = bundle of many neurones
- All sensory/All motor/Mix
Synapse
- Synapse = junctions, physical gaps
between neurones; e.impulses must cross
- Chem. released into gap when impulse reaches
(cannot leap gap
- Chem. picked up on next neurone receptors
Sets up new e.impulse from one neurone to other
- Synapse permits neuron transmission of impulses
Brain
Fatal Medulla Damage
- Controls many unconscious activities
(breathing, heart rate, gut movement etc.)
- Destruction = patient can no longer carry out
basic function - death
Partial Cerebellum Damage
- Controls balance, co-ordination
- Damage = might fall, problems w/ balance
- Become very clumsy, uncoordinated
Cerebral Damage Ambiguity
- Inc. in many funct. (intelligence, emotion etc.)
- Difficult prediction - CC covers most of brain,
specific area damage dependant
- May cause memory loss, intelligence loss,
Emotional changes
MRI
Early Dead brain scans
- Allowed scientists to map brain,
correlate damage in certain areas w/ behaviour
Early Stationary MRI scans
- MRI scans allow scientist to confirm mapping
- Identify damaged brain areas (stroke, trauma etc.)
- Relate to live patient's effects
Modern MRI scans
- Shows active brain areas during particular tasks
- Demonstrate how brain works normally
Eye problems
Cataract (milky lens)
- Lens lets light through to retina
- Refracts light to bring focus on retina
- Lens becomes cloudy, less light through,
can't focus clearly
Detached retina (complete blindness)
- Retina contains light-sense receptor cells,
respond to light, send impulse to brain
- Retina detached = receptor cells lost
- Impulses can't reach brain
Egg-shaped eyeballs (Myopia)
- Egg shape becomes abnormal
- Lens brings distant objects in focus,
in front of retina instead of on it
- Distant objects look blurred
Incr. eyeball pressure (Glaucoma)
- Optic nerve squeezed (carries receptor
cells impulse to brain)
- Squeezing = damage, can't carry impulses
- Impulses can't reach brain