Download notes - Other Places you want to go

Exploring Creation through General Science
Module 16: The Human Nervous System
Nervous System
Neurons – composed of dendrites, axons, and cell bodies
Synapse – gap between the axon of a neuron and the receiving
cell
Neuroglia – support neurons by preforming various tasks so
neurons can do their job
**Know Figure 16.3 for test** (see Neuron handout)
Parts of the Neuron:
 Dendrites – conduct electrical signals towards the
neuron’s cell body
 Axons – direct electrical signals away from the neuron’s
cell body
Tasks of Neurons:
1. Neurons pass signals to other neurons
2. Neurons pass signals to muscle or gland cells
3. Neurons receive signals, process the information, and send
out new signals to other neurons
Neurotransmitter – chemicals that travel across the synapse,
transmitting a signal from the end of an axon to the receiving
cell
Two parts of the Nervous System:
 Central Nervous System (CNS) – includes the brain and
spinal cord
 Peripheral Nervous System (PNS) – includes all nerves
that run off of the spinal cord and go to the body
Cerebrospinal fluid:
 Surrounds brain and spinal cord
 Colorless fluid that contains chemicals that have many
functions
 Includes lymphocytes to fight infection
 Main function is to protect brain and spinal cord
***Know Figure 16.5 (see Brain handout to study)***
Functions of some parts of the brain:
 Cerebrum – deals with “higher-level” brain functions
 Gray matter – composed almost exclusively of the cell
bodies of neurons
 White matter – found under gray matter, lighter color is
from myelin which covers axons
 Corpus callosum – allows the two hemispheres of the
brain to communicate with each other
 Brain stem – controls basic functions like breathing, heart
rate and the pressure which is used to pump blood
 Hypothalamus – (in addition to controlling pituitary gland)
regulates thirst, hunger and body temperature
Blood – Brain barrier:
 Capillaries in brain are different than the rest of the bodies
 No gaps between the cells
 Keeps blood from exposing the brain cells to many harmful
chemicals
 Not ALL toxins are held back by this barrier
Deeper look at the Peripheral Nervous System
Nerve groups:
 Ganglia – made by cell bodies grouping or clustering
together
 Plexus – clusters of ganglia
Three main divisions of the PNS (NEED TO KNOW FULL
definitions of these:
 Autonomic nervous system – the system of nerves which
carries instructions from the CNS to the body’s smooth
muscles, cardiac muscle and glands
 Sensory nervous system – the system of nerves which
carries information from the body’s receptors to the CNS
 Motor nervous system – the system of nerves which
carries instructions from the CNS to the skeletal muscles
Two parts of the autonomic nervous system:
 Sympathetic division – increases the rate and strength of
the heartbeat and raises the blood pressure
 Parasympathetic division – slows the heart rate and
lowers the blood pressure
Sense of Taste
***know handout with tongue and taste areas to study***
Papillae – bumps on tongue
Taste buds – found at base of papillae and are sensitive to
certain chemicals, making us sensitive to: sweet, sour, salty,
bitter and umami (savory or meaty taste)
Sense of Vision
***Know Figure 16.7 (or human eye handout to study)***
Ciliary muscle – deforms the lens in the eye to adjust focus
Optic nerve – transmits the information from your eye to your
brain
Sense of Hearing
***Know Figure 16.9 (see ear handout and study)***
Cochlea – converts the rocking motion of the ossicles into
electrical signals that the brain interprets as sound
Ossicles – 3 bones found in the middle ear
Overall
Many say “we use less than 10% of our brains” – clearly this is
NOT true. If a small portion of your brain was removed it would
effect the person GREATLY