Transcript Responding to the environment humans

HUMAN NERVOUS SYSTEM &
SENSE ORGANS p118 - 157
Sub topic 1:
Human nervous system
P120 - 121
Nervous system
Stimuli
Endocrine system
•Hormones as well as nerves
enable all animals to respond to
internal and external changes &
stimuli.
•They also help the animal to coordinate 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
Cerebrum
Cerebellum
Corpus callosum
Medulla oblongata Spinal cord
Sub topic 3:
Peripheral nervous system
P125 - 126
Peripheral Nervous System
Sub topic 4:
Autonomic nervous system
P126 - 127
Autonomic Nervous System
Sub topic 5:
Structure and Functioning
of a Nerve
P127 - 129
Myelin Sheath
Dendrite
Axon
Sub topic 6:
A simple reflex arc
P130
Reflex action
Receptor
Reflex arc
Effector
Reflex action: punching,
blinking, sneezing,
coughing, ducking,
squealing, vomiting etc.
Reflex arc:
PNS
CNS
Sensory
Inter
PNS
Motor
Receptors:
Organ Eye Nose Tongue Ear Skin
Sense Sight Smell Taste Hear Touch
Effectors:
Muscle - Contracts, Relaxes =
functions antagonistically
Gland - Endocrine or Exocrine =
Hormones / Bodily fluids.
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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.
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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
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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:
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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
Proprioceptors
Exteroceptors
Sub topic 11:
Human Eye p141 - 148
Binocular vision
Pupil reflex
Long-sightedness
Cataracts
Accommodation
Short-sightedness
Astigmatism
Accommodation of the eye
Objects closer than 6m
1. Ciliary body (muscle)
contracts
2. Ring shaped muscle
contracts
3. Suspensory ligaments
relax
4. Pulling force on lens
decreases
5. Lens more convex /
rounder
Objects further than 6m
1. Ciliary body (muscle)
relaxes
2. Ring shaped muscle
relaxes
3. Suspensory ligaments
contract
4. Puling force on lens
increases
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