the nervous system

What is the nervous system?

Network of cells in our body that uses electrical & chemical signals to communicate internally

What are the two main functions of the nervous system?

• To collect, process & respond to info in the environment

• to co-ordinate the working of different organs + cells in the body

What are the two subsystems of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

CNS (central nervous system)

• Processes info from the senses + uses it to co-ordinate everything from voluntary actions like walking to automatic functions like breathing and heart rate

• consists of the brain and spinal cord- brain has an outer layer called cerebral cortex and is more highly developed in humans than animals

• has 2 hemispheres

• spinal cord: passes messages to and from brain + connects nerves to PNS

• it controls reflex actions

PNS (peripheral nervous system)

• transmits messages via millions of neurons to and from CNS

• consists of: ANS & SNS

What does the autonomic nervous system do?

• Transmits information to and from internal bodily organs.

• Controls vital functions e.g., breathing, heart rate, digestion, sexual arousal, stress responses

• Consists of sympathetic nervous system and parasympathetic nervous system

• Sympathetic nervous system works alongside endocrine system to bring about physiological arousal and prepare body for f/f resp during times of acute stress

• Parasympathetic nerv syst works alongside the endocrine syst to relax body and return body to its 'normal' resting state in the rest & digest resp

What does the somatic nervous system do?

• transmits info from sense organs to CNS and info from CNS to effectors such as muscles