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