Bring in info from the senses and internal organs

- Bring in info from the senses and internal organs
- Assess, process, interpret, relay information
- Output behaviour
General Layout of the Nervous System
1. Central Nervous System
- Brain
- Spinal Cord
2. Peripheral Nervous System
- Located outside of the skull and spine
- Serves to bring information into the CNS and carry signals out of the CNS
 Somatic Nervous System

 Interacts with external environment
 Bringing info in from the senses and carrying motor output to muscles
o Afferent-- sensory to CNS
o Efferent-- motor from CNS
 Autonomic Nervous System
 Controls the automatic functions of the body
 Afferent-- sensory from internal organs to CNS
 Efferent-- motor from CNS to internal organs: 2 kinds
o Sympathetic Nervous System: fight or flight response,
automatically accelerates heart rate, breathing, dilates pupils,
slows down digestion
o Parasympathetic Nervous System: automatically slows us down
after a stressful event, heart rate and breathing slow down, pupils
constrict and digestion speeds up
Differences Between Parasympathetic and Sympathetic Nerves System
- They generally have opposite effects
 Sympathetic: fight or flight
 Parasympathetic: rest and relaxation
- All are two-stage neural paths
 Sympathetic: synapse close to spinal cord
 Parasympathetic: synapse far from spinal cord, close to target organ
- Where they exit the spinal cord
 Sympathetic: thoracic and lumber
 Parasympathetic: cranial and sacral
Cranial Nerves
- Most nerves from PNS project from spinal cord but CN projects from brain
- Numbered l-Xll, anterior to posterior
- Most serve sensory and motor functions of head and neck (except X)
- Because of functions and locations specific- can provide clues about tumours and other
pathologies
- Oh oh oh to touch and feel very good velvet ahhh heaven
 l- Olfactory nerve  smell
 ll- Optic nerve  vision
 lll- Oculomotor  eye movements, control of pupil, lens and tears
 lV- Trochlear  eye movements
 V- Trigeminal nerve  facial sensations and chewing
 Vl- Abducens  eye movements
 Vll- Facial  facial movements, salivary glands, taste
 Vlll- Vestibulo- Cochlear nerve  acoustic branch and vestibular branch
 IX- Glossopharyngeal  throat muscles, salivary glands, taste

 X- Vagus  control and sensation of internal thoracic and abdominal viscera such
as bronchioles, heart and stomach
 Xl- Spinal Accessory nerve  head and neck muscles
 Xll- Hypoglossal  tongue muscles
Protecting the Brain
1. Protection from physical dangers
- Skull
- Meninges
- Cerebrospinal fluid (CSF)
2. Protection from chemical dangers
- Blood-brain barrier
- Psychoactive drugs
Meninges and CSF
- CNS—covered by three meninges and encased in bone (skull or spinal cord)
 Dura Mater  tough outer membrane
 Arachnoid Membrane  weblike
 Pia Mater  adheres to CNS surface
- Cerebral Spinal Fluid
 Fluid serves as cushion
 Found in:
 Subarachnoid Space  between arachnoid membrane and pia mater
 Ventricles 