The Nervous System
Nervous System The nervous system is made of: The brain The spinal cord The nerves The senses
The Central Nervous System Brain Spinal cord
The Brain (FYI) Protected by : The skull/cranium Meninges – A membrane that covers the brain and spinal cord
Parts of the Brain (FYI) Cerebrum Cerebellum Brain Stem
Cerebrum (FYI) Divided into 4 lobes
Cerebrum (FYI) Frontal: emotion, reasoning, planning, movement, speech, personality Parietal: touch, pain, taste, pressure, temperature Temporal: hearing, memory, meaning, language Occipital: vision
Divided into 2 Hemispheres (FYI) Right Hemisphere Controls left side of body Left Hemisphere Controls right side of body
Functions of the Brain Controls voluntary movements Interprets messages picked up by the senses Controls Intelligence Controls Emotion Regulates physiological functions (hunger, alertness, body temperature) Centre of balance and movement coordination Helps us to do many activities all at once Controls internal stimuli Controls involuntary movement
The Spinal Cord *Protected by vertebrae* 2 Functions: Carries nerve impulses The reflex centre
The Spinal Cord What is a reflex? A rapid involuntary reaction to a stimulus Quick reaction time in an emergency Ex: Pulling arm away from sharp object
The Spinal Cord Reflex Arc The series of nerve impulses that occur during a reflex
Peripheral Nervous System Connects body to the CNS. Made up of all the nerves
Peripheral Nervous System Role: Transportation of nerve impulses from senses to brain (sensory nerves) Transportation of nerve impulses from brain to muscles (motor nerves)
Staying Sharp! Physical activity Challenging your brain (mental activities) Interacting with people (social activities) Positive thinking (reduce stress factors) Healthy eating habits (omegas!) Getting enough sleep! Avoid drugs...
The Neuron Specialized nerve cells in the nervous system that receive and transmit messages. FYI: the human body has an average of 100 billion neurons!!!
The Neuron Parts of the neuron Dendrites – receive message Cell body - contain nucleus Axon – transmit message Axon terminals – send message
Role of Neurons To pick up stimuli, transform them into nerve impulses and transmit these
Stimulus A stimulus is a change in the environment. Example: a hot stove tripping over a rock
Nerve Impulse An electrical signal transmitted by a neuron
Characteristics of the Neuron (FYI) Can be stimulated – by a stimulus by changing it into nerve impulse Conductive – transmits nerve impulse from one neuron to another until reaches its target Consumes a lot of Oxygen and Glucose. Lives only a few minutes without oxygen Live more than 100 yrs. Cannot reproduce or be replaced if destroyed
Transmission of nerve impulses (FYI) A nerve impulse travels from neuron to neuron until it reaches its target. It travels from dendrites to axon terminals
Transmission of nerve impulses (FYI) Nerve impulses travel from one to another by Neurotransmitters (chemical substances) secreted by axon terminals The transition zone between 2 neurons is called a synapse.
Nerve Impulses (FYI) Nerve impulses move quickly from neuron to neuron and can reach up to speeds of 430km/h. Making sure there is rapid transmission of information to many parts of body.