The Nervous System

Nervous system is split up into

Peripheral Nervous System

• relay information to and the from the CNS

• cranial nerves → to the brain; concern head, neck and face

• spinal nerves → come from spinal chord, enter through dorsal side, form dorsal root ganglion, leave through ventral, ventral root (in spinal chord)

  • serve somatic (voluntary)

  • autonomic (involuntary

advantage of autonomic nervous system

• involuntarily and automatically control internal and involuntary activities

visceral reflex

• involuntary response - maintains homeostasis

what is ANS controlled by

• medulla oblongata and hypothalamus

preganglionic neuron and postganglionic neuron

• pre → relays information to the ganglia from the CNS - myelinated

• post → relays information to effector from ganglia - unmyelinated

what does ANS consist of

• 2 antagonistic divisions

• parasympathetic

  • sympathetic

Parasympathetic Nervous System (not responses)

• slows down activity of visceral organs

• activated during rest and digest

• response is localized

• neurotransmittor is acetylcholine

• ganglia is close to organs being innervated

• preganglionic neurons start from cranium and tip of spinal chord

Responses of Parasympathetic Nervous System

• slower heart rate

• stimulation of flow of saliva

• bladder contracts

• stimulates peristalsis and secretion

• release of bile

Sympathetic nervous system

• accelerates activity of all visceral organs

• during fight or flight → stress response

• ganglia are far from organs being innervated

• neurotransmitter is noradrenaline

• preganglionic neurons originate from spinal chord

• response is diffused

Responses of sympathetic Nervous System

• dilates pupils

• accelerates heartbeat

• stimulates conversion of glycogen into glucose

• inhibits peristalsis

• inhibits flow of saliva

• inhibits bladder contraction

• dilates bronchi

central nervous system is protected by

• bones

• Meninges

• CSF - cerebrospinal fluid

Bones

• cranium and vertebrae

Meninges

• 3 layered membrane

• line skull and cover brain

  • protect it from being bruised + friction

  • nourish CNS tissues (grey + white matter)

  • bacterium → meningitis (inflammation)

where is csf produced

• choroid plexus -network of blood vessels and epithelial cells in the ventricles of the brain

• produce csf

Cerebrospinal Fluid

• central canal between spinal chord and also in ventricles of brain

• fills space between meninges

  • blood vessels which supply nutrients and oxygen to brain

  • lymphocytes → immunity

  • lubrication

  • removes waste from brain and spinal chord

  • shock absorbed