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 PARTS OF THE NERVOUS SYSTEM & THE BRAIN 

DIVISIONS OF THE NERVOUS SYSTEM

The Central Nervous System:

  1. Receives ALL sensory input from the body

  2. Performs INTEGRATION by determining a response to the stimulus 

  3. Generates a motor response through effector cells (muscles and glands)​

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** Spinal cord links the brain with the rest of the body in the CNS 

  • Spinal cord and brain make up the entire CNS 

  • The spinal cord carries signals to and from the brain. It can bypass the brain with sudden reflex actions.

DIAgrAM OF NERVOUS SYSTEM

CNS & PNS

CNS is made up of the brain and spinal cord. It receives signals from the sensory nerves. It performs integration and sends out a response. 

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PNS consists of all nerves outside the CNS. Communicates signals between CNS and the body.

Sensory & Motor Division
Sensory (Afferent) Division conducts signals to the CNS and is made up of sensory neurons
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Motor (Efferent) Division carries signals from the CNS to effector cells and is made up of motor neurons. 

 High Concentration of H2O

Somatic & Autonomic NS

Somatic Nervous System controls voluntary actions of skeletal muscles. 

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Autonomic Nervous System controls involuntary actions.

 Low Concentration of H2O

Sympathetic & Parasympathetic Division 
Sympathetic Division is the fight or flight response and mobilizes body systems for flight or fight

The Brain 

The Brain is made up of three regions during development: Forebrain, Midbrain and Hindbrain

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HINDBRAIN:

This part of the brain is the oldest part

It is made up of the Medulla Oblongata, Cerebellum and Pons 

 

THE MEDULLA OBLONGATA:

Functions in homeostasis: breathing, heart and blood vessel activity, swallowing, vomiting, digestion, coordination of movement, conduction of information

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CEREBELLUM:

Functions in coordinating the body 

Receives information about position of joints, length of muscles as well as information from visual and auditory systems

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PONS:

Helps control breathing, hearing, taste, balance and helps brain communicate with other parts 

FOREBRAIN:

Contains the cerebrum, thalamus and hypothalamus

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CEREBRUM:

Is the forepart of the brain and the largest portion of it . Cerebrum is the highest center for integrating information and formulating a response and is divided into four regions. 

  1. Frontal Lobe: thinking, planning, problem-solving, emotions and personality centre

  2. Motor Cortex: movement 

  3. Sensory Cortex: sensations 

  4. Parietal Lobe: spelling and making sense of the world

  5. OccupitalLobe: vision 

  6. Temporal Lobe: memory, understanding, language 

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Cerebrum divides into two hemispheres which are connected by a bridge of nerve fibres called CORPUS CALLOSUM

  • RIGHT SIDE: creativity, imagination, art and music awareness, left hand function

  • LEFT SIDE: logic, language reason, math science written number control, right hand function 

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THALAMUS:

Functions to serve as a main input center for sensory information going to the brain and for motor information leaving 

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HYPOTHALAMUS:

Regulates homeostasis control and links nervous and endocrine systems together. It controls the Autonomic Nervous System and regulates sleep, appetite, thirst and body temperature. It receives information from the brain and forms an endocrine response (ie. releases hormones)

EFFECTS ON THE NERVOUS SYSTEM

Effects of Drugs: 

  • Drugs exert their effects on the Nervous System by mimicking neurotransmitters at synapse (agonist) or through blocking neurotransmitters at the synapse (antagonists)

  • Drugs, even in small amounts, can have huge impacts on the Nervous System and its ability to transmit impulses because of the small amounts of neurotransmitters in your body.

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