1. Digestive System Nervous System

2. The Digestive System

3. 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

4. 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

5. 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

6. 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

7. 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!!!

8. The Nervous System

9. 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

10. Peripheral Nervous System NEURONS – cells that transfer messages throughout the body; fast-moving electrical energy

11. Neuron Structure DENDRITES – bring messages INTO cell body CELL BODY – main part of neuron (contains nucleus) AXONS – carry messages AWAY from cell body

12. 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

13. Nerves Axons bundled together with blood vessels and tissue Transmits info from spinal cord to body

14. 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

15. Central Nervous System SPINAL CORD – contains neurons and bundles of axons that pass info to and from brain VERTEBRAE – protective bones around spinal cord

16. Path of Nerve Impulse 1. SENSORY NEURONS 2. SPINAL CORD 3. BRAIN 4. SPINAL CORD 5. MOTOR NEURONS