Why Do Animals Need a Nervous System Because

Why Do Animals Need a Nervous System? • Because the world is always coming at you!

Many animals have nervous tissue, but mammals have the most organized and efficient nervous system.

Nervous System • Central nervous system – brain & spinal chord • Peripheral nervous system – nerves from senses – nerves to muscles cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Nerve Cells • Neuron – building blocks of the nervous system – sends signals so your body can respond to the environment LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Labeling A Nerve Cell 1. Cell Body 2. Nucleus 3. Dendrites 9. Terminal branch 4. Axon 7. Node of Ranvier 5. Schwann cell nucleus 6. Schwann cell 8. Myelin Sheath. LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL 10. Synaptic knobs

LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Fun Facts about Nerve Cells • Most specialized cell in animals • Longest cell – blue whale neuron • 10 -30 meters – giraffe axon • 5 meters – human neuron • 1 -2 meters Nervous system allows for 1 millisecond response time

Myelin Coating • Axon coated with insulation made of myelin cells – controls speed of signal • signal hops from node to node myelin coating Multiple Sclerosis § immune system (T cells) attacks myelin coating § loss of signal

Synapse • Junction between nerve cells – Can be electrical or chemical Each axon may have synapses with up to 1000 other neurons LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Synapse • A chemical synapse involves release of a neurotransmitter. • Neurotransmitters are removed from a synapse by enzymes, or they are reabsorbed from the presynaptic neuron. • This is where drugs effect the system. LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Reflexes • Now that we know about neurons…how do they work in the system as a whole? • They work by reflexes, or automatic response LEARNING TARGET: I CAN LABEL THE PARTS OF A NEURON AND DESCRIBE THE PATHWAY A SIGNAL

Sensory Neuron - RECEPTORS • Sensory Neuron neurons activated by sensory input (vision, touch, hearing, etc. ), which send external stimuli to the central nervous system • A receptor is a structure which receives something

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Interneuron • A neuron that forms a connection between other neurons. • These neurons receive signals in the brain and spinal cord.

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Motor Neuron - EFFECTORS • Neurons that receive signals from the brain to perform motor functions. – Movement – Twitch – Run/Walk/Etc • The effectors are the organs which respond to the signals

sensory neuron (from senses) interneuron (brain & spinal cord) motor neuron (to muscle)

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Simplest Nerve Circuit • Reflex, or automatic response rapid response § automated u signal only goes to spinal cord § no higher level processing u advantage § essential actions § don’t need to think or make decisions about § blinking § balance § pupil dilation § startle u

Testing Your Reflexes - Video

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Nerve Potential • Nerve cells use IONS to function.

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Nerve Potential • Membrane Potential – difference in electrical charge (caused by ions) across cell membrane. • How many ions on each side? • Action Potential – causes a nerve impulse – uses ions • Resting Potential – membrane potential of a neuron at rest, neuron not working – but can when needed (all or none response).

LEARNING TARGET: I CAN LIST THE 3 PARTS OF A NERVE CIRCUIT AND DRAW THE PATHWAY IN CORRECT ORDER. Types of Responce • Autonamic Response – • Somatic Response -

Human Brain

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Primitive Brain • The “lower brain” – medulla oblongata – pons – cerebellum • Functions – basic body functions • breathing, heart, digestion, swallowing, vomiting People in – homeostasis – coordination of movement “vegetative” states only use their primitive brain.

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Higher Brain • Cerebrum – 2 hemispheres – left = right side of body – right = left side of body • The right side of your brain perceives and controls the left side of your body • Left side of brain perceives and controls right side of your body

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Higher Brain • Corpus callosum – connection between 2 hemispheres – When your corpus callosum is severed, you can use each half of the brain independently These two sides work together. It’s difficult to use only one side of the brain. For example: Have your right hand tap your head while your left hand rubs your stomach

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Division of Brain Function • Left hemisphere – “logic side” – language, math, logic operations, vision & hearing details – fine motor control • Right hemisphere – “creative side” – pattern recognition, spatial relationships, non-verbal ideas, emotions, multi-tasking Corpus Callosum

Activity – Left or Right Test • Clockwise = Right Dominant • Counter-Clockwise = Left Dominant

e 5 T 55 55 st Cerebrum Specialization • Regions specialized for different functions • Lobes parietal frontal – frontal • speech, control of emotions – temporal • smell, hearing – occipital • vision – parietal • speech, taste reading temporal occipital

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Limbic System Controls basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory Memory Loss and Amnesia is due to Limbic System Damage

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Speaking of Memory…. • Do you really pay attention? How much stuff do you miss when you think you’re observing carefully… Attention Video

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. The Ear • Your ears convert sound waves into electrical signals that are interpreted by your brain • The cochlea is the auditory portion of the inner ear. It is shaped like a snail shell. • Bones of the ear: – Anvil – Hammer – Stirrup

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. The Eye • Eyes enable us to see in color and to distinguish fine details and movement. • The retina is the lining on back inner surface of the eye – consists of photoreceptors. • The optic nerve exits the back of the eye and connects in the brain to the thalamus. It contains many neurons that process visual information. • – Rods - respond to dim light and black and white shading. – Cones- respond to bright light and enables the sight of the colors.

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. The Eye Lens Cornea Iris Pupil

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART.

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. The Tongue

LEARNING TARGET: I CAN LABEL THE PARTS OF THE BRAIN AND DESCRIBE THE FUNCTION OF EACH PART. Optical Illusions