Control and Co-ordination — Class 12 Maharashtra HSC Biology revision notes
A 10-page visual revision sheet for Control and Co-ordination, written for Class 12 Maharashtra HSC Biology. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Control and Co-ordination in one look
a nerve net without a brain, then a brain with sixty regions, then a second, slower system running on hormones
From diffuse net to centralized brain
- sponges show division of labour among cells but no true nervous system
- Hydra: the first true nervous system, a nerve net with no polarity, impulse spreads any direction
- Planaria: first animal with a true CNS, a cerebral ganglion plus ventral cords
- cords joined ladder-fashion by transverse commissures, the ladder-type system
Neuron, structure
- structural and functional unit of the nervous system: cyton, dendron, axon
- cyton: nucleus, Nissl's granules (riboprotein, make transmitter enzymes), neurofibrils (impulse transmission)
- dendrons: many branched processes, carry signals TOWARD the cyton
- axon: single, unbranched, carries signals AWAY from the cyton, arising at the axon hillock
- axon ends in telodendrons and holds no Nissl's granules
Nerve vs tract, myelination
- an axon bundle OUTSIDE the CNS is a nerve, the same INSIDE is a tract
- medullated nerves: medullary sheath plus neurilemma. non-medullated: neurilemma only
- medullated conduction is ~50x faster than non-medullated
- nerve wrapping, inner to outer: endoneurium (per fibre), perineurium (per bundle), epineurium (whole nerve)
Neuroglia, by location
| Cell type | Location | Function |
|---|---|---|
| Oligodendrocytes | CNS | form the myelin sheath (white matter) |
| Microglia | CNS | brain macrophages, from monocytes, clear debris |
| Astrocytes | CNS | star shaped, most abundant, maintain blood-brain barrier |
| Ependymal cells | CNS | line ventricles/central canal, make and circulate CSF |
| Schwann cells | PNS | form the myelin sheath of PNS nerves |
| Satellite cells | PNS | support neuron cell bodies |
Page 1 of 10. The full sheet, all 10 pages, opens free in the app.
What this Control and Co-ordination sheet covers
- From diffuse net to centralized brain
- Neuron, structure
- Nerve vs tract, myelination
- Neuroglia, by location
- Electrical vs Chemical synapse
- Electrical
- Chemical
- Properties of nerve fibres
- Threshold & summation
- All-or-none law
- Refractory period
- Synaptic delay & fatigue
- Resting potential
- Generating and conducting an impulse
- Depolarization
- Repolarization
- Na+/K+ pump resets
- The impulse, drawn two ways
- Saltatory conduction
- Human nervous system, three divisions
- Meninges and CSF
- Cerebrum, the largest part
- Cerebral lobes, one job each
- Frontal
- Parietal
- Temporal
- Occipital
- Diencephalon
- Midbrain and hindbrain
- Ventricles
- Spinal cord
- Cranial nerves, by function
- Cranial nerves, three facts worth keeping
- Spinal nerves, by region
- Spinal nerve, formation
- Reflex actions, two ways to sort them
- By synapse count
- By centre / origin
- Autonomic Nervous System, overview
- Sympathetic vs Parasympathetic effects
- Sympathetic
- Parasympathetic
- Nervous system disorders
- Sensory receptors, classified
- Eye, three wall layers
- Rods, cones, and the blind spot
- How an image is perceived
- Light on rods/cones
- Bipolar to ganglion cells
- Optic nerve to cortex
- Ear, three regions
- Cochlea and balance receptors
- Chemical coordination: hormones
- Four chemical families of hormones
- Two mechanisms of hormone action
- Membrane receptor route
- Intracellular receptor route
- Endocrine glands: hormone and main action
- Endocrine disorders
- Abbreviations
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Biology chapter by chapter against your real exam dates and free hours, and when the plan reaches Control and Co-ordination the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
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