HUMAN NERVOUS SYSTEM & SENSE
ORGANS p118 - 157
Sub topic 1: Human nervous system
P120 - 121
Nervous system
Endocrine system
Stimuli
•Hormones as well as nerves enable all animals to respond to internal and external changes & stimuli.
•They also help the animal to co-ordinate various activities of the body.
•Internal stimuli = hunger, fright, reproductive urges etc.
•External stimuli = heat, cold, danger etc.
Sub topic 2: Central nervous system
P122 - 125
Meninges CerebrumCerebellum Corpus
callosumMedulla oblongata
Spinal cord
Sub topic 3: Peripheral nervous
systemP125 - 126
Peripheral Nervous System
Sub topic 4: Autonomic nervous
systemP126 - 127
Autonomic Nervous System
Sub topic 5: Structure and
Functioning of a NerveP127 - 129
Myelin Sheath AxonDendrite
Sub topic 6: A simple reflex arc
P130
Reflex action Reflex arcReceptor Effector
Reflex action: punching, blinking, sneezing, coughing, ducking,
squealing, vomiting etc.
Reflex arc: PNS CNS PNS Sensory Inter Motor
Receptors:Organ Eye Nose Tongue Tongue Ear
Skin
Sense Sight Smell Taste Taste Hear Touch
Effectors:
Muscle - Contracts, Relaxes = functions antagonistically
Gland - Endocrine or Exocrine = Hormones / Bodily fluids.
Nerve impulses are electrical messages that travel along the nerves at about 100m/s (roughly 360km/h).
The myelin sheath that consists of fat helps to insulate the electrical impulse to avoid the leaking of information.
Nodes of Ranvier act as booster sites to speed up the transmission.
Nerves / Neurons do not touch each other , there is always a space between the terminal branches of one and the dendrite of another.
The gap between neurons is called a SYNAPSE. p131
Because the gap exists, the electrical message is transformed into a chemical message and back to electrical.
The chemical transmission across the synapse is achieved via a NEUROTRANSMITTER.
Types of neurotransmitters: Acetylcholine Dopamine Epinephrine Serotonin
Sub topic 7: Disorders of the CNS
P134 - 135
Sub topic 8: Injuries to the CNS P136 -
137
Sub topic 9: Effects of drugs on the
CNS P138 - 139
Sub topic 10: Receptors p140
Interoceptors ExteroceptorsProprioceptors
Sub topic 11: Human Eye p141 - 148
Binocular vision AccommodationPupil reflex Short-
sightednessLong-sightedness AstigmatismCataracts
Accommodation of the eyeObjects closer than
6mObjects further than 6m
1. Ciliary body (muscle) contracts
1. Ciliary body (muscle) relaxes
2. Ring shaped muscle contracts
2. Ring shaped muscle relaxes
3. Suspensory ligaments relax
3. Suspensory ligaments contract
4. Pulling force on lens decreases
4. Puling force on lens increases
5. Lens more convex / rounder
5. Lens less convex / rounder (more concave)
6. Light rays are broken more
6. Light rays are broken less
Pupil Reflex / Pupillary Mechanism
Short-sightedness
Long – sightedness / Far sighted (Hyperopia)
Astigmatism
Cataracts
Sub topic 12: Human Ear p149 - 151