Transcript PowerPoint on Organization of NS

The Nervous System
• First Major division
– Central vs. Peripheral
• Central (CNS)
– brain and spinal cord
• Peripheral– nerves connecting CNS to
muscles and organs
Central Nervous System
Peripheral Nervous System
Peripheral Nervous System
• 3 kinds of neurons
– Interneurons connect within the
CNS to the body (peripheral)
– Sensory
• receptors to CNS
– Motor
• Messages from CNS to
muscles/organs
Brain
Spinal
Cord
Nerves
Peripheral Nervous System
Peripheral Nervous System
Skeletal
(Somatic)
Autonomic
Sympathetic
Parasympathetic
Skeletal/Somatic System
• Nerves to/from spinal cord (sensory/motor)
– control muscle movements
– somatosensory inputs
• Voluntary also reflex movements
Brain
• Skeletal Reflexes
– simplest is spinal reflex arc
Sensory
Neuron
Skin receptors
Motor
Neuro
Interneuron
n
Muscle
Autonomic System
• Two divisions:
– sympathetic
– Parasympatheitic
• Control involuntary functions
–
–
–
–
–
heartbeat
blood pressure
respiration
perspiration
digestion
• Can be influenced by thought and emotion
Sympathetic
CENTRAL NERVOUS SYSTEM SYMPATHETIC
• “ Fight or flight”
response
• Release adrenaline
and noradrenaline
• Increases heart rate
and blood pressure
• Increases blood flow
to skeletal muscles
• Inhibits digestive
functions
Brain
Dilates pupil
Stimulates salivation
Relaxes bronchi
Spinal
cord
Salivary
glands
Lungs
Accelerates heartbeat
Inhibits activity
Heart
Stomach
Pancreas
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Sympathetic Stimulates ejaculation
ganglia
in male
Liver
Adrenal
gland
Kidney
Parasympathetic
CENTRAL NERVOUS SYSTEM PARASYMPATHETIC
Brain
• “ Rest and digest
” system
• Calms body to
conserve and
maintain energy
• Lowers heartbeat,
breathing rate,
blood pressure
Contracts pupil
Stimulates salivation
Spinal
cord
Constricts bronchi
Slows heartbeat
Stimulates activity
Stimulates gallbladder
Gallbladder
Contracts bladder
Stimulates erection
of sex organs
Summary of autonomic
differences
Autonomic nervous system controls physiological arousal
Sympathetic
division (arousing)
Pupils dilate
Decreases
Parasympathetic
division (calming)
EYES
Pupils contract
SALVATION
Increases
Perspires
SKIN
Dries
Increases
RESPERATION
Decreases
Accelerates
HEART
Slows
Inhibits
DIGESTION
Activates
Secrete stress
hormones
ADRENAL
GLANDS
Decrease secretion
of stress hormones