Transcript Human Biology Human Body Systems Nervous System

Biology
Human Body Systems
Nervous System
NERVOUS SYSTEM –
Regulates all body activities,
learning and memory.
Composed of nerve cells that
carry nerve impulses by way of
electrical charges and chemical
reactions.
Ultimate coordinator of
homeostasis.
· speedy review
AXON
DENDRITES
NUCLEUS
CELL BODY
MYELIN
Nerve impulse
Travels via electrical current.
RESTING POTENTIAL no impulse
being conducted
once in motion the ACTION POTENTIAL
keeps the impulse moving along the
axon to the SYNAPSE
The synapse is the space between the terminal end of one
Neuron and the dendrites of the next neuron.
at the synapse NEUROTRANSMITTERS carry
the signal to the next neuron, muscle, etc.
o
MYELIN acts as a short cut—
shortens the time it takes for the
impulse to travel
Central Nervous System
brain & spinal cord
Peripheral Nervous system
everything else
nerves and ganglia that lie outside the CNS.
(spinal nerves, cranial nerves, ganglia,
motor and sensory neurons.)
Sensory Neuron
Pick up sensory information from the sense
organs and relay the information to the
interneurons.( brain and spinal cord)
Interneuron
Relay information from sensory neurons to
motor neurons .
Motor Neuron
Stimulate muscles or glands in effector organs
to cause a response.
Two Types of Motor Neurons
Somatic - voluntary - skeletal muscles
Autonomic - involuntary - smooth muscles,
cardiac muscle, and glands
Autonomic Nervous system
Sympathetic - Fight or flight
Parasympathetic - sleep or snack
Structures in the CNS- Brain and
spinal cord
CEREBRUM is the largest part of the brain. It
takes care of conscious movement and
thought. It’s two hemispheres are joined by
the CORPUS CALLOSUM


WRINKLES provide more surface area
Each hemisphere controls the
opposite side of the body
o
CEREBELLUM is found below and to the back of the
cerebrum. It coordinates commands from the cerebrum. This
action is involuntary
o
THALAMUS & HYPOTHALAMUS
Relays sensory input to
The right places in cerebrum
Maintains
homeostasis
(hunger,
thirst,
body temp, sleep, H20
balance, blood
pressure)
o
BRAINSTEM position is self
explanatory. Coordinates and serves as
port for coming/going info.; regulates
heart rate and respiration.
o
SPINAL CORD links the brain and
PNS. It also stimulates reflexes
Organization of the PNS—starts with two
major divisions
Sensory (incoming info)
Motor (outgoing info)
Somatic (voluntary)
Autonomic (involuntary)
Sympathetic
Parasympathetic
SPEEDY REVIEW
Structures of PNS
SENSORY NEURON ~ senses stimulus and
alerts CNS
Gets its info from a RECEPTOR ORGAN
INTERNEURON ~ w/i CNS, tells brain what’s
going on
MOTOR NEURON ~ takes info from CNS
and initiates a reaction in the EFFECTOR
ORGANS
GANGLIA ~ a group of neural cell bodies
that is found outside of the CNS (w/i the PNS)

Receptor organs make up all our
senses
(excepting ESP)

Sight—eyes, rods and cones

Hearing & balance—ears, eardrums &
bones & and semicircular canals

Smell—nose, olfactory nerves

Taste—tongue, taste buds

Touch (heat/cold, pressure,
pain)—receptors in skin