Download Nervous and Endocrine Systems

Life ch 19 – Nervous and Endocrine Systems
Aim: parts of the nervous system
Response to stimuli
 Stimuli – _____
Homeostasis – _____
 Breathing, heart rate, digestion
Neurons – nerve cells (3 parts)
 _____
 _____ – receive messages and give to cell body (can collect from many sources)
 _____ – carries message away from cell body (can go to many other cells from 1
cell)
 Impulse – message carried by a neuron
Receptors – in all sense organs
 Respond to _____
 Sensory – _____
 Interneurons – _____
 Motor neurons – _____
Aim: 2 Parts of the nervous system: the CNS
Synapse – _____
 At end of axon a chemical is released, crosses the synapse and binds to the
dendrite on the other side to begin again
CNS – _____
PNS – _____
 Brain coordinates all body activities except _____
 3 parts, 100 billion neurons
o cerebrum – _____
 impulses interpreted
 memory stored
 voluntary muscle control
o cerebellum – _____
o brainstem – _____
 connects brain to spinal cord
 midbrain, pons and medulla
o spinal cord – _____
o as wide as your thumb around and about 43 cm long
 protected by skull and vertebrae and 3 membrane layers with cerebrospinal fluid
in between
Aim: PNS
12 pairs of cranial nerves and 31 pairs of spinal nerves
Somatic – _____
Autonomic – _____
 _____ – sensory receptors to interneuron in spinal cord to another interneuron to
motor neuron
o brain acts second
 Drug effects
o Alcohol – _____
 Impairs judgment, reasoning memory and muscle functions
o Caffeine – _____, can cause physical dependence, stopping can cause
headaches and nausea
Aim: Senses
Hearing – when an object vibrates/moves, it causes the air around it to move. This
produces sound waves.
Sound waves – bones in ear to nerves to brain and gets interpreted as sound
 _____– traps and funnels sound waves down ear canal to eardrum
 _____ - vibrates and moves the bones of the middle ear
 _____consists of hammer, stapes, and stirrup. Stirrup rests on 2nd membrane and
vibrates it.
 _____ (cochlea and semicircular canals for balance) cochlea is fluid filled so it
vibrates when the 2nd membrane vibrates. Shaped like a snail shell.
Vision – cornea and lens bend light as it enters your eye and directs it towards the retina
 Retina – _____
o Rods – _____
o Cones – _____
o Collect at back and go to optic nerve and via that to the brain
 Lens – _____ (thickest at middle) causes rays to come together at a focal point
and this magnifies things (magnifying lens)
o Use these to correct vision – eyeball is too long and focal point is in front
of retina (nearsitedness) get concave lenses and vice versa for farsitedness
Smell – nasal passages contain _____ cells
 Stimulated by _____
 Moisture from mucous glands dissolve molecules
 When enough molecules are present and stimulate enough cells, the impulse goes
to the brain
Taste – _____
Touch – both inside and outside the body (includes _____)
 Certain receptors at certain body parts
o Fingertips – surface type (rough, smooth etc)
o Lips – heat
o Skin – pressure (injury)