Journal 2/9/17 Objective Tonight’s Homework Tell me everything you know about brains. Objective Tonight’s Homework To learn how animals control functions and senses Get vocab definitions for the Nervous system page

Nervous Systems What’s the point of a brain? The brain is part of what we call the “nervous system”. The job of the nervous system is to coordinate the body. It sends commands to some parts, instructions to others, and deals with the senses so an animals knows what’s going on around it. It also controls instinct and reaction. Nervous systems range from non-existent to incredibly complex. We have 3 types: - Nerve net, Ganglia, and Brains.

Nervous Systems Sponges are simple in every way. They don’t need respiration and circulation because each cell gets what it needs on its own. Well guess what. Same thing with the nervous system. Each cell is capable of getting what it needs and dealing with its surroundings on its own. This means a sponge can’t feel. Anything. At all. No pain, heat, sight, reactions, response. A sponge doesn’t even know its alive.

Nervous Systems Boring. If we move up a step, we reach the hydra. A food-tube with tentacles. Simple. But the hydra has what’s called a “nerve net”. This isn’t a brain. It’s just a bunch of nerve cells spread over the body. But it does do something.

Nervous Systems The hydra responds to touch. If food touches it, the tentacles pull it in. If a pin touches it, the hydra curls up. That’s literally all the hydra’s nervous system does, but it’s a big step up from nothing. The jellyfish has a similar system. It drifts through the water until something touches it.

Nervous Systems Next we take a big step up to ganglia. A ganglion is a lump of nerve cells that can start to act like a brain. They can control some functions and give an animal senses. Most creatures with ganglia have multiple. Their “brain” is spread out like knots on a string. Worms, insects, snails, sea stars, squid. All these types of animals have ganglia.

Nervous Systems Proper brains are found mostly in chordates – animals with a spine. Brains usually have a couple features that are in all animals, so let’s take a look at the parts that are found in most.

Nervous Systems Olfactory Lobe: This part of the brain processes smell. In some animals – like fish – this part is huge. In other animals it can be quite small Optic Lobe: This lobe deals with vision. A lot of animals rely on vision to survive, so for most this is very large. Medulla: This part of the brain controls the stuff that you don’t do on your own. Breathing, heartbeat, digestion. That sort of stuff.

Nervous Systems Cerebrum: This is the part of the brain that controls all voluntary actions. Animals choosing what to hunt, animals reacting to danger. Humans having conscious thought. Cerebellum: This part of the brain helps coordinate motion. Balance, dexterity. Fine control. It can also help with emotional responses. Fear, happiness, safety.

Circulatory Systems DIAGRAM Nervous Systems Nerve net Ganglion Brain Vocab: <define each> Nerve Net Neuron Ganglia Nerve Cord Cerebrum Cerebellum Olfactory Midbrain Medulla The job of the nervous system is to control senses, body functions, and response DIAGRAM 3 types of nervous system Nerve net Ganglion Brain Nervous

Exit Question What is the job of the nervous system? a) To control the senses b) To control basic body functions c) To control how an animal responds to its environment d) To control instinct and animal behavior. e) All of the above f) None of the above