Divisions of the nervous system Flashcards
Nervous system
Consists of the central nervous system and the peripheral nervous system
Central nervous system (CNS)
Consists of the brain and the spinal cord and is the origin of all complex commands and decisions. It passes messages to and from the brain and connects nerves to the peripheral nervous system.
The Brain
The brain is the centre of all conscious awareness. The cerebral cortex is the outer layer of the brain and is what distinguishes human mental functions from animals. The brain is divided into two hemispheres – the left and the right. Each hemisphere has four lobes – frontal, parietal, occipital and temporal.
The Spinal Cord
The spinal cord is an extension of the brain. It is responsible for reflex actions. It passes messages to and from the brain and connects nerves to the PNS.
The Peripheral Nervous System
The PNS transmits messages, via millions of neurons (nerve cells), to and from the CNS. It is subdivided into the autonomic nervous system and the somatic nervous system.
The Autonomic Nervous System
Governs vital functions in the body such as breathing, heart rate, digestion and stress responses. It has an involuntary effect.
The Autonomic Nervous System subdivisions
-sympathetic nervous system
-parasympathetic nervous system
sympathetic nervous system
Activates internal organs and increases bodily activities
Parasympathetic nervous system
Relaxes internal organs and decreases bodily activities
The Somatic Nervous System
The SNS transmits information from receptor cells in the sense organs to the CNS. It receives information from the CNS that directs muscles to act. It has a voluntary effect
