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Digestive SystemNervous System
The Digestive System
Main Parts of the Digestive SystemTEETH – 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 SystemSTOMACH – 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 SystemSMALL 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 SystemLARGE 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 SystemCENTRAL 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 SystemBRAIN – 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 SystemSPINAL CORD – contains
neurons and bundles of axons that pass info to and from brain
VERTEBRAE – protective bones around spinal cord
Path of Nerve Impulse1. SENSORY NEURONS 2. SPINAL CORD3. BRAIN4. SPINAL CORD5. MOTOR NEURONS