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Digestive System
Nervous System
The Digestive System
Main Parts of the Digestive System
 TEETH – mechanical digestion,
physically break down food
 SALIVARY GLANDS – produce
saliva (spit) which mixes with food;
releases an enzyme that begins
chemical digestion
 ESOPHAGUS – long, straight tube
which connects the throat to the
stomach
Main Parts of the Digestive System
 STOMACH – muscular, baglike
organ


physical digestion – muscles
squeeze food
chemical digestion - glands in
stomach produce enzymes and
acids, break down food into
nutrients
 CHYME – soupy mixture made in
stomach; slowly released to small
intestine
Main Parts of the Digestive System
 SMALL INTESTINE – 6 meter
muscular tube connected to stomach;
mixes chyme with fluids from liver
and pancreas
 VILLI – line the small intestine;
absorb nutrients from the chyme and
send to bloodstream
Main Parts of the Digestive System
 PANCREAS – fish-shaped organ between
stomach and small intestines; makes juices which
flow to small intestine to neutralize acid
 LIVER – large organ on right side above
stomach; MAKES bile (breaks up fat); breaks
down toxic substances (ALCOHOL and
DRUGS)
 GALLBLADDER – small baglike organ;
STORES bile, then squeezed into small intestine
 These organs are linked to the small intestine,
but food DOES NOT move through them
Main Parts of the Digestive System
 LARGE INTESTINE (COLON) –
1.5 m organ that stores, compacts,
and gets rid of anything left that the
body doesn’t need; 7.5 cm diameter
(LARGE)
 RECTUM – last part of large
intestine; stores feces
 ANUS – opening of rectum
 Digestion takes 24 hours!!!
The Nervous System
The Nervous System
 CENTRAL NERVOUS
SYSTEM (CNS) – brain and
spinal cord; processes
incoming/outgoing messages
 PERIPHERAL NERVOUS
SYSTEM (PNS) – nerves that
connect all areas of your body
to CNS
Peripheral Nervous System
 NEURONS – cells that
transfer messages
throughout the body;
fast-moving electrical
energy
Neuron Structure
 DENDRITES – bring
messages INTO cell
body
 CELL BODY – main
part of neuron
(contains nucleus)
 AXONS – carry
messages AWAY from
cell body
Types of Neurons
 SENSORY NEURONS
– gather info about
what is happening using
receptors; send to
CNS; IN
 MOTOR NEURONS
- send impulses from
brain and spinal cord
for muscles “to move”;
OUT
Nerves
 Axons bundled
together with blood
vessels and tissue
 Transmits info from
spinal cord to body
Central Nervous System
 BRAIN – largest organ; 3 parts
 CEREBRUM – thoughts,
memories, senses
 CEREBELLUM – balance
 MEDULLA – brain stem;
involuntary activity (blood
pressure, heart rate, breathing);
connects to spinal cord
Central Nervous System
 SPINAL CORD – contains
neurons and bundles of axons that
pass info to and from brain
 VERTEBRAE – protective bones
around spinal cord
Path of Nerve Impulse
 1. SENSORY NEURONS
 2. SPINAL CORD
 3. BRAIN
 4. SPINAL CORD
 5. MOTOR NEURONS