Presentation on theme: "Main Function: This communication system controls and coordinates functions throughout the body and responds to internal and external stimuli. Our nervous."— Presentation transcript:
Consists of: Sensory division and Motor division -includes all sensory neurons, motor neurons, and sense organs
Consists of: brain, spinal cord, nerves and sense organs Sense Organs: Eyes, Skin, Ears, Nose & Tongue
A nerve is an organ containing a bundle of nerve cells called neurons. Neurons carry electrical messages called impulses throughout the body. Picture shows hundreds of severed neuron axons
cell body muscle tissue TYPICAL MOTOR NEURON Axon dendrite synapse cell body
Because neurons never touch, chemical signalers called neurotransmitters must travel through the space called synapse between two neurons. Neurotransmitters Synapse (gap) The message is transferred when RECEPTORS receive neurotrans- mitters. (pink spheres)
Parts of a Neuron 1.Cell body: contains nucleus & most of the cytoplasm 2.Dendrites: projections that bring impulses into the neuron to the cell body. 3.Axon: long projection that carries impulses away from cell body 1 3 2
Sensory Neuron Interneuron Motor Neuron Sensory Neuron Interneuron Motor Neuron Muscle Contracts Synapse
Sensory Neuron carry impulses from sense organs to spinal cord & brain Fun Fact: Where can the largest cells in the world be found? The giraffe’s sensory and motor neurons! Some must bring impulses from the bottom of their legs to their spinal cord several meters away!!
Interneuron -processes impulses in brain and spinal cord - connect sensory and motor neurons
Motor Motor Neurons carry impulses from the brain & spinal cord to muscles & glands Axon End Axons branching out to muscle fibers
Nerves work together with muscles for movement. An impulse begins when one neuron is stimulated by another neuron or by the sense organs. The impulse travels down the axons of Sensory neurons to the brain cells called Interneurons. The brain will then send an impulse through motor neurons to the necessary muscle or organs, telling it to contract.
A reflex is an involuntary response that is processed in the spinal cord not the brain. Reflexes protect the body before the brain knows what is going on. Reflex Arc
Cerebrum (forebrain) Largest part of the brain, surface is greatly folded; divided into right and left hemispheres Voluntary or conscious activities of the body- learning, judgment Cerebellum (hindbrain) 10% of brain volume; 5% of brain’s neurons Coordinates and balances the actions of the muscles (develop as a child) Medulla Oblongata (Brain Stem) attached to the spinal cord at the base of the brain; contains gray matter that receives signals from the spinal cord Controls involuntary actions like blood pressure (vasometer centre), heart rate (cardiac centre), breathing (respiratory centre), and swallowing
Divisions of the Cerebrum frontal lobe: motor areas (control muscles), integration of info (think, reason and plan action) parietal lobe: received sensory info from the skin and skeletal muscles; sense of taste occipital lobe: receives info from the eyes temporal lobe: receive info from eyes
Thalamus contains paired masses of gray matter that are arranged into bodies called nuclei and act as a relay station – receives sensation of touch, pain, heat and cold and info from the muscles
HYPOTHALAMUS Controls physiological equilibrium of the body via nerve impulses acting a main control center for the autonomic nervous system and endocrine system
The master gland – attached to the hypothalamus and under its control Made up of two glands – posterior (back) lobe that releases ADH and oxytocin and the anterior (front) lobe Produces hormones that control many of the endocrine glands
Located in the brainstem; the pons contains bundles of axons travelling between the cerebellum and the rest of the CNS (bridge) Functions with the medulla in regulation of breathing and has reflex centres involved in head movement
MIDBRAIN short segment of the brainstem between the cerebrum and pons contains fibers that transmit sensory impulses from the spinal cord to the thalamus and motor impulses from the cerebral cortex back to the spinal cord also involved with sight and hearing
ventricles cavities within the brain that produce and store cerebrospinal fluid (cushions the brain) include lateral, third and fourth
The cerebral cortex is the thin outer layer of the brain (covers cerebrum) often referred to as gray matter (billions of cells). Enables us to experience sensation, voluntary movement and all thought processes associated with consciousness.
Layer of white matter that joins the two cerebral hemispheres and carries signals between