The Nervous and Endocrine Systems Chapter 25 Sections 1 & 2

Illusions WHAT DO YOU SEE????

Jobs of the Nervous System Receiving Information – Happening inside/outside the body Responding to Information – React to Stimuli Maintaining Homeostasis – Keeping everything in balance

2 Systems Central Nervous (CNS) and Peripheral Nervous (PNS) – CNS Brain and Spinal Cord – Process and respond to all messages coming from the PNS – PNS All other parts of the Nervous System – Connects all parts of the body to the CNS » Nerves (43 pairs) Carry all the information overview of the system

Nerves Somatic/Autonomic Nervous Systems Peripheral Nervous System – Somatic Nervous System Conscious Control – Control Voluntary Movements – Autonomic Nervous System Do not need conscious control – Control body systems we do not think about – 2 Divisions » Sympathetic: Fight or Flight » Parasympathetic: Rest and Digest

Neuron Nerve Cell – Specialized to transfer messages in the form of fast moving electrical energy Electrical Energy: Impulses Structure – Cell Body Center – Nucleus and Organelles – Dendrites Short Extensions of the Cell Receive info from other cells – Axons Elongated Extensions of the Cell Impulses carried away to other cells

Collection and Delivering 3 Kinds of Neurons Sensory Neurons – Picks up stimuli and turns it into an impulse Receptors Motor Neurons – Send impulses from the brain and spinal cord to our muscles Cause muscle contractions Interneurons – Carries nerve impulses from one neuron to another

Central Nervous System Control Center – The Brain 3 main parts – Cerebrum – Cerebellum – Medulla /Brain Stem

Cerebrum Largest part of the brain – Think – Memory storage – Controls voluntary movements – 5 Senses 2 Halves – Hemispheres Left works right Right works left

Cerebellum 2 nd largest part – Coordinates muscle actions and keeps our balance

Medulla:Lower Half of Brainstem Connects Brain to Spinal Cord – Controls all involuntary movements – CANNOT LIVE WITHOUT THE MEDULLA! – Medulla Medulla

Spinal Cord Made of – Neurons and axons Protective bones: vertebrae Nerve Fibers – Allows for communication between the brain and the PNS 31 pairs of nerves

Senses Vision – Eye Respond to stimulus of light Convert into impulses so we can see (brain interprets) – Cornea Clear tissue that covers front of the eye – Pupil (behind the cornea) allows light to enter the eye – Iris(around the pupil) regulates how light enters and gives them color – Lens flexible structure that focuses light

How to See Retina – Receptor cells in the back of the eye 130 million cells 2 types – Rods: work in dim light and enables us to see black, white, and gray – Cones: work in bright light and enables us to see color

Hearing Ears – Sense organs that respond to sound Sound to nerve impulses interpreted by the brain Sound is produced by vibrations – Cochlea responds to the vibrations – Controls Balance Semicircular canals

Endocrine System Regulates body processes – Through various hormones – Produced by the Endocrine Glands and sent directly into the bloodstream Can affect many organs at once – Looks for its target cells – Example: Adrenaline (Epinephrine) » Adrenal Gland

Endocrine Glands Hypothalamus – Links the nervous system to the Endocrine Pituitary – Stimulates Labor – Stimulates Skeletal Growth Works with the Thyroid – Responds to the Hypothalamus Thyroid – Control Metabolism – Controls our use of energy